Unit 1: Proteomics & Protein Structure 2

Question 1

The four levels of protein structure are;

Answer 1

• Primary
• Secondary
• Tertiary
• Quaternary

Question 2

The basic structure of an amino acid is

Answer 2

Question 3

What are the four classes of amino acids?

Answer 3

1. Polar
2. Non-Polar
3. Acidic
4. Basic

Question 4

What term is used to describe an amino acid, that has both a negative and positive charge?

Answer 4

A Zwitterion

Question 5

What is the structure of an amino acid zwitterion?

Answer 5

Question 6

Acids are free to

Answer 6

donate hydrogen ions

Question 7

Bases are free to

Answer 7

accept hydrogen ions

Question 8

What is the primary structure of a protein?

Answer 8

A polypeptide chain of amino acids

Question 9

Describe the formation of the peptide bond in the polypeptide chain of amino acids?

Answer 9

The peptide bond forms between the carboxylic acid (-COOH) and (-NH2) by a condensation reaction.

Question 10

What is the form of bonding along the backbone of the protein results in alpha-helices and beta sheets?

Answer 10

Hydrogen bonding

Question 11

In secondary protein structure where does hydrogen bonding occur?

Answer 11

Along the backbone of the protein strand

Question 12

In an alpha helix hydrogen bonding occurs between what two chemical groups?

Answer 12

N-H and C=O

Question 13

In beta sheet what are the two types of twisting that can occur?

Answer 13

Antiparallel and Parallel

Question 14

What are R groups in amino acids?

Answer 14

Residues or Side chains

Question 15

Hydrophobic molecules are…

Answer 15

non polar

Question 16

Hydrophillic molecules are…

Answer 16

polar

Question 17

R groups that are positively charged are

Answer 17

basic

Question 18

R groups that are negatively charged are

Answer 18

acidic

Question 19

R groups give the proteins it’s … as they intereact with other structures associated with the protein

Answer 19

function

Question 20

The conformation of the tertiary structure is decided by

Answer 20

interactions between the R groups

Question 21

Name the 5 bons/interactions that occur between R groups cause further folding of the polypeptide?

Answer 21

1. Hydrophobic interactions
2. Ionic bonds
3. Hydrogen bonds
4. Van Der Waals
5. Disulfide bridges

Question 22

Prosthetic groups do what?

Answer 22

Give proteins added function

Question 23

Where do hydrophobic interactions occur?

Answer 23

Between non-polar R groups along the length of the polypeptide

Question 24

Folding of the polypeptide occurs forming a

Answer 24

central hydrophobic core

Question 25

Hydrophobic sections of proteins are usually found in the

Answer 25

phospholipid bilayer of a cell

Question 26

The hydrophillic polar parts are free to interact with the

Answer 26

extracellular and intracellular solutions

Question 27

Ionic bonding occurs between

Answer 27

oppositely charged polar R groups

Question 28

pH affects _____ bonding

Answer 28

ionic

Question 29

At extremes of pH what interacts with the chrage across the ionic bond?

Answer 29

The H+ ions and OH-

Question 30

Hydrogen bonding is a weak

Answer 30

polar interaction

Question 31

Van Der Waals occurs between

Answer 31

adjacent atoms

Question 32

Disulfide briges are _____ bonds that from between adjacent _____ amino acids

Answer 32

covalent, cysteine

Question 33

Disulfide bridges can occur …

Answer 33

within a polypeptide or between adjacent polypeptides

Question 34

Prosthetic groups are

Answer 34

additional non-protein structures that give the protein molecule it’s function

Question 35

An example of a prosthetic group is

Answer 35

Haem foudn in red bloods cells in haemoglobin responsible for oxygen carriage

Question 36

Quaternary structure is made up of

Answer 36

several connected polypeptide subunits held together by various interactions

Question 37

An example of a quaternary structure is

Answer 37

Haemoglobin

Question 38

Temperature increases the kinetic energy of the protein molecule placing stress on

Answer 38

bonds and breaking them expecially weak interactions

Question 39

The r groups at the surface of a protein determine it’s

Answer 39

location within a cell

Question 40

Regions of hydrophobic R groups allow strong hydrophibic interactions that hold ____ proteins within the phospholipid bilayer

Answer 40

integral

Question 41

Give an example of a receptor

Answer 41

G-proteins

Question 42

Give an example of a transporter

Answer 42

Sodium potassium pump

Question 43

Give an example of a channel proteins

Answer 43

active transport

Question 44

Peripheral/extrinsic proteins have fewer …

Answer 44

hydrophobic R groups interacting with the phospholipids

Question 45

Peripheral/extrinsic proteins are responsible for

Answer 45

cell to cell interactions

Question 46

Peripheral/extrinsic proteins are responsible for junctions

Answer 46

between cells

Question 47

Name the four junctions between cells;

Answer 47

plasmodesmata, tight junction, gap junction, desmosomes

Question 48

An example of tight junction could be found in the

Answer 48

stomach where it prevents acid leaking out

Question 49

Plasmodesmata junctions are found only in

Answer 49

plants