Glossary

Question 1

What is a gene?

Answer 1

A section of a chromosome that codes for a protein.

Question 2

What is an allele?

Answer 2

The different versions of the same gene.

E.g. brown eyes, blue eyes, green eyes

Question 3

Define chromosome

Answer 3

They are made of long lengths of DNA

Question 4

Define DNA

Answer 4

Carries genetic instructions that are used to make structural or functional proteins. It is made of repeating nucleotides.

Question 5

What are the three parts of a nucleotide?

Answer 5

Phosphate, 5C (Carbon) sugar, 1 of 4 bases (A - C - T - G)

Question 6

What is a mutation?

Answer 6

A random, permanent change to the DNA base sequence.
Considered to be “the ultimate source of variation.”
Can be helpful, harmful or neutral

Question 7

What is a genotype?

Answer 7

A set of genes in our DNA that is responsible for a particular trait/characteristic

Question 8

What is a phenotype?

Answer 8

A physical/observable characteristics of an organism.

Question 9

What is a gamete?

Answer 9

An organism’s reproductive cell.
Only carries one copy of each chromosomes.
Female gametes = ova/egg cell
Male gamete = sperm

Question 10

What is a zygote?

Answer 10

Form through the fertilisation of ova by the sperm.

Contains genetic information necessary to form a new individual

Question 11

Define dominant

Answer 11

A variant of a gene that masks or overrides the effect of a different variant of the same gene on the other copy of the chromosome

Question 12

Define recessive

Answer 12

A variant of the gene that is masked or overridden by the dominant gene

Question 13

Define homozygous

Answer 13

Two identical alleles

Question 14

Define heterozygous

Answer 14

Having two different alleles

Question 15

What is pure breeding?

Answer 15

When identical organisms that produce offspring of the same phenotype

Question 16

What is meiosis?

Answer 16

The process where gamete cells are made that are used for sexual reproduction.
Type of cell division that results in genetic variation

Question 17

How many daughter cells are produced in meiosis?

Answer 17

4 daughter cells from one parent cell.

Have half the number of chromosomes from the parent cell

Question 18

What is mitosis?

Answer 18

Process of cell division for growth and repair.

Question 19

How many daughter cells are produced in meiosis?

Answer 19

2 identical daughter cells from one parent cell

Question 20

Define crossing over

Answer 20

The exchange of genes between homologous chromosomes.

The mixture of parental characteristics in offspring

Question 21

Define independent assortment

Answer 21

The formation of random combinations of chromosomes.

The random order of homologous pairs line up on the spindle fibre

Question 22

What is a punnet square?

Answer 22

A square diagram used to predict the genotype of organisms

Question 23

What is test crossing?

Answer 23

Used by breeders to determine if the dominant phenotype has a genotype of homozygous dominant or heterozygous
e.g. Hh or HH

Question 24

What is a pedigree chart?

Answer 24

Looks at the genotype of past generations.

Used to determine whether traits are dominant or recessive