Introduction to Amino Acids

Question 1

What are proteins?

Answer 1

Proteins are macromolecules made up of a chain of amino acids joined by peptide bonds

Question 2

How are proteins made?

Answer 2

Made by the transcription of DNA to RNA and then translation of RNA to protein

Question 3

How are dietary proteins broken down?

Answer 3

They are broken down by proteases (pepsin) and hydrochloric acid in the stomach

Question 4

Give three uses of amino acids.

Answer 4

Production of hormones

Production of enzymes

Production of proteins

Question 5

What are amino acids?

Answer 5

The building blocks of proteins

An amine group
A carboxylic acid group
A variable group (R)
And a hydrogen all bonded to a single carbon

Question 6

What is an amine group?

Answer 6

NH2

Question 7

What is a carboxylic acid group?

Answer 7

COOH (where C=O and C-OH)

Question 8

How can the bonds between amino acids be broken?

Answer 8

Broken via acid or enzyme action

Question 9

How would you describe the shape of amino acids?

Answer 9

Tetrahedral structures

Carbon at the centre with four bonds stretching out at the furthest angle from each other

Question 10

In general what are the two different ways amino acids can be configured?

Answer 10

L amino acids (Left-handed)

D amino acids (Right-handed)

Question 11

In relation to its configuration, how does glycine compare to all the other amino acids?

Answer 11

Glycine is the only amino acid that is not a stereoisomer

Question 12

What is a steriosomer?

Answer 12

A molecule that are mirror images of their structure

Question 13

Explain what is meant by L and D amino acids.

Answer 13

L and D refers to whether or not the configuration of an amino acid is the left mirror image or the right mirror image of an amino acid

Question 14

In general, where are L amino acids made?

Answer 14

They are manufactured in cells

Question 15

What are L amino acids generally used for?

Answer 15

The are generally incorporated into proteins

Question 16

Where are D amino acids generally found?

Answer 16

In the cell wall of bacteria

Question 17

Define essential amino acids.

2

Answer 17

Amino acids that cannot be produced by the body

They must be acquired via dietary or supplementary means

Question 18

Define conditionally non-essential amino acids.

Answer 18

Amino acids produced by the body but in lower amounts and outside supplementation may be required e.g. in case of pregnancy

Question 19

Define non-essential amino acids.

Answer 19

Amino acids that can be produced by the body and therefore not required via dietary or supplementary means

Question 20

List some of the essential amino acids.

4

Answer 20

Leucine
Isoleucine
Phenylalanine
Tryptophan

Question 21

List the four non-essential amino acids.

Answer 21

Alanine
Asparatate
Cysteine
Glutamate

Question 22

List some conditionally non-essential amino acids.

Answer 22

Asparagine
Glycine
Glutamine
Tyrosine

Question 23

What are the three ways to classify amino acids?

Answer 23

On the basis of R group

On the basis of nutrition

On the basis of catabolism

Question 24

How can amino acids be classified according to their R group?
(4)

Answer 24

Hydrophobic

Hydrophilic

Acidic

Basic

Question 25

How can amino acids be classified on the basis of nutrition? (3)

Answer 25

Essential Conditionally non essential Non essential

Question 26

How can amino acids be classified on the basis of catabolism? (3)

Answer 26

Glucogenic Ketogenic Both Glucogenic and Ketogenic

Question 27

Where are most hydrophobic amino acids found?

Answer 27

Most are found buried within the core of a protein structure

Question 28

Where are most hydrophilic amino acids found?

Answer 28

Most are found on the outside of a protein structure

Question 29

What can hydrophobic amino acids also be called?

Answer 29

Polar amino acids

Question 30

What can hydrophilic amino acids also be called?

Answer 30

Non polar amino acids

Question 31

Give four examples of hydrophobic amino acids.

Answer 31

Phenylalanine Tryptophan Leucine Isoleucine

Question 32

Give four examples of hydrophilic amino acids/

Answer 32

Asparagine Glutamine Tyrosine Cysteine

Question 33

How do you know if an amino acid is hydrophilic or hydrophobic?

Answer 33

Hydrophilic amino acids will have an electronegative atom such as O, S or N as part of their variable group Hydrophobic amino acids will have only carbons and hydrogens as part of their variable group

Question 34

List two acidic amino acids.

Answer 34

Aspartic acid | Glutamic acid

Question 35

How do you know if an amino acid is acidic?

Answer 35

The presence of O- | COO-

Question 36

List three basic amino acids.

Answer 36

Lysine Arginine Histidine

Question 37

How do you know if an amino acid is basic?

Answer 37

The presence of a nitrogen, hydrogen molecule with an overall positive charge

Question 38

What are glucogenic amino acids?

Answer 38

Amino acids that can be converted into glucose

Question 39

What are ketogenic amino acids?

Answer 39

Amino acids that can be degraded directly into acetyl-CoA

Question 40

List the only two ketogenic amino acids.

Answer 40

Leucine | Lysine