protein synthesis

Question 1

what is a gene

Answer 1

the base sequene of DNA that codes for the amino acid sequence of a polyppetide, a functional RNA.

Question 2

how does RNA differ from DNA

Answer 2

RNA has a U base instead of T base

Question 3

what are the 3 types of RNA

Answer 3

-messenger RNA. transfer RNA. ribosomal RNA.

Question 4

what is a codon

Answer 4

3 adjacent bases on the MRNA

Question 5

what is mRNA

Answer 5

a single polynucleotide strand. mRNA carries the genetic code from the DNA in the nucleus to the cytoplasm/ribosomes, where its used to make a protein during translation.

Question 6

what is tRNA structure

Answer 6

a single polynucleotide strand thats folded into a clover shape. has an anticodon at one end, and amino acid binding site at the other end

Question 7

how is tRNA held in a clover shape

Answer 7

hydrogen bonds between specific base pairs hold the molecule in this shape

Question 8

where do u find codons

Answer 8

in mRNA

Question 9

where do u find anti codon

Answer 9

in tRNA

Question 10

where is mRNA made

Answer 10

the nucleus, during transcription

Question 11

where is tRNA found

Answer 11

the cytoplasm

Question 12

what is tRNA for

Answer 12

carries the amino acids that are used to make proteins to the ribosomes

Question 13

what is special between anticodons on tRNA and codons on mRNA

Answer 13

they are complimentary to one another

Question 14

what is rRNA

Answer 14

it forms the 2 subunits in a ribosome, along w proteins

Question 15

what does rRNA do

Answer 15

the ribosome moves along the rRNA strand during protein synthesis. the rRNA in the ribosomes helps to catalyse the formation of peptide bonds between the amino acids

Question 16

what is the genetic code

Answer 16

the triplet code - ecah amino acid is coded for by a sequence of 3 bases

Question 17

where are proteins made

Answer 17

ribosomes

Question 18

what are the 2 stages of protein synthesis

Answer 18

transcription + translation

Question 19

what does DNA code for

Answer 19

proteins

Question 20

Why does DNA convert to MRNA

Answer 20

DNA (codes for proteins) is too big to leave the nucleus so cannot travel to ribosomes

Question 21

What is the process of DNA turning to MRNA called

Answer 21

Transcription

Question 22

Where does transcription occur

Answer 22

Nucleus

Question 23

What are the 5 steps of transcription

Answer 23

1 - DNA helicase attaches to DNA at the beginning of a gene
2 - This causes unwinding of DNA helix and breaking of H bonds between the two DNA strands
3 - The template strand is used to make an MRNA copy of the DNA. U REPLACES T
4 - Free MRNA nucleotides line up by complementary base pairing next to exposed DNA bases on the template strand
5 - RNA polymerase joins the sugar phosphate backbone of the new MRNA molecule being made.
(after becoming functional the functional mrna leaves the nucleus + travels to a ribosome)

Question 24

What are the two separated strands called

Answer 24

coding strand and template strand

Question 25

What are introns

Answer 25

Non coding DNA

Question 26

What is pre MRNA and why is is not functional huh

Answer 26

introns are located in the MRNA duh isis. introns make it unfuctional

Question 26

Whar are exons penchodah

Answer 26

Coding DNA

Question 27

HOW do u make functional MRNA

Answer 27

INTRONS ARE CUT OUT OF THE MRNA BEFORE IT LEAVES THE NUCLEUS. THE MRNA IS ALSO CAPPED BEFORE IT LEAVES TO PREVENT IT FROM BEING DAMAGED IN THE CYTOPLASM

Question 28

when does translation happen

Answer 28

once the mrna leaves the nucleus and attaches to a ribosome (or on the RER)

Question 29

what are the 9 steps for translation

Answer 29

1 - the genetic code on the MRNA will be used to assemble a corresponding chain of amino acids
2 - the MRNA attaches to a ribosome (free or on RER), every group of 3 bases on the mrna is called a codon
3 - trna molecule contain triplets of bases at one end called anticodons. these line up next to the codons on the MRNA by complementary base pairing
4 - the other end of the TRNA molecule has a specific amino acid attached
5 - the ribosome can hold 2 TRNA molecules in position at the same tie allowing their amino acids to join by a peptide bond
6 - the first TRNA molecule now leaves the ribosome, leaving its amino acid behind, and another TRNA arrives with its amino acid
7 - the ribosome moves along so that the next 2 TRNA molecules are in position allowing their amino acids to join then the 2nd TRNA molecule moves away and so the process continues
8 - this happens untila stop codon on the MRNA is reached, signaling the polypeptide is now complete
9 - the polypeptide is then released into the cytoplasm, this is the primary protein structure, and is then built up further into a complete functioning protein.

Question 30

how can lots of the same polypeptide be made

Answer 30

if several ribosomes move along the same piece of MRNA at once

Question 31

what does a degenerate code mean

Question 32

code is non overlapping what does this mean

Answer 32

it means base triplets do not share their bases, each triplet is different from the next (GUC/UCA).

Question 33

with the bases G U C, what orders would make them overlappin

Answer 33

GUC/UCU/CUC

Question 34

code is universal, what does that mean

Question 35

what are the 3 natures of the genetic code

Answer 35

degenerate, non overlapping, universal

Question 36

what is splicing

Answer 36

removing introns

Question 37

spliced pre MRNA =?

Answer 37

mrna