3.8 Using genome projects and recombinant DNA technology

Question 1

What is a proteome ?

Answer 1

The complete set of proteins expressed by an organism

Question 2

What is the function of regulatory genes ?

Answer 2

• They encode transcription factors and other proteins that interact with the genome
• They are very important in controlling cell processes and ensuring the correct cells are doing the correct function

Question 3

What is the genome ?

Answer 3

The complete set of genes present in an organism

Question 4

Why is DNA a universal code ?

Answer 4

As every organism uses the same four bases as the code to produce proteins

Question 5

What is the job of reverse transcriptase ?

Answer 5

It catalyses the formation of a double strand of DNA from a single strand on RNA

Question 6

Why are sticky ends important ?

Answer 6

As if the same restriction endonuclease is used to cut the two DNA fragments then the ends will be complementary

Question 7

What is the DNA produced from reverse transcriptase called ?

Answer 7

Complementary DNA (cDNA)

Question 8

What is a palindromic base pair ?

Answer 8

They have sequence of base pairs that are the same but in the opposite direction

Question 9

Which enzyme attaches the sticky ends of DNA fragments and vector DNA together?

Answer 9

DNA Ligase

Question 10

What is the job of a vector ?

Answer 10

Transfers the recombinant DNA to the host cells

Question 11

Outline the process of PCR

Answer 11

1- DNA fragments, primers, DNA polymerase and free floating nucleotides are added to the reaction mixture
2- Heated to 95 degrees
3- Cool to 65 degrees
4- Heat to 72 degrees
5- Repeat

Question 12

Why is the PCR cooled to 65 degrees ?

Answer 12

To allow the primers to anneal to the separate strands of DNA

Question 13

Why is the PCR heated to 95 degrees ?

Answer 13

In order to break hydrogen bonds between DNA strands

Question 14

Why is the PCR heated to 72 degrees ?

Answer 14

This is the optimum temp for DNA polymerase activity to create complementary strands using DNA nucleotides

Question 15

The number of DNA fragments is _____ in each cycle of PCR

Answer 15

Doubled

Question 16

What type of amplification is performed inside the organism?

Answer 16

In Vivo

Question 17

What are some uses of recombinant DNA ?

Answer 17

• GM crops
• GM livestock
• Increased nutritional value of food
• Treating diseases
• In the industry for manufacturing enzymes

Question 18

What is gene therapy ?

Answer 18

A technique used to cure disease

Question 19

What is involved in gene therapy ?

Answer 19

It involves the introduction of a target gene (the gene that confers a beneficial trait) into the genome

Question 20

What is a DNA probe ?

Answer 20

A section of single stranded DNA that is complementary to the DNA of the target allele

Question 21

What is electrophoresis ?

Answer 21

A technique that separates fragments of DNA according to size

Question 22

What are VNTR’s ?

Answer 22

Sections of DNA that do not code for any proteins called variable number tandem repeats. VNTRs are used in genetic fingerprinting

Question 23

What is gel electrophoresis ?

Answer 23

The technique used to compare the genetic fingerprints of individuals

Question 24

Outline the process of gel electrophoresis

Answer 24

1- DNA sample is extracted from human and amplified in a PCR machine
2- DNA fragments are labelled using fluorescent markers
3- DNA fragments are inserted at negative end of the gel
4- Electrical current is passed though gel and DNA moves towards positive electrode
5- DNA can be identified by exposing gel to UV light

Question 25

Is DNA negatively or positively charged ?

Answer 25

Negatively charged so will travel away from negative electrode in gel electrophoresis