Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biochemistry > Amino Acids > Flashcards

Amino Acids Flashcards

1
Q

What is the structure of an amino acid?

A 
Central carbon
Amine group
Carboxyl group 
Hydrogen
R group
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

When is the central carbon a chiral centre?

A

If the four groups bonded to it are different

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How many different amino acids are commonly found in proteins?

A

20

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

When are two molecules stereoisomers?

A

When they are made of the same atoms connected in the same sequence but the atoms are positioned differently in space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the names of the two forms of stereoisomers and what do they tell you about their positioning?

A

L- (amine group on the left of the central carbon)

D- (amine group on the right of the central carbon)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How are amino acids classified?

A

By their R groups

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the different types of R groups an amino acid can have?

A 
Non polar, aliphatic R groups
Polar R groups 
Aromatic R groups 
Positively charged R groups 
Negatively charged R groups
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe and give examples of amino acids with non polar aliphatic R groups.

A

Aliphatic = chains with a high density of carbons and hydrogens
Aliphatic chains can be straight, branched or in ring structures
Non polar = they cannot form hydrogen bonds
Hydrophobic
Examples ; Glycine, Proline (distinctive cyclic side chain structure)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe and give examples of amino acids with polar R groups.

A

Polar = they can form hydrogen bonds with water
Hydrophilic
Examples ; Glutamine, Asparginine, Cysteine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe and give examples of amino acids with aromatic R groups.

A

Aromatic = a substance consisting of or more rings that contain alternating single and double bonds
Only amino acids that absorbs UV light
Relatively non polar
Examples ; Tyrosine, Tryptophan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe and give examples of amino acids with positively charged R groups.

A

‘Basic’ amino acids
Hydrophilic
Examples ; Lysine, Arginine, Histidine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe and give examples of amino acids with negatively charged R groups.

A

Acidic
Hydrophilic
Examples ; Aspartate, Glutamate (both have a second carboxyl group)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How does selenocysteine differ from cysteine?

A

Similar to cysteine but has a selenium group in place of the sulphur group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Name the four types of mutations that occur in proteins.

A

Silent
Conservative
Non conservative
Nonsense

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is a silent mutation?

A

A change in DNA but no change in the amino acid sequence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is a conservative mutation?

A

A change in DNA and a change in amino acid but within the same classification

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is a non-conservative mutation?

A

A change in DNA and a change in amino acid from another classification

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is a nonsense mutation?

A

A change in DNA that causes the insertion of a stop codon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What happens to the red blood cells of a person with sickle cell anemia?

A

They are sickle shaped

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What type of mutation results in sickle cell anemia?

A

Non-conservative (glutamate is changed to valine)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What happens to amino acids when the pH of its environment is changed?

A

Groups within the amino acid become protonated or deprotonated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What does a pKa value indicate?

A

The strength of an acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the pKa of carboxylic acid?

A

4.8

24
Q

What is the pKa of the amine group?

A

10.6

25
Q

What is the isoelectric point?

A

The pH at which an amino acid is charged neutral

26
Q

What R groups are affected by changes in pH?

A

R groups with an explicit positive or negative charge

27
Q

How do you calculate PI?

A

the sum of the pKa’s either side of the PI / 2

28
Q

Name 3 buffer systems and where they work.

A

Phosphate - intracellular
Bicarbonate - blood and small intestine
Histidine - in neutral pH’s

29
Q

What form is nitrogen found in the atmosphere?

A

N2

30
Q

What is the equation of nitrogen fixing?

A

N2 + 3H2 = 2NH3

31
Q

How many ATP molecules are used in nitrogen fixing?

A

16

32
Q

What is the equation for the production of glutamate from ammonia?

A

Ammonia + alpha-ketoglutarate + NADPH = glutamate + NADP + water

33
Q

What is the equation for the production of glutamine from ammonia?

A

Ammonia + glutamate + ATP = glutamine

34
Q

What compound supplies nitrogen to most reactions?

A

Glutamine

35
Q

What compound allows nitrogen to be transported in the blood without being in the form of ammonia?

A

Glutamine

36
Q

How is glutamine synthetase regulated?

A

Allosterically - glutamine provides nitrogen for the production of other compounds, these compounds inhibit the conversion of glutamate to glutamine

37
Q

What is protein turnover?

A

The balance between protein synthesis and protein degradation

38
Q

Describe the process of transamination.

A

Amino acids lose their amine group

The amine group is transferred to alpha-ketoglutarate to produce glutamate and alpha-keto acid

39
Q

What enzyme catalyses the production of glutamate from an amine group?

A

Glutamate dehydrogenase

40
Q

Where is the carbon backbone (amino acid without amine group) metabolised?

A

In the krebs cycle

41
Q

What enzyme catalyses the production of glutamine from glutamate and ammonia?

A

Glutamine synthase

42
Q

Where is glutamate synthesised?

A

In all cells other than skeletal muscle

43
Q

Describe the steps in the glucose alanine cycle.

A
  1. Glucose is metabolised to pyruvate in skeletal muscle
  2. Pyruvate is converted to alanine by the addition of an amine group
  3. Alanine is transported to the liver
  4. The liver breaks down alanine to pyruvate and an amine group
  5. The amine group is used to form urea
  6. Pyruvate is used to make glucose
44
Q

Why is the glucose alanine cycle important?

A

It prevents the build up of lactic acid

45
Q

Why is it more efficient to transport nitrogen in the form of glutamine rather than glutamate?

A

Because glutamine contains two nitrogens where as glutamate only contains one

46
Q

What three substrates donate an amine group amine group during the urea cycle?

A

Glutamine
Glutamate
Aspartate
(Alanine is converted to glutamate which then donates an amine group)

47
Q

Describe the process of the urea cycle.

A

Glutamate undergoes oxidative deamination producing alpha-ketoglutarate and ammonia
Ammonia combines with carbon dioxide to form urea
Urea is transported to the kidney where it is converted to urine and excreted

48
Q

How many nitrogen molecules are transported for one urea molecule?

A

2

49
Q

What is the name of amino acids that are used to make glucose?

A

Glucogenic amino acids

50
Q

What is the name of amino acids that are used to make acetyl CoA?

A

Ketogenic amino acids

51
Q

Name the only two amino acids that are explicitly ketogenic.

A

Leucine

Lysine

52
Q

What is acetyl CoA used for?

A

To make ketone bodies

In the krebs cycle

53
Q

What are ketone bodies?

A

A form of energy used when glucose levels are low

54
Q

What inability do people with Phenylketonuria (PKU) have?

A

An inability to metabolise phenylalanine

55
Q

What inability do people with maple syrup urinary disease have?

A

An inability to degrade branched amino acids (valine, leucine)

Biochemistry (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions