as level biology exam-style questions (all topics)

Question 1

a coenzyme is a non-protein molecule that activates the enzyme. what is the difference in the molecular structure of the enzyme and the coenzyme?

Answer 1

an enzyme contains amino acids but a coenzyme does not

Question 1

to what category of macromolecules do most enzymes belong?

Answer 1

proteins

Question 2

how does the reduction in activation energy by an enzyme affect a chemical reaction?

Answer 2

the reaction proceeds at a faster rate

Question 3

what causes tomatoes to ripen much more slowly in a refrigerator than they do if left on a table at room temperature?

Answer 3

low temperatures reduce the action of ripening enzymes

Question 4

the graph shows the optimum temperature of two enzymes. which does this information suggest?

Answer 4

different enzymes perform best at different temperatures, depending on where they function

Question 5

the diagram illustrates a biochemical process that occurs in organisms, the substance labelled catalyst is also known as an…

Answer 5

enzyme

Question 6

many biochemical reactions in living systems would occur at a rate too slow to sustain life without the action of enzymes to catalyse the reaction. what is the function of the enzymes?

Answer 6

they decrease the activation energy

Question 7

ATPases are enzymes that help convert ATP into ADP in cells. when a person exercises, ATPases directly increase which of the following?

Answer 7

the amount of energy released in muscle cells

Question 8

which of the following roles does an enzyme play when the body processes sucrose (table sugar) into glucose and fructose?

Answer 8

an enzyme increases the rate at which the sucrose breaks down

Question 9

overheating an enzyme results in the enzymes loss of…

Answer 9

ability to catalyse a reaction

Question 10

which of the following statements about enzymes is NOT true?

Answer 10

all enzymes have the same shape as their substrates

Question 11

the graph shows how the concentration of the enzymes amylase affects the breakdown of starch, a common carbohydrate. what can you conclude about their relationship?

Answer 11

reaction rate increases with increasing enzyme

Question 12

substance X + substance Y (ENZYME C) –> substance W

the equation above represent a chemical reaction that occurs in humans. to support the hypothesis that enzyme C works best in a slightly basic environment, data should be collected about…

Answer 12

the amount of substance W produced at various pH levels

Question 13

some snake venoms are harmful because they contain enzymes that destroy blood cells or tissues. the damage caused by such a snakebite could best be slowed by…

Answer 13

applying ice to the bitten area

Question 14

a student and his lab partner perform an experiment in which they measure the effect of temperature on amylase, an enzyme found in saliva that digests starch. their results are shown on the graph. use the graph to determine the humans average body temperature?

Answer 14

37oC

Question 15

a student and his lab partner perform an experiment in which they measure the effect of temperature on amylase, an enzyme found in saliva that digests starch. what would happen if the enzyme amylase did not exist in the saliva?

Answer 15

starch digestion would not be possible

Question 16

which enzyme would have the most activity in humans?

Answer 16

enzyme X

Question 17

trypsin is an enzyme from pancreatic juice (a clear alkaline secretion of pancreatic enzymes as trypsin and lipase that flows into the small intestine and acts on food already acted on by the gastric juice and saliva). the graph shows its activity at various pH levels. what conclusion can be drawn about the activity of trypsin?

Answer 17

trypsin works best at a pH of 6.5

Question 18

fresh pineapple contains an enzyme that digests proteins. adding fresh pineapple to gelatin (a protein) prevents it from setting or jelling. however, adding cooked or canned pineapple does not have this effect and the gelatin can set normally. what would account for the difference in the results?

Answer 18

cooked or canned pineapple contain denatured enzymes

Question 19

what would you expect to happen if you increased the substrate concentration in the presence of a fixed amount of enzyme?

Answer 19

the rate of reaction with increase to a point and then remain at a maximum level

Question 20

some people experience gas and discomfort after eating vegetables, grains, beans, and other high-fiber foods. there is an enzyme product called “BEANO” that breaks down the complex carbohydrates (long chains of sugars) into simple sugars. do you think that the enzyme in BEANO will work to digest the lactose in milk? explain why or why not.

Answer 20

the enzyme BEANO would work to break down lactose as lactose is a sugar which is something BEANO breaks down. it would be broken down into galactose and glucose

Question 21

what name is given to the condition of stability enabled by a set of processes such as those involved in the maintenance of internal body temperature?

Answer 21

homeostasis

Question 22

acidic pH levels would be…

Answer 22

below pH 7

Question 23

alkaline pH levels would be…

Answer 23

above pH 7

Question 24

the best pH levels to maintain homeostasis in the body would be…

Answer 24

close to pH 7

Question 25

the best temperature to maintain homeostasis in the body would be…

Answer 25

37oC

Question 26

what is an example of the human body achieving homeostasis through thermoregulation?

Answer 26

sweat is produced when exercising to keep the body cool

Question 27

in order for the body to maintain homeostasis, the chemical decomposition of food to produce energy must be followed by…

Answer 27

waste removal

Question 28

______ digestion takes places from the mouth to the stomach but ______ digestion occurs in the small intestine only

Answer 28

mechanical
chemical

Question 29

the increased breathing rate signalled by the brain serves…

Answer 29

to increase the O2 levels in the body

Question 30

the graph shows evidence of disease in the human body. a disruption in the dynamic equilibrium is indicated by the temperature change that occurs between points…

Answer 30

C and D

Question 31

which of the following correctly describes a positive feedback mechanism?

Answer 31

the response increases the stimulus

Question 32

the human thermostat is the…

Answer 32

hypothalamus

Question 33

the nervous system coordinates…

Answer 33

rapid response called reflexes

Question 34

hormones are chemical signals that are secreted from the…

Answer 34

all of the others

Question 35

the purpose of insulin in the body is to…

Answer 35

maintain energy homeostasis

Question 36

which of the following is an example of positive feedback?

Answer 36

blood clotting

Question 37

which of the following MUST be maintained in order to achieve homeostasis?

Answer 37

all of the others

Question 38

the feedback loop that regulates blood glucose level in the blood is…

Answer 38

negative feedbackt

Question 39

the feedback loop that regulates dehydration is…

Answer 39

negative feedback

Question 40

the feedback loop that regulates childbirth is…

Answer 40

positive feedback

Question 41

dopamine is a neurotransmitter that is released in the brain when you learn. it rewards you with a feeling of happiness and euphoria. is this a positive or negative feedback mechanism? justify your reasoning.

Answer 41

this is a positive feedback mechanism as it is encouraging you to increase the stimulus more often so that the response can be created increasingly, which basically rewards you.