Topic 3 - Alleles

Question 1

what are alleles?

Answer 1

Different versions of the same gene

Question 2

Name 2 examples of alleles

Answer 2

Eye colour - blue/green/brown
Hair colour - brown/blonde/black

Question 3

What’s the structure of homologous chromosomes?

Answer 3

• same length
• same centromere location
• can have different alles

Question 4

What’s the structure of sister chromatids?

Answer 4

• same alleles
• held together by centromere

Question 5

What’s the difference between sister chromatids and homologous chromosomes?

Answer 5

Sister chromatids are formed during DNA replication therefore are identical
Homologous chromosomes are paired up after fertilisation so one is from your mum and one from your dad