DNA and Chromosomes I GCSE Biology I Primrose Kitten

DNA

The genetic code in the nucleus of cells

Chromosomes

Structures in the nucleus made of coiled DNA

Gene

Section of DNA containing the code for a protein

Cell

Basic structural and functional unit of all living organisms

Nucleus

Structure within a eukaryotic cell containing DNA

Fertilisation

Process of combining egg and sperm to form a new cell

Body chromosomes

22 pairs of chromosomes in humans, excluding sex chromosomes

Sex chromosomes

Chromosomes determining biological sex (XX or XY)

Allele

Different versions of a gene located at the same position on a chromosome

How many pairs of chromosomes does a human cell have?

23 pairs

How much DNA is inherited from each parent?

50% from each parent

What happens during fertilization in terms of chromosomes?

23 chromosomes from the egg and 23 from the sperm combine to form 46 chromosomes

What are different versions of genes called?

Alleles

How many chromosomes does a human cell have?

46

True or false, all organisms have 46 chromosomes.

False. Different species can have different numbers of chromosomes.

True or false, pairs of chromosomes are identical.

False, each chromosome in a pair carries the same types of genes but can have different alleles from each parent.

Which is largest? A cell or a nucleus

A cell, a nucleus fits inside a cell

Which is largest? A gene or a chromosome

A chromosome, a gene is a small section of a chromosome

Which is largest? A gene or DNA

DNA, a gene is a small section of the long DNA molecule

Which is largest? A chromosome or DNA

A chromosome, it is made up of DNA