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. Significant cooling would be required to reverse melting of glaciers and the Greenland ice sheet, which formed during past cold climates. The present CO2-induced warming of the Earth is, therefore, fundamentally irreversible on human lifespan. The quantity and rate of further warming will depend almost entirely on ho... |
South Sudan fossil fuel use. Place limits on the amount of carbon that polluters are allowed to emit. • Build a clean energy economy by investing in efficient energy technologies, industries, and approaches. • Reduce tropical deforestation while increasing tree planting. • Move near your workplace or work from home to... |
.1 Given that composition of inhaled and exhaled air as tabulated in Table 4.1 below, design a bar chart to compare the inhaled and exhaled air. Table 4.1 Composition of inhaled and exhaled air Substance Nitrogen Oxygen Carbon (IV) oxide Inhaled air (%) Exhaled air (%) 78 21 0.39 78 16 4 (a) What do you observe from th... |
group. 8. Write down what you observe. Explain the reason for your observation. 9. Using the bicycle pump, pump fresh air into conical flask B. 10. Write down what you observe. • Explain the reason for your observation. • Compile a group report and present it to the rest of the class highlighting: – What you have lear... |
ous exchange. • Moist and permeable surfaces. • Highly ventilated. • Highly vascularised. • One cell thick squamous epithelium. • Close association with respiratory pigment. field. 2. Put it in a specimen bottle. 3. Using a hand lens, observe how it is breathing in and out. 4. Release the grasshopper back to its enviro... |
ole of when the insect is active and when resting. The tracheal system is extensive spreading to every tissue, close to each cell. This reduces the distance the air has to diffuse to get to respiring cells. Tracheoles penetrate into every tissue up to the cell membrane, reducing the distance of diffusion. Tracheoles ar... |
mouth than in the atmospheric pressure. Air rushes into the mouth cavity through the nostril due to the reduced pressure. The nostril close and the floor of the mouth is raised to force air into the lungs. Nostril Glottis Fig. 4.9: Lungs of a frog. 91 Gill filaments Gill rakers Gaseous exchange takes place between the... |
Gills are highly vascularised to maintain a high concentration gradient in favour of oxygen diffusing into the blood and carbon (IV) oxide diffusing out. The gill filaments are thin. This reduces the distance of diffusion of the gases. Bony gill arches provide support to gill filaments. Gill rakers are bony hairlike p... |
oxygen). It is highly vascularised, ensuring a large concentration gradient in favour of gaseous exchange. Pulmonary arteriole Blood flow Capillary network on surface of alveolus Blood flow Pulmonary venule Fig. 4.13: Capillaries surrounding alveolus. 94 Its epithelial lining is covered by a thin layer of moisture or w... |
this fire? What types of energy transformations are occurring as the wood burns? Suggest the type of molecules burning in the wood. Suggest how the burning wood molecules compare with glucose in your body cell cytoplasm. Would you put your finger in the fire? Why? What is the difference between the carbon molecules in... |
nastic movements in plants, and tropisms. • Growth and development: Formation of new cells in the process of mitotic cell division, and synthesis of proteins from amino acids. • Excretion and Homeostasis: This involves maintaining constant body temperature in homeotherms so that enzymes have optimum temperature to fun... |
step of this process requires energy as ATP to increase the free energy of the glucose molecule and convert it into fructose-1,6-diphosphate. This is called phosphorylation. This molecule has two phosphate groups and six-carbon atoms, therefore, it can be broken down into two molecules of 3 carbon sugar each also call... |
produced? 38 molecules of ATP from each molecule of glucose. Are there further reactions? For how long can the reaction occur in your body? How fast is ATP production process? Is oxygen needed? How efficient is it? Did you know? Yes 40% Carbon (IV) oxide and Ethanol in plants or yeast, and lactic acid in animals or ba... |
in the muscles would change the pH of the tissue fluid around the muscle cells and is therefore toxic and can cause cramps. Faster heartbeat after the running quickly carries the blood containing lactic acid to the liver where it is oxidised to carbon (IV) oxide and water by the lactic acid dehydrogenase enzyme or int... |
in aerobic respiration? 5. Name the substrate and products of the Krebs’ cycle. 6. How do fatty acids enter the Krebs’ cycle? Factors affecting the rate of respiration • Temperature affects all chemical and enzyme driven reactions. Low temperatures below optimum slow down the rate of respiration while temperatures opt... |
8. Put the syringe in place in the cork of the flask but do not push the plunger as yet. WAIT. 9. Apply petroleum jelly at all joints of the setup. 10. Push the plunger of the syringe with the potato paste to add 1 ml paste into the hydrogen peroxide and immediately start the stop watch. 104 11. After 20 seconds, make... |
parts of enzymes are called active sites and catalytic abilities. The reacting molecules called substrates have to fix into the active sites for the enzyme to work on them and form a temporally enzyme-substrate complex. Substrate Active sites Enzymes Enzyme-substrate complex Fig. 4.22: Enzyme-substrate complex formati... |
glucose to glucose-6-phosphate by adding a phosphate group. • Hexose phosphate isomerase converts glucose-6-phosphate to fructose-6-phosphate. • Dehydrogenase removes hydrogen ions from various molecules. • Aldolase splits the fructose -1,6-diphosphate (6-carbon) to 3-phosphoglyceraldehyde (triose sugar). • ATP syntha... |
). The carbon (IV) oxide produced turns limewater cloudy. Air dissolved in sucrose solution can be expelled by boiling and the yeasts are killed by boiling at 100° C. Tap Capillary tube Beaker Boiling tube Limewater Yeast + sucrose (Solution A) Rubber cork Rubber tubing Capillary tube Test tube Boiling tube Boiled yeas... |
tubes? Why? 2. Would your observation agree with hypothesis that yeast’s respire anaerobically? 3. How has this experiment ensured that the evidence of respiration is because of yeast anaerobic respiration and not anything else? 4. What assumptions have you made in this experiment? 5. How will you setup a control expe... |
per the Figure 4.31. 8. Connect the capillary tube and insert in a beaker half full of water. 9. Use a permanent marker pen to mark the level of water in the capillary tubing. 10. Apply petroleum jelly at all fixings joints. 11. Leave both flasks in a warm place for 48 hours. 12. At the end of two days, note how many ... |
cycle showing how carbon circulates between the living organisms (biotic) and their environment (abiotic). Practical Activity 4.7: Investigating the presence of carbon (IV) oxide in a living organism Requirements • Eye protection gear • Crushed natural chalk • Vinegar (or hydrochloric acid) • Flask • Balloon • Test tu... |
processes, organisms exchange carbon with their environment: • Respiration: The living plants, decomposers and animals respire, therefore, release carbon (IV) oxide to the atmosphere. • • Deforestation for charcoal and firewood: Firewood and charcoal burning and use release carbon (IV) oxide to the atmosphere and redu... |
respiration is the same as the rate of consumption of carbon (IV) oxide (by photosynthesis). This point at which the rate of respiration is equal to that of photosynthesis is called compensation point. In most plants, compensation point is reached at around dawn. Carbon IV oxide uptake C B A Carbon (IV) oxide release ... |
take place in (a) and (b). 8. What is the significance of stepwise oxidation of organic molecules instead of one step reaction? is photorespiration? the significance of 9. What 10. List the substrates that enter and the products produced in (a) glycolysis (b) Krebs cycle 11. How is yeast useful in industry? Give any t... |
.3 15.2 0.018 134 216 2736 4360 4347 4971 Pig Human Dog Mouse (a) According to the table, what is the total amount of energy used each day by (i) a human being? (ii) a mouse? (b) Which of these two shows a greater rate of respiration in the body cells? (c) Why do you think there is so little difference in the energy ex... |
it is delivered to the stomach. After the stomach the food will be moved along the intestines and remaining undigested food is egested. 5.1 Digestion in animals How does the process of digestion occur in animals? Human digestive system Practical Activity 5.1 You are provided with the following items: • Any starchy foo... |
mandibular gland Fig. 5.2: Salivary glands 123 Did you know? A healthy average person secretes about 1 litre of saliva every day (equivalent to 3 standard bottles of soda a day or 21 bottles in a week). Saliva also contains an enzyme salivary amylase which begins the extracellular chemical digestion of starch even befo... |
ine solution (10 ml) pH universal indicator Standard colour chart • • • • pH range Description Colour Strong acid Red < 3 3 – 6 Weak acid Orange or yellow Green Neutral 7 8 – 11 Weak base Blue >11 Strong base Violet or indigo Fig 5.6 pH colour chart Procedure 1. Wash the test tubes, beaker and droppers provided before ... |
. 14. Wash your mouth of food particles with clean safe water and spit into test tube labelled 6 containing universal indicator to test the pH of your mouth. 15. What was the pH in your mouth? Why is this important? 16. Enter your observations in the table below. Table 5.1 Table of results Tube Starch solution and amyl... |
Activates conversion of pepsinogen into pepsin. the enzyme • Denatures the salivary amylase. In the stomach of infants and young ruminants, rennin curdles milk increasing its surface area for digestion by pepsin. Gastrin hormone gastric glands in the stomach wall to secrete stomach. into gastric stimulates juice the t... |
of water and mineral salts and rectum is the site for temporary storage of undigested and indigestible materials. Did you know? Detergents claiming to remove oil and blood stains contain digestive enzymes like salivary amylase, pancreatic lipase and proteases like pepsin. Physical exercises are known to increase diges... |
food. In Figure 5.10, you observe that ruminants have four chambered stomachs with rumen, where digestion of cellulose takes place due to the presence of bacteria and protozoa; that selects enzyme cellulase. In Figure 5.10, the food swallowed enters the rumen the largest chamber, where fermentation occurs. The ferment... |
posterior of the crop are gizzard and gastric caecae. Gastric caecae secrete digestive enzymes and provide a larger surface area for absorption while the gizzard is an active grinding organ using ridges of cuticle. The oesophagus, crop, gizzard and gastric caecae form the fore gut. 131 Oesophagus Crop Gizzard Stomach ... |
fish on the bases of feeding mode. Table 5.2: Summary on digestion in fish Digestive system part Carnivorous fish digestive Mouth Teeth Gill rakers Oesophagus system Large Pointed jaw and pharyngeal teeth Fine filters Mucus lubricated Stomach Pylorus Pylorus caeca Posterior to stomach Elastic muscular wall Control sph... |
bile. It also stimulates the pancreas to produce pancreatic juice. Pancreatic juice contains trypsinogen which is converted into active trypsin. By the action of enterokinase, trypsin then digests polypeptides into dipeptides. The dipeptides are then digested into amino acids by peptidase produced in the ileum. Rememb... |
, C and D • 2% starch solution • Amylase solution Iodine solution • • Benedict’s solution • Measuring cylinder Procedure 1. Using the measuring cylinder, place 5 cm3 of 2% starch solution in each test tube. 2. Rinse the measuring cylinder then use it to add 2 cm3 amylase solution in each of tubes B and D then shake the... |
particles. Chewing produces a greater surface area for the action of enzymes. The physical digestion of food is possible by mastication and churning of food particles to fine pieces and emulsification of lipids to smaller lipid droplets. Mastication, churning and emulsification increase the surface area of foods for t... |
Maltase which hydrolyses or changes or converts maltose to glucose, Sucrose which hydrolyses sucrose to glucose and fructose, lactase which to glucose and hydrolyses galactose. These are then absorbed into the blood capillaries in villi. the then moves The chyme duodenum through sphincters. Presence of food in the duo... |
pancreatic juice which contains sodium carbonate that neutralises acidic chyme from the stomach providing alkaline medium for pancreatic enzymes action, pancreatic amylase enzyme that digest starch into maltose, pancreatic lipase that digest fats or lipids into fatty acids and glycerol, and trypsin enzyme that digests... |
produced by digestion. The column headings should be titled: region of alimentary, digestive gland, digestive juice produced, enzymes in the juice, class of food acted upon and end substance produced. 2. Given an illustration of the digestive system in human beings, plus a ruler, pen and paper, how would you be able t... |
�s examination. 6. 7. After the first reading change roles until each learner has had the chance to be a doctor, a nurse, a patient and a patient attendant. NB: Respect the patient’s rights as the doctor and do not touch the patient inappropriately. 141 8. Why do doctors listen to your heartbeat as they examine you at ... |
circulatory system and ultrafiltration at the body tissues forms tissue fluid. Table 5.5: Comparison of open circulatory system and closed circulatory system Open circulatory system Blood is pumped into body cavities Closed circulatory system Blood vessels contain the blood throughout Blood flows at lower pressure Blo... |
ated blood from the left atrium and pumps it through aortic semilunar valve to the aorta, then arteries and rest of the body. Go to the systemic capillaries. 145 VenulesVenulesArteriolesAortaArteryArteryArteriolesPulmonary arteryPulmonary veinVeinRight heartLeft heartVeinLUNGSLUNGSTissue capillariesTissue capillariesAr... |
left and the right atrium are full of blood the atrium contracts to pump blood past the cuspid valves, which are two: The left cuspid valves are called the bicuspid valves while the right cuspid valves are called the tricuspid valves. The contraction of the atria is simultaneous and is self-generated by the pacemaker ... |
the following questions. labelled M? (e) Explain how parts K and M, in terms of their functions, are related. (f) What do you think makes K function as well as it does? 148 The facts Structural adaptations of the mammalian heart to its function The heart has valves namely atrioventricular valves (cuspid valves) and th... |
as it pumps blood. The pericardium secretes pericardial fluid, which lubricates its interior and reduces friction between the pericardial membranes as the heart moves within the inner membrane. The deposit of spongy fatty layer on the pericardium mechanically protects and cushions the heart. Work to do • Read the sect... |
pressure in the veins is reduced by capillary resistance before it enters the veins. Did you know? A red blood cell’s diameter is slightly smaller than the internal diameter of the blood capillaries, therefore, they form a single-file line to fit through the blood capillaries in the body. Table 5.6: Functional differe... |
ria of the heart secrete a hormone called atrial natriuretic peptide responsible for lowering blood pressure through vasodilation and increase water loss by the kidney. Flight hormones released by the adrenal gland increase blood pressure too by increasing vasoconstriction and pulse rate. • Role of the heart in blood f... |
Because the left ventricle makes more powerful contractions than the right side. Hormones and heart rate the Your heartbeat speed may be increased autonomic or decreased by nervous system. There are two types of autonomic nervous systems, namely the sympathetic nervous system and the parasympathetic nervous system. Th... |
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