Question

Short answer type questions

1. State the role of HCl in our stomach?

2. How are fats digested in our body?

3. Differentiate between

a) Artery and vein

b) Aerobic and anaerobic respirations

c) Excretion and Egestion

d) Anaerobic respirations in plants and animals

e) Dark and light reaction

4. State the function of the following

a) Kidney

b) Ureter

c) Urinary bladder

d) Pulmonary artery

e) Aorta

f) Stomata

g) Tracheids and vessels

h) Anus

Answer 1

1.The gastric chief cells of the stomachsecrete enzymes for protein breakdown (inactive pepsinogen, and in infancy rennin). Hydrochloric acidactivates pepsinogen into the enzyme pepsin, which then helps digestion by breaking the bonds linking amino acids, a process known as proteolysis.
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2.Bile salts break them down into smaller globules increasing the efficiency of enzyme action. The pancreas secretes pancreatic juice, which contains enzymes like trypsin for digesting proteins and lipase for breaking down emulsified fats. The walls of the small intestine contain glands, which secrete intestinal juice.
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3.a)Arteries carry blood from the heart to the rest of the body, whereas veinscarry blood from the rest of the body back to the heart. 2. Almost all arteriescarry oxygenated blood and almost allveins carry deoxygenated blood. ...Arteries have a thick elastic muscle layer, whereas the muscle layer forveins is much thinner.
b)Both aerobic and anaerobic respiration involve chemical reactions which take place in the cell to produce energy, which is needed for active processes. Aerobic respiration takes place in the mitochondria and requires oxygen and glucose, and produces carbon dioxide, water, and energy.
c)Excretion is the removal of waste products from the body. It is differentfrom egestion - which is the removal of undigested semi-solid waste (faeces) from your anus. You need to be able name and locate the main organs involved in excretion: skin.
d)Almost all animals and humans are obligate aerobes that require oxygen for respiration, whereas anaerobic yeast is an example of facilitative anaerobe bacteria. Individual human cells are also facilitative anaerobes: They switch to lactic acid fermentation if oxygen is not available.
e)Dark reactions make use of these organic energy molecules (ATP and NADPH). This reaction cycle is also called Calvin Benison Cycle, and it occurs in the stroma. ATP provides the energy while NADPH provides the electrons required to fix the CO2(carbon dioxide) into carbohydrates.
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4.a)The kidneys are two bean-shaped organs that extract waste from blood, balance body fluids, form urine, and aid in other important functions of the body. They reside against the back muscles in the upper abdominal cavity. They sit opposite each other on either side of the spine.
5.