Protein Synthesis

Question 1

what are the two main stages of protein synthesis?

Answer 1

the two main stages of protein synthesis are transcription and translation.

Question 2

what does protein synthesis start with?

Answer 2

protein synthesis starts with a gene.

Question 3

what is the central dogma of molecular biology?

Answer 3

the central dogma is DNA = RNA = Protein
DNA to RNA = Transcription
RNA to Protein =
Translation

Question 4

There is a flow of?

Answer 4

information in the cell from DNA to protein.

Question 5

what is the intermediate molecule?

Answer 5

the intermediate molecule is RNA

Question 6

what is the monomer of ribonucleic acid?

Answer 6

the monomer of rna is ribonucleotide

Question 7

what are the components of a ribonucleotide?

Answer 7

• nitrogenous base: a, u, c, g
• phosphate group
• sugar: ribose

Question 8

what are the differences between rna and dna?

Answer 8

rna is single stranded, dna is double stranded
rna contains uracil instead of thymine
rna contains ribose sugar instead of deoxyribose

Question 9

what are the 3 types of rna?

Answer 9

• messenger rna
• ribosomal rna
• transfer rna

Question 10

which one of the 3 types of rna carries the information to make an amino acid?

Answer 10

mrna

Question 11

what enzyme is responsible for making rna from dna?

Answer 11

the rna polymerase is responsible for making rna from dna

Question 12

what is transcription?

Answer 12

dna to rna
transcription is a process by which an rna molecule is synthesized from dna.

Question 13

how many strands of dna are used to make rna? and what is it called?

Answer 13

only one strand of dna is used to make rna. this strand is called the template strand.

Question 14

what happens in dna replication?

Answer 14

both strands act as a template for the synthesis of a new strand: semiconservative replication

Question 15

unlike dna replication, transcription is…?

Answer 15

unlike dna replication, transcription is asymmetric. only one strand of dna is used as a template for transcription.

Question 16

rna synthesis occurs in what direction?

Answer 16

rna synthesis occurs in 5’ to 3’ direction.

Question 17

therefore the start of a gene is at the?

Answer 17

3’ end of the template strand.

Question 18

rna polymerase uses the?

Answer 18

template strand to add in complementary bases.

Question 19

unlike dna polymerase, rna polymerase does not require the use of?

Answer 19

primer

Question 20

the synthesized rna molecule will be ___ to the template strand and ___ to the nontemplate strand (except for us replacing ts)

Answer 20

the synthesized rna molecule will be complementary to the template strand and identical to the non template strand.

Question 21

this is the sequence of nontemplate dna: 5’ GCTATAGGCC 3’. write the sequence of the template strand of dna. what is the sequence of mrna indicating the 5’ and 3’ ends.

Answer 21

template strand of dna:
3’ CGATATCCGG 5’
mrna strand:
5’ GCUAUAGGCC 3’

Question 22

what are the 4 stages of transcription?

Answer 22

1. binding of rna polymerase to dna
2. initiation
3. elongation
4. termination
   BIET

Question 23

first step is binding of rna polymerase to dna. how does rna polymerase know where the start of a gene is?

Answer 23

rna polymerase knows where the start of a gene is due to specific sequences along the dna that mark where the beginning of a gene is. these are alled promoters.

Question 24

once the rna polymerase has binded…?

Answer 24

transcription can be initiated

Question 25

whats the next step after rna polymerase has binded to the dna?

Answer 25

initiation: the rna polymerase unwinds the dna forming a transcription bubble. rna synthesis begins.

Question 26

whats the next step after initiation?

Answer 26

elongation: rna polymerase adds complementary nucleotides to the growing chain

Question 27

whats after elongation?

Answer 27

at a specific sequence, rna polymerase and the newly formed rna transcript detaches from the dna

Question 28

where does this process take place in prokaryotes vs eukaryotes?

Answer 28

in prokaryotes: transcription and translation occurs in the cytoplasm
in eukaryotes:
transcription occurs in the nucleus but translation occurs in the cytoplasm

Question 29

how is the information in mrna used to make the polypeptide?

Answer 29

• mrna carries the genetic code from dna
• the mrna is made up of codons. the codon is base triplets of mrna that code for each amino acid.
• one codon specifies one amino acid

Question 30

the genetic code is?

Answer 30

degenerate

Question 31

what does it mean by the genetic code is degenerate?

Answer 31

more than one codon can specify for a single amino acid. for example, there are 6 codons for serine.

Question 32

codon for guu, aug, cua?

Answer 32

valine, methionine, leucine

Question 33

how many nucleotides in length must a mrna be if it produces a polypeptide that is 100 amino acids long?

Answer 33

300 nucleotides

Question 34

if the 4 nucleotides acug were written in all possible triplet combinations, there would be a total of how many different codons?

Answer 34

64 possible codons

Question 35

of the 64 codons, only ___?

Answer 35

61 direct amino acids into polypeptides. the remaining 3 are stop codons which are useless and will terminate translation.

Question 36

the genetic code is?

Answer 36

• degenerate
• universal, all organisms use the same code.
• nonoverlapping: there is a single starting point with only one way in which the nucleotides are read this is called the reading frame.

Question 37

the codon that begins translation is

Answer 37

aug.

Question 38

what is the genetic code?

Answer 38

the genetic code is the way by which the nucleotides on the mrna are converted into amino acids in the polypeptide.

Question 39

below is a portion of a gene sequence on the template dna strand. what is the amino acid sequence?

Answer 39

3’ TACGTATCT 5’
rna: 5’ AUGCAUAGA
amino acid:
met, his, arg