Sac 1

Question 1

Define recombinant

Answer 1

DNA that has been formed artificially by combining components from different organisms

Question 2

Define transform

Answer 2

The process where a cell takes up foreign DNA and takes it up into its own plasmid or genome

Question 3

Define transgenic

Answer 3

An organism that contains genes from another species through genetic engineering

Question 4

Define Synthesis

Answer 4

The process of creating a complex compound substance from simpler materials (making something new from other parts)

Question 5

Define vector

Answer 5

A vehicle, such as a plasmid or virus, used to transfer genetic material into a cell

Question 6

What is the purpose of a coding strand in transcription?

Answer 6

Has the coded info to be sent out to a ribosome to be used to make a protein

Question 7

What is the purpose of a non-coding (template) strand of DNA in transcription?

Answer 7

RNA polymerase attaches to this strand to create mRNA.

Question 8

What is RNA polymerase?

Answer 8

An enzyme of quaternary structure that unwinds the DNA (unzips)

Question 9

What is a trinucleotide?

Answer 9

3 consecutive nucleotides

Question 10

Process of transcription: STEP 1

Answer 10

1. RNA polymerase enzymes run along the template strand in a 3’ to 5’ direction, unzipping the DNA

Question 11

Process of transcription: STEP 2

Answer 11

As the RNA polymerase runs along, it creates the mRNA copy of the template strand, which has the same code as the coding strand, built in a 5’ to 3’ direction

Question 12

Process of transcription: STEP 3

Answer 12

After the process is finished, the coding strand will join back on to the template strand, and a the strip of DNA is left as well as pre-mRNA

Question 13

What is pre-mRNA?

Answer 13

The primary transcript of RNA from transcription. Still has both exons and introns.

Question 14

Methyl

Answer 14

CH3

Question 15

What is a poly-A tail?

Answer 15

Series of adenine nucleotides attached to the 3’ end of mRNA

Question 16

Steps of RNA processing:

Answer 16

1. Introns (Irrelevant) get cut out and exons get joined together
2. Methyl cap gets added to 5’ end
3. Poly-A tail gets added to 3’ end

Question 17

Define codon

Answer 17

Sequence of 3 nucleotides in mRNA and coding strand of DNA

Question 18

Definitely anti-codon

Answer 18

Sequence of 3 unpaired nucleotides in tRNA

Question 19

Process of translation: STEP 1

Answer 19

mRNA leaves the nucleus, goes out into the cytoplasm and goes into a ribosome (AKA attaches to) 5’ end first

Question 20

Process of translation: STEP 3

Answer 20

Inside the ribosome, the anticodon of tRNA attaches to the specific corresponding codon of the mRNA

Question 21

Process of translation: STEP 2

Answer 21

The tRNA carries amino acids to the ribosome and each anticodon is specific to a type of amino acid

Question 22

Process of translation: STEP 4

Answer 22

Once the anticodons of the tRNA have attached to the mRNA, the attached amino acids form a peptide bond with each other

Question 23

What does universal mean?

Answer 23

The genetic code is the same in all organisms (AGTCU)

Question 24

Process of amino acid condensation polymerisation:

Answer 24

1. Hydroxyl group breaks off
2. Hydrogen breaks off
3. The two make water (H2O)
4. Residues form a peptide bond
5. Polypeptide breaks off

Question 25

Define degenerate

Answer 25

Most amino acids can be coded for by more than one codon

Question 26

Define unambiguous

Answer 26

Each codon specifies only one amino acid

Question 27

Define chaperone

Answer 27

A protein that assists the folding of a polypeptide into its tertiary structure

Question 28

Define methylation

Answer 28

Adding a methyl (CH3) group

Question 29

What is post-translational modification?

Answer 29

Once a polypeptide is synthesised it can be differentiated out

Question 30

Purpose of gene regulation

Answer 30

Some genes need to be switched off to save energy as protein synthesis is very energy expensive. Others may need to be turned off to allow the cell to differentiate for particular functions

Question 31

Tryptophan

Answer 31

The rarest of the 20 naturally occurring amino acids

Question 32

How does the trp operon work?

Answer 32

Tryptophan is very energy expensive to make so when there is enough in the cell, the tryptophan will attach to a repressor. This changes the repressors shape, making it complimentary to the operator. It attaches to the operator and stops the polymerase from producing any more tryptophan

Question 33

Polymerase enzymes

Answer 33

Enzymes that build a polymer by going along the template strand of DNA and synthesising the polymer of DNA in a 5’ to 3’ direction and amplify the synthesis of DNA

Question 34

Ligase

Answer 34

AKA molecular glue. Repairs the sugar-phosphate bond to create continuous strand of DNA

Question 35

Endonucleases

Answer 35

AKA molecular scissors. Breaks the sugar-phosphate bonds, either leaving sticky or blunt ends. Cut DNA at a specific sequence

Question 36

Restriction endonucleases

Answer 36

Cut a section of DNA with a specific palindromic repeat

Question 37

What are plasmids?

Answer 37

Vectors used to transport foreign DNA into bacterial cells. Small seperate DNA molecules that replicate independently and are used for genetic engineering

Question 38

Region of origin (ROI)

Answer 38

Section of DNA that works like a promoter region