Kaplan: Biochemistry: Chapter One

Question 1

Where are amino acids found?

Answer 1

They are found in proteins.

Question 2

What are alpha-amino acids?

Answer 2

Alpha-amino acids are those in which the amino group and the carboxyl group are bonded to the same carbon.

Question 3

How the fuck do we know where the alpha-position is?

Answer 3

The alpha carbon will always be the carbon that is ADJACENT to the carboxyl carbon ( the carbon that is double-bonded to the oxygen AND bonded to the hydroxyl).

Question 4

Describe the four groups that make-up an amino acid! GO

Answer 4

an amino (-NH2), the carboxyl group (-COOH), the hydrogen (H), AND the sidechain ( denoted R)

Question 5

What makes each amino acid different from the other???

Answer 5

THE MF SIDECHAIN

Question 6

Say it with me now!

Answer 6

STRUCTURE DETERMINES FUNCTION

Question 7

True or False: Amino acids do not need to have the amino group and the carboxyl group attached to the same carbon. Explain why or why not.

Answer 7

This is obviously false babes… BECAUSE take methionine for example, the nitrogen is attached to the cyclic pentagon group but not attached to the alpha carbon.

Question 8

Bitch is this true or false? Every amino acid found in the human body is specified by a codon in the genetic code or incorporated into proteins.

Answer 8

FALSE

Question 9

What are we describing when we say proteinogenic amino acids???

Answer 9

There are various amino acids HOWEVERRR, there are 20 alpha-amino acids that the human body encodes.

Question 10

Is glycine a chiral molecule?

Answer 10

NOSIREE! that bitch contains a hydrogen as its sidechain making two of the groups ze same.

Question 11

Why is the amino group drawn on the left in Fischer projections?

Answer 11

The amino group is drawn to the left because all chiral amino acids used in eukaryotes are L-amino acids.

Question 12

What is the configuration for all CHIRAL amino acids (not including glycine and cysteine)?

Answer 12

S-configuration

Question 13

Which amino acid has an R-configuration?

Answer 13

Cysteine

Question 14

What is a D-amino acid?

Answer 14

A D-amino acid is one in which the amino group is drawn to the right in a Fischer projection.

Question 15

What does it mean to be non polar?

Answer 15

There is no overall charge.

Question 16

What does it mean to be non-aromatic?

Answer 16

There is no hexagonal ring and there are no pi bonds.

Question 17

What are the seven amino acids that are non polar and non-aromatic?

Answer 17

glycine, alanine, valine, leucine, isoleucine, methionine, AND proline

Question 18

Which is the smallest amino acid?

Answer 18

The smallest amino acid is glycine

Question 19

Describe the sidechain of glycine

Answer 19

The sidechain of glycine is hydrogen which is why the amino acid is NOT chiral

Question 20

Describe the sidechain of alanine, valine, leucine, and isoleucine

Answer 20

They have alkyl side chains containing one to four carbons. Alkyl groups are alkane groups that are missing a hydrogen. CH4——–>CH3

Question 21

Describe the sidechain of methionine.

Answer 21

The sidechain of methionine contains a sulfur atom ( 1 of the 2 amino acids who have one) IN its sidechain

Question 22

Why is methionine considered non polar?

Answer 22

Even though it has a big fat sulfur atom in it, the methyl group keeps it relatively non-polar.

Question 23

Describe the sidechain of proline

Answer 23

It forms a cyclic amino acid, the amino nitrogen becomes a part of the side chain forming a five-membered ring.

Question 24

Describe the side chain of tryptophan

Answer 24

Tryptophan is the biggest of the aromatic group, it has a double-ring system and one of the rings contain a nitrogen giving this compound 2 nitrogen’s in its structure

Question 25

describe the sidechain of phenylalanine

Answer 25

This amino acid only has one benzyl ring ( meaning a benzene ring + a ch2 group)

Question 26

describe the sidechain of tyrosine

Answer 26

tyrosine’s sidechain sort of resembles phenylalanine but it has a hydroxyl group attached to the benzyl side chain

Question 27

How many amino acids are non-polar and non-aromatic?

Answer 27

seven

Question 28

How many amino acids have non-polar aromatic sidechains, what are they?

Answer 28

there are three of them, tryptophan, phenylalanine AND tyrosine

Question 29

How many amino acids have polar side chains? What are they?

Answer 29

There are five of them, serine, threonine, asparagine, glutamine, cysteine

Question 30

Describe the side chains of serine and threonine

Answer 30

Their side chains have a hydroxyl group which makes them POLAR AF and able to participate in hydrogen bonding, member NOF

Question 31

Describe the side chains of asparagine and glutamine

Answer 31

Their side chains have lovely amides ( -NH2 + double-bonded O on the same carbon) The amides do not become charged, leave those bitches alone

Question 32

How can you remember the difference between serine and threonine, structurally?

Answer 32

serine has one alkyl group (CH2) and threonine has one alkyl group ( CH3)

Question 33

Describe the side chains of cysteine

Answer 33

Cysteine is the other 1 of 2 aminos that have sulfur in its structure BUT the major difference is that the sulfur atom is bonded to a hydrogen which makes it a thiol

Question 34

What makes asparagine and glutamine structurally different?

Answer 34

Asparagine has one alkyl group (CH2) and glutamine has two alkyl groups ( CH2 x2)

Question 35

How many negatively charged (acidic) side chained amino acids? What are they?

Answer 35

There are two of them, aspartic acid AND glutamic acid. They anions are aspartate and glutamate, respectively.

Question 36

What are the three amino acids that have positively charges (basic) side chains

Answer 36

arginine, lysine, and histidine

Question 37

Which amino acids are hydrophobic and why?

Answer 37

The ones with long alkyl chains ( alanine, isoleucine, leucine, valine, and phenylalanine). They are most likely to be found in the interior of proteins.

Question 38

Which amino acids are hydrophilic and why?

Answer 38

All the amino acids with charged ( - or +) side chains are hydrophilic, these include arginine, histidine, lysine and the IONS aspartate and glutamate.