Effect of nitrate concentration on the growth of Duckweeds
Introduction & Method At the beginning of the experiment, I put on a lab coat to protect myself from any danger that may occur. I made sure that all my equipments were clean and dry before I started, and I also measured the temperature of the room to confirm it was around room temperature. I then made sure that the ice cube tray was clean, I put a little label on one end of the tray to indicate my starting point row of the ice cube tray. I then made a little note to myself that the label indicated the row which will contain the 0.0% x 10-3 concentration of nitrate in the solution, and the rows onwards will contain the concentration of nitrogen in solution in ascending orders which I will use (0.0, 0.4, 0.8, 1.2, 1.6 and 2.4 % x 10-3). I Whilst pouring the solutions into a glass beaker I put on goggles and gloves to protect my eyes and hands from any contacts with the ammonium nitrate solution, as any contact can lead to irritation of the skin and eye. I poured 80-90cm3 of the 1st concentration which contained 0.0% x 10-3 of nitrate into a 100cm3 glass beaker. Next I used a clean syringe to measure out 25cm3 of the solution into the 1st well (near my label). The tray had 3 wells in a row and there were 6 rows, I repeatedly added 25 cm3 of the same ammonium nitrate solution into the remaining two wells of that row, so that I will obtain a result of three replicates with each
Discuss the Impact of Genome Sequences on the Study of Development
Cells and Development Discuss the Impact of Genome Sequences on the Study of Development Development refers to the biological process an organism undergoes during growth. The introduction of genetics this century has greatly accelerated our understanding in this field. It appears to be exponential, continually more scientists are being drawn into the field and more data is being generated. In this essay I will briefly outline the course of development as a subject over the past 100 years (with a slight bias towards animal development) commenting on how important the use of model organisms has become and the contribution to the field their genomes have made. Development started with Aristotle in the 4th century BC. He noted the different ways in which animals were born, oviparity, viviparity etc, and began to look at the transition from conception to adulthood. Not much happened in the study for about 2000 years, until a man named William Harves in 1651 made the profound statement that all animals are from eggs, "ex ovo omnia". The subject never really took off because the specimens were too small to analyse. The invention of the microscope revolutionised the science and allowed study of these once unseen structures. This coupled with the Morgan's' use of Mendel's' genetic theory to create the chromosomal theory of inheritance allowed scientists to begin to make
effect of temperature on the rate of respiration in yeast
Effect of temperature on the rate of respiration in yeast Aim: My aim is to investigate the effect of temperature on the rate of respiration in yeast by using a universal indicator. Background theory: Enzyme: Enzymes are organic catalysts that speed up the rate of a chemical reaction without being permanently altered in the process. Enzyme Characteristics * Lower the energy of activation * Form reversible complex with substrate. * Not consumed in the reaction therefore they are effect in small amounts * Very specific - (Induced fit hypothesis) react with only a single substrate. * Many need cofactors, such as certain vitamins, to be activated. * 2000+ enzymes per cell, different cells have different enzymes. * Enzymes are produced by genes. * Genetic disorders are the result of faulty enzymes. * Operate best in optimum conditions of pH, temperature, etc. * Are controlled by feedback mechanisms. Enzyme mechanism: Key and theory: The substrates (reactants) are attracted to the enzyme molecule. They join forming an enzyme-substrate complex. The reaction occurs on an area of the enzyme molecule known as the active site producing new substrates(s) or products. Induced fit hypothesis: The attraction of the substrate and enzyme form an enzyme-substrate complex. It was originally referred to as the Lock and Key Enzyme Theory. The current theory
Explain how twin and adoption studies attempt to distinguish genetic and environmental factors underlying the onset of schizophrenia within families. Review the studies and discuss two limitations of this.
Psychology Essay Explain how twin and adoption studies attempt to distinguish genetic and environmental factors underlying the onset of schizophrenia within families. Review the studies and discuss two limitations of this. Schizophrenia is the label applied to a group of disorders characterised by severe personality disorganisation, distortion of reality, and an inability to function in daily life. Symptoms are mainly disturbances of thought processes, but also extend to disturbances of emotion and behaviour. There are two symptom categories - acute schizophrenia characterised by positive symptoms, such as hallucinations and delusions; and chronic schizophrenia, characterised by negative symptoms such as apathy and withdrawal. However, DSM-IV has now moved away from these definitions and classified schizophrenia into three main sub-types: paranoid, disorganised and catatonic. Understanding Schizophrenia More research has, probably, been devoted to trying to understand the nature of schizophrenia than any other mental disorder. Somatogenic approaches have focused on the role of genetic mechanisms influencing the propensity to develop schizophrenia, while psychogenic approaches emphasise the effect of adverse childhood experiences, particularly abnormalities in family interaction in the aetiology of the disorder. Twin studies Twin studies offer a
An investigation into the effect of different sugars on respiration in yeast.
An investigation into the effect of different sugars on respiration in yeast. I am going to carry out an experiment, measuring the effect of different sugars on the respiration in yeast. In order to make a justified prediction I have researched different aspects of scientific knowledge, including respiration, yeast, sugar structure, enzymes and the collision theory. Glycolysis http://people.eku.edu/ritchisong/301notes1.htm Glycolysis is the splitting of a monosaccharide into two molecules of pyruvate. It takes part in the cytoplasm of a cell. Glycolysis begins with a monosaccharide with six carbon atoms, and ends with two molecules of pyruvate, each with three carbon atoms. For the first steps of glycolysis, energy from ATP is needed. However, energy is released in later steps to generate ATP. For every molecule of glucose, a net gain of two molecules of ATP is produced. The first stage of glycolysis is called phosphorylation, and results in hexose bisphosphate. This is shown in green on the above diagram. Hexose bisphosphate then breaks down into two molecules of triose phosphate. Hydrogen is removed from the triose phosphate and transferred to NAD to produce reduced NAD. These hydrogen's can then be used in oxidative phosphorylation to produce ATP. The end products of glycolysis are pyruvates, which still contains a lot of chemical potential energy. There are two
Revision notes - origins of life on Earth, chemistry of life
8.4 LIFE ON EARTH 8.4.1 Origin of life 8.4.1.1 Identify the r/ship between the conditions on early Earth and the origin of organic molecules * Early earth contained no ozone layer › large amounts of UV radiation reached the earth * Little free oxygen (anoxic) therefore no ozone layer. * The volcanic emissions filled the atmosphere with methane (CH4), ammonia (NH3), H, CO2, CO and small amounts of water vapour. * The violent electrical storms and acidic rain formed the present warm and mineral-rich oceans. * There are only two possible ways organic molecules could have formed either - formed on earth from simpler molecules (Abiogenesis) - arrived from the cosmos (Panspermia) 8.4.1.2 Discuss the implications of the existence of organic molecules in the cosmos for the origin of life on Earth Panspermia * Elements found in space (H, He, C, O, N, P) can combine to form organic molecules. * Some of these compounds including amino acids have been found in meteors that have struck the earth's surface. * Panspermia proposes that living organisms were seeded on earth as passengers on comets and meteors (ie. Life evolved elsewhere and travelled to earth) 8.4.1.3 Describe two scientific theories relating to the evolution of the chemicals of life and discuss their significance in understanding the origin of life Chemosynthesis * Formation of complex organic molecules on
descrive the biological importance of water
Making up between 70 and 95% of the mass of a cell, and covering over three quarters of the planets surface, water is one of the most important compounds on this planet. A single water molecule is made up of one oxygen atom covalently bonded to two hydrogen atoms. Covalent bonds are formed by sharing electrons between the outer shells of the oxygen and hydrogen atoms. However, what makes water so unique is the fact that it remains a liquid at room temperature. Many similar sized molecules (ammonia has a molecular mass equal to that of water-18) remain in their gaseous form at this temperature. The reasons for this unique thermal property are hydrogen bonds. The nucleus of an oxygen atom is larger and therefore contains many more protons that that of a hydrogen atom. Therefore, the electrons shared in the covalent bond between the oxygen and hydrogen atoms have a greater affinity for the oxygen atom than either hydrogen atom. This pulls the electrons closer to the oxygen atom and away from the hydrogen atoms resulting in the oxygen atom having a slightly negative charge and the hydrogen atoms developing slightly positive charges. These slight charges mean that when water molecules are close together, positively charged hydrogen atoms are attracted to the negatively charged oxygen atoms of a different water molecule. These attractions are known as hydrogen bonds and
Effect of Anaerobic Respiration On Yeast
The Effect of Temperature on the Anaerobic Respiration of Yeast Aim: To investigate the effect of temperature on the rate of respiration in a suspension of yeast Saccharomyces cerevisiae. Background Knowledge: Yeasts are a form of eukaryotic microorganisms classified in the kingdom Fungi, with approximately 1,500 species known. They reproduce asexually by budding mainly, although some species reproduce by binary fission. They are unicellular, although some species with yeast forms may become multicellular due to way in which they normally reproduce. Typically the size of a yeast cell is approximately 3-4 µm in diameter but this can vary greatly depending on the species. The yeast species Saccharomyces cerevisiae has been used in baking and fermenting alcoholic beverages for thousands of years. It is also extremely important as a model organism in modern cell biology research, and is the most thoroughly researched eukaryotic microorganism. Researchers can use it to gather information into the biology of the eukaryotic cell and human biology. These microbes are thought to be one of the first domesticated organisms. People have used yeast for fermentation and baking throughout history. Archaeologists digging in Egyptian ruins found early grinding stones and baking chambers for yeasted bread, as well as drawings of 4,000-year-old bakeries and breweries. It has many
The comparison of antibacterial properties of herbal products and standard antibiotics
The comparison of antibacterial properties of herbal products and standard antibiotics Introduction: This is As biology coursework, studying the area of microbiology the main investigation contains the comparison of antibacterial properties of herbal products and standard antibiotics. Aim: The aim is to investigate the effect of herbal products against standard antibiotics on bacteria growth. To examine the extent to which the herbal products (tea tree oil and peppermint oil) and the standard antibiotics (penicillin and streptomycin), reduce bacteria growth of E.coli and M.luteus. This will be discovered by measuring the growth of bacteria on the agar plates and comparing the results. Background information: The proposed aim surrounds the study of bacteria growth and various other products, which can have an affect on the growth rate; it is therefore necessary to look deeper into the topic criteria to get a wider understanding and to help design an appropriate hypothesis. From self-knowledge antibiotics are chemicals produced by microorganisms, which are designed to inhibit and destroy specific pathogens when used at low temperatures. Antibiotics release chemicals, which inhibit bacterial growth and work on a specific action site. The first founded antibiotic was penicillin discovered accidentally by Alexander Fleming in 1928 from a mold culture. It can be
Investigate the water potential of celeriac.
Aim Investigate the water potential of celeriac. Apparatus Celeriac - this is the specimen that we will be finding the water potential of. .00 mol dm-3 sucrose solution - this will be placed in the test tube in which the experiment will take place. We will dilute the solution to produce a range of concentrations. 0.0ml Graduated Pipettes (x2) - I had a choice of 5.0ml, 10.0ml and 20.0ml graduated pipettes. I chose this size pipette because it is time efficient and accurate at the same time. It is an accurate piece of equipment because as opposed to standard pipettes, this graduated pipette has 0.1ml graduations to ensure the utmost accuracy. One pipette will be used for water and one will be used for sucrose solution. 250ml Beakers (x2) - these will be used to hold water and the 1.00 mol dm-3 sucrose solution in a safe environment. Cork Borer - this will be used to cut the precise shape of the celeriac. This will also ensure that the surface area to volume ratio is constant throughout the experiment. Razor - this will be used to cut the pieces of celeriac to a precise length. Ruler - this will be used to measure the length of celeriac that will be used in the experiment. Scales - they will be used to measure the mass of celeriac before and after the experiment with accuracy. Therefore, the mass increase/decrease can be calculated after the experiment. These scales
