Passing of genes

Question 1

What does DNA look like?

Answer 1

DNA is a spiral chain-like molecule

Question 2

What is a gene?

Answer 2

A long stretch of DNA with a specific sequence of GACTs that code for proteins

Question 3

Why do individuals have different traits?

Answer 3

because of differences or mutations in genetic code which cause changes in proteins (and hence function) or when and how much of a protein is produced

Question 4

What are chromosomes?

Answer 4

A chromosome is an entire chain of DNA (with stabilising proteins)

Question 5

Describe in more detail the structure of a chromosome

Answer 5

Chromosomes are made out of threads called chromatin fibre

(a bit like a yarn of wool)

The ‘fibres’ of the thread are called histones that wrap up the DNA providing the visible structure of the chromosome

Normally, the chromosomes float in the nucleus like spaghetti or loose wool to keep the analogy going

Only in cell production do chromosomes take on the packed X shape we know and love

Question 6

How many chromosomes does a human possess?

Answer 6

23 pairs = 46 in total