SPECIES?

HIERARCHY?

PHYLOGENETIC GROUP

DNA helicase is important in DNA replication. Explain why.

Explain how water enters xylem from the endodermis in the root and is then
transported to the leaves.

Abdominal pumping increases the efficiency of gas exchange between the tracheoles
and muscle tissue of the insect. Explain why.

Abdominal pumping is an adaptation not found in many small insects. These small
insects obtain sufficient oxygen by diffusion.
Explain how their small size enables gas exchange to be efficient without the need for
abdominal pumping.

An arteriole is described as an organ. Explain why

Explain why a lack of protein in the blood causes a build up of tissue fluid.

The fertility of cheetahs is low. The proportion of abnormal sperm cells produced is
higher in cheetahs than in other members of the family Felidae. Suggest an
explanation for this.

Using x to treat diseases caused by other species of bacteria could increase
the chance of the bacterium that causes tuberculosis becoming resistant to x.
Use your knowledge of gene transmission to explain how

Explain how a larger body size is an adaptation to a colder climate.

Describe how DNA is replicated.

Base pairing is important in DNA replication. Explain how

DNA polymerase is involved in DNA replication. Explain how

The chromosome number is halved during meiosis. Describe how.

It is important that gametes contain the haploid number of chromosomes.
Explain why.

Explain how an allele of a gene may produce a non-functional protein

The mass of DNA in cells from a tissue in which mitosis was occurring was measured.
Some cells were found to have 9.4 units of DNA and others 4.7 units.
Explain why these cells had different amounts of DNA.

Explain why the DNA base sequences of homologous chromosomes are almost the
same.

Explain the importance of meiosis in the life cycle of organisms that reproduce
sexually

Apart from increasing genetic variation, explain why meiosis is important in organisms
which reproduce sexually.

Many athletes eat food high in carbohydrate for three to four days before a race.
This is known as ‘glycogen loading’ and improves performance.
Suggest and explain one advantage of ‘glycogen loading’

Ions enter a root hair cell from the soil. Describe how

Describe and explain four ways in which the structure of a capillary adapts it for the
exchange of substances between blood and the surrounding tissue.

Describe and explain how tissue fluid is formed and how it is returned to the blood.

In dry conditions, the rate of transpiration is affected by an increase in temperature.
Describe and explain how.

In some diseases, lymph vessels in the legs may become blocked. Explain how this
leads to swelling of the tissues in the feet and ankles.

Give two differences between the structure of arteries and the
structure of veins.

Describe how water is taken up by root hairs and reaches the xylem in the root.

Use your knowledge of the cohesion-tension theory to explain how water in the xylem in the roots moves up the stem.

Describe and explain how water in the mesophyll cells passes out of the leaf.

Explain how xylem tissue is adapted for its function.