DNA sequencing

Question 1

Define genome

Answer 1

all genetic material an organism contains

Question 2

what is the aim of the human genome project

Answer 2

work out the sequence of all base pairs in human genome to identify all the genes to develop faster methods for sequencing DNA

Question 3

the human genome consists of ….. base pairs and …. genes

Answer 3

3 billion
20,000

Question 4

define proteome

Answer 4

all the proteins a cell can produce

Question 5

where can a proteome be derived from

Answer 5

genetic code if genome sequence is known
- only in simple organisms

Question 6

what is the purpose of DNA sequencing projects

Answer 6

read genomes of many organisms which allows DNA screening to identify medical problems

Question 7

what is the importance of identifying a proteome?

Answer 7

allows identification of antigens for use in vaccine production

Question 8

why can’t the proteome be derived from genetic sequences in more complex organisms?

Answer 8

non coding DNA and regulatory genes prevent the genome being easily translated into a proteome

Question 9

what is a terminator base?

Answer 9

modified versions of nucleotide bases that stop DNA synthesis when they are read

Question 10

summarise, in 6 stages, the process of DNA sequencing

Answer 10

• DNA polymerase, primer, excess nucleotides, terminator bases and DNA mixed together in a thermocycler
• DNA polymerase adds complementary bases to create new DNA
• terminators are added randomly to terminate DNA synthesis at different points on each replicating strand
• this continues until all DNA chains are produced with a terminator at each base
• terminators are labelled with different fluorescent colours to identify them
• DNA fragments are separated using gel electrophoresis according to length

Question 11

describe how the DNA sequence is worked out after DNA sequencing process

Answer 11

by fragment length and base colour

Question 12

what is high throughput sequencing?

Answer 12

processing and sequencing many DNA fragments simultaneously

Question 13

describe the first DNA sequencing?

Answer 13

• done by hand
• designed to read the base sequences of viral and bacterial DNA
• used radioactive markers and gel electrophoresis to separate sections of DNA

Question 14

what are the weaknesses of the first DNA sequencing techniques?

Answer 14

• time consuming
• only study small sections of DNA at a time