Aerobic Respiration Oxygen is required for aerobic respiration. Two waste products, water and carbon dioxide are made.

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1 Dr Smith Page 1 19/09/2011 INVESTIGATING AEROBIC RESPIRATION Need for Energy Living cells are the site of a number of chemical reactions. Together these chemical reactions are called metabolism. Some of these reactions release energy. Living cells need energy for: Cell division e.g. growth & repair Maintaining body temperature (birds & mammals) Movement Chemical reactions e.g. making enzymes, digesting food RESPIRATION is the process by which cells release ENERGY from GLUCOSE. It happens in all living cells (plant & animal) all the time. Aerobic Respiration Oxygen is required for aerobic respiration. Two waste products, water and carbon dioxide are made. Equation for aerobic respiration: GLUCOSE + OXYGEN WATER + CARBON DIOXIDE + ENERGY Reactants waste products useful product The carbon dioxide released can be detected by Turning limewater milky Turning bicarbonate indicator from red to yellow Aerobic respiration occurs in many small steps, each controlled by an enzyme. This allows the energy to be released in small amounts. Credit Material in italics GDS 1

2 Dr Smith Page 2 19/09/2011 The energy in food molecules such as glucose is CHEMICAL ENERGY. Green plants capture LIGHT ENERGY and convert it into chemical energy in photosynthesis (Error! Bookmark not defined.). Animals obtain their food from plants (Error! Bookmark not defined.). The quantity of energy contained in foods can be found by burning a measured mass of food and using the heat energy released to heat a measured volume of water. The energy content of different foods differs: Fats contain TWICE as much energy as proteins or carbohydrates (e.g. glucose & starch) Respirometers A respirometer can be used to measure the rate of respiration The use of respirometers depends on three factors: The volume of oxygen used up is equal to the volume of carbon dioxide produced The carbon dioxide can be absorbed by a chemical (e.g. soda lime, potassium hydroxide) and so the uptake of oxygen is seen as a drop in the volume of air in the respirometer There is no change in the temperature of the apparatus. (changes in temperature cause changes in the volume of gases!) In the apparatus above, the taps are closed at the start of the experiment. As the oxygen is removed the volume of air in the tube decreases and this sucks the coloured liquid up the tube towards the earthworm s tube. Credit Material in italics GDS 2

3 Dr Smith Page 3 19/09/2011 The control should be a non respiring material (i.e. dead animal or glass beads) and of the same volume as the respiring animal. The syringe is used to return the volume back to its original level. In this way, the volume of oxygen taken in can be measured and if the time taken to produce the change is known, the rate of respiration (oxygen uptake per minute) can be calculated. Energy release During respiration some of the energy is released as heat energy. As a result in a confined space the temperature of the surroundings is raised. The heat can be detected using an air thermometer. The heat released by the respiring animal expands the air in the tube and pushes the coloured liquid. There is no expansion in the control side. Credit Material in italics GDS 3

4 Dr Smith Page 4 19/09/2011 ANIMAL SURVIVAL THE NEED FOR FOOD Food provides energy and raw materials for growth. Food contains 3 types of food molecule: Food Molecule Carbohydrates: Fats Proteins Use in Body Source of energy Source of energy/ Store of energy/ Raw materials for growth & repair Structure of Food Molecules: carbon sugar give starch. Polymers (long chains) to to give cellulose 20 amino proteins. acid nitrogen fatty acid to form a fat molecule hydrogen glycerol glycerol fatty acid units Credit Material in italics GDS 4

5 Dr Smith Page 5 19/09/2011 Parts of the Mammalian Alimentary Canal (gut) Digestion Food is made of large particles containing large, insoluble molecules. Large, insoluble molecules cannot pass across the wall of the intestine. Food molecules can only be absorbed if they are soluble. Digestion is the process in which large, insoluble food particles are broken down into small soluble molecules, which can pass across the wall of the small intestine. Mechanical Digestion This when the teeth are used to break large pieces of food into smaller pieces. This increases the surface area of the food on which enzymes (Error! Bookmark not defined.) can act. Teeth are specially adapted to suit the diet of the organisms: Herbivore Animal that eats only plants, e.g. Cow, sheep Carnivore Animal that eats only meat (other animals) e.g. Lion, dog Omnivore Animal that eats both plants and animals e.g. human, bear. Credit Material in italics GDS 5

6 Dr Smith Page 6 19/09/2011 (HERBIVORES) (CARNIVORES) (OMNIVORES) Credit Material in italics GDS 6

7 Dr Smith Page 7 19/09/2011 Chemical Digestion Chemical digestion is carried out by enzymes in digestive juices. They are: Digestive Juice Site of Production Main Enzymes Saliva Salivary Glands Salivary Amylase Gastric juice Stomach Pepsin Bile Liver (stored in gall bladder) Bile is not an enzyme, but helps in fat digestion. Pancreatic juice Pancreas (secreted into small intestine) Intestinal juice Wall of small intestine Action of digestive enzymes Pancreatic amylase; Lipase; Protease Proteases A digestive enzyme is a chemical which speeds up the breakdown of food ENZYME SITE PRODUCED SUBSTRATE PRODUCT Amylase Saliva (salivary amylase) STARCH MALTOSE Pancreas (into small intestine) Lipase Pancreas (into small intestine) FATS FATTY ACID & GLYCEROL Proteases e.g. pepsin stomach PROTEINS PEPTIDES OR AMINO e.g. peptidase pancreas (into small ACIDS intestine) Structure of the Small Intestine The small intestine is where all soluble food molecules are absorbed. It is adapted to fulfil this role: It has a large surface area for absorption because: It is very long Its lining has finger-like projections (villi) It can rapidly absorb digested food molecules by diffusion because: The lining is very thin Lots of blood vessels carry away absorbed food Part of small intestine Finger-like projections called villi One villus Thin surface layer Blood capillary lacteal Credit Material in italics GDS 7

8 Dr Smith Page 8 19/09/2011 Absorption of Digested Foods Feature Function Thin lining Allows rapid diffusion of products of digestion Blood capillaries Absorption and transport of glucose and amino acids Lacteal Absorption of products of fat digestion Lymph vessels Transports fats from villus Role of the Large Intestine - Reabsorption of water and elimination of undigested remains (FAECES) Faeces are collected in the rectum and then passed out through the anus. Movement of Food along the Gut PERISTALSIS = contractions of the muscular wall of the gut pushing food along. MECHANISM OF PERISTALSIS Muscles behind contract Muscles in front relax A wave of this muscular contraction and relaxation sweeps down the gut, pushing the food ahead of it. Muscles behind contract Muscles in front relax gut STOMACH CONTRACTIONS: Muscles in the stomach wall contract and relax, helping churn the food with digestive juices, speeding up the digestion of food. Credit Material in italics GDS 8

9 Dr Smith Page 9 19/09/2011 REPRODUCTION Asexual reproduction Sexual reproduction - one parent, no sex organs, no sex cells - two parents, sex organs, sex cells (gametes) are made Sex cells: Sperm Male sex cell Head nucleus and tail Can swim Small Sperm are attracted to egg cells Egg Female sex cell Nucleus and food store Cannot swim Large Fertilisation: The nucleus of the male sex cell joins with the nucleus of the female sex cell Fertilisation can be internal or external. External fertilisation takes place outside the body and internal fertilisation occurs inside the female s body. Sperm need to swim to the egg so external fertilisation must take place in water. In internal fertilisation the sperm swim in the semen. Internal fertilisation allows land living animals to reproduce without returning to the water. External Fertilisation e.g trout, frog Produce many sex cells* Release sex cells into water Have courtship rituals or synchronise release of sex cells* * This increases the chances of an egg being fertilised. Credit Material in italics GDS 9

10 Dr Smith Page 10 19/09/2011 Credit Material in italics GDS 10

11 Dr Smith Page 11 19/09/2011 Internal Fertilisation e.g. human, and other mammals Produce few sex cells (especially eggs) Male places sperm inside the female s body. The egg is fertilised in the OVIDUCT. Immediately following fertilisation, a FERTILISATION MEMBRANE forms around the egg. This prevents a second sperm from entering the egg. If a second sperm was to penetrate the egg, the resulting zygote would have the wrong number of sperm and so would not develop normally (see S4 notes). The fertilised egg (ZYGOTE) develops into an EMBRYO. It develops in the uterus. Feeding/ Caring for the young Fish A fertilised fish egg consists of: An embryo A food store A protective, flexible covering (jelly/ membrane) A newly hatched trout Feeds from yolk in the yolk sac Receives no parental care and so looks after itself Finds food for itself after its yolk sac is used up Credit Material in italics GDS 11

12 Dr Smith Page 12 19/09/2011 Mammalian Egg The egg is fertilised in the oviduct As it travels down the oviduct to the uterus, it divides many times, forming a ball of cells The ball of cells implants into the spongy wall of the uterus Here the embryo develops a placenta. It is connected to the placenta by the umbilical cord The embryo grows inside a sac called the AMNION, filled with amniotic fluid. This supports the embryo and protects it from bumps STRUCTURE & FUNCTION OF THE PLACENTA An embryo mammal develops a PLACENTA which is a flattened cushion-like organ. A long twisted coil of blood vessel, called the umbilical cord, stretches from the embryo to the placenta. In the placenta, the blood of the mother and embryo pass very close to each other but do not actually mix. Passes from mother to embryo Passes from embryo to mother Oxygen Carbon Dioxide Glucose, Amino Acid (food) Urea (& other wastes) Harmful substances (e.g. drugs, alcohol, nicotine) Mammals are born through the vagina. Once born, it suckles milk from its mother. Mammals receive a large amount of care and protection from their parents. Number of eggs and chances of survival The more care offspring receive, the more likely they will survive to reproduce, so the fewer are produced e.g. turtles lay many eggs, bury them & leave. Many young lost due to predation. polar bears produce two or three young, feed and protect them for around two years. Most of them survive Animals with INTERNAL fertilisation and much care of the young, need to produce very few eggs, as each has a high chance of survival Animals with EXTERNAL fertilisation and no parental care need to produce huige numbers of eggs as each has such a low chance of survival. Credit Material in italics GDS 12

13 Dr Smith Page 13 19/09/2011 WATER & WASTE Our bodies contain much water This amount needs to be kept constant if we are to remain healthy Water is lost or gained in a variety of ways Daily water Gain Daily water loss DRINK SWEAT BREATH FOOD URINE CHEMICAL REACTIONS e.g FAECES aerobic respiration WATER GAIN = WATER LOSS The Human Urinary System The functions of these parts of the urinary system are: Part Function Renal artery Carries blood TO the kidney Renal vein Carries blood FROM the kidney Kidney Regulates water Ureter Carries urine from kidney to bladder Bladder Stores urine Credit Material in italics GDS 13

14 Dr Smith Page 14 19/09/2011 The kidneys are the main organs for regulating water content of blood change the VOLUME & CONCENTRATION of URINE remove poisonous waste, called urea*, from the blood * Urea is produced from the breakdown of amino acids. This happens in the liver. The urea is then transported, dissolved in the plasma of the blood to the kidney, where it is excreted. How the Kidney works The kidneys function by: FILTRATION REABSORPTION FILTRATION occurs in the glomerulus, both poisonous and useful substances are filtered from the blood. The glomerular filtrate is captured by the Bowman s Capsule, and moves into the tubule. In the tubule, useful substances, glucose, most of the water are reabsorbed, back into the blood. They go into the blood capillary running alongside the tubule. Credit Material in italics GDS 14

15 Dr Smith Page 15 19/09/2011 The role of ADH in regulating Water Balance ADH (Anti diuretic hormone) Hormone, made of protein Produced in the pituitary gland (at base of the brain) Increases permeability of tubule to water Causes more water to be reabsorbed (reduces volume/ increases concentration of urine) If there is too little water in the blood*, the brain detects this and causes the pituitary gland to produce more ADH. This causes the kidney to reabsorb more water from the glomerular filtrate and so reduces the volume of urine produced. The concentration of urine is increased. If there is too much water in the blood, the brain senses this and causes the pituitary gland to produce less ADH. This causes the kidney tubule to reabsorb less water. The volume of urine is produced increases, the concentration decreases. * Too little water in the blood is caused by sweating a lot, not drinking enough or eating lots of salt. Credit Material in italics GDS 15

16 Dr Smith Page 16 19/09/2011 If the kidneys become damaged (diseases, accident) then toxic wastes build up in the body. This is fatal if left untreated. 2 treatments are possible. Kidney dialysis on a kidney machine Kidney transplant In the kidney machine, only harmful substances are filtered out of the blood, useful substances stay in the blood, so there is no need fro reabsorption. Comparison of Machines and Transplants Benefits Drawbacks Kidney Machine Prevent death Expensive Restrictive (dialysis takes several hours, 2 or 3 times a week) Transplant Allows a normal life to be lead Donor shortage Possible rejection of kidney so drugs taken rest of life Credit Material in italics GDS 16

17 Dr Smith Page 17 19/09/2011 RESPONDING TO THE ENVIRONMENT Animals need to respond to changes in their environment to ensure their survival e.g. Animals Stimulus Response Survival Value Woodlouse Dampness Move towards it (high humidity) Prevent drying out Flatworms Extract of liver Moves towards it Source of food Earthworms Light Moves away from it Escapes predation/ drying out Euglena Light Moves towards it Euglena photosynthesises Rhythmical Behaviour Animal behaviour shows regular changes triggered by environmental changes. e.g. Light & dark, long/ short days. Migration in geese is an annual rhythmical behaviour triggered by changes in daylength. Activity in shore crabs is a TIDAL rhythm triggered by tidal movements. The main features of rhythmical behaviour are: Regular - occurs at fixed intervals Triggered - started by an external stimulus Persistent - continues even if the trigger stimulus is absent (e.g. shore crabs show behaviour patterns related to tidal changes even when placed in a non tidal tank Rhythmical behaviour helps animals exploit regular changes in their environment. e.g. it makes sure They have their young at a time when food is plentiful and weather is fine (daylength triggers mating in deer, sheep & blue tits). This increases the chances of survival. For shore crabs, being active during specific periods of the tide cycle allows them to obtain food as the tide comes in and escape predation by hiding when the tide is receding. Credit Material in italics GDS 17

18 Dr Smith Page 18 19/09/2011 Percentage Calculations. PROBLEM SOLVING 3 Types of percentage calculation can be asked: Percentage change (increase or decrease): To find the change Percentage change = End value start value Start value X 100 To change to a percentage STEP 1 - Find the START Value (in the question) STEP 2 - Find the END value (in the question) STEP 3 - FIND OUT HOW MUCH IT HAS CHANGED (use a calculator!!!!!): END VALUE START VALUE STEP 4 - Divide this answer by the START VALUE STEP 5 - Multiply that answer by 100 If the answer is negative the factor has decreased, if it is positive the factor has increased e.g. Calculate the percentage change in blood flow to the skeletal muscles during exercise, if it rises from 10 l/min to 30l /min. Percentage change = X 100 = X 100 = 200% change (increase). Percentage of: This asks what percentage a subset is of the total To calculate the proportion the subset forms of the total Percentage of = Size of subset Total X100 To change to a percentage e.g. What percent of the whole population has blood group AB? Blood Group A B AB O Number Total = = 188 Subset = 33 Percentage = X 100 = 17.6%% How many, if the percentage is already given: Number = Total X Percentage 100 e.g. If 20% of a class of 40 have blue eyes, how many of the class has blue eyes? Total =40 Number = 40 X = = 8 Credit Material in italics GDS 18

19 Dr Smith Page 19 19/09/2011 Ratios A ratio is a way of showing the relationship between two or more values. For example a forest contains two types of deer, Roe deer and Fallow deer. The deer are counted and 360 Roe deer are found, but only 120 Fallow deer are present. To express this as a ratio a number of steps can carried out. 1. Try to divide the large number by the small number 360 : 120 each by 120 3:1 this is the simplest whole number ratio. Second example. The head teacher wishes to know the ratio of male staff to female staff in the school. There are 32 male staff and 56 female staff 1. Try to divide the large number by the small number 32: 56 each by 32 1:1.75, not a whole number ratio so move to next step 2. Divide both sides by the largest number which goes in evenly, 32:56 each by 4 8: 14 each by 2 4:7 This is the simplest whole number ratio, the two numbers cannot be divided evenly by the same number! Third example The EU fishery minister suggested that the North Sea contained very little cod, but much more herring. The survey shows that there were 175 cod, and 1,260 herring. What is the ratio of cod: herring. 1. Try to divide the large number by the small number 175 : 1260 each by :1, not a whole number so move to next step 2.Find a number that will divide evenly into both sides (the same number for each side) 175: 1260 each by 5 35:252 can they be divided again? 35:252 each by 7 5:36 This is the simplest whole number ratio, the two numbers cannot be divided evenly by the same number! Credit Material in italics GDS 19

20 GREE Dr Smith Page 20 19/09/2011 Chemical Tests ph Scale (Acidity/ Alkalinity) The ph Scale gives a measure of how acidic or alkaline a solution is: ph COLOUR of ph indicator RED ORANG YELLOW BLUE PURPLE ph is measured using ph indictor or paper The ph falls (becomes more acidic) when fats are broken down to fatty acids (& glycerol), or protein are broken down (to give amino acids) Carbon Dioxide Carbon dioxide is the gas used up in photosynthesis and produced in aerobic respiration in animals and plants (along with water) and in anaerobic respiration in plants (along with alcohol). In experiments it can be absorbed by soda lime or potassium hydroxide. Carbon dioxide turns limewater milky. Bicarbonate indicator can be used to tell how much carbon dioxide is present Carbon Dioxide Zero Normal (0.03% High Colour of Bicarbonate Indicator Purple Red Yellow Experimental Design In a scientific experiment a test is only fair if only one variable factor has been changed at a time. Examples of variable factors are time, lengths, volumes, weights and concentrations. If more than is changed between experiments the test is not fair. A fair test is also a VALID test. Experiments are repeated to make them more RELIABLE or REPRESENTATIVE. To make an experiment more accurate better equipment must be used e.g. a more accurate balance or replace a ruler having centimetre divisions with one having millimetre divisions. Food Tests Food Type Reagent Procedure Positive result Glucose (sugar) Benedict s Heat with sample at 95 C Turns from blue to orange Starch Iodine Add to sample Turns from orange to blue/ black Protein Biuret Heat with sample Turns from to violet Fats Alcohol and water Shake with sample. Solution goes cloudy one is Credit Material in italics GDS 20

21 Germination (%) RED BLUE YELLOW WHITE GREEN Number Dr Smith Page 21 19/09/2011 Charts/Graphs In Biology two types of chart are used: Usually a question tells you which to draw. BAR CHART the BAR chart and the LINE GRAPH When data concerns the numbers in various groups, then a bar chart is used Colour of Flower Number RED 37 BLUE 15 YELLOW 7 WHITE 3 GREEN 24 Label; axes names and units (if any) 5 copy the column headings. The first set of information goes on the horizontal axis, the 0 second on the vertical axis. Devise a scale (divide the axis up evenly). Find the highest value in your data. 37 Colour of Flower Count the number of large squares on your vertical axis 8 Divide the highest value by the number of squares, 37/8 = round your answer up to the nearest easy* number. i.e. 5 Each large square is worth 5 *easy numbers are usually 1, 2, 5, 10, 50, 100 etc. Draw the bars (you should make each bar the same width and leave a gap between the bars (you won t lose marks if you don t) LINE GRAPH Line graphs are used when both sets of data are numbers. A scale must be used on both axes. Temperature (ºC) Germination (%) Label axes by copying the column headings 10 (first 1st horizontal, 2nd column vertical) 0 Devise scales for both axes Horizontal 50/10 = Each big box is worth 5 ºC Temperature (ºC) Vertical 74/8 = 9.25, Each big box is worth 10% Plot the points and join with a straight line (Only join 0,0 if that point is in the data) Credit Material in italics GDS 21

22 Dr Smith Page 22 19/09/2011 ADH Aerobic respiration Amino acid Amnotic sac Amylase Anus Bowman's capsule Canine Carbohydrate Carnivore Collecting duct Fat Fatty acid /Glycerol Fertilisation Gall bladder Glomerulus Herbivore Incisor Tooth Lacteal Large intestine Lipase Metabolism Molar/Premolar Nephron Oesophagus (gullet) Omnivore Ovary Oviduct Ovum (egg) Pancreas Penis Peristalsis Placenta Protease Protein Rectum Renal artery Renal vein Rhythmical Behaviour Salivary glands Small intestine Sperm Stimulus Stomach Hormone which regulates water chemical reaction to release energy which requires oxygen Basic unit of protein molecule Membrane surrounding the developing foetus Enzyme which breaks down starch into simple sugars Opening through which faeces are ejected End of the kidney tubule which collects the filtrate Tooth used for ripping and tearing Chemical containing carbon, hydrogen and oxygen Meat-eater Tube which takes urine from the tubules to the ureter Chemical containing carbon, hydrogen and oxygen Basic units of fats Fusion of an egg and a sperm cell Stores bile Knot of capillary blood vessels Plant eater used for cutting Small lymph vessel in the villus which absorbs the products of fat digestion where water is absorbed An enzyme which breaks down fat into fatty acid and glycerol all of the chemical activity taking place within an organism Tooth used for grinding and chewing Kidney filtration unit Connects mouth to stomach Eats plants and meat Site of production of ova (eggs) Tube which carries the ova; site of fertilisation Female gamete Makes digestive juices containing enzymes Organ for transferring sperm into the female Muscular contractions which move food through the intestines Region of the uterus wall where materials are exchanged An enzyme which breaks down protein into amino acids Chemical containing carbon, hydrogen, oxygen and nitrogen Area of bowel for temporary storage of waste Blood vessel carrying blood to the kidney Blood vessel carrying blood away from the kidney shown on a regular, predictable pattern Site of saliva production Site of absorption of products of digestion Male gamete Change in the environment Main site of chemical digestion

23 Dr Smith Page 23 19/09/2011 Testes Urea Ureter Urethra Uterus Vagina Villus Yolk sac Zygote Site of sperm production Waste product from the breakdown of amino acids Tube which carries urine to bladder Tube which carries urine from bladder to outside the body Organ in which the foetus develops Organ in which sperm are deposited Finger-like fold in the wall of the small intestine Food store used by fish embryo Fertilised egg