structured questions

Question 1

a lipase enzyme only acts on one substrate.
explain why it does not act on other substrate

Answer 1

the active site of lipase is only complementary to the shape of fats.
other substrate will not be able to bind to lipase.
hence no reaction occurs

Question 2

describe the lock and key hypothesis of enzyme action

Answer 2

the enzyme has an active site complementary to the shape of the substrate.
the substrate fits into the active site, forming enzyme-substrate complex
hence reaction occurs

Question 3

cells in the palisade layer have more chloroplasts than cells in the spongy layer. suggest a reason for this

Answer 3

the palisade layer is nearer to the top surface hence it is exposed to more sunlight for chloroplasts to carry out photosynthesis

Question 4

name the process by which water is lost through stomata

Answer 4

transpiration

Question 5

suggest how the guard cells prevent wilting on a hot day

Answer 5

when guard cells become flaccid, stomata closes

Question 6

suggest a reason why a person may feel tired when the valves fail to work properly

Answer 6

blood flowing to the body contains less oxygen

Question 7

describe ad explain one difference in the structure of arteries and veins

Answer 7

veins contain valves while arteries do not
because blood flow in veins is under low pressure. vales prevent the back flow of blood to the heart

Question 8

suggest how a person knows they have a build up of lactic acid

Answer 8

muscles fatigue
cramps

Question 9

describe the process that occurs in mitochondria

Answer 9

describe aerobic respiration

Question 10

suggest in terms of the function of a sperm cell, why it has a large no. of mitochondria

Answer 10

so as to release energy during aerobic respiration so that the sperm can swim towards the oviduct

Question 11

suggest and explain what would happen to the patient´s heart if he did not undergo the by-pass surgery

Answer 11

the cardiac muscles will not receive sufficient blood which transports oxygen and glucose. the muscular walls may die resulting in heart attack

Question 12

what is the function of the thin film of moisture on the surface of the spongy mesophyll cells

Answer 12

it is to dissolve gases

Question 13

describe how water is lost from the leaves from the intercellular spaces in the leaves

Answer 13

water vapour diffuses out of the stomata of the leaves

Question 14

which blood vessels contains blood that has both high oxygen concentration and high blood pressure

Answer 14

aorta

Question 15

state two health benefits for a smoking who stops smoking

Answer 15

the person would experience improved cardiovascular and immune health which decreases the risk of heart attack, stroke and lung cancer
person would not have a cough as much and have less respiratory problems

Question 16

suggest what measures might be taken by government to reduce the harmful effects of smoking on health

Answer 16

implement higher taxes
education on the harmful effects of smoking

Question 17

explain why is there no lactic acid found in the muscles at the first 2 minutes of race/ exercising etc

Answer 17

it is because there was enough energy released from aerobic respiration

Question 18

explain how smoking leads to the development of bronchitis

Answer 18

it contains irritants that paralyses cilia
mucus builds up, causing difficulties breating

Question 19

2 health benefits for a smoker who stops smoking

Answer 19

reduce risk of disease (lung cancer & heart disease)

Question 20

explain why smoker has less oxygen in their blood than the healthy person

Answer 20

the rate of diffusion is reduced due to smaller surface area of damaged alveoli
healthy lung has a larger surface area than damaged lung

Question 21

why athletes train at a height of 2000m

Answer 21

at high altitude, the body produces more red blood cells, this increases the capacity of oxygen delivered to muscles for respiration

Question 22

stomata open smaller means that

Answer 22

slower rate of photosynthesis

Question 23

where is more stomata found

Answer 23

more stomata found on the lower than upper surface

Question 24

describe how water is lost from the leaves from the intercellular spaces in the leaves

Answer 24

water vapour diffuses out of the stomata

Question 25

do stomata close or reduce in size? and how this resulted in change of the shape of stomata

Answer 25

it reduce in size. guard cells bcm flaccid and change shape to close stomata

Question 26

describe how wilting occurs and the changes in the leafy shoo when it wilts

Answer 26

rate of water loss is greater than water absorbed, the plant cell become flaccid. stomata closes and plant wilts

Question 27

explain how water containing red dye reaches the leaves

Answer 27

due to transpiration water vapour is lost through the stomata of the leaves creates suction force whichcauses red dye solution to be absorbed into the xylem tissues at the base of the stalk

Question 28

pathway taken by the water as it moves from the potometer through plant stem and into the surrounding air

Answer 28

water transported up the xylem to the leaves by transpiration pull in the leaf, water will move out of the xylem and into the surface of mesophyll cells by osmosis, forming a layer of moisture around the surface water evaporates into the cellular air space and diffuses out through the stomata to the surrounding air

Question 29

why is it beneficial to place the plant shoot upside down

Answer 29

since stomata are found on the underside of the leaf allow gases produced to escape more easily

Question 30

describe what happens to each products after photosynthesis

Answer 30

glucose stored in the leaves. it converts into starch for plant to use oxygen diffuse out of the leaves from the stomata it can also be used in respiration in plants glucose - aerobic respiration glucose - cellulose found in cell wall '

Question 31

what happens when ventricle fail to work properly. suggest why a person may feel tired

Answer 31

an insufficient oxygen blood is pumped around the body blood consist of oxygen, thus a person may feel tired

Question 32

suggest why amount of exercise may have an effect on the chance of a person dying from coronary heart disease

Answer 32

exercise is a form of stress relief exercise helps to increase metabolic rate and burn excess fat preventing the deposition of fats

Question 33

explain why lactic acid is produced in the muscle cells of the athletes

Answer 33

insufficient oxygen therefore anerobic respiration occurs

Question 34

why blood sugar level rise and then falls in the hours after breakfast

Answer 34

blood sugar level rise as food (carbs) digest in small intestine and being absorbed into bloodstream decreased as liver will be stimulated by insulin to convert into glycogen

Question 35

physical digestion in small intestine

Answer 35

break down large food to small molecules using bile emulsification

Question 36

chemical digestion

Answer 36

breaks down of large food to smaller soluble molecules by enzymes

Question 37

physical digestion of mouth

Answer 37

chewing

Question 38

physical digestion of stomach

Answer 38

churning

Question 39

does xylem contain nucleus

Answer 39

no

Question 40

the order of formation of blood clot

Answer 40

platelet prothrombin fibrinogen fibrin

Question 41

explain why cells in the alimentary canal contain many ribosomes

Answer 41

to synthesis proteins as enzymes are needed in the digestion of food

Question 42

the function of capillary

Answer 42

allows for diffusion and exchange of substances

Question 43

explain why lactic acid is produced in the muscle cells of the athlete

Answer 43

insufficient oxygen therefore anaerobic respiration

Question 44

what happens to the amino acid when it enters to the bloodstream

Answer 44

used by cells to make proteins excess amino acids undergo deamination forming urea in the liver

Question 45

what happens to the glucose when it enters to the bloodstream

Answer 45

release energy by respiration it is converted to glycogen in the liver for storage one

Question 46

one adaptation of villi and its function

Answer 46

the walls of villi are one cell thick this reduces diffusion distance allowing for faster absorption of nutrients

Question 47

is nucleus found in a root hair cell of a plant

Answer 47

yes

Question 48

name the process by which water vapour is lost through the stomata

Answer 48

transpiration

Question 49

darker green colour of leaf means...

Answer 49

more chlorophyll

Question 50

suggest why babies born to mothers who smoke have lower birth weight than average

Answer 50

babies receive less oxygen and it is needed for cell growth

Question 51

why hepatic portal vein has the highest concentration of amino acids and glucose

Answer 51

as it is absorbs glucose and amino acids and is transported from small intestine to liver liver has lower concentration cos excess glucose is converted into glycogen and excess amino acids are broken down by deamination

Question 52

describe what happens in respiring muscle cells during exercise

Answer 52

rate of aerobic respiration increases energy released during aerobic respiration occurs lactic acid is produced