The Human Genome

Question 1

What is the human genome?

Answer 1

Genome describes the total of all sequences of DNA in a cell
Human genome = nuclear DNA + mitochondrial DNA

Plant genome -same w chloroplast
bacterial - nuclear and plasmid

Question 2

How many base pairs and genes are there?

Answer 2

3 billion base pairs
25,000 genes
23 pairs of chromosomes (55-250 million bp long)

Question 3

Look at human genome diagram

Question 4

What is a gene?

Answer 4

A length of DNA that usually codes for the sequence of a specific protein
Composed of sequences called exons and introns

Question 5

What are exons?

Answer 5

CODING
Contains the DNA sequence for the protein product of the gene

Question 6

What are introns?

Answer 6

NONCODING
-Number can vary from 0 to greater than 50
-Usually larger than exon sequence
-Must be spliced out before the biological info can be used to synthesise a protein

Question 7

Do prokaryotes have exons and introns?

Answer 7

Prokaryotic genes don’t have exon and intron structure - dont need to be spliced

Question 8

What happens introns and exons in RNA?

Answer 8

All transcribed including introns in RNA but introns removed before translated into a protein

Question 9

What does alternative splicing result in?

Answer 9

Results in multiple proteins from a single gene
Most genes have alternative splicing - one gene can produce +- 3 proteins