L.1 Amino Acids & Protein (2) Flashcards Preview

Kaplan Biochemistry > L.1 Amino Acids & Protein (2) > Flashcards

Flashcards in L.1 Amino Acids & Protein (2) Deck (13)
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1
Q

How many amino acid residues does a _____ have?

dipeptide?

tripeptide?

oligopeptide?

polypeptide?

A
  1. 2
  2. 3
  3. 20 or less
  4. more than 20
2
Q

Forming a peptide is a ________ or _________ reaction.

A

Condensation or dehydration (releasing a water molecule)

3
Q

In a peptide bond formation, what molecule is the nucleophile?

What kind of bond is formed?

A

The nucleophilic amino group of one amino caid attacks the electrophilic carbonyl of the other amino acid.

The new amide bond is rigid because of resonance.

4
Q

Breaking a peptide is a ________ reaction.

A

Hydrolysis

5
Q

What is the primary structure of a protein?

What are the stabilizing bonds?

A

Linear sequence of an amino acid chain.

Peptide bond (covalent)

6
Q

What is the secondary structure of a protein?

What are the stabilizing bonds?

A

Local structure determined by nearby amino acids

Alpha helices

and

Beta-pleated sheets

(can be parallel and anti-parallel)

Proline can interrupt secondary structure

because of its rigid cyclic structure

Hydrogen bonds.

7
Q

What is the tertiary structure of a Protein?

What are the interactions?

A

3D-Shape

Hydrophobic Interactions

Acis/base interactions

Disulfide salt bridges/links

(When two cysteine molecules are oxidized and create a covalent bond with each other creating cystine)

8
Q

What is the quaternary structure of proteins?

A

Interactions between separate subunits

of a multisubunit protein

(Conjugated Proteins)

9
Q

What is a prosthetic group?

A

Proteins with covalently attached molecules are called conjugated proteins.

These molecules are called prosthetic groups.

  • metal ion*
  • vitamin*
  • lipid*
  • carbohydrate*
  • nucleic acid*
10
Q

What are the names of the conjugated proteins that hold a ________ prosthetic group?

Lipid?

Carbohydrates?

Nucleic Acid?

A

Lipoprotein

Glycoprotein

Nucleoprotein

11
Q

Why are quaternary structures in proteins favorable?

A
  1. Lower qty of DNA
  2. Catalytic sites of multiple units are closer together.
  3. Cooperativity or allosteric effects.
12
Q

What two things can cause denaturation in a protein?

A

Increasing heat and increasing Solute!

13
Q

Why do hydrophobic regions of proteins fold inward?

A

Entropy!

Water cannot form bonds with hydrophobic molecules,

thus they arrange in a specific form to maximize their bonds, this increases entropy and is unfavorable.