Year 10 Exam - March 6th

Question 1

Define a ‘phenotype’.

Answer 1

The physical feature, trait or characteristic of a living thing

Question 2

Define a ‘genotype’.

Answer 2

The genetic code of a living thing, e.g. BB, Bb or bb

Question 3

What is mitosis?

Answer 3

Cell reproduction/copying for growth and repair

Question 4

What is meiosis?

Answer 4

A type of cell division that takes place for sexual reproduction

Question 5

What is the difference between ‘homozygous’ and ‘heterozygous’?

Answer 5

Homozygous is a genotype in which alleles are the same, whereas heterozygous is a genotype in which alleles are different

Question 6

What are genes?

Answer 6

Genes are a part of the DNA that codes for heritable characteristics

Question 7

What are alleles?

Answer 7

Alleles are different versions of the same gene. For example, alleles for eye colour may be green, blue, brown etc.

Question 8

Define a ‘dominant gene’.

Answer 8

A dominant gene is a version of a gene that is expressed even when only one copy is present - the “stronger gene”.

Question 9

Define a ‘recessive gene’.

Answer 9

A recessive gene is a version of a gene that is only expressed when two copies are present - both parents have to carry the gene in order for it to express itself in offspring.

Question 10

Name 3 traits in humans that are mainly or totally controlled by genes.

Answer 10

Possible answers: eyes, hair colour, hair type, skin colour etc

Question 11

What is a chromosome?

Answer 11

Chromosomes are the storers of all genetic information.

Question 12

Define ‘asexual reproduction’.

Answer 12

Asexual reproduction is another name for mitosis. It is the reproduction of cells so that our bodies can grow and heal. It is called asexual reproduction because two seperate organisms are not needed to reproduce these cells.

Question 13

What is the difference between asexual reproduction and sexual reproduction?

Answer 13

Asexual reproduction takes place within a single organism, whereas sexual reproduction needs two organisms in order to reproduce.

Question 14

Where are chromosomes found in a cell?

Answer 14

Chromosomes are found in the nucleus of a cell.

Question 15

How many chromosomes are in human cells?

Answer 15

In human cells, there are 23 pairs of chromosomes - 46 in total.

Question 16

What are base pairs in DNA?

Answer 16

Base pairs are two molecules that pair together to form a ‘rung’ on the DNA ladder.

Question 17

In sexual reproduction, why do chromosomes have matching pairs?

Answer 17

Chromosomes have matching pairs because each pair contains one chromosome from each parent. During sexual reproduction, an offspring is given an equal amount of chromosomes (23) from each parent, to form a total of 46.

Question 18

What does PMAT stand for?

Answer 18

PMAT stands for Prophase, Metaphase, Anaphase and Telophase.

Question 19

What happens during Interphase?

Answer 19

During Interphase, a cell will grow, replicate its chromosomes, and prepare for cell division.

Question 20

What are gametes?

Answer 20

Gametes are sex cells. (eggs and sperm)

Question 21

Why are chromosomes halved during meiosis?

Answer 21

Chromosomes from the male and female are halved during meiosis so that the offspring gets a total number of 46 chromosomes, which is the number of chromosomes humans need in order to have no complications.