2/24- Ch.5 (Exam 2)

Question 1

What are the functions of proteins?

Answer 1

1) act as enzymes (biological catalyst)
2) antibodies
3) protein hormones (chemical messengers)
4) muscle proteins (contraction of actin and myosin)
5) structural proteins (collagen)
6) transport (hemoglobin)

Question 2

What are amino acids?

Answer 2

Monomer of proteins

20 naturally occurring amino acids

All have general structure

Question 3

What are polypeptides?

Answer 3

Polymer of amino acid

Question 4

What is a polypeptide with a known structure?

Answer 4

Protein

Question 5

What are the R groups or side groups?

Answer 5

Distinguishes amino acid

Question 6

What are the 3 categories of r groups or side groups?

Answer 6

1) non polar and hydrophobic
2) polar and hydrophilic
3) electrically charged and hydrophilic

Question 7

How does a peptide bond form?

Answer 7

By dehydration synthesis

Gets OH from carbonyl group
Gets H from amines

Question 8

What is the first level of a protein structure and explain

Answer 8

Primary structure

• sequence of amino acids
• most important level
• determines other structures

Question 9

What is the secondary structure?

Answer 9

Secondary structure

2 types:

1) pleated or beta pleated sheet
2) alpha helix

• formed by hydrogen bonds between H-N of one amino acid and O=C of another amino acid
• depends where the bond is formed to make it one or the other

Question 10

What is the third structure of a protein?

Answer 10

Tertiary structure

• interaction between R groups
• 3D shape (conformation)
• most important for functions

Question 11

What are examples of the tertiary structure?

Answer 11

Disulfide Bridge (S-S) (cysteine)

H-bond between R groups

Ionic bonds between acid and base

Van der Waals forces (weak hydrophobic interactions)

Question 12

What is the quaternary structure?

Answer 12

4th structure

• only occurs in proteins with more than one polypeptide chain
• interaction between polypeptide chains
• Ex: collagen and hemoglobin

Question 13

What does denature mean?

Answer 13

Proteins lose their 3 D shape

Loss of structure= loss of function

Causes:

• high temp
• high/ low pH

Question 14

What does DNA stand for?

Answer 14

Deoxyribonucleic acid

Question 15

What does RNA stand for?

Answer 15

Ribonucleic acid

Question 16

What is DNA?

Answer 16

Polymer of nucleic acids

Info storage molecule To make proteins

Hereditary material

Pentose- deoxyribose

Double helix

Question 17

What is messenger RNA?

Answer 17

Copies info from DNA

Question 18

What is ribosomal RNA?

Answer 18

In ribosome

Protein synthesis

Question 19

What is transfer RNA?

Answer 19

Functions during protein synthesis

Question 20

What is micro RNA?

Answer 20

Regulation of info flow

Question 21

What is the info flow in a cell?

Answer 21

DNA to mRNA to protein

Question 22

What is the monomer of a nucleic acid?

Answer 22

Nucleotide

Question 23

What is a nucleotides?

Answer 23

Nitrogenous vase

5 carbon sugar- pentose

Phosphate group

Question 24

What is the pentose for RNA?

Answer 24

ribose

Question 25

What is pyrimidines?

Answer 25

Cytosine (C) Uracil (U) Thymine (T)

Question 26

What are purines?

Answer 26

Adenine (A) Guanine (G)

Question 27

What are the complimentary base pairs for DNA?

Answer 27

A-T C-G

Question 28

What are the complimentary base pairs for RNA?

Answer 28

A-U C-G

Question 29

How are the 2 strands of DNA linked together?

Answer 29

Hydrogen bonds between nucleotides

Question 30

What is ATP?

Answer 30

Energy currency Nucleotide