1.2 Proteins

Question 1

What are the features of a Basic amino acid?

Answer 1

Generally have an NH2 on the R group. Allows them to accept H+ and become positively charged and strongly hydrophilic.

Question 2

What are the features of an Acidic amino acid?

Answer 2

Have a COOH on the R group. This allows them to donate a proton and become negatively charged and strongly hydrophilic.

Question 3

What are the features of a Polar Amino Acid?

Answer 3

All have O2, N2 or S8 on their side chain. They are hydrophilic and have no charge

Question 4

What are the features of a hydrophobic Amino acid?

Answer 4

The R group doesn’t contain OH, COOH, NH2 or SH
Uncharged and hydrophobic

Question 5

What are the three secondary protein structures?

Answer 5

Alpha helix and Beta sheets and Turns

Question 6

What does the alpha helix do?

Answer 6

Twists into a spiral with the R groups sticking outwards

Question 7

What do the Beta Sheets do?

Answer 7

The R groups sit above and below the sheets. Polypeptide chains can fold back to form a turn.
Can be parallel or antiparalell

Question 8

(tertiary) What are hydrophobic Interactions?

Answer 8

The hydrophobic R groups are repelled by water

Question 9

(Tertiary) What are ionic bonds?

Answer 9

Occur between oppositely charged R groups

Question 10

(Tertiary) What are LDFS?

Answer 10

Weak but collectively contribute to maintaining protein structures

Question 11

(Tertiary) what are hydrogen bonds?

Answer 11

Occurs when an electropositive hydrogen atom is shared between two electronegative atoms

Question 12

(Tertiary) what is a disulphide bridge?

Answer 12

Form between R groups and contains sulphur

Question 13

What are Quaternary proteins?

Answer 13

Proteins with several connected polypeptide subunits and hells together by Tertiary interactions

Question 14

What are prosthetic groups?

Answer 14

Additional non protein structures that are associated with the protein molecule or give it is final functionality e.g. chlorophyll

Question 15

What can temperature do when it denatures a protein?

Answer 15

Disrupts bonds

Question 16

What can pH do when it denatures a protein?

Answer 16

Ionic bonds between R groups are lost

Question 17

Alternative RNA splicing…

Answer 17

Results in different exons being spliced into the mature transcripts

Question 18

What are the factors that can change protein expression?

Answer 18

Metabolic activity of the cell
Cellular stress
Response to signaling molecules
Disease

Question 19

Membranes within the cell are called

Answer 19

Intracellular membranes

Question 20

What is the Endoplasmic Reticulum?

Answer 20

A network of membrane tubules continuous with the nuclear membrane

Question 21

What are lysosomes?

Answer 21

Membrane bound organelles that contain a variety of hydrolases

Question 22

What are hydrolases?

Answer 22

Enzyme that catalyse the cleavage of a covalent bond with water

Question 23

What do vesicles do?

Answer 23

Transport materials between membrane compartments

Question 24

What is the difference between the rough and smooth endoplasmic reticulum?

Answer 24

Rough has ribosomes on its cytosolic face and smooth lacks them

Question 25

Two examples of Post Translational Modification?

Answer 25

The addition of carbohydrate groups
Proteolytic Cleavage

Question 26

Cooperativity is when..

Answer 26

the binding of a ligand to one subunit of the protein increases the ligand affinity of the remaining subunits.

Question 27

ER stands for?

Answer 27

Endoplasmic Reticulum

Question 28

Definition of primary structure?

Answer 28

Order of amino acids.

Question 29

A prosthetic group is?

Answer 29

A non protein structure that gives final functionality e.g. chlorophyll

Question 30

Addition or removal of a phosphate causes…

Answer 30

…a reversible conformational change to the protein

Question 31

Kinase catalyses…

Answer 31

The transfer of phosphate

Question 32

Phosphatase catalyzes..

Answer 32

dephosphorylation