Genomes

Question 1

How many base pairs are in the human genome?

Answer 1

3 million

Question 2

What is the only somatic cell that doesn’t have the same genes as the rest?

Answer 2

B lymphocyte

Question 3

Define transcriptome

Answer 3

Entire set of mRNA Hexpressed from the genes of an organism

Question 4

Define proteome

Answer 4

Entire set of proteins expressed by an organism

Question 5

What are housekeeping genes?

Answer 5

Genes that are expressed in all cell types

Question 6

How many pairs of autosomes do humans have?

Answer 6

22 pairs

Question 7

How many chromosomes does a human have?

Answer 7

46/ 23 pairs

Question 8

What is a telomere?

Answer 8

specialised nucleotide sequence at the end of a linear chromosome that is repeated

Question 9

What enzyme replenishes the telomere after each division?

Answer 9

Telomerase

Question 10

What does telomerase do?

Answer 10

Adds copies of the end sequence - dynamic equilibrium

Question 11

What is the point of a telomere?

Answer 11

They act as protective caps –> prevent chromosomes from being degraded during replication
Also prevents chromosomes from sticking to each other

Question 12

3 main structural components of a chromosome

Answer 12

Telomere, Centromere and origin of replication

Question 13

What is a centromere?

Answer 13

Specialised, repetitive DNA sequences to which the mitotic/meiotic spindle is attached during cell division. Allows chromosome segragation

Question 14

What do centromeres facilitate?

Answer 14

Chromosome attachment to the spindle via the kinetochore

Question 15

What is a kinetochore?

Answer 15

“Landing pad” for microtubules to attach to centromere

Question 16

What is an origin of replication?

Answer 16

Located within DNA molecules and creates 2 replications forks that move away from each other

Question 17

How many origins of replication are there?

Answer 17

Eukaryotic cells may have multiple origins of replication in order to replicate chromosomes quicker

Question 18

DNA replication in E. coli

Answer 18

Bidirectional replication
Initiator prettiness bind to specific DNA regions in the origin of replication
This wraps the DNA around the proteins to form a complex that destabilise the adjacent double helix
The complex attracts two DNA helices, each bound to a helices loader which keeps helices inactive
The DNA helicases are then properly loaded onto the replication fork and the loaders dissociate and helices unwinds the double helix
This exposes enough ssDNA for DNA primes to synthesise RNA primers…

Question 19

Where is the E. coli genome contained?

Answer 19

Contained in a single circular chromosomal DNA molecule

Question 20

Where is DNA replication regulated in E. coli?

Answer 20

At initiation stage

Question 21

How is DNA replication regulated in E. coli?

Answer 21

• Make sure there are sufficient nutrients for an entire round of replication
• Only one round of DNA replication occurs for each cell division…after replication, initiator protein deactivated by hydrolysis of bound ATP

Question 22

How is the initiator protein deactivated in DNA replication?

Answer 22

Hydrolysis of bound ATP

Question 23

Are genome sizes larger in more complex organisms?

Answer 23

Yes

Question 24

How does the number of introns and exons differ ion larger more complex organisms?

Answer 24

More introns but similar number of exons as smaller organisms