Cell Theory - Discuss the theory that living organisms are composed of cells.

        

2. Enzymes (2h)

11. Define enzyme and active site.

Enzyme - specialized protein catalyst that lowers the energy required for a reaction

Active site - place where the enzyme binds onto a substrate - shaped to attach to a specific substrate

12. Explain enzyme-substrate specificity.

For every enzyme there is only one shape of substrate that will fit into the enzyme’s active site.

13. Explain the effects of temperature, pH, and substrate concentration on enzyme activity.

Increased substrate concentration = increased enzyme activity

Moving away from optimal temperature decreases enzyme activity

Changing the pH denatures the enzyme

14. Define denaturation.

Denaturation: shape of active site changes, enzyme has different shape as substrate

15. Explain the use of pectinase in fruit juice production, and one other commercial application of enzymes in biotechnology.

• restriction enzymes: cut DNA into fragments at predetermined locations
• reverse transcriptase: translate viral RNA into more easily managed DNA
• ligase: join DNA fragments together by complementary base pairing

2.4        DNA Structure (1h)

1. Outline DNA nucleotide structure in terms of sugar (deoxyribose), base and phosphate.

SEPARATE PAPER

2. State the names of the four bases in DNA.

• adenine (purine)
• guanine (purine)
• thymine (pyrimidine)
• cytosine (pyrimidine)

3. Outline how the DNA nucleotides are linked together by covalent bonds into a single strand.

• phosphate and sugar share an electron (covalent bonding)
• nucleotides join to form polymer (DNA strand)
• backbone = phosphate-sugar-phosphate-sugar
• bases project to one side of polymer

4. Explain how a DNA double helix is formed using complementary base pairing and hydrogen bonds.

• DNA unzips with assistance of helicase enzyme
• free floating nucleotides form hydrogen bonds (purine-pyrimidine) with DNA strand
• complementary base pairing = purine-pyrimidine pairs adenine-thymine, cytosine-guanine

5. Draw a simple diagram of the molecular structure of DNA.

SEPARATE PAPER

2.5        DNA Replication (1h)

1. State the DNA replication is semi-conservative.

• Semi-conservative: half of each DNA helix is from original

2. Explain DNA replication in terms of unwinding of the double helix and separation of the strands by helicase, followed by formation of the new complementary strands by DNA polymerase.

• DNA unzips: helicase breaks down hydrogen bonds between nitrogen bases
• during complementary base pairing, DNA polymerase bonds phosphate with sugar

3. Explain the significance of the complementary base pairing in the conservation of the base sequence of DNA.

• complementary base pairing = every replicated DNA strand will be identical to original
• semi-conservative strands preserve original code

2.6        Transcription and Translation (2h)

1. Compare the structure of RNA and DNA.

DNA                                         RNA

Sugar                 deoxyribose                                 ribose

Bases         adenine, guanine, thymine, cytosine                 adenine, guanine, uracil, cytosine

Strands         double stranded                         single stranded

Helix                         yes                                 no

2. Outline DNA transcription in terms of the formation of an RNA strand complementary to the DNA strand by RNA polymerase.

• DNA strands by RNA polymerase.
• mRNA forms by complementary base pairing to DNA strand
• RNA polymerase binds sugar and phosphate groups together
• mRNA strand completed

3. Describe the genetic code in terms of codons composed of triplets of bases.

• genetic code expressed in three-letter codons
• each codon specifies a certain amino acid

4. Explain the process of translation, leading to peptide linkage formation. Including the role of messenger RNA (mRNA), transfer RNA (tRNA), codons, anticodons and ribosomes.

• mRNA moves to cytoplasm and ribosomes attach
• tRNA anticodons carry specified amino acids to the mRNA
• complementary base pairing between codon and anticodon adds amino acid to sequence
• peptide bond forms between amino acid and growing polypeptide

5. Define the terms degenerate and universal as they relate to the genetic code.

Degeneracy - there is more than one codon for a particular amino acid

Universal - all organisms utilize the same codons for the same amino acids

6. Explain the relationship between one gene and one polypeptide.

• each polypeptide is encoded in a specific gene on the DNA helix
• gene controls amino acid sequence in a polypeptide

2.7        Cell Respiration (2h)

1. Define cell respiration.

Cellular respiration= the oxygen–requiring reactions, occurring in mitochondria, that break down the end products of glycolysis into carbon dioxide and water while capturing large amounts of energy as ATP.

2. State that in cell respiration, glucose in the cytoplasm is broken down to pyruvate with a small yield of ATP.

In cell respiration, glucose in the cytoplasm is broken down to pyruvate with a small yield of ATP

3. Explain that in anaerobic cell respiration, pyruvate is converted into lactate or ethanol plus carbon dioxide in the cytoplasm, with no further yield of ATP.

Anaerobic cellular respiration:

Pyruvate→ lactate/ethanol

Lactate/Ethanol + CO2 (in cytoplasm) → No further yield of ATP

4. Explain that in aerobic cell respiration, pyruvate is broken down in the mitchocondrion into carbon dioxide and water with a large yield of ATP.

Aerobic cellular respiration:

Pyruvate → broken down (in mitchocondrion) → CO2 +H2O→ large yield of ATP

2.8        Photosynthesis (3h)

1. State that photosynthesis involves conversion of light energy into chemical energy

6CO2 + 6H2O + sunlight (light energy) → C6H12O6 (chemical energy) + 6O2

2. State that white light from the sun is composed of a range of wavelengths (colors).

Sunlight is composed of range of wavelengths, including: Infrared, red, orange, yellow, green, blue, violet, ultraviolet

3. State that chlorophyll is the main photosynthetic pigment.

Chlorophyll: main photosynthetic pigment

4. Outline the differences in absorptions of red, blue and green light by chlorophyll.

Chlorophyll absorption:

• absorption peak at 440 nm (violet)
• absorption peak at 675 nm (red)
• green least absorbed;
• longer blue wavelengths absorbed
• shorter blue wavelengths not absorbed

5. State that light energy is used to split water molecules (photolysis) to give oxygen and hydrogen, and to produce ATP.

Light energy ==> split water molecules ==> O2 + H ==> ATP

6. State that ATP and hydrogen (derived from the photolysis of water) are used to fix carbon dioxide to make organic molecules.

ATP + H ==> fix CO2 ==> produce organic molecules

7. Explain that the rate of photosynthesis can be measured directly by the production of oxygen or the up take of carbon dioxide, or indirectly by the increase in biomass.

O2 production

• enclose plants in clear chambers, measure change in O2 concentration
• increased O2 levels means O2 produced by photosynthesis

CO2 uptake

• enclose plants in clear chambers, measure change in CO2 concentration
• decreased CO2 levels means CO2 used by photosynthesis

Biomass increase

• cut, dry, and weigh plants at end of growing season
• plant growth means energy entered ecosystem; ie, photosynthesis has occurred

8. Outline the effects of temperature, light intensity and carbon dioxide concentration on the rate of photosynthesis

Temperature

• increases rate of photosynthesis until optimal point
• decreases rate of photosynthesis after optimal point

Light intensity

• increases rate of photosynthesis
• compensation point at higher temperature
• requires more CO2
• saturation point at higher temperature

CO2 concentration

• increases rate of photosynthesis

Unit 3

3.1        Chromosomes, Genes, Alleles and Mutations (1h)

1. State that eukaryote chromosomes are made of DNA and protein.

eukaryote chromosome = DNA + protein

2. State that in karyotyping chromosomes are arranged in pairs according to their structure.

In karyotyping chromosomes are arranged in pairs according to their structure

3. Describe one application of karyotyping.

Karyotyping - determining defects before birth:

• extract cell sample from placenta
• add colchine to stop cell division at prophase / metaphase
• add water to burst cell
• create a photographic image of scattered chromosomes
• cut out and pair chromosomes by their length and position of the centromere
• observe deviation from normal chromosome set

4. Define gene, allele and genome

Gene - a unit of hereditary information on a DNA strand controlling expression

Allele - an alternative form of a gene that occurs at a given chromosome site (locus)

Genome - a complete set of genes from any one species

5. Define gene mutation

Gene mutation - an alteration from the normal nucleotide sequence

6. Explain the consequence of base substitution mutation in relation to the process of transcription and translation, using the example of sickle cell anemia.

Mutation: GAA → GTA

Transcription: CUU → CAU

Translation: valine→glutamic acid

Result: HbA → HbS (Sickle Cell Anemia)

3.2        Meiosis (2h)

1. State that meiosis is a reduction division in terms of diploid and haploid numbers of chromosomes.

Meiosis: reduction division from diploid to haploid number of chromosomes

2. Define homologous chromosome.

Homologous chromosomes - have the same shape and contain genes for the same traits.

3. Outline the process of meiosis, including pairing of chromosomes followed by two divisions, which results in four haploid cells.

First meiotic division

• Interphase - DNA replicates, centrioles double
• Prophase I - nucleus disappears, spindle forms, centrioles move, synopsis: dyad → tetrad
• Metaphase I - tetrads line up at centre, centromere attaches to spindle fibers
• Anaphase I - dyads separate
• Telophase I - furrowing, nucleus reforms, spindle disappears

Second meiotic division

Interkinesis - centrioles double

• Prophase II - nucleus disappears, spindle forms, centrioles move
• Metaphase II - dyads line up at centre, centromere attaches to spindle fibers
• Anaphase II - chromosomes separate
• Telophase II - furrowing, nucleus reforms, spindle disappears

Result: 4 haploid cells

4. Explain how the movement of chromosomes during meiosis can give rise to genetic variety in the resulting haploid cells.

Homologous chromosomes separate = one gene from each parent via independent assortment

5. Explain that nondisjunction can lead to changes in chromosome number, illustrated by reference to Down syndrome.

Three 21 chromosomes in one cell = Down syndrome

6. State Mendel’s law of segregation.

Mendel’s Law of Segregation: Allele pairs separate during gamete formation and randomly reform pairs during fusion of gametes at fertilization.

7. Explain the relationship between Mendel’s law of segregation and meiosis.

• meiosis produces haploid cells which typically contain only one of each allele
• alleles reform when gametes fertilize

3.3        Theoretical Genetics (6h)

1. Define: genotype, phenotype, dominant allele, recessive allele, co dominant alleles, locus, homozygous, heterozygous, carrier and test cross.

Genotype: the genetic makeup that comprises the expression of a characteristic

Phenotype: the outward appearance caused by a genotype

Dominant allele: an allele that is expressed over another allele when other allele is present

Recessive allele: an allele that is masked when a corresponding allele is present

Co dominant allele: a phenotypic situation where both alleles are expressed in a heterozygote

Locus: the place on a chromosome where a gene is located

Homozygous: having two identical alleles

Heterozygous: having different corresponding alleles

Carrier: possessing a recessive sex-linked gene that does not express itself

Test cross: crossing an organism with a homozygous recessive organism to determine if the unknown organism is homozygous or heterozygous.

2. Construct a Punnett grid.

SEPARATE PAPER

3. Construct a pedigree chart

SEPARATE PAPER

4. State that some genes have more than two alleles (multiple alleles).

Multiple alleles = more than two alleles (present for some genes)

5. Describe ABO blood groups as an example of codominance and multiple alleles.

Codominance: A and B are expressed simultaneously if present

Multiple alleles: 3 alleles are available: A, B, and O

6. Outline how the sex chromosomes determine gender by referring to the inheritance of X and Y chromosomes in humans.

X X = female; X Y = male in gamete formation, female passes on an X, and male passes on an X or a Y to determine gender

7. State that some genes are present on the X chromosome and absent from the shorter Y chromosome in humans.

Some genes are present on the X chromosome and absent from the shorter Y chromosome in humans

8. Define sex linkage.

Sex linkage: genes carried on the sex chromosomes, and therefore are more prevalent on males

9. State two examples of sex linkage.

Color blindness - inability to differentiate between different colors

Hemophilia - absence of clotting substance in blood

10. State that a human female can be homozygous or heterozygous with respect to sex-linked genes.

Human female can be homozygous or heterozygous for sex-linked genes

11. Explain that female carriers are heterozygous for X-linked recessive alleles.

Carrier: needs one normal allele to mask defective allele and needs one defective allele to be a carrier

12. Calculate and predict the genotypic and phenotypic ratios of offspring of monohybrid crosses involving any of the above patterns of inheritance.

SEPARATE PAPER

13. Deduce the genotypes or phenotypes of individuals in pedigree charts.

Genotypic Ratio: 1:2:1

Phenotypic Ratio: 3:1

3.4        Genetic Engineering and Other Aspects of Biotechnology (6h)

1. State that PCR (polymerase chain reaction) copies and amplifies minute quantities of nucleic acid.

PCR (polymerase chain reaction) copies and amplifies minute quantities of nucleic acid

2. State that gel electrophoresis involves the separation of fragmented pieces of DNA according to their charge and size.

Gel electrophoresis = separate fragmented pieces of DNA according to charge + size

3. State that gel electrophoresis of DNA is used in DNA profiling.

DNA profiling is DNA fingerprinting.

4. Describe two applications of DNA profiling.

• engineering bacteria to produce insulin
• isolate good traits to create a better crop
• criminal profiling

5. Define genetic screening

Genetic Screening: test for detecting genetic disease

6. Discuss three advantages and/or disadvantages of genetic screening.

• Advantages

- Early diagnosis

- Prenatal health of child

- Reproductive and lifestyle decision

• Disadvantages

- Anxiety and pressure on personal choice

- Disclosure of info about family members who declined testing

- Discrimination

7. Sate that the Human Genome Project is an international cooperative venture established to sequence the complete human genome.

International research effort, an attempt to map all genes on human chromosomes

8. Describe two possible advantageous outcomes of this project

Eliminate genetic defects, develop new drugs, and develop gene therapy to fight disease

9. State that genetic material can be transferred between species because the genetic code is universal

Genetic code is universal therefore, genetic material can be transferred between species

10. Outline a basic technique used for gene transfer involving plasmids, a host cell (bacterium, yeast,), restriction enzymes (endonuclease) and DNA ligase.

• donor DNA removed from cell
• restriction enzyme cut out selected fragment
• plasmid removed from host cell
• restriction enzyme cut hole in plasmid to insert fragment
• fragment mixed with plasmid and DNA ligase
• DNA ligase anneals fragment into plasmid

11. State two examples of the current uses of genetically modified crops or animals.

• disease resistant crops and animals
• bacteria-manufactured insulin

12. Discuss the potential benefits and possible harmful effects of one example of genetic modification.

• more resilient diseases: disease pressured to change, and so will become tougher and harsher

13. Outline the process of gene therapy using a named example

Gene Therapy: Insulin Production

• cells removed from liver
• cells grown in culture
• gene for insulin production inserted into cells
• cells implanted back into liver

14. Define clone.

Clone: genetically identical organism, descended from single ancestor cell

15. Outline a technique for cloning using differentiated cells.

Cloning:

• cells taken from donor
• cells placed in culture with low nutrients stop cell growth
• unfertilized egg taken from female; nucleus removed
• electric pulse fuses cell and egg; cell division starts
• embryo implanted in female uterus
• clone is genetically identical to donor

16. Discuss the ethical issues of cloning in humans.

Interests and rights of clones and reason for cloning

Unit 4

4.1        Communities and Ecosystems (5h)

1. Define ecology, ecosystems, population, community, species and habitat.

Ecology - the study of the natural environment and of the relations of organisms to each other and to their surroundings

Ecosystem - all the interacting parts of the physical and biological worlds

Population - the number of a specific group of organisms in a given area

Community - an association of interacting populations, usually defined by the nature of their interaction or the place in which they live

Species - a group of actually or potentially interbreeding populations that are reproductively isolated from all other kinds of organisms

Habitat - place where an animal or plant normally lives, often characterized by a dominant plant form or physical characteristic (eg, the stream habitat, the forest habitat)

2. Explain how the biosphere consists of interdependent and interrelated ecosystems.

Biosphere - the atmosphere, lithosphere, hydrosphere, and all life forms residing in these areas

3. Define autotroph (producer), heterotroph (consumer), detritivore and saprotroph (decomposer).

Autotroph - an organism that assimilates energy from either sunlight (green plants) or inorganic compounds (sulphur bacteria)

Heterotroph - an organism that utilizes organic materials as a source of energy and nutrients

Detrivore - an organism that feeds on freshly dead or partially decomposed organic matter

Saprotroph - an organism that breaks down dead or decaying matter

4. Describe what is meant by a food chain giving three examples, each with at least three linkages (four organisms).

Food chain - a representation of the passage of energy through populations in the community

1) Apple tree → aphid →ladybug →bird

2) Phytoplankton →zooplankton → salmon →orca

3) Leaf →leafcutter ant →army ant →anteater

5. Describe what is meant by a food web.

Food web - a representation of the various paths of energy flow through populations in the community

6. Define trophic level.

Trophic level - position in the food chain, determined by the number of energy-transfer steps to that level

7. Deduce the trophic level of organisms in a food chain and a food web.

SEPARATE PAPER

8. Construct a food web containing up to 10 organisms, given appropriate information.

SEPARATE PAPER

9. State that light is the initial energy source for almost all communities.

Light = initial source of energy

10. Explain the energy flow of a food chain.

High → Low

11. State that when energy transformations take place, including those in living organisms, the process is never 100% efficient, commonly being 10-20%.

• energy transformation is never 100% efficient (usually 10-20%)
• energy transformation converts some energy into heat

12. Explain what is meant by a pyramid of energy and the reasons for its shape.

• the concept that the energy flux through a given link in the food chain decreases at progressively higher trophic levels
• breadth of each bar represents net productivity of each trophic level in the ecosystem
• each trophic level dissipates energy before consumed by next trophic level

13. Explain that energy can enter and leave the ecosystem, but that nutrients must be recycled.

• enters ecosystem as light (usually)
• leaves ecosystem as heat
• nutrients are matter, cannot disappear, therefore are recycled

14. Draw the carbon cycle to show the processes involved.

SEPARATE PAPER

15. Explain the role of saprotrophic bacteria & fungi (decomposers) in recycling nutrients.

Saprotrophs: release nitrogen for use by plants

4.2        Populations (3h)

1. Outline how population size can be affected by natality, immigration, morality and emigration.

Natality

• population increases as new members are born
• balanced by mortality

Immigration

• population increases as new members move in
• balanced by emigration

Mortality

• population decreases as old members die
• balanced by natality

Emigration

• population decreases as old members move out
• balanced by immigration

2. Draw a graph showing the sigmoid (S-shaped) population growth curve.

SEPARATE PAPER

3. Explain reasons for the exponential growth phase, the plateau phase and the transitional phase between these two phases.

Exponential growth phase- population grows exponentially to limit of food supply

Plateau phase- food supply can support a limited number of organisms

Transitional phase- excess organisms die

4. Define carrying capacity.

Carrying capacity - the maximum density of organisms that a particular environment can sustain in perpetuity

5. List three factors which set limits to population increase.

1) food supply

2) predator population

3) disease

6. Define random sample

Random sample - an unbiased survey on selected members of a population

7. Describe on technique used to estimate the population size of an animal species based on a capture-mark-release-recapture method.

• capture a preset number of animals from one area
• mark these animals with a distinguishing visual characteristic
• release the animals to the wild
• several days later, capture another preset number of animals
• count the number of recaptured marked animals

Population size = (recapture / capture) * (10000 / recapture)

8. Describe one method of random sampling used to compare the population numbers of two plant species, based on quadrat methods.

• divide area to be sampled into four quadrants
• in each quadrant, mark off area to be sampled
• count number of plant species in each sample

9. Calculate the mean of a set of values.

Mean - the average found by adding the individual terms together and dividing by the number of terms

10. State that the term standard deviation is used to summarize the spread of ecological data between two or more populations.

• standard deviation indicates variation from the normal
• allows statistical comparison between normal distribution in different locations

4.3        Evolution (2h)

1. Define evolution.

Evolution is the descent of modern organisms with modification from preexisting life forms; strictly speaking, any change in the proportion of different genotypes in a population from one generation to the next

2. State that populations tend to produce more offspring than the environment can support.

Populations produce more offspring than environment can support

3. Explain that the consequence of the potential overproduction of offspring is a struggle for survival.

Overproduction of offspring ==> struggle for survival

4. State that members of a species show variation.

Members of a species show variation

5. Explain how sexual reproduction promotes variation in a species.

The more reproduction the more the gene’s get shuffled around

6. Explain how natural selection leads to the increased reproduction of individuals with favorable heritable variations.

The strong only survive to reproduce so the strong genes are reproduced thus eventually everyone with the weaker gene will have died out and the strong gene lives on in the strong.

7. Discuss the theory that species evolve by natural selection.

Natural Selection:

• chooses best adapted to breed
• organisms not suited to the environment die and are eliminated
• organisms suited to the environment survive

Three kinds of natural selection:

• directional selection - population shows a steady change through time
• stabilizing selection - organisms within a population that represent extreme departures from the norm eliminated, therefore maintaining the ”status quo„
• disruptive selection - abnormal features in organisms have a high survival rate

8. Explain two examples of evolution in response to environmental change; one must be multiple antibiotic resistances in bacteria.

The peppered moth example and multiple antibiotics (resistance in bacteria)

4.4        Classification (2h)

1. Define species.

Species: a specific group of similarly constructed organisms that are capable of interbreeding and producing fertile offspring; organisms that share a common gene pool.

2. Describe the value of classifying organisms.

Knowing the ancestry and relations between certain organisms

3. State that organisms are classified into the kingdoms Prokaryotae, Protoctista, Fungi, Plantea and Animilia.

Organisms are classified into the kingdoms Prokaryotae, Protoctista, Fungi, Plantea and Animilia.

4. List the seven levels in hierarchy of taxa -kingdom, phylum, class, order, family, genus and species- using an example from two different kingdoms for each level.

Common Name         Human                 Corn

Kingdom         Animalia         Plantae

Phylum                 Chordata         Angiospermophyta

Class                 Mammalia        Monocotyledoneae

Order                 Primates         Commelinales

Family                 Hominidae         Poaceae

Genus                 Homo                 Zea

Species         sapiens         mays

5. Apply and/or design a key for a group of up to eight organisms.

SEPARATE PAPER

4.5        Human Impact (2h)

1. Outline two local or global example of human impact causing damage to an ecosystem or the biosphere. One example must be the increased greenhouse effect.

+

2. Explain the causes and effects of the two examples in 4.5.1, supported by data.

1)                                 Global Warming

Increased CO2 and CFC emissions  →        Diminishing ozone layer → Less ozone → more ultraviolet light entering biosphere →  more ultraviolet radiation

→        less healthy plants and animals → increased chances of cancer

→        more ionised water →        water leaves cells → El nino / la nina        →change ocean currents

2)                        Salmon Habitat Destruction

Cut down trees → increased sunlight = increased temperature → Salmon do not swim up river → Salmon cant reproduce therefore it dies out

Toxins in river        →Salmon die before spawning → parasites thrive on salmon remains / eggs

Dams in river → Salmon cannot swim to spawning grounds

→ currents in spawning areas → Salmon eggs washed away

3. Discuss measures which could be taken to contain or reduce the impact of the two examples, with reference to the functioning of the ecosystem.

1)                        Global Warming

Reduce emissions →top killing ozone layer→less ultraviolet light entering biosphere→ more healthy plants+animals

→Less ionized water → water stays in cells →no El nino / la nina → currents stay; fish live

2)                Salmon Habitat Destruction

Artificial spawning habitats →Salmon spawn and eggs cared for

Reduce toxin pollution →Salmon can swim to sea without dying

Plant trees by site→lower temperature to let salmon spawn

Fish ladder →allow salmon to swim past dams

Unit 5

5.1        Digestion (3h)

1. Explain why digestion of large food molecules is essential.

• macromolecules digested chemically + mechanically
• absorption into body
• convert into energy and essential molecules

2. Explain the need for enzymes in digestion.

• speed up digestion
• lower activation energy

3. State the source, substrate, products and optimum pH conditions for one amylase, one protease and one lipase.

Amylase

• source: saliva, pancreas
• substrate: starch
• products: starch + H2O maltose
• optimum pH: 7

Protease: Pepsin

• source: stomach wall
• substrate: protein
• products: protein + H2O peptide
• optimum pH: 2

Protease: Trypsin

• source: pancreas
• substrate: protein
• products: protein + H2O peptide
• optimum pH: 8

Lipase

• source: pancreas
• substrate: lipids
• products: fat droplets + H2O glycerol + fatty acids
• optimum pH: 8

4. Draw a diagram of the digestive system.

SEPARATE PAPER

5. Outline the function of the stomach, small intestine and large intestine.

6. Distinguish between absorption and assimilation.

Absorption – movement of digested food molecules across the lining of the alminary canal and into the blood.

Assimilation- movement of food molecules from the blood into cells in body tissues

7. Explain how the structure of the villus is related to its role in absorption of the end products of digestion.

_____

5.2        The Transport System (3h)

1. Draw a diagram of the heart showing all four chambers associated blood vessels and valves.

SEPARATE PAPER

2. Describe the action of the heart in terms of collecting of the blood pumping of blood and opening and closing valves.

• blood collected from superior and inferior vena cava into right auricle
• blood passes through tricuspid valve into right ventricle
• right ventricle pumps blood through pulmonary valve to lungs for re oxygenation
• blood returning from lungs enter left auricle
• blood passes through mitral valve into left ventricle
• left ventricle pumps blood to aorta for circulation
• left ventricle stronger than right ventricle to pump blood throughout body
• opening / closing of valves regulates ’pulse“ to produce more pressure on release, allowing  the blood to travel farther after it is ’pumped“ from the heart

3. Outline the way the heart beats and is regulated in terms of its myogenic nature, nerve and hormone simulation.

• Sinoatrial node sends impulse across atria  atria contract
• Atrioventricular node picks up stimulus from sinoatrial node   signal purkinje fiber (nerve)
• Purkinje fiber causes ventricle to contract blood goes up

4. Explain the relationship between the structure and function of arteries, capillaries and veins.

Arteries = thick walls - holds in strong, pulsing current

Capillaries = thin walls - allows more goodies to diffuse and narrow - permits blood to diffuse goodies more efficiently to the surrounding cells

Veins = thin walled - does not need to restrain strong, pulsing current and valves - prevents blood from flowing in the wrong direction as it returns to the heart

5. State that blood is composed of plasma, erythrocytes (red blood cells), leukocytes (white blood cells) (phagocytes and lymphocytes) and platelets.

plasma - a liquid matrix containing all the blood cells

erythrocytes (red blood cells) - contains hemoglobin; carries oxygen from lungs to tissues

leucocytes (white blood cells) - several types, each having a specific function in protecting the body from invasion by foreign substances and organisms

platelets - formed elements necessary for blood clotting

6. State that the following are transported by the blood: heat nutrients, oxygen, carbon dioxide, hormones, antibodies, waste products (urea).

• heat - maintain constant body temperature
• nutrients - provide body with products necessary for cellular metabolism
• oxygen - required for aerobic cellular respiration
• carbon dioxide - remove for exhalation in lungs
• hormones - allow communication between various organs in the body
• antibodies - natural defense against invaders
• waste products - remove toxins

        

5.5        Gas Exchange (2h)

1. List the features of alveoli that adapt them to gas exchange.

• thin walls (1 cell wide)
• capillary network to increase surface area for diffusion
• lipoprotein lining -lower surface tension
• balloon-shaped -maximize surface area

2. State the difference between ventilation, gas exchange and cell respiration.

Gas Exchange: Process of swapping over gas for another

Cell Respiration: O2 used and CO2 produced

Ventilation: maintains gradients between O2 and CO2

3. Explain the necessity for a ventilation system.

Ventilation system:

• allows gaseous exchange
• releases unneeded CO2
• takes in needed O2

1. Draw a diagram of the ventilation system including trachea, bronchi, bronchioles and lungs.

SEPARATE PAPER

2. Explain the mechanism of ventilation in human lungs including the action of the internal and external intercostals muscles, the diaphragm and the abdominal muscles.

SEPARATE PAPER

5.6        Homeostasis and Excretion (5h)

1. State that homeostasis involves maintaining the internal environment at a constant level or between narrow limits, including blood pH, oxygen and carbon dioxide concentrations, blood glucose, body temperature and water balance.

Homeostasis involves maintaining the internal environment at a constant level or between narrow limits, including blood pH, oxygen and carbon dioxide concentrations, blood glucose, body temperature and water balance.

2. Explain that homeostasis involves monitoring levels of variables and correcting changes in levels by negative feedback mechanisms.

Homeostasis of blood glucose:

• liver regulates glucose level - excess stored as glycogen
• kept at 0.1% blood sugar

3. State that the nervous and the endocrine systems are both involved in homeostasis.

The nervous and endocrine systems are both involved in homeostasis

4. State that the nervous system consists of the central nervous system (CNS) and peripheral nerves and is composed of special cells called neurons that can carry electrical impulses rapidly.

• nervous system: central nervous system + peripheral nervous system
• peripheral nerves made of neurons (special cells that carry electrical impulses rapidly)

5. Describe the control of body temperature including the transfer of heat in blood, the role if sweat glands and skin arterioles, and shivering.

Homeostasis of body temperature:

• blood circulation distributes heat equally throughout body
• reflex: shivering, goose bumps to conserve heat
• reflex: sweating to reduce heat
• kept at 37 0 C / 98 0 F

6. State that the endocrine system consists of glands which release hormones that are transported by the blood.

• endocrine system made of hormone-releasing glands
• hormones transported in blood

7. Explain the control of blood glucose concentration, including the roles of glucagon and insulin secretion, Alfa and Beta cells in the pancreatic islets, hypothalamus and feelings of hunger and satiety.

Homeostasis of blood glucose:

• liver regulates glucose level - excess stored as glycogen
• kept at 0.1% blood sugar

8. Define excretion.

Excretion: removal of metabolic wastes from the body

9. Outline the role of the kidney in excretion and the maintenance of water balance (osmoregulation).

_____

Unit 6

6.1        DNA Structure (1h)

1. Outline the structure of nucleosome.

DNA wraps around the core of a histone molecule

2. State that only a small proportion of the DNA in the nucleus constitutes genes and that the majority of DNA consists of repetitive sequences.

Only a small proportion of the DNA in the nucleus constitutes genes and that the majority of DNA consists of repetitive sequences

3. Describe the structure of DNA including the antiparallel strand, 3’-5’ linkages and hydrogen bonding between purines and pyrimidines.

_____

6.2        DNA Replication (1h)

1. State that DNA replication occurs in a 5’→ 3’ direction.

DNA replication occurs in a 5’→ 3’ direction

2. Explain the process of DNA replication in eukaryotes including the role of enzymes (helicase, DNA polymerase III, RNA primase, DNA polymerase I and DNA linkage), Okazaki fragments and deoxynucleoside triphosphates.

DNA replication:

• DNA unzips with help of helicase enzyme
• free floating nucleotides complementary base pair with exposed nucleotides
• DNA polymerase checks correct complementary base pairing
• Okazaki fragments form on lower strand b/c direction of synthesis
• DNA ligase seals Okazaki fragments together
• result: two semi-conservative DNA strands

3. State that in eukaryotic chromosomes, replication is initiated at many points.

Replication initiated at many points in eukaryote chromosome

6.3        Transcription (2h)

1. State that transcription is carried out in a 5’→ 3’ direction.

Transcription carried out in 5‘ → 3‘ direction

2. Outline the lac operon model as an example of the control of gene expression in prokaryotes.

• regulator gene codes for repressor
• repressor inhibits transcription of controlled gene
• presence of inducer inhibits binding to operator repressor-inducer complex
• inducer allows transcription of controlled gene

3. Explain the process of transcription in eukaryotes including the role of the promoter region, RNA polymerase, nucleoside triphosphates and the terminator.

• promoter codes for expression of gene
• DNA unzips to reveal gene
• free floating nucleotides complementary base pair with exposed nucleotides
• RNA polymerase checks complementary base pairing
• ATP required to make RNA polymerase move
• terminator codon releases RNA sequence

4. Distinguish between the sense and anitsense strands of DNA.

Sense strand is the coding strand and has the same base pair sequence ad the mRNA

Anitsense strand is the template strand has the same sequence as the tRNA.

5. State that eukaryotic RNA needs the removal of introns to form mature mRNA.

• eukaryote DNA needs removal of introns →mature mRNA
• splicing: removal of introns from mRNA

6. State that reverse transcriptase catalyses the production of DNA from RNA.

Reverse transcriptase catalyses the production of DNA from RNA

7. Explain how reverse transcriptase is used in molecular biology.

• allows biologists to reconstruct DNA from RNA
• allows biologists to transfer genetic information from viruses into other hosts

6.4        Translation (2h)

1. Explain how the structure of tRNA allows recognition by a tRNA-activating enzyme that binds a specific amino acid to tRNA using ATP.

• tRNA structure allows regocnition by tRNA activating enzyme
• tRNA activating enzyme binds specific amino acid (uses ATP)

2. Outline the structure of ribosomes including protein and RNA composition, large and small subunits, two tRNA binding sites and mRNA binding sites.

• composed of proteins and ribosomal RNA (rRNA)
• 1 large protein unit
• 1 small rRNA unit
• tRNA binding sites (tRNA + next amino acid added to polypeptide chain via complementary base pairing)

3. State that translation consists of initiation, elongation and termination.

• initiator codon - begins translation
• elongation - polypeptide chain grows as amino acids are added by complementary base pairing and peptide bondage
• termination - terminator codon releases polypeptide chain

4. State that translation occurs in a 5’→ 3’ direction.

Translation occurs in 5‘ - 3‘ direction

5. Explain the process of translation including ribosomes, polysomes, start codons and stop codons.

Translation:

• ribosome: made of rRNA and protein
• polysome: ribosome group working cooperatively to speed up translation
• start codon: initiates translation
• GTP (guanidine triphosphate) hydrolysis provides energy for peptide bondage between amino acids
• peptidyl transferase: catalyzes peptide bond forming between amino acids; lets tRNA exit ribosome
• stop codon: releases ribosome, disassembles mRNA

6. State that free ribosomes synthesize proteins for use primarily within the cell and that bound ribosomes synthesize proteins primarily for secretion or for lysosomes.

• Free ribosomes group together to form polysomes (make proteins for intracellular use)
• Bound ribosomes on rER (make proteins for secretion and lysosomes)

5. Proteins (1h)

1. Explain the four levels of protein structure, indicating each level’s significance.

• primary structure: sequence of amino acids
• secondary structure: tight coil of amino acids
• tertiary structure: three-dimensional folding of amino acid coil
• quaternary structure: two or more tertiary proteins lock together (eg. insulin A & B)

2. Outline the difference between fibrous and globular proteins, with reference to two examples of each protein type.

Fibrous – proteins form long parallel chains which can be molded into tough long fibers or sheets. Examples are collagen and keratin and spider silk.

Globular – proteins are tightly folded and complex tertiary structures. Examples all enzymes, antibodies and hemoglobin.

3. State six functions of proteins, giving a named example of each.

Functions of proteins:

• support - eg. keratin
• pores - eg. Na+ / K+ pump
• enzymes - eg. pepsin
• cell markers - eg. Rh+
• genetic coding - eg. DNA polymerase
• receptors - eg. excitory receptors for neurotransmitters
• hormones - eg. FSH (follicle-stimulating hormone)
• regulatory - eg. lac operon

4. Explain the significance of polar and non polar amino acids.

• polar amino acid has side-group charge
• non-polar amino acid lacks side-group charge
• side-group size and charge affects folding of polypeptide

6. Enzymes (2h)

5. State that metabolic pathways consist of chains and cycles of enzyme catalyzed reactions.

Metabolic pathways have chains and cycles of enzyme catalyzed reactions

6. Describe the induced fit model.

Induced fit model:

• enzyme has distinct, but flexible shape
• when substrate enters active site, shape of site modified around it to form complex
• products leave enzyme reverts back to inactive, relaxed form

7. Explain that enzymes lower the activation energy of the chemical reactions that they catalyze.

Enzymes lower activation energy of the reactions they catalyze

8. Explain the difference between competitive and non-competitive inhibition, with reference to one example of each.

Competitive inhibition:

• other molecule close in shape to enzyme‘s substrate →compete for active site
• eg. penicillin inhibits enzyme needed to form bacterial cell wall →bacteria die

Non-competitive inhibition:

• molecule binds to enzyme at site other than active site
• causes enzyme to change shape →prevent binding with substrate (normal)
• eg. isoleucine inhibits to threonine deaminase →threonine not broken down

9. Explain the role of allostery in the control of metabolic pathways by end-product inhibition.

Allostery:

• molecule that binds outside active site
• changes enzyme structure to increase reaction rate

Feedback inhibition:

• final product binds to allosteric site on first enzyme to inhibit enzyme action

Unit 7

7.1        Cell Respiration (5h)

1. State that oxidation involves a loss of electrons from an element whereas reduction involves a gain in electrons, and that oxidation frequently involves gaining oxygen or losing hydrogen.

Oxidation                                 Reduction

electron loss                                 electron gain

gain oxygen / lose hydrogen                 lose oxygen / gain hydrogen

2. Outline the process of glycolysis including phosphorilation, lysis, oxidation and ATP formation.

These reactions release some of the energy stored in the sugar. Lysis= splitting. In the cytoplasm, one hexose is split into two pyruvates. NADH + H+ is produced by the reduction of NAD+ using electrons gained from the oxidation of the sugar. Phosphorilation is the adding of a phosphate group on a molecule: the process through which ATP is made from ADP + Phosphate. Some of the energy releases as the sugar is oxidized is used to power this endergonic reaction. The net gain from all the reactions of glycolysis is two ATP and two NADH + H+ or reduced NAD.

3. Draw the structure of a mitochondrion as seen in electron micrographs.

SEPARATE PAPER

4. Explain aerobic respiration including oxidative decarboxylation of pyruvate the Krebs cycle, NADH + H+, the electron transport chain and the role of oxygen.

C6H12O6 + 6O2 + ADP + P → 6CO2 + 6H2O + ATP

5. Explain oxidative phosphorilation in terms of chemiosmosis.

Oxidative phosphorylation:

• attatchment of high-energy phosphate group to another molecule by oxidation
• high-energy electrons →electron transfer chain
• protons →proton pump →accumulate in cristae of mitochondria
• proton gradient →drives ATP synthesis
• ATP synthetase → catalyze ADP →ATP

6. Explain the relationship between the structure of the mitochondrion and its function.

• Cristae - maximize surface area for energy production
• Matrix - contain enzymes that allow respiration

7. Describe the central role of acetyl CoA in carbohydrate and fat metabolism.

• Glucose →pyruvic acid
• Pyrovic acid →acetyl CoA
• Acetyl from acetyl Coa → Kreb‘s cycle →metabolize fat

7.2        Photosynthesis (5h)

1. Draw the structure of a chloroplast as seen in electron micrographs.

SEPARATE PAPER

2. State that photosynthesis consists of light-dependant and light-independent reactions.

Photosynthesis consists of light-dependant and light-independent reactions

3. Explain the light-dependant reactions.

Include the photoactivation of photosystem II, photolysis of water, electron transport chain, cyclic and non-cyclic photophosphorilation, photo activation of photosystem I and reduction of NADH.

4. Explain photophosphorilation in terms of chemiosmosis.

Electron transport causes the pumping of protons to the inside of the thylakoids. They accumulate and eventually move out the stroma through protein channels in the ATP synthetase enzymes. As in mitochondria, this provides energy for ATP synthesis.

5. Explain the light independent reactions.

SEPARATE PAPER

6. Explain the relationship between the structure of the chloroplast and its function.

SEPARATE PAPER

7. Draw the action spectrum of photosynthesis.

SEPARATE PAPER

8. Explain the relationship between the action spectrum and the absorption spectrum of photosynthetic pigments in green plants.

SEPARATE PAPER

9. Explain the concept of limiting factors with reference to light intensity, temperature and concentration of carbon dioxide.

• temperature increase a little = increase transpiration = faster reaction
• temperature increase a lot = stomata close = less CO2 available

Unit 8

8.1        Meiosis (2h)

1. Describe the behavior of the chromosomes in the phases of meiosis.

• Meiosis I - homologous chromosomes separate
• Meiosis II - chromatids separate

2. Outline the process of crossing over and the formation of chaismata.

• corresponding segments of genetic material between chromatids of homologous chromosomes exchange
• occurs during synapses in prophase I

Chiasmata = X-shaped, microscopically visible region representing homologous chromatids that have exchanged genetic material through crossing over during mitosis.

3. Explain how meiosis results in an effectively infinite genetic variety in gametes through crossing over into prophase I and random orientation in metaphase I.

• Prophase I - homologous chromosomes, each one composed of chromatids, synapse

• chromatids exchange genetic material, resulting in new combinations of genes

• Metaphase I - chromosomes line up at the equator randomly

-        daughter cells have different genetic makeup from mother cell

4. Define recombination.

Recombination - occurs during meiosis and fertilization; promotes genetic variety

- when crossing over has taken place

- when resultant cell has genetic makeup distinct from parent cell

5. State Mendel’s law of independent assortment.

Law of Independent Assortment - Genes sort themselves randomly in the next generation through gametes

6. Explain the relationship between Mendel’s law of independent assortment and meiosis.

• Law of segregation - during meiosis the alleles separate from each other into gametes
• Law of Independent Assortment - genes sort themselves randomly through crossing over and random orientation in meiosis

8.2        Dihybrid Crosses (2h)

8.2.1        Calculate and predict the genotypic and phenotypic rations of offspring of dihybrid crosses involving unlinked autosomal genes.

SEPARATE PAPER

8.2.2         Identify which of the offspring in dihybrid crosses are recombinants.

Recombinant offspring display recombinant trait

8.2.3        Outline the use of the chi-square test in analyzing monohybrid/dihybrid crosses using given values.

SEPARATE PAPER

8.3        Autosomal Gene Linkage (2h)

1. State the difference between autosomes and sex chromosomes.

Autosomes - all chromosomes except the X and Y chromosomes.

Sex chromosomes - X and Y chromosomes. They carry genes that determine sex

2. Explain how crossing over in prophase I (between non-sister chromatids of a homologous pair) can result in an exchange of alleles.

• pieces of chromosomes exchanged between chromatid pairs during crossing
• alleles of crossed section exchanged

3. Define linkage group.

Linkage group - group of genes inherited as a unit (usually on same chromosome)

4. Explain an example of a cross between two linked genes.

red hair & freckles stick together

HhFf X HhFf = HHFF; HhFf; hhff

5. Identify which of the offspring in such dihybrid crosses are recombinants.

Recombinant offspring display recombinant traits.

8.4        Polygenic Inheritance (1h)

1. Define polygenic inheritance.

Polygenic inheritance - two or more genes affecting the same trait in an additive fashion - eg. height, skin color.

2. Explain that polygenic inheritance can contribute to continuous variation using two examples. One example must be human skin color.

• hair color
• skin color - black (BBBB), dark (BBBW), mulatto (BBWW), light (BWWW),white (WWWW)
• height

Unit 11

11.1        Nerves (3h)

1. Outline the general organization of the human nervous system including CNS (brain and spinal cord) and PNS (nerves).

SEPARATE PAPER

2. Draw the structure of a motor neuron.

SEPARATE PAPER

3. Define resting potential and action potential.

Resting potential: voltage recorded inside a neuron when not conducting a nerve impulse

Acting potential: change in potential propagated along the membrane of a neuron (nerve impulse)

4. Explain how a nerve impulse passes along a non-myelinated neuron (axon) including the role of Na+ ions, K+ ion, voltage-gated ion channels, active transport and changes in membrane polarization.

Nerve impulse:

• resting phase (charge -65mV)
• Na+ outside; K+ / large organic negatively charged proteins inside
• action potential: depolarization (charge increasing)
• sodium channels open: Na+ goes inside
• apex: majority of Na+ inside (charge +40mV)
• action potential: repolarization (charge decreasing)
• K+ channels open: K+ goes outside
• recovery (refractory) phase (charge -65mV)
• Na+ / K+ pump returns ions to original position

5. Explain the principles of synaptic transmission. Including Ca2+ influx and release, diffusion and binding pf neurotransmitter, depolarization of the post-synaptic membrane and subsequent removal of neurotransmitter. Refer to the all or none response

Synaptic transmission:

• Ca2+ influx causes polarization of pre-synaptic membrane
• Ca2+ release stimulates contractile fibres to contract
• contractile fibres move neurotransmitter vesicles to pre-synaptic membrane
• vesicles release neurotransmitter into synaptic cleft
• excitory receptors pick up neurotransmitter
• if enough hits, post-synaptic membrane becomes polarized
• signal continues down dendrite
• if not enough hits, signal stops
• neurotransmitter reabsorbed by pre-synaptic membrane
• enzymes clean up remaining neurotransmitters

11.2        Muscles and Movement (3h)

1. Outline the great diversity in the animal kingdom as exemplified by movement in an earthworm, swimming in a bony fish, flying in a bird and walking in an arthropod.

SEPARATE PAPER

2. Describe the role of nerves, muscles and bones in producing movement or locomotion.

Movement:

• nerves send impulse
• Ca2+ released
• Ca2+ causes muscles to contract
• bone acts as support
• limb doesn‘t bend

3. Draw a diagram of the human elbow joint including cartilage, synovial fluid, tendons, ligaments, named bones and named bones and named antagonistic muscles.

SEPARATE PAPER

4. Outline the functions of the above named structures of the elbow joint.

SEPARATE PAPER

5. Draw the structure of skeletal muscle fibers as seen in electron micrographs.

SEPARATE PAPER

6. Explain how skeletal muscle contracts by the sliding of filaments. Including the roles of the sarcoplasmic reticulum, Ca2+ ions, troponin, tropomyosin, actin, myosin, cross-bridge formation, movement (sliding filaments) and breakage (separation of filaments), and ATP.

• nerve impulse reaches neuromuscular junction
• acetylcholine depolarizes muscle membrane action potential
• action potential enters T-tubule network
• sacroplasmic reticulum lets Ca2+ enter from myofibrils
• Ca2+ bind to troponon-tropomyosin complex binding
• active site on actin molecules uncovered
• myosin heads bind to active sites on actin
• cross bridges form between myosin and actin
• myosin heads bend toward center of sacromere
• ATP causes myosin to release actin and reset to original position
• process repeats as long as Ca2+ is bound to complex

Unit 1

12.1        Excretion (1h)

1. Outline the need for excretion in all living organisms.

• all living organisms produce toxins
• accumulation of toxins will kill organism or waste energy to maintain
• hence organism must excrete toxins

2. State that excretory products in plants including oxygen, and in animals including carbon dioxide and nitrogenous compounds.

Excretory products:

Plants: O2

Animals: CO2 / nitrogenous compounds

3. Discuss the relationship between the different nitrogenous waste products and habitat in mammals, birds, amphibians and fish.

SEPARATE PAPER

12.2        The Human Kidney (4h)

1. Draw the structure of the kidney including cortex, medulla, pelvis, ureter and renal blood vessels.

SEPARATE PAPER

2. Draw the structure of a glomerulus and associated nephron.

SEPARATE PAPER

3. Explain the process of ultrafiltration (also called glomerular “filtration”) including blood pressure, fenestrated blood capillaries, and basement membrane.

Ultrafiltration:

• blood pressure pushes blood through glomerulus
• amino acids / glucose / H2O / Na+ / Cl- reabsorbed into efferent arteriole
• NH2 / H2O / Na+ / Cl- descend into loop of Henle
• H2O / Na+ reabsorbed
• tubular excretion occurs in distal convoluted tube - large molecules enter for excretion
• collecting duct carries wastes to renal pyramid

4. Define osmoregulation.

Osmoregulation: control of water balance of the body brought about largely by the kidney

5. Explain the reabsorption of glucose, water and salts in the proximal convoluted tubule including the role of microvilli, osmosis and active transport.

SEPARATE PAPER

6. Explain the roles of the loop of Henle, medulla, collecting duct, ADH in maintaining water balance of the blood.

SEPARATE PAPER

7. Compare the composition of blood in the renal artery and renal vein, and glomelular filtrate and urine.

Blood composition:

• renal artery: blood with wastes
• renal vein: blood without wastes
• glomerular filtrate: amino acids, glucose, Na+, Cl-, NH2, urea, nutrient excess, nitrogenous waste, [H+], H2O
• urine: wastes - urea, Na+, Cl-, NH2, H2O, large molecules

8. Outline the structure and action of kidney dialysis machines.

Kidney dialysis machine:

• blood from artery goes to dialysis chamber
• dialysis tubing allows nitrogenous wastes to diffuse from blood
• blood returns to vein
• fresh dialysis solution replaces used dialysis solution in dialysis chamber