Amino Acids Flashcards Preview

Biochem - Year 1 Biomed > Amino Acids > Flashcards

Flashcards in Amino Acids Deck (25)
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1
Q

Name the 3 groups making up an amino acid

A

Side chain (R)

Primary amine (NH3+)

Carboxylate (COO-)

2
Q

Amino acid has no net charge due to opposite charges, what is this called

A

Zwitterion

3
Q

Name the ends of the amino acids

A

N terminus. And C terminus

4
Q

What is the carbon in the middle of an amino acid called

A

Alpha carbon

5
Q

What is the importance of the position of amino acids (CORN)

A

To be used in a protein they all need to be the L isomer Eg L alanine instead of D isomer

This follows the CO R N rule

6
Q

Peptide bonds are rigid due to partial double bonds. What gives it its double bond

A

The carbonyl oxygen gives the double bond between N = C. And the single bond swaps to the carbonyl oxygen

7
Q

Bonds can sometimes rotate in amino acids. The trans bond is the common one with the hydrogen on bottom of N, what is it called when hydrogen swaps to the top of nitrogen to be aligned with oxygen ?

A

Cis bond

8
Q

Why is the alpha carbon called asymmetric?

A

Different elements on each side of it. Eg side chain, NH3, coo

9
Q

Give the name of the 4 hydrophobic amino acids (due to hydrocarbon chains)

A

Valine - val V
Leucine - Leu L
Isoleucine - IIE I
Methionine - Met M

10
Q

3 aromatic amino acids

A

Phenylaline - Phe - F

Tryptophan - trp - W

Tyrosine - Tyr - Y

11
Q

Why is proline amino acid special?

A

It’s side chain joins back to the primary amine

12
Q

Give the codes for asparagine amino acid

A

Asn

N

13
Q

What is the one letter code for glutamine

A

Q

14
Q

Name the 2 negatively charged amino acids

(Due to the O-) and carboxylate chain

A

Aspartate - Asp - D

Glutamate - Glu - E

15
Q

Name the 2 positive amino acids (due to NH3+) side chains

A

Lysine - K - Lys

Arginine - Arg - R

16
Q

What makes hydrophobic amino acids hydrophobic? (Made of hydrocarbon chains)

A

Electro negativity is the same in carbon and hydrogen - ability to attract electrons

Electrons spread which gives them no overall charge (non polar) - can’t mix in water

17
Q

Aspartate and glutamate are negative, what gives them negative charge when in water

A

The carboxylate OH loses the H proton leaving it with just O-

18
Q

What happens to lysine and arginine to give them a positive charge

A

They start off as NH2 but a proton H associates in water and becomes NH3+

19
Q

Why is glycine not an L or D isomer

A

The side chain is H, this is the same as another chain meaning 2 same chains = no isomer

20
Q

Why is glycine in flexible regions of proteins

A

Because of the small side chain

21
Q

Cysteine contains SH which is unique. Why is this side chain so important for proteins

A

When SH oxidised. Sulfur makes cross links in proteins via DISULFIDE BONDS- needed in extra cellular proteins

Also can bind to metals like ZN++ to form a protein metal binding site

22
Q

Why is SH called a Thiol group?

A

Because the H is lost so easily. Ie allowing disulfide bonds

23
Q

Why is histidine partially positive charged

A

It is ionising like the others Eg glutamate- this is because it can accept or donate a positive proton.

24
Q

Can histidine bind to metals like ZN++?

A

Yes if there are 2 histidine in the case of ZN

25
Q

Why are aromatic amino acids hydrophobic

A

CH rings, electro negativity is equal which means floating electrons. No charge