1.3 - Gene Expression

Question 1

What proportion of genes in a cell are expressed?

Answer 1

a small number

Question 2

Gene expression involves what two main processes on DNA sequences?

Answer 2

Transcription and translation

Question 3

What types of RNA are involved in gene expression?

Answer 3

mRNA, tRNA, rRNA

Question 4

RNA contains what 3 distinct features from DNA?

Answer 4

single stranded, uracil instead of thymine, ribose sugar

Question 5

The m in mRNA stands for what?

Answer 5

messenger

Question 6

What is mRNA’s role in gene expression?

Answer 6

to carry a copy of the DNA code to from the nucleus to the ribosome

Question 7

What happens to mRNA in the nucleus?

Answer 7

it is transcribed from DNA

Question 8

What happens to mRNA in the ribosome?

Answer 8

it is translated into proteins

Question 9

Where are ribosomes located?

Answer 9

the cytoplasm

Question 10

What is a codon?

Answer 10

a triplet of bases on mRNA

Question 11

What does a codon do?

Answer 11

codes for a specific amino acid

Question 12

What does the t in tRNA stand for?

Answer 12

transfer

Question 13

What is special about tRNA’s structure and why is it this way?

Answer 13

it is folded due to complementary base pairing(hydrogen bonds)

Question 14

What is tRNA’s role in transcription?

Answer 14

to carry its specific amino acid to the ribosome

Question 15

What are the main features of tRNA?

Answer 15

anticodon, specific amino acid attachment site

Question 16

What does the r in rRNA stand for?

Answer 16

ribosomal

Question 17

What does rRNA do?

Answer 17

forms a ribosome along with proteins

Question 18

What does RNA polymerase do to DNA?

Answer 18

it moves along DNA, unwinding it and breaking the hydrogen bonds between bases

Question 19

What does RNA polymerase synthesise?

Answer 19

a primary transcript of mRNA

Question 20

How does RNA polymerase synthesise a primary transcript of mRNA?

Answer 20

using RNA nucleotides by complementary base pairing

Question 21

What process creates a mature transcript of mRNA?

Answer 21

RNA splicing

Question 22

What are introns and are they retained?

Answer 22

non-coding regions (for proteins) - no

Question 23

What are exons and are they retained?

Answer 23

coding region(for proteins) - yes

Question 24

What is notable about the order of retained exons?

Answer 24

it is unchanged

Question 25

What is the function of translation?

Answer 25

to “translate” a mature transcript of mRNA into a polypeptide

Question 26

How is translation commenced and ceased?

Answer 26

a start and stop codon

Question 27

How do codons and anticodons bond?

Answer 27

by complementary base pairing

Question 28

synonym of this: “mature mRNA transcript –> polypeptide”

Answer 28

genetic code –> sequence of amino acids/protein

Question 29

What links amino acids and what does this form?

Answer 29

peptide bonds - polypeptide/protein

Question 30

What is the fate of tRNA after translation?

Answer 30

leaves the ribosome to be reused

Question 31

What process means different proteins can be expressed from one gene?

Answer 31

alternative RNA splicing

Question 32

Different mature transcripts of mRNA are dependant on what?

Answer 32

which exons are retained

Question 33

What difference in structure is there between a polypeptide and a protein?

Answer 33

proteins are 3D shapes

Question 34

What holds proteins in their 3D shape?

Answer 34

hydrogen bonds and other interactions between individual amino acids

Question 35

A protein’s shape determines what?

Answer 35

its function

Question 36

What determines phenotype?

Answer 36

proteins produced from gene expression and environmental factors(influences)