Photosynthesis - Absorption spectrum.
Photosynthesis light Water + carbon dioxide › glucose + oxygen 6H2O + 6CO2 › C6H12O6 + 6O2 Absorption Spectrum An absorption spectrum shows which wavelength of light a molecule absorbs. Action Spectrum An action spectrum shows the effect of each wavelength of light on the rate of photosynthesis The absorption spectrum of chlorophyll is very similar to the action spectrum of photosynthesis. This is evidence that chlorophyll absorbs light for photosynthesis. The Light and Dark Reaction ) The light reaction light 6H2O›12H + 3O2 Light splits water into hydrogen ions and oxygen. 2) The dark reaction enzymes 2H + 6CO2 › C6H12O6 + 3O2 Glucose is then formed from the hydrogen ions and carbon dioxide. (This reaction does not occur in the dark). Factors affecting the rate of photosynthesis The Light Reaction Chlorophyll can split more water molecules at higher light intensities. Photosynthesis will reach a maximum rate when chlorophyll is saturated by sunlight. The Dark Reaction An increase in temperature will increase the rate of glucose production until it reaches the optimum temperature for the enzymes. The enzymes will be denatured if it goes above a certain temperature. An increase in carbon dioxide will also increase the rate of glucose production. Millions of years ago there was much more carbon dioxide in the atmosphere, the plants sucked up the
You are required to plan a procedure that will allow you to compare quantitatively the glucose concentrations in samples of fresh orange, lemon and grapefruit.
You are required to plan a procedure that will allow you to compare quantitatively the glucose concentrations in samples of fresh orange, lemon and grapefruit. I predict that orange juice is the most concentrated out of the three juices. Orange juice should have a higher concentration of glucose, followed by Grapefruit then lemon. I have predicted this because of a source I have obtained which showed that orange has the greatest number of grams of monosaccharide. The juice sample The amount of monosaccharide in grams (g) Orange 8.5 Grapefruit 5.3 Lemon .6 ("Manuel of Nutrition" by J. Mafa) If there is a greater number of monosaccharides there would be a higher concentration of glucose present. Benedict's test can prove this as the more reducing sugar present the greater the amount and the darker the colour of the precipitate. A Benedict's test is a test, which can be used to show the presence of reducing sugars. I predict that orange juice would have the a more red precipitate colour solution followed by grapefruit with a slight brownish yellow precipitate, then will be lemon juice with the lightest colours of these precipitate. I predict that the orange juice will form a more reddish colour then the grapefruit or the lemon juice, this is based on the amounts of monosaccharides in grams shown above. To prove my prediction I will require quantitative results, this
AS biology coursework on enzymes
BIOLOGY COURSEWORK ON ENZYMES AIM: To investigate the effect of substrate concentration on the rate of an enzyme catalysed reaction. INDEPENDENT VARIABLE: My independent variable will be the substrate concentration used in my experiment. It is the factor that I will change throughout my experiment. I have decided to use five different ranges of starch so I can see how substrate concentration affects the rate of reaction. In theory as substrate concentration increases, the rate of reaction will increase up to a point. This is because there are many more substrate molecules available to lock onto the enzymes active sites. Once the enzymes active sites have all been filled up, adding more substrate concentration will not have an affect on the rate of reaction anymore which means slows down the rate of enzyme/substrate complexes being formed. Below is a table showing how I will gather my five different ranges of substrate concentration that I will use in my experiment. Substrate Concentration / % Substrate Volume / cm3 Distilled Water Volume / cm3 Enzyme Volume / cm3 0.2 2.0 8.0 10.0 0.4 4.0 6.0 10.0 0.6 6.0 4.0 10.0 0.8 8.0 2.0 10.0 1.0 10.0 0.0 10.0 As seen from the table my total volume for each range will add up to 20cm3. I am using five different ranges of substrate concentration and some of them will be less than 10cm3 (1%). This will
Homeostasis and excretion.
Homeostasis and excretion. Homeostasis: mechanism that maintains the internal environment at a constant level. This including the blood pH, the O2 and CO2 levels, blood glucose level, blood temperature and the water balance. This is all controlled by a negative feedback system; in this the product controls its own production. This system has three parts to it: . Sense organ that senses the difference, 2. Control centre generates a message for 3 to act, 3. Response organ this brings on the change, after receiving the message. Due to these parts, homeostasis needs the CNS and the endocrine systems to help it control it all. Thermo-regulation: Thermo-receptors in the skin monitor the skin temperature. For the body the main source of heat is the liver and muscle movement, thus shivering when cold, to enhance muscle movement to obtain some sort of heat. Regulation: is through: . Sweating when water on the skin evaporates it has a cooling effect 2. Radiation of heat the heat is radiated into the air or is conducted (transferred) to any object touching the body. This is done through blood vessels under the skin that either dilate when the body is hot or constrict when the body is cold. Body warm = vasodilatation, body cold = vasoconstriction. 3. Convection heat lost due to normal air circulation: wind=cold. The skin has hairs on it that are controlled by hair erector
Reproduction, Gamete formation and fertilisation
Biology Assignment 8 Reproduction, Gamete formation and fertilisation Katie Bennett Reproductive system Male Reproductive System The Male system produces sex cells (Gametes) called Sperm. Sperm production is continuous and reduces with age. The main reproductive organs in males include the Testes and Penis. http://www.drstandley.com/images/male.gif The testes lie outside the body in a pouch of skin called the Scrotum, where they can maintain the optimum temperature for sperm production- approximately 3 0C (50F) lower then body temperature. Testes are responsible for sperm production and the sex-hormone Testosterone. From each testis, sperm pass into a coiled tube - The Epididymis - for the final stages of maturation. They are stored in the Epididymides until they are either broken down or reabsorbed, or ejaculated - forced by movement of seminal fluid from the accessory glands down a duct called the Vas deferens. Inside the Male Scrotum http://www.zianet.com/nlynch/scrotum/testicle1.gif Scrotal Layers http://www.phyto-2000.co.uk/images/reproductive-system2.jpg Each testis is covered by a thin tissue layer, the Tunica vaginalis around which is a layer of connective tissue called Fascia. A Muscle layer called the Dartos muscle relaxes in hot weather to drop the testes away from the body to keep them cool. In cold weather the muscle contracts to draw up the
Digestion coursework
Biology Test on Nutrients and Digestion Nutrients Carbohydrates * Contain: carbon, oxygen, hydrogen * Found in pasta, potatoes, bread, rice and sugars * Needed for energy-movement, digestion and warmth * Excess stored as glycogen in liver and muscles * Made from: Monosaccharide- single sugar unit e.g. glucose, fructose, galactose - Soluble - Small (not digested, pass directly in blood stream) Disaccharides- two sugar units e.g. sucrose, lactose, maltose - Soluble - Too large (needs to be digested) Sucrose glucose + fructose Lactose glucose + galactose Maltose glucose + glucose Polysaccharides - many sugar units: - Starch- plant storage substance, digested by amylase enzymes in salvia and pancreatic juice - Cellulose- found in plan cell walls, cannot be digested by mammals as do not have cellulase, helps stimulate muscles in gut (peristalsis) - Glycogen- animal storage Too much carb causes obesity Too much sugar can rot teeth Fats * Contain: carbon, hydrogen, oxygen * Found in: butter, oil, margarine, peanuts, fatty meat * Needed for a) energy b) Insulation c) Storage of vit A and D * Excess stored under skin and around body organs * Made from fatty acids and glycerol Too much cholesterol blocks arteries Too much fat causes obesity Proteins * Contain: carbon, hydrogen, oxygen, nitrogen * Found: meat, eggs, fish, cheese, pulses *
Rate of Respiration
Aim The purpose of this investigation is to discover whether different respiratory substrates will affect the rate of respiration of yeast. I will investigate this by measuring the amount of C02 evolved during anaerobic respiration. As C02 is a waste product produced during respiration, measuring the volume of c02 produced will allow me to evaluate which of the sugars are best metabolized during respiration (of yeast). Background information Yeast Yeasts are a form of eukaryotic microorganisms that are used heavily in industry to be used for fermentation of alcohols and baking. Yeast digest the sugars using extracellular enzymes to break down the compounds, thus yeast are known as saprophytes, which the products will be transported into the cell of the yeast by facilitated diffusion to be respired. The yeast synthesises the enzymes required that will be specific to the substrate that they will be digesting. For example, domestic yeast is sold in as a sucrose solution, and the cell membrane of the yeast contains a high concentration of sucrose enzymes, thus the yeast adapts its digestive enzymes to its environments to digest specific sugars. Yeast can respire both through aerobic and anaerobic respiration, depending on the availability of oxygen present within the surrounding area. If oxygen is not present then fermentation occurs which converts sugars i.e. glucose into
How Structure and Function of Squamous Epithelium, Erythrocytes and Blood Vessels is Related
How Structure and Function of Squamous Epithelium, Erythrocytes and Blood Vessels is Related Blood vessels transport cells such as erythrocytes, whilst tissues such as squamous epithelium which have a protective function, enable substances to be transported from one area to another more efficiently. The process, by which substances are transported in this case, is by diffusion. Diffusion is the net movement of materials from an area of higher concentration to an area of lower concentration. The relationships between the factors affecting diffusion are presented in Fick's law of diffusion: Rate of diffusion Surface area Difference in Concentration Diffusion Distance Fick's law states: * The larger the surface area and the difference in concentration, the faster the rate of diffusion * The greater the diffusion distance, the slower the rate of diffusion Diffusion occurs between most cells, and tissues in the body. Squamous epithelium produces a smooth lining surface; it lines vessels such as arteries and veins and also allows diffusion to take place through the wall of capillaries. In a way it is similar to red blood cells which are involved in transporting respiratory gases. Both types of cells have features that provide them with a large surface area. For instance, red blood cells are bi-concave shaped giving them a large surface area to volume
Set up an investigation to show the correct strength sugar solution he should use, in which the store the chips. The chips must not gain water or loose water.
Osmosis Task: Charles Chip owned a popular fish and chip shop and his chips were the best in the area. Set up an investigation to show the correct strength sugar solution he should use, in which the store the chips. The chips must not gain water or loose water. Planning The variables I could investigate are the type of potato, the temperature of the solution, the strength or dilution of the sugar solution, time, and container and the size of the chip. I have chosen to investigate the strength of the sucrose solution because of osmosis and the movement of water molecules. I will have a range of six; these will be 1 molar --> distilled water. In each test I will put the same sized chips, the same mass, length and diameter of chip will also be the same and also the same type of chip. I will measure accurately by using electronic balance, 30cm ruler and a calibrated pipette. I have made this a fair test by only using one variable. To make sure my investigation is reliable I will make sure it's a fair test. I will know the correct solution to store the chips in because the chips will be the same size and mass as when they were when we started the investigation. Predictions I think that the correct solution to store chips in will be a week solution because in "Biology, a Functional approach" by MBV Roberts. Nelson Publishers say; "The molarity of sucrose that causes no
Nerve Impulses - Action Potentials.
Nerve Impulses - Action Potentials An impulse or action potential is a temporary and local reversal of the resting potential, arising when an axon is stimulated. During an action potential, the membrane potential falls until the inside of the membrane becomes positively charged with respect to the exterior (-70mv to +40mv). The membrane is then said to be depolarised. The change in potential across a membrane comes about because of ion channels in the membrane that, when open, allow particular ions to pass. One type of protein is permeable to sodium ions and another type is permeable to potassium ions. During the resting potential these channels are closed. When an impulse is transmitted they start to open. Sodium channels open first, allowing a large number of sodium ions to flow in. The axoplasm becomes progressively more positive with respect to the outside of the membrane. Then, almost instantly, the permeability of the membrane to sodium ceases (net flow stops). Potassium ion channels start to open and potassium ions flow from the axoplasm where they are in high concentration. The axoplasm now starts to become less positive again (process of re-establishing the resting potential). An Action Potential (impulse) The impulse, in the form of this reversal of charge, then runs the length of the neurone fibre: The transmission of an impulse The Refractory Period For
