What are proteins?

Question 1

what are proteins composed of

Answer 1

peptides connected with peptide bonds

Question 2

what determines the specificity of an amino acid

Answer 2

R group side chains

Question 3

how many different proteins do humans make in a typical cell

Answer 3

~10 000 proteins

Question 4

how many protein encoding genes do humans have? how many total types of proteins?

Answer 4

~21 000 protein encoding genes

~100 000 proteins

Question 5

how do we have more proteins than protein encoding genes

Answer 5

alternative splicing

Question 6

average length of a human protein

Answer 6

450 amino acids

Question 7

largest protein?

Answer 7

Titan at 34 000 amino acids

Question 8

primary structure

Answer 8

sequence of amino acids linked together by peptide bonds, forming a polypeptide

Question 9

secondary structure

Answer 9

local regions of a polypeptide coiling into an alpha helix or folding into a beta pleated sheet

Question 10

tertiary structure

Answer 10

regions of secondary structure interact and fold

Question 11

quaternary structure

Answer 11

association of 2 or more polypeptides in a multimeric protein

Question 12

4 depictions of protein structure

Answer 12

1. primary structure only
2. space filling model
3. ball-and-stick model
4. spiral-and-ribbon model

Question 13

what is the spiral-and-ribbon model useful for illustrating

Answer 13

secondary structure

Question 14

9 protein functions

Answer 14

1. enzymes
2. structural proteins
3. motility proteins
4. regulatory proteins
5. hormonal proteins
6. receptor proteins
7. defensive proteins
8. storage proteins
9. transport proteins

Question 15

3 protein shapes

Answer 15

1. globular (round)
2. membrane
3. fibrous

Question 16

protein domains

Answer 16

regions of proteins that can fold, function, and evolve independently of each other

Question 17

example of a protein with 4 domains

Answer 17

botulinum A neurotoxin

Question 18

4 domains of BoNT/A

Answer 18

1. entry into cell domain
2. entry into cytosol domain
3. catalytic domain
4. zinc atom

Question 19

how is protein synthesis regulated

Answer 19

mostly at the level of RNA synthesis initiation

Question 20

what are genes regulated by?

Answer 20

transcription factor proteins

Question 21

2 types of transcription factors

Answer 21

1. positive

2. negative

Question 22

positive transcription factors

Answer 22

recruit RNA polymerase

Question 23

negative transcription factors

Answer 23

block the promoter

Question 24

how is protein activity regulated

Answer 24

some by nucleotides/phosphates

some by activator or inhibitor proteins

Question 25

regulation of protein destruction

Answer 25

lysosomes and proteasomes are in charge of this

Question 26

what is used to mark proteins for destruction

Answer 26

the attachment of small ubiquitin proteins

Question 27

proteasomes

Answer 27

protein complexes in charge of destroying other proteins