Theory 2~

Question 1

What is the function of the stigma?

Answer 1

catch pollen grains

Question 2

What is the function of the sepals?

Answer 2

protect the flower while it is a bud

Question 3

What is the function of the petals?

Answer 3

attract insects to the flower

Question 4

What do pollen grains contain?

Answer 4

male gametes of flower

Question 5

How is the upper epidermis adapted for photosynthesis?

Answer 5

Translucent to allow light to pass through to palisade mesophyll cells. Tightly packed together to reduce quantity of water escaping from the leaf.

Question 6

How is the xylem adapted for photosynthesis?

Answer 6

Hollow, dead cells joined end to end form a continuous tube to allow for the transport of water and minerals. Walls are made of cellulose. Lignin as well which prevents the collapse of the water column, helps support the plant.

Question 7

How is phloem adapted for photosynthesis?

Answer 7

Phloem is a plant tissue made up of living cells joined end to end. It transports substances made in the plant such as sucrose and amino acids.

Question 8

What are the female parts of a flower called?

Answer 8

Carpel. Flower can have 1 or more carpel in centre.

Question 9

What part of the pollen grain protects it during pollination?

Answer 9

a hard coat that can survive in difficult conditions

Question 10

Explain how pollen is made.

Answer 10

A young anther has four pollen sacs. Some cells around the edge of the pollen sacs divide to make pollen grains. When the flower bud opens, the anthers split open. Now, the pollen is on the outside of the anther.

Question 11

The greater quantity of starch stored in the leaves grown in a high carbon dioxide concentration
means, when needed, more sucrose can be produced for transport in the phloem, so the leaves act as a ……….

Answer 11

source

Question 12

Explain the effect of exercise on the rate and depth of breathing.

Answer 12

Increases. More oxygen is needed for aerobic respiration to release energy. Muscles require more energy for contraction, which raises carbon dioxide levels and lowers blood pH.

The brain detects this change and sends signals to the diaphragm and intercostal muscles, stimulating faster contractions to remove more carbon dioxide.

Adrenaline released during exercise increases breathing rate.

Question 13

When the temperature moves away from the set point, the mechanism ………….. returns the temperature to the set point.

Answer 13

negative feedback

Question 14

The fermenter is kept at the optimum temperature for the bacteria.
Explain why this is important for enzyme function.

Answer 14

The active site is complementary to, substrate. Sufficient kinetic energy allows many enzymesubstrate complexes to form ; Optimum maximises enzyme enzyme activity. So that the active site does not change shape.

Question 15

Define adaption.

Answer 15

Process resulting from natural selection.
Populations become more and more better suited to their environment over many generations.

Question 16

Describe two visible adaptive features of an xerophyte. (they photosynthesis very slowly) (transpiration)

Answer 16

feature: leaves reduced to spines
explanation: reduced surface area for, transpiration / water loss or defence
against animals killing plant 

feature: more stomata on lower side/ fewer stomata
explanation: reduce transpiration

Question 17

Describe two visible adaptive features of an xerophyte in terms of trunks. (they photosynthesis very slowly)

Answer 17

feature : swollen trunk ;
explanation: store water ;

feature: corrugated trunk ;
explanation: increased shading reduces, evaporation / transpiration ;

Question 18

Describe and explain the death phase.

Answer 18

Limited nutrients and space. Increased competition for nutrients and space. High concentration of waste. Increase in temperature.

Question 19

What is pepsin secreted by and where is it secreted into?

Answer 19

stomach, found in gastric juices secreted by stomach walls, works at pH 2

Question 20

Where is trypsin secreted and where does it work?

Answer 20

secreted by pancreas and works in duodenum

Question 21

Optimum for trypsin and how?

Answer 21

Just above pH 7. Neutralised by alkaline substances in bile and pancreatic juice.

Question 22

What is the optimum temperature for digestive enzymes to work?

Answer 22

38

Question 23

Where does the bile duct and pancreatic duct carry the substances to?

Answer 23

duodenum

Question 24

What is the function of the cytoplasm?

Answer 24

where metabolic reactions take place

Question 25

Describe how a stigma from a wind‑pollinated plant is adapted for pollination.

Answer 25

long, feathery and hanging outside the flower

Question 26

Suggest why the rate of production of
molecules B and C from A decreases after molecule D is added.

Answer 26

Molecule D has a similar shape to Molecule A. This reduces A binding to the enzyme.

Question 27

State two changes that could cause an enzyme to denature.

Answer 27

increased temperature
extreme pH

Question 28

State two conditions needed for the germination of seeds.

Answer 28

water and oxygen
a suitable temperature

Question 29

Explain the benefits of growing wheat with increased pest resistance.

Answer 29

less pesticides used, higher yield of crop because less are damaged

Question 30

State the principal source of energy for this food web.

Answer 30

sunlight

Question 31

Describe the evidence showing that the mammal has a double circulatory system.

Answer 31

Blood passes through the heart twice in a single circuit around the body. There are two circuits: one from the heart to the lungs, one from the heart to the rest of the body. Has two sides.

Question 32

What enzymes are secreted in the pancreas?

Answer 32

amylase, trypsin, lipase

Question 33

Describe and explain the evidence shown that cystic fibrosis is caused by a
recessive allele.

Answer 33

The parents of the people with cystic fibrosis do not have cystic fibrosis, so they must be carriers.

Question 34

Explain how protein in the cattle manure is converted to the type of ions that plants can absorb.

Answer 34

Protein is broken down into amino acids by decomposers using protease enzymes. The amino acids undergo deamination, the nitrogen-containing part is removed, so ammonium ions are produced. Ammonium ions are converted to nitrate ions by nitrifying bacteria.

Question 35

Suggest the advantage to farmers of having snap bean plants that have a large number of root nodules.

Answer 35

farmers use less fertiliser

Question 36

Explain the benefits to other organisms on Mount Mulanje of conserving the Mulanje cedar
tree in its natural habitat.

Answer 36

• food source
• nutrient recycling
• resources for humans (make paper)

Question 37

process Q produces
haploid sperm and eggs

Answer 37

meiosis

Question 38

process T occurs so that
cell S can grow into an
embryo

Answer 38

mitosis

Question 39

process U occurs so that
the embryo can gain
oxygen and nutrients
from the mother’s blood

Answer 39

implantation

Question 40

State why it is important that sperm and egg cells are haploid and not diploid.

Answer 40

Maintenance of same number of chromosomes from generation to generation.

Question 41

Each different type of vaccine contains one or more ………………………………………..
taken from the ……………………………………….. that causes the disease.

Answer 41

Each different type of vaccine contains one or more …………antigens………………..
taken from the ………..pathogen……………. that causes the disease.