May 2021 SL

Question 1

In mammals, mature red blood cells are specialized in that they lack nuclei, mitochondria or
ribosomes. Which statement applies to red blood cells?

Answer 1

They cannot produce new enzymes.

Question 2

What do chloroplasts and mitochondria have in common?

Answer 2

Both are found in the cells of Filicinophyta.

Question 3

The Davson–Danielli model of membrane structure proposed that membranes were composed of a
phospholipid bilayer that lies between two layers of globular proteins. What evidence supported this model?

Answer 3

An electron micrograph that showed two dark lines with a lighter band in between

Question 4

A human organ is being prepared for transplant. In what type of solution must it be bathed?

Answer 4

A solution with the same osmolarity as the organ tissue

Question 5

Which living structure is an exception to the cell theory?

Answer 5

Striated muscle fibres

Question 6

Which statement applies to cholesterol?

Answer 6

It impacts membrane fluidity.

Question 7

What is the mitotic index?

Answer 7

0.25

Question 8

What distinguishes cellulose from glycogen and starch?

Answer 8

Cellulose has a structural role whereas starch and glycogen function in energy storage.

Question 9

The hydrolysis of a pure sample of an organic molecule produces a pentose sugar, thymine,
guanine and cytosine. What other substances could be expected to be present in the
hydrolysed sample?

Answer 9

Phosphate

Question 10

Which molecule is depicted in the diagram?

Answer 10

A saturated fatty acid

Question 11

What is a difference between aerobic respiration and anaerobic respiration in yeast?

Answer 11

Anaerobic respiration produces ethanol, aerobic respiration does not.

Question 12

What is the term for the attraction of water molecules to other water molecules?

Answer 12

Cohesion

Question 13

What is the approximate reduction in body mass that a person of height 155cm and mass 95kg
would have to lose to reach normal body mass?

Answer 13

36kg

Question 14

Which statement applies to enzymes?

Answer 14

Enzyme function depends on collisions between substrate and active sites.

Question 15

Which enzyme is matched to its function?

Answer 15

DNA polymerase forms a covalent bond between DNA nucleotides

Question 16

If a plant is exposed to light, which colour of light would lead to the lowest rate of oxygen release
by a green plant?

Answer 16

Green

Question 17

What is the relationship between the two adult sea urchins?

Answer 17

They are clones.

Question 18

Which statement applies to meiosis and mitosis?

Answer 18

Separation of chromatids occurs in both meiosis and mitosis.

Question 19

Which genotype would be normally found in a gamete?

Answer 19

RS

Question 20

Over time, the hull of a sunken ship may become colonized by a wide range of marine organisms.
What term is used to describe all of the organisms living in and on a sunken ship?

Answer 20

A community

Question 21

In a typical terrestrial ecosystem, which trophic level would have the highest biomass?

Answer 21

Autotrophs

Question 22

Which process results in decreased variation?

Answer 22

Natural selection

Question 23

A locust is an arthropod. For invertebrate groups, which recognition feature is found only in arthropods?

Answer 23

Jointed appendages

Question 24

A dichotomous key can be used to distinguish four types of plant. Which of the plants could be
a bryophyte?

Answer 24

Vascular tissue present . . . . . . . . . . . . . . . . . . . . . . . . . . go to 2
Vascular tissue not present . . . . . . . . . . . . . . . . . . . . . . . Plant A.

Question 25

What is the most likely explanation for these diff erences?

Answer 25

Gradual divergence

Question 26

A fluid sample is taken from the digestive tract of a mammal. The sample is basic (alkaline) and
able to digest starch and proteins. From which part of the digestive tract was the fluid taken?

Answer 26

Small intestine

Question 27

What is a property of arteries?

Answer 27

Arteries have elastic walls.

Question 28

Which line on the graph represents progesterone?

Answer 28

Line D

Question 29

What blood flow does the right semilunar valve prevent?

Answer 29

Blood flowing from the pulmonary artery to the right ventricle when the heart is relaxing

Question 30

Which reaction occurs in blood clotting?

Answer 30

fibrinogen (thrombin) →fibrin