The Human Genome

Question 1

What is the human genome

Answer 1

The total of all sequences of DNA in a cell

Question 2

Where is the DNA that makes up the human genome

Answer 2

• Nuclear DNA
• Mitochondrial DNA

Question 3

How many genes in the human genome

Answer 3

25,000

Question 4

How many base pairs in the human genome

Answer 4

3 billion

Question 5

What is the nuclear genome made of (2)

Answer 5

1. Genes & gene related DNA - 25%
2. Extragenic DNA - 75%

Question 6

2 subdivisions of extragenic DNA

Answer 6

1. Unique low copy number DNA - 60%
2. Repetitive DNA - 40%

Question 7

2 subdivisions of repetitive DNA

Answer 7

1. Interspersed repeats
2. Tandem repeats (same sequence one after the other)

Question 8

3 further subdivisions of non coding DNA

Answer 8

1. Pseudogenes (genes now redundant to evolution)
2. Gene fragments
3. Introns, untranslated sequences etc.. (removed from genes before expression)

Question 9

What is a gene

Answer 9

A length of DNA that usually codes for the sequence of a specified protein

Question 10

What do exons contain

Answer 10

Contain the DNA sequence for the protein product of the gene

Question 11

What must be done to introns

Answer 11

They must be spliced out before the biological info can be used to synthesise a protein.
So exons can be connected & the info can be expressed.

Question 12

Which are larger; exons or introns

Answer 12

Introns are usually larger than the exon sequences

Question 13

What is done to get rid of introns

Answer 13

RNA splicing

Question 14

What does alternative splicing result in

Answer 14

Results in multiple proteins from a single gene

Question 15

Pro of alternative splicing

Answer 15

Protein diversity

Question 16

Does alternative splicing clip out some exons also

Answer 16

Yes