Module 1: Lesson 4

Question 1

What is the largest consumer of energy during proliferation?

Answer 1

Protein synthesis

Question 2

What plays a pivotal role in regulation of gene expression?

Answer 2

Control of mRNA translation

Question 3

Where does transcription take place?

Answer 3

Nucleus

Question 4

Where does translation take place?

Answer 4

Cytoplasm

Question 5

What do the 5’ cap and 3’ PolyA tail do?

Answer 5

Increase stability of mRNA, facilitate mRNA export from the nucleus to the cytoplasm, and indicate that the RNA in mRNA (required for protein synthesis machinery to begin translation).

Question 6

What components does “export ready” RNA have?

Answer 6

Cap binding complex, PolyA-binding proteins, proteins marking complete RNA splices, and a nuclear transport receptor.

Question 7

What directs the synthesis of proteins?

Answer 7

Genetic information

Question 8

What is a codon?

Answer 8

A nucleotide triplet

Question 9

What is the state of the genetic code?

Answer 9

Degenerate/redundant

Question 10

How many reading frames are possible for an mRNA molecule?

Answer 10

3 reading frames (organisms have different codon bias)

Question 11

What is the molecular adaptor between codons and corresponding amino acids?

Answer 11

tRNA

Question 12

What is an anticodon?

Answer 12

A set of three consecutive nucleotides on tRNA that pairs with the complementary codon on mRNA.

Question 13

What is the 3’ end?

Answer 13

A short single-stranded region where the amino acid is attached to the tRNA.

Question 14

What is the role of aminoacyl-tRNA synthetases enzymes?

Answer 14

Synthetases couple tRNAs to the correct amino acid. There is a different synthetase enzyme for each amino acid.

Question 15

What end of the tRNA does a synthetase bind to?

Answer 15

3’ end

Question 16

Where is protein synthesis performed?

Answer 16

Ribosome

Question 17

What are the different binding sites of a ribosome?

Answer 17

Aminoacyl-tRNA (A), peptidyl-tRNA (P), exit (E)

Question 18

What is the role of rRNA?

Answer 18

Ribosomal structure and catalytic function – peptide bond formation

Question 19

What are the steps in protein synthesis?

Answer 19

Initiation, elongation, and termination

Question 20

What is Charcot-Marie-Tooth (CMT) disease?

Answer 20

A peripheral neuropathy affecting both sensory and motor neurons through axonal degeneration or demyelination of neurons.

Question 21

How many different mutations is CMT disease linked to, and where?

Answer 21

CMT disease is linked to six mutations in Aminoacyl-tRNA-Synthetase reactions (but are not the only mutations responsible for CMT).

Question 22

How does a polypeptide chain grow?

Answer 22

Stepwise addition of amino acids to the C-terminal end

Question 23

What is a svedberg (S)?

Answer 23

The sedimentation rate of a particle in the centrifuge

Question 24

What are the steps to add an amino acid to the elongation chain?

Answer 24

tRNA binding, peptide bond formation, large subunit translocation, small subunit translocation

Question 25

What is the role of tetracycline in protein synthesis blockage?

Answer 25

Blocks binding of aminoacyl tRNA to A site of ribosome

Question 26

What is the role of chloramphenicol in protein synthesis blockage?

Answer 26

Blocks the peptide transferase reaction on ribosomes

Question 27

What is the role of erythromycin in protein synthesis blockage?

Answer 27

Blocks the translocation step in translation

Question 28

What are proteins synthesized on?

Answer 28

Polyribosomes

Question 29

What are the different structures of proteins called?

Answer 29

Primary, secondary, tertiary, and quaternary

Question 30

What is a primary structure?

Answer 30

A linear amino acid sequence

Question 31

What are types of secondary structures?

Answer 31

Alpha helices and beta sheets

Question 32

What is a tertiary structure?

Answer 32

Full three-dimensional structure formed by an entire polypeptide chain, including a-helices and b-sheets

Question 33

What is a quaternary structure?

Answer 33

A protein molecule formed as a complex of more than one polypeptide chain

Question 34

What non-covalent interact in proteins?

Answer 34

Electrostatic attractions, van der Waals attractions, and hydrogen bonds

Question 35

What role do non-covalent bonds have on proteins?

Answer 35

Help the protein fold and stabilize its folded shape

Question 36

What functional groups on proteins do hydrogen bonds use to form?

Answer 36

Amine (-NH) and carbonyl (C=O) groups in the backbone

Question 37

What is the role of chaperone proteins?

Answer 37

To aid protein folding by binding to reversibly to misfolded proteins to prevent aggregation

Question 38

What are intermediate folded proteins prone to?

Answer 38

Aggregation and misfolding

Question 39

What are disulfide bonds and what is their role in protein synthesis?

Answer 39

Disulfide bonds are covalent bonds that stabilize extracellular proteins.

Question 40

What is a ligand?

Answer 40

Any substance that can bind to a protein (ie. another protein, ion, small molecular, or other macromolecule)

Question 41

What is a binding site?

Answer 41

The region of the protein that associates with a ligand.

Question 42

What is specificity?

Answer 42

The ability of a protein to bind to just one or a few molecules out of many thousands of different molecules it encounters.

Question 43

What are the criteria needed for protein binding?

Answer 43

Structural fit AND weak, non-covalent bonds interactions that form simultaneously

Question 44

What is feedback inhibition?

Answer 44

Prevention of proteins acting due to activity produced later in the pathway.

Question 45

What types of molecular switches are there?

Answer 45

GTPases and phosphates/kinases