Meiosis

Figure 12 shows some characteristics of pea plants.

The allele for purple flowers is dominant to the allele for white flowers.

Which term describes the allele for white flowers?

A scientist crossed a pea plant that produced round seeds (Rr) with a pea plant that produced wrinkled seeds (rr).

Complete the Punnett square.

State the percentage of the offspring that will produce round seeds.

The scientist crossed two purple flowering pea plants.

The offspring were:

• 133 plants with purple flowers

• 46 plants with white flowers

Calculate the ratio of offspring with purple flowers to offspring with white flowers.

Give your answer to the nearest whole number.

Explain why it was possible for this cross to produce some offspring with white flowers.

The cells in pea plants are diploid.

These cells have 14 chromosomes.

Explain why pea plant gametes have only seven chromosomes.

Describe what happens at fertilisation.

Figure 12 shows a height percentile chart for boys.

The numbers on the right-hand side of the graph show the percentiles of the population for each growth curve.

A 10-year-old boy has a height of 140 cm.

Which is the percentile range for height for this boy?

State how percentile charts are used.

As we grow, we make new cells by mitosis and meiosis.

The cells that are made can become specialised.

Figure 13 shows a diagram of a sperm cell.

Describe two ways that the sperm cell is specialised.

Complete the table to show the results when a cell divides by mitosis or meiosis in humans.

Human body cells, except gametes, have 23 pairs of chromosomes.

The tips of plant roots are where many cells are dividing by mitosis.

Which term describes the area of a root where many cells are dividing by mitosis?

Plant root cells contain an enzyme that joins glucose molecules together to make starch.

Devise a plan to investigate the effect of pH on the activity of this enzyme.

Gregor Mendel studied inheritance in pea plants.

Pea plants can produce either yellow pea pods or green pea pods.

Mendel crossed plants that always produce yellow pea pods with plants that always produce green pea pods.

Symbol A represents the dominant allele.

Symbol a represents the recessive allele.

Which is the genotype of the pea pods produced from this cross?

Mendel grew many plants from the seeds in these pea pods.

These plants were then crossed with each other.

The seeds from this second cross produced 5 496 plants with yellow pea pods and 1 832 plants with green pea pods.

Give this as a ratio in its simplest form.

Complete the Punnett square to show the outcome of a cross where both parent pea plants are heterozygous.

Show the percentage probability of homozygous recessive offspring in your answer.

percentage probability of homozygous recessive offspring_........

Some plants reproduce sexually.

Give one advantage of this type of reproduction.

Name the process that forms gametes for sexual reproduction.

Farmers selectively breed chickens to produce larger chickens.

Figure 9 shows how the size of chickens has changed over time.

Explain how farmers have used selective breeding to produce larger chickens.

Describe one benefit and one risk of selectively breeding chickens.

The body cells of chickens have 78 chromosomes in their nuclei.

State the number of chromosomes found in each sex cell of a chicken.

Name the type of cell division which produces sex cells.

What is the correct definition of a genome?

A new project called the Earth BioGenome Project aims to discover the sequence of bases in the DNA for all plants and animals.

State two benefits of discovering the sequence of bases for all plants and animals.

A karyogram is a picture of the chromosomes found in the nucleus of a single cell.

Figure 8 shows a human karyogram.

State two reasons why this karyogram cannot be from a gamete (sex cell).

State the gender shown by this karyogram.

Complete the Punnett square to show how gender is inherited.

State the probability that a child will be male.

Figure 9 shows two sperm cells.

Name structure Z.

Sperm B has a larger middle section than sperm A.

Explain why sperm B will be more likely to fertilise an egg than sperm A if they were both released at the same time.

James Watson and Francis Crick built a model that showed that DNA has a double helix structure.

Which statement about DNA is correct?

Figure 13 shows the percentage of each base in human DNA.

Describe how this data provides evidence for base pairing in DNA.

A scientist obtained a mass of 0.0062 nanograms of DNA from a diploid human cell.

Calculate the mass of DNA the scientist should obtain from a haploid human cell.

Give your answer in picograms.

(1 nanogram = 1000 picograms)

A student used the method shown in Figure 14 to compare the mass of DNA extracted from strawberry fruit cells and from kiwi fruit cells.

State why ethanol is used.

State two variables the student needs to control when using this method to compare the mass of DNA from these two fruits.

The student repeated the experiment.

Give one reason why.

Mitosis and meiosis are processes that produce new cells.

Compare the outcomes of mitosis and meiosis.

A scientist obtained a mass of 0.0062 nanograms of DNA from a diploid human cell.

Calculate the mass of DNA the scientist should obtain from a haploid human cell.

Give your answer in picograms.

(1 nanogram = 1000 picograms)

A student used the method shown in Figure 3 to compare the mass of DNA extracted from strawberry fruit cells and from kiwi fruit cells.

crush the fruit cells in a buffer solution

filter to separate the soluble DNA from the cell fragments

State why ethanol is used.

State two variables the student needs to control when using this method to compare the mass of DNA from these two fruits.

The student repeated the experiment.

Give one reason why.

Mitosis and meiosis are processes that produce new cells.

Compare the outcomes of mitosis and meiosis.