Unit 3 - Translation and Mutation

Question 1

Amino Acid and Polypeptide composition (2)

Answer 1

*All amino acids have a central carbon, an amino group, and a carboxyl group (COO)

*Enzymes in ribosomes catalyze peptide bonds (type of covailent bond) between the carboxyl group of one amino acid, and the amino group of the next = Polypeptides aka protiens

Question 2

Tranlation (3)

Answer 2

*Initiation: In initiation, the ribosome assembles around the mRNA to be read and the first tRNA (carrying the amino acid methionine, which matches the start codon, AUG).

*Elongation: mRNA expresses a single codon, which binds to a tRNA via an anticodon on the P site. The next tRNA brings it’s amino acid to the A site and binds to its respective codon. The Amino acid on P site binds to acid on A site, the newly unbound tRNA moves to E site and exits. The bound amino acids move the P site, and the process repeates!

NOTE to help with elongation, remember APE (like monke) and E for exit!

*Termithe ribosomation: stop codon in the mRNA (UAA, UAG, or UGA) enters the A site.
Stop codons are recognized by proteins called release factors, which fit neatly into the P site (though they aren’t tRNAs). Release factors make the ribosome add a water molecule to the last amino acid of the chain. This reaction separates the chain from the tRNA, and the newly made protein (polypeptide) is released.

Question 3

Codon

Answer 3

A sequence of 3 nucleotides that code an amino acid

Question 4

anit-codon

Answer 4

the inverse of a codon
UAG (codon) -> AUC (Anti-codon)

Question 5

Wobble codon

Answer 5

the 3rd nucleotide in a codon, much loser of a bind with tRNA than the frist 2, allows for differnet kinds of bonds

Question 6

tRNA

Answer 6

Transfer RNA, serves as an adapter between mRNA and the amino acid chain

Question 7

consensus sequence

Answer 7

most common neucleotide in a series of sequences
EX:
1. GATATTC
2. GCTTATC
3. ACTTATG

in coloumn 1 we have 2G’s and 1 A so the CS would be G for that coloum.

CS :GCTTATC

If you have an even amount of Pyrimidines (TCTC) or Purines (AGAG) then use Y for pYrimidines and R for puRines. If its an even amount of both use N for nucleotide!

Question 8

Start Codon

Answer 8

AUG (Methonine or M) is the start codon

Question 9

Stop codon

Answer 9

UAA, UAG, UGA. They do NOT code for an amino acid

Question 10

Open reading frame

Answer 10

The span of mRNA between the start and stop codons

Question 11

polyribosome

Answer 11

a group a multiple ribosomes tranlating a single mRNA strand

Question 12

Transition mutation

Answer 12

changing a purine to another purine (A->G) or a pyrimidine to another pyrimidine (T->C)

Question 13

Transversion mutation

Answer 13

changing a purine to a pyrimidine (A -> T) or vice versa (C ->G)

Question 14

Draw out slide 91 on lecture 2

Answer 14

just do it

Question 15

5’ and 3’ UTR

Answer 15

the up and downstream un-translated regions

Question 15

Polypeptide structure (4 levels)

Answer 15

Primary: Sequence of Amino acids in a chain, Stabelized by peptide bonds

Secondary: Alpha helixes and beta sheets. stabelized by hydrogen bonds in the backbone

Tertiary: 3D shape of polypeptide = multiple alpha helixes or beta sheets. Stabelized by interactions from R groups

Quaturnaty: Multiple tertiary subunits bound togeather by R groups and peptide bonds

Question 16

Silent Mutation

Answer 16

a mutation where there is no change to the organisms PHENOTYPE

Question 17

Neutral Mutation

Answer 17

A mutation where the resulting PHENOTYPE is neither good or bad for the organisms. IE not effected by natural selection

Question 18

Missense Mutation

Answer 18

Results in a differnet amino acid being created

Question 19

Nonsense mutation

Answer 19

a base-pair change that creates a stop codon in place of a codon specifying an amino acid

Question 20

Synomous mutation

Answer 20

a base-pair change that does not alter the resulting amino acid

Question 21

Frameshift mutation

Answer 21

insertion or deletion of nucleotide bases in numbers that are not multiples of three. Shifting the entire code

Question 22

Heritable Mutation

Answer 22

a Mutation that can be passed on to your child (Sex-linked)

Question 23

Non-heritable mutation

Answer 23

a mutation that cannot be passed on