1.3

Question 1

what does gene expression involve

Answer 1

the transcription and translation of dna

Question 2

what is the first step of protein synthesis

Answer 2

transcription

Question 3

what is transcription

Answer 3

when the gene on the dna strand that codes for the protein is copied into a molecule of mRNA

Question 4

where does translation take place

Answer 4

at the ribosome

Question 5

what is the structure of RNA

Answer 5

• a ribose sugar
• a phosphate group
• a base (A, U, G or C)

Question 6

what types of RNA are involved in transcription and translation

Answer 6

• messenger RNA (mRNA)
• transfer RNA (tRNA)
• ribosomal RNA (rRNA)

Question 7

what does mRNA do

Answer 7

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

Question 8

what is each triplet of based called

Answer 8

a codon

Question 9

what does a codon do

Answer 9

it codes for a specific amino acid

Question 10

where is tRNA found

Answer 10

in the cytoplasm

Question 11

what is tRNA made of

Answer 11

single strand of RNA nucleotides

Question 12

what forms between the bases

Answer 12

weak hydrogen bonds

Question 13

what are the complimentary base pairs
(RNA)

Answer 13

uracil-adenine
guanine-cytosine

Question 14


what does a tRNA molecule fold to expose

Answer 14

a triplet of bases called an anticodon

Question 15

what does a trna molecule do

Answer 15

it carries its specific amino acid to the ribosome during translation

Question 16

why does trna fold

Answer 16

due to complimentary base pairing of a-u, g-c

Question 17

where is the site of protein synthesis

Answer 17

ribosome

Question 18

what is another name for protein synthesis

Answer 18

translation

Question 19

what are ribosome made up of

Answer 19

ribosomal rna (rrna) and proteins

Question 20

what is the ribosomes function

Answer 20

to bring trna molecules with amino acids into contact with mrna molecules during translation

Question 21

what is transcription

Answer 21

the synthesis of a mrna molecule from a section of dna by rna polymerase

Question 22

what are the steps of transcription

Answer 22

rna polymerase moves alone the dna, unwinds the strands and breaks the hydrogen bond

then it synthesises the primary mrna transcript using rna nucleotides by complimentary base pairing
(a-u, g-c)

Question 23

what comes first transcription or translation

Answer 23

transcription

Question 24

what does rna splicing do

Answer 24

it forms the mature mrna transcript

Question 25

what is the process of rna splicing

Answer 25

the introns of the primary transcript are removed and the exons are joined together to form the mature mrna transcript

Question 26

is the order of exons changed during splicing

Answer 26

no

Question 27

what is translation

Answer 27

the translation of mrna into a polypeptide (protein)

Question 28

where does translation take place

Answer 28

at a ribosome

Question 29

where does translation begin and end in the ribosome

Answer 29

it starts at a start codon and ends at a stop codon

Question 30

what are the steps of translation

Answer 30

trna anticodons bond to mrna codons by complimentary base pairing this translates the mrna genetic code into a sequence of amino acids each trna leaves the ribosome as the polypeptide is formed and free to pick up another ribosome

Question 31

how are amino acids held together

Answer 31

by peptide bonds

Question 32

what does alternative rna splicing result in

Answer 32

different proteins being expressed

Question 33

what does alternative rna splicing produce

Answer 33

it produces different mature mrna transcripts from the same primary transcript depending on which introns and exons are retained or removed

Question 34

what are proteins made up of

Answer 34

chains of amino acids

Question 35

how many amino acids are there

Answer 35

20

Question 36

what causes the length of a protein

Answer 36

the amount of amino acids in a chain

Question 37

how are amino acids linked

Answer 37

peptide bonds

Question 38

what do linked amino acids form

Answer 38

polypeptide chain

Question 39

what do polypeptides fold to form

Answer 39

the 3d shape of a protein

Question 40

how are proteins held together

Answer 40

by hydrogen bonds and other interactions between individual amino acids

Question 41

what does the shape of a protein determine

Answer 41

it’s function

Question 42

what is gel electrophoresis

Answer 42

the technique used to separate negatively charged protein molecules

Question 43

how does electrophoresis work

Answer 43

the proteins are subjected to an electrical current which forces proteins to move through a sheet of gel the smaller proteins move faster and further along the gel than the larger proteins

Question 44

what determines a cells phenotypes

Answer 44

the sequence of bases in its dna

Question 45

what does the sequence of bases determine

Answer 45

the order of proteins produced

Question 46

what is an other factors that influence phenotypes

Answer 46

environmental factors

Question 47

what are the steps of translation

Answer 47

trna anticodons bond to mrna codons by complimentary base pairing this translates the mrna genetic code into a sequence of amino acids each trna leaves the ribosome as the polypeptide is formed and free to pick up another ribosome

Question 48

how does electrophoresis work

Answer 48

the proteins are subiected to an electrical current which forces proteins to move through a sheet of gel the smaller proteins move faster and further along the gel than the larger proteins