RNA translation and transcription

Question 1

What are genes?

Answer 1

Sections of DNA within the nucleus of cells

Question 2

What do genes contain?

Answer 2

The specific instructions for the sequence of amino acids required to make a protein

Question 3

Where does protein synthesis take place?

Answer 3

Cytoplasm

Question 4

What is the name of the process to go from DNA to mRNA?

Answer 4

Transcription

Question 5

What is the name of the process to go from mRNA to a protein?

Answer 5

Translation

Question 6

What is mRNA?

Answer 6

Messenger RNA

Question 7

What does the base sequence of mRNA reflect?

Answer 7

The DNA sequence

Question 8

What is mRNA complimentary to?

Answer 8

The DNA template

Question 9

Does mRNA vary in length?

Answer 9

Yes

Depending on the gene

Question 10

Which enzyme synthesises RNA?

Answer 10

RNA polymerase

Question 11

What are the three things RNA polymerase needs?

Answer 11

A template
Activated precursors
A metal

Question 12

What template does RNA polymerase prefer?

Answer 12

Double stranded DNA

Question 13

What are the activated precursors that RNA polymerase needs?

Answer 13

All 4 ribonucleoside triphosphates

ATP, GTP, UTP, CTP

Question 14

Which metal does RNA polymerase need?

Answer 14

Mn2+ or Mg2+

Question 15

Does RNA polymerase require a primer?

Answer 15

No

Question 16

What are promoter sites?

Answer 16

DNA templates contain promoter sites that bind to RNA polymerase and position it in the correct place to start synthesis

Question 17

Where are the promoter sites found?

Answer 17

5’ side of the DNA

Question 18

Where are the two promoter sites in humans found?

Answer 18

CAAT box

TATA box

Question 19

Where is the CAAT box?

Answer 19

75 bases up

Question 20

Where is the TATA box?

Answer 20

25 bases up

Question 21

What is an exon?

Answer 21

The region of DNA which codes for a protein

Question 22

What is a codon?

Answer 22

Three coding bases

Question 23

What does degenerate?

Answer 23

Some amino acids are coded for by more than one codon

Question 24

What is the start codon?

Answer 24

Met

Question 25

What are the stop codons?

Answer 25

UAA UAG UGA

Question 26

What does a ribosome do?

Answer 26

Makes the proteins

Question 27

Generally how does the ribosome make the protein?

Answer 27

Uses the instructions from the mRNA to build a new protein

Question 28

What is tRNA?

Answer 28

Transfer RNA

Question 29

What is the function of tRNA?

Answer 29

Carry an activated Amino acid to the ribosome to add it to the chain

Question 30

How many tRNA units can one ribosome hold? Why?

Answer 30

2 | Allows the peptide bond to form between them

Question 31

In translation, what is the leaving group?

Answer 31

tRNA

Question 32

In translation, how does the peptide bond form?

Answer 32

Nucleophilic attack of the A site amino acid NH2 of the P site of the carboxyl group

Question 33

How many nucleotides long is tRNA?

Answer 33

73-93

Question 34

Is tRNA single stranded or double stranded?

Answer 34

Single stranded in the shape of a clover

Question 35

Which end of tRNA is usually phosphorylated?

Answer 35

5'

Question 36

What is the base sequence at the end of a tRNA molecule?

Answer 36

CCA

Question 37

How is the activated amino acid attached to the tRNA?

Answer 37

Using an ester group to the 3'OH of the ribose unit

Question 38

How is the clover shape of tRNA caused?

Answer 38

It hybridises to itself

Question 39

What is tRNA recycled by?

Answer 39

A group of enzymes that recognise the specific tRNA and add a new amino acid unit called tRNA synthetases

Question 40

How many different types of tRNA syntheses are there?

Answer 40

There is one for each amino acids

Question 41

Are reactions involving tRNA synthetases specific?

Answer 41

yes | Highly specific reactions

Question 42

Why are reactions involving tRNA synthetases highly specific?

Answer 42

The enzyme must be able to recognise the matching tRNA and the incoming amino acid which may only differ by a CH2 group

Question 43

What are the features for unfolding of proteins?

Answer 43

Conformational entropy means there is more disorder | There is hydrogen bonding to water

Question 44

How much energy per mole is there in unfolding proteins?

Answer 44

+190 kCal/mole

Question 45

What are the features of folding proteins?

Answer 45

Hydrophobic collapse is favoured Intramolecular hydrogen bonding Van der Waals interactions

Question 46

How much energy per mole is there in folding proteins?

Answer 46

-200 kCal/mole

Question 47

Do proteins fold randomly?

Answer 47

No they don't fold randomly

Question 48

How many stages does protein folding occur in?

Answer 48

2

Question 49

What are the stages of protein folding?

Answer 49

1) hydrophobic collapse to a molten globule | 2) Progressive stabilisation of secondary and tertiary structure

Question 50

What does secondary structure formation depend on?

Answer 50

The surroundings

Question 51

What do secondary structures formed in the molten globule interact with?

Answer 51

Other nearby structures

Question 52

When secondary structures interact with other nearby structures, how does this affect the structure?

Answer 52

It can either stabilise or destabilise