Molecular biochemistry W5

Question 1

Give an example of a start codons

Answer 1

AUG

Question 2

Guve 3 examples of stop codons

Answer 2

• UAA, UAG, UGA

Question 3

Explain codon redundancy

Answer 3

• First 2 bases of a codon are the same, the 3rd can very

Question 4

Name 2 amino acids

Answer 4

Proteinogenic amino acids
Non-proteinogenic amino acids

Question 5

What is the function of proteinogenic amino acids

Answer 5

• Used to build proteins

Question 6

What is the function of non- proteinogenic amino acids

Answer 6

-Have other roles

Question 7

Where is essential amino acids obtained from

Answer 7

Diet

Question 8

What happens to nonessential amino acids

Answer 8

• Body can synthesize them

Question 9

Where are conditionaly essential amino acids obtained from

Answer 9

The diet under certain conditions

Question 10

Name 2 types of mRNA

Answer 10

• monocistronic mRNA
  -polyscistronic mRNA

Question 11

What is the function of monocistronic mRNA/ what does it code for

Answer 11

Codes for one protein

Question 12

What does polycistronic mRNA code for

Answer 12

Multiple proteins

Question 13

What is ribosome made up of

Answer 13

2/3 RNA and 1/3 protein

Question 14

What is Ribsome composed of

Answer 14

• Large and small subunits assembled in the nucleolus

Question 15

Where are the subunits exported to and why

Answer 15

Exported to cytoplasm, where they combine on an mRNA to begin protein synthesis

Question 16

What does tRNA act as

Answer 16

Adaptors, linking codons(mRNA) to amino acids

Question 17

What does each tRNA have

Answer 17

Anticodon which carriesa
specific amino acid at is 3 end

Question 18

What is tRNA synthesized by

Answer 18

RNA polymerase 3

Question 19

Explain the strucure of tRNA

Answer 19

• Has a clover leaf structure with modified bases
  -Folded into an L shape

Question 20

What is the function Aminoacyl-tRNA synthetases+ what does it use

Answer 20

• Enzymes that charge tRNAs by attching the correct amino acid
• Uses ATP

Question 21

How many synthetases are there for 1 amino acid

Answer 21

20

Question 22

Name 2 initiation signals

Answer 22

• Shine-Dalgarno sequence( prokaryotes)
  -Kozak sequence(eukaryotes)

Question 23

What is the function of shine-Dalgarno

Answer 23

Aligns ribosomes with the start codon

Question 24

What is the function of the Kozak sequence

Answer 24

Helps with ribosomes assemby and ensurec correct translation initiaion

Question 25

Explain what happens inthe initiation phase in translation

Answer 25

1. Initiation factors (eIFs) assist translation initiation 2. Small ribosmal subunit binds mRNA at the 5 end 3.It locates the start codon 4. tRNA carrying methionine binds to AUG 5. Large ribosomal subunit joins to form the initiation complex

Question 26

Name the 3 different ribosomal sites

Answer 26

A site- Aminoacyl site P site- Peptidyl site E site- Exit site

Question 27

What happens in the A site- Aminoacyl site

Answer 27

- Enetry point for new tRNA

Question 28

wHAT happens in the P site -peptidyl site

Answer 28

Holds the growing amino acid chain

Question 29

What happens in the E site - Exit site

Answer 29

- Where empty tRNAs exit the ribosome

Question 30

What is found at the wobble position in tRNA

Answer 30

- Inosine

Question 31

What peptide bond formation catalyzed by

Answer 31

- Peptidyl transferase

Question 32

Explain what happens in the peptide bond formation

Answer 32

- Chain is transferred from tRNA in the P site to amino acid in A site -Translation proceeds from N terminal to C terminal

Question 33

In the elongation ohase of translation what is it coordinated by

Answer 33

Elongation factors

Question 34

Explain the steps that occur in elogation

Answer 34

Aminoacyl-tRNA binds A-site. Peptide bond forms between amino acids in A and P sites. Ribosome translocates one codon forward. tRNA shifts to P and E sites, old tRNA exits. A-site is free for the next tRNA.

Question 35

When does protein folding begin and continue

Answer 35

Begins during translation and continues after

Question 36

What is the primary sturcture

Answer 36

Sequence of amino acids

Question 37

What is the secondary structure

Answer 37

The formation of alpha helices and beta pleated sheet via hydrogen bonds

Question 38

What is the tertiary structure

Answer 38

3D foldign with interactions like hydrophobic, ionic and covalent bond

Question 39

What is teh quaterny structure?

Answer 39

When there is multipe poltpeptides forming a functional unit

Question 40

What are palindromic sequences+ what are they recognized by

Answer 40

They are sequences that read the same 5 - 3 end on both strands -Recognized by restriction enzymes

Question 40

What do many antibiotics target to inhibit translation

Answer 40

- Prokaryotic ribosomes

Question 41

What is the functions of restriction enzymes

Answer 41

Cut DNA at specific palindromic sequences + can create -Sticky ends -Blunt ends

Question 42

Wht are sticky ends

Answer 42

- Overhanging sequences

Question 43

What are blunt ends

Answer 43

- Straight cuts

Question 44

Explain the gene cloning process

Answer 44

Use restriction enzymes to cut a gene of interest and a plasmid. Combine them to form recombinant DNA. Insert recombinant plasmid into bacteria. Bacteria replicate, producing many copies of the gene.