B1.2 Proteins

Question 1

OH in condensation reaction comes from…

Answer 1

COOH Group

Question 2

H comes from… in condensation reaction.

Answer 2

NH2 Group

Question 3

Essential amino acids are..

Answer 3

Amino acids that cannot be synthesized by the body and must be obtained from diet.

Question 4

How many essential amino acids are there?

Answer 4

9

Question 5

Phenylaline is…

Answer 5

Essential

Question 6

What determines the sequence of amino acids in a polypeptide?

Answer 6

The sequence of bases in the DNA of the gene it’s is coded for by.

Question 7

How many polypeptides have been identified?

Answer 7

Over 2 million

Question 8

What does heat do to proteins?

Answer 8

Causes vibrations that break intermolecular H bonds and cause their conformation to change

Question 9

Half of R-Groups are

Answer 9

Hydrophobic, some with rings of atoms and one containing sulfur (methionine).

Question 10

1st Third of Hydrophilic R-groups are

Answer 10

• polar, but don’t ionize
• Can form H bonds with other r-groups

Question 11

2nd third of hydrophilic R-groups…

Answer 11

are basic as they have an amine group that can accept a proton

Question 12

Final third of hydrophilic R-Groups…

Answer 12

are acidic because they can donate a proton and can form ionic bonds with positive R-Groups.

Question 13

Pairs of R-groups that are mildly hydrophilic and contain a -SH group form:

Answer 13

a covalent S-S bond called a disulfide bond

Question 14

Glycine has a

Answer 14

single hydrogen atom

Question 15

Largest R-Group?

Answer 15

Tryptophan

Question 16

Primary Structure

Answer 16

The number and sequence of amino acs in a polypeptide

Question 17

Carbon and changes in structure?

Answer 17

Due to bond rotation, alternative structures for the same compound can be formed.

Question 18

Each N in the repairing sequence of the polypeptide back bone has…

Answer 18

an H bonded to it

Question 19

Hydrogen bonds on secondary structures are formed between…

Answer 19

N-H groups and C=O groups

Question 20

Four types of interaction between amino acids in a tertiary structure:

Answer 20

• Hydrogen bonds between polar R-groups
• Ionic bonds between NH+ and COO- groups
• S-S covalent bonds
• Hydrophobic interactions between non-polar R-groups

Question 21

Proteins with ……… amino acids on their outer surface have …… amino acids at there core.

What does that do?

Answer 21

• 1) Hydrophilic, Hydrophobic
• Stabilizes protein’s tertiary structure in aqueous solutions.

Question 22

Some proteins have hydrophobic amino acids on their outer surface and are therefore attracted to the non-polar core of membranes, what does that make them?

Answer 22

Integral Membrane proteins

Question 23

What determines the tertiary structure of proteins and where they are located in cells?

Answer 23

The distribution of polar and non-polar amino acids.

Question 24

Water soluble protein are more likely to be located where in a cell?

Answer 24

Dissolved in cytoplasm or in aqueous solutions

Question 25

Proteins that contain a non-polypeptide structure known as a “prosthetic” group are called…

Answer 25

Conjugated Proteins

Question 26

Why is Hemoglobin a conjugated protein?

Answer 26

It contains haem groups which are not polypeptides.

Question 27

Quaternary structures?

Answer 27

Structures that contain two or more polypeptides linked to form a protein.

Question 28

What form feature of fibrous proteins gives them structural roles within and between cells?

Answer 28

- Unfolded Polypeptides, which give them a narrow and elongated shape.

Question 29

Why do globular proteins have a rounded shape?

Answer 29

They have folded polypeptides

Question 30

Collagen is a ….. protein.

Answer 30

Fibrous

Question 31

What feature of collagen allows it to be wound together into a triple helix?

Answer 31

It has three polypeptides that are more elongated than then alpha helix.

Question 32

Form: Collagen has three polypeptides with an amino acid sequence that prevents the formation of an alpha helix. What is the function?

Answer 32

This gives it a rope-like formation, it can withstand tensions by stretching rather than breaking, it’s released into extracellular matrix of tissues where tensile strength is needed. (Skin, bones, tendons, and ligaments.)

Question 33

Insulin is a ……. Protein

Answer 33

Globular

Question 34

Form: Insulin has a small size and a hydrophilic surface. What is the function?

Answer 34

Allows insulin to be carried dissolved in blood plasma.

Question 35

Form: Insulin has a distinctive shape Function?

Answer 35

Allows it to bind to a site on a specific receptor protein located in the plasma membrane of target cells.

Question 36

Insulin’s A-Chain has …… amino acids.

Answer 36

21

Question 37

Insulin’s chain has ……. amino acids.

Answer 37

30