Mitosis

Plant diseases often reduce the rate of plant growth.

Meristem tissue is found at the tips of shoots and roots in plants.

Which process happens in meristem tissue?

Tick (✓) one box.

Fertilisation

Meiosis

Mitosis

Transpiration

Oranges are grown on farms.

Oranges grow on trees that can become infected with bacteria.

The bacteria enter the trees when an insect feeds on the leaves.

The tree responds to the infection by blocking phloem tissue.

Suggest one advantage to the infected tree of blocking phloem tissue.

Blocking phloem tissue causes oranges to contain a lower concentration of sugar than oranges from trees that are not infected.

Explain why.

Eventually, the blocked phloem tissue causes the tree to die.

Explain why blocked phloem tissue causes the tree to die.

Farmers want to reduce the spread of the bacteria between orange trees.

Explain one way farmers can reduce the spread of bacteria between orange trees.

Oranges can be made into fruit juice.

A student used the test for sugar to compare the concentration of sugar in five types of fruit juice.

The test for sugar produces a range of colours depending on the concentration of sugar present.

Figure 6 shows the colour chart for the test for sugar.

Describe a method the student could have used to compare the concentration of sugar in the different fruit juices.

The student’s results will not accurately show the concentration of sugar in juice from oranges.

Explain why.

Figure 7 shows an oak tree.

The binomial name of the oak tree is Quercus robur.

What is the genus name of the oak tree?

Tick (✓) one box.

Oak

Quercus

Robur

Other species of tree are in the same genus as Quercus robur.

What does it mean if two species of tree are in the same genus?

Tick (✓) one box.

The two species are always found in the same place.

The two species are closely related to each other.

The two species look exactly the same.

Oak trees grow at points where cells can divide.

Growth in oak trees happens at the tips of the branches.

Name the type of tissue at the tips of the branches.

Oak trees reproduce by sexual reproduction to produce seeds.

An acorn is a nut that contains a seed.

The seed may become a new oak tree.

Which process produces the cell that grows into the seed?

Tick (✓) one box.

Evolution

Fertilisation

Translocation

One type of insect lays eggs in acorns.

The insect eggs cause the acorn to grow abnormally.

The abnormal growth is called a gall.

Insect embryos grow inside the gall.

Figure 8 shows a normal acorn and an acorn that has grown a gall.

The gall is made from oak tree cells that have divided.

The cells of the gall contain two sets of chromosomes.

Which process produces the cells of the gall?

Tick (✓) one box.

Circulation

Digestion

Mitosis

The insects have changed over time and caused a gall to grow on acorns.

The gall increases the chance of survival of the insects inside the gall.

What name is given to the process of the insects changing over time?

Tick (✓) one box.

Clone production

Evolution

Inbreeding

The oak tree transports water and nutrients to the insect embryos inside the gall.

Water moves from the roots to the leaves.

Name the process that moves water from the roots to the leaves.

This question is about plant tissues.

Plant meristem tissue is found in the growing tips of shoots and roots.

Name two processes in plants that only occur in meristem tissue.

An acorn is a nut that contains the seed of an oak tree.

When one type of insect lays an egg in an acorn, the acorn grows abnormally.

The abnormal growth is called a gall.

An insect embryo grows inside the gall.

Figure 8 shows a normal acorn and an acorn that has grown a gall.

The seed in an acorn forms from one original cell with two sets of oak tree chromosomes.

The original cell in each seed was produced by sexual reproduction.

The gall has cells that contain two sets of oak tree chromosomes.

Compare the process that produced the original cell in each seed with the process that produced cells in the gall.

The insect embryo inside the acorn:

causes the growth of the gall

uses nutrients from the gall to grow

causes lignin to form around the outside of the gall.

The lignin around the gall protects the acorn from being eaten by herbivores.

Which other structure in the oak tree contains lignin?

Tick (✓) one box.

Phloem

Root hair cells

Xylem

Many years ago, a mutation of an insect embryo led to the embryo causing lignin production in an acorn.

Explain how the mutation could have produced a population of insects that all cause lignin production.

The genetic material in a cell is made of DNA.

A DNA molecule is made from two strands twisted around each other.

What scientific term describes the structure of DNA?

Cells divide in a series of stages called the cell cycle.

Figure 13 shows a cell cycle for a human cell.

What happens during the mitosis stage of the cell cycle?

Tick (✓) one box.

Chromosomes move to opposite ends of the cell.

Copies of the organelles are made.

The cell increases in size.

Before a cell divides by mitosis, the mass of DNA in the cell is 6 picograms.

What mass of DNA will be in each of the new cells at the end of cell division?

Tick (✓) one box.

3 picograms

6 picograms

12 picograms

One cell takes 16 hours to divide and form two new cells.

Estimate the total number of cells produced from one cell at the end of 48 hours.

Use the following steps.

Calculate the number of divisions in 48 hours

Calculate the number of cells after 48 hours

Give one factor that can cause a mutation in DNA.

Do not refer to ionising radiation in your answer.

A mutation in DNA may cause cells to become cancerous.

Figure 14 shows the change in the number of cancerous cells and non-cancerous cells during 6 days.

Describe three patterns shown in Figure 14.

Use data from Figure 14.

Predict the number of non-cancerous cells on day 7 if the pattern from day 4 continued.

You should extend the line for non-cancerous cells on the graph in Figure 14.

Number of cells = ____________________ thousand

Figure 10 shows a rock pool on a sea shore.

Rock pools are flooded twice a day with fresh sea water.

What is the community of the rock pool?

Tick (✓) one box.

The living organisms and abiotic factors in the rock pool

The number of different species in the rock pool

The number of predators and prey in the rock pool

The populations of all the species that live in the rock pool

Starfish are animals that live in rock pools.

A scientist investigated the effect that starfish had on the number of species in rock pools.

This is the method used.

1. Count the number of species in rock pool A and in rock pool B.

2. Regularly remove all the starfish from rock pool B.

3. Count the number of species in rock pool A and in rock pool B each year for 10 years.

Figure 11 shows the results.

Figure 12 shows a food web in the rock pools.

Starfish usually prefer to feed on mussels.

Mussels reproduce and grow more quickly than limpets, chitons, and barnacles.

After 10 years the only species left in rock pool B was mussels.

Explain the results shown in Figure 11 for rock pool B.

Use Figure 11 and Figure 12.

Explain the results shown in Figure 11 for rock pool A.

Some species of starfish can reproduce by cloning (asexual reproduction) and also by sexual reproduction.

Figure 13 shows what happens when starfish P reproduces by each type of reproduction.

During cloning a small piece of the starfish develops into a new starfish.

Before cell division, chromosomes replicate and the number of organelles increases.

Describe the stages in the process of cell division that produces offspring X.

Explain one advantage to the starfish of reproducing by cloning rather than reproducing by sexual reproduction.

Stem cells are found in human embryos and in meristem tissue.

Which organisms is meristem tissue found in?

Tick (✓) one box.

Animals

Bacteria

Plants

New cells are produced during the formation of an embryo.

Figure 14 shows how a human baby is formed.

Some people believe using embryonic stem cells in medical research is unethical.

Give one reason why.

Bone cells divide to repair damage.

Give one other reason why bone cells divide.

Scientists tested a new drug to treat tumours in mice.

All the mice had the same type of tumour.

This is the method used.

1. Inject six mice with the drug once a day for 24 days.

2. Measure the volume of the tumour every 4 days.

3. Repeat steps 1 and 2, injecting a new group of mice with the drug twice a day.

Figure 15 shows the results.

Six other mice were given an injection that did not contain the drug.

Why did the scientists use mice that were not given the drug?

Tick (✓) one box.

As a clinical trial

As a control

As an anomaly

Describe how the drug injected once a day and the drug injected twice a day affected the volume of the tumour.

Use data from Figure 15.

A plant shoot is made of several tissues.

What is a tissue?

Tick (✓) one box.

What is the name of the tissue at the growing tip of a plant shoot?

Tick (✓) one box.

Plant cells divide by mitosis so that the plant can grow.

Give one other reason plant cells divide by mitosis.

Do not refer to growth in your answer.

Figure 9 shows a cell cycle.

Which two processes happen during cell growth in the cell cycle?

Tick (✓) two boxes.

In mitosis and meiosis cells divide to produce new cells.

Cell division by meiosis produces gametes.

Figure 10 shows a cell dividing by mitosis and a different cell dividing by meiosis.

Describe how the cells produced by mitosis are different from the cells produced by meiosis.

Use information from Figure 10.

A scientist investigated cell division in the growing tip of a plant shoot.

The scientist recorded data at different distances from the tip of the shoot.

Table 6 shows the results.

Give two conclusions from the data in Table 6.

Bananas from wild banana plants are not eaten by humans.

Edible banana plants are grown commercially.

Humans can eat bananas from edible banana plants because they do not contain seeds.

The edible banana plant evolved from the wild banana plant.

Figure 12 shows how scientists think the edible banana plant may have evolved.

What is process X in Figure 12 ?

Tick (✓) one box.

Explain why the edible banana plant cannot produce gametes.

Cloning is used to reproduce edible banana plants.

The cloned cells divide by mitosis.

Describe the process of mitosis.

Banana plants can become infected by the TR4 fungus.

The fungus enters the plant through the roots and grows within the xylem vessels.

The xylem vessels become blocked and the leaves turn yellow.

Describe why blockage of the xylem vessels causes the leaves to turn yellow.

TR4 fungus is a threat to the global banana industry.

Some wild banana plants have a gene for resistance to the TR4 fungus.

What could scientists do to protect edible banana plants from the TR4 fungus?

Tick (✓) one box.