Proteins and Nucleic Acids

Question 1

What type of bonds link Amino Acids?

Answer 1

Peptide bonds

(dehydration reaction, bc you’re FORMING a macromolecule type: proteins)

Question 2

Primary Protein Structure

Answer 2

Chain of amino acids links by peptide bonds

Question 3

Secondary Protein Structure

Answer 3

Polypeptide chains held together by H-bonding

1.) Alpha helix
2.) Beta Pleated Sheet

Question 4

Tertiary Protein Structure

Answer 4

Secondary structure folds onto itself

-driven by hydrophobic interactions
-stabilized by disulfide bridges and ionic interactions

• tertiary structure determined by ionic and covalent interactions of R-groups of AA’s in peptide chains

Question 5

Quaternary Protein Structure

Answer 5

Independent polypeptides form a functional protein
*Multiple polypeptide chains
-assembled from 3’ structure
Ex: Collagen

Question 6

What is protein denaturation?

Answer 6

Higher protein structures breakdown from alterations in pH, salt concentration, temperature, environmental factors, etc

Question 7

Clicker:
Sickle-cell disease is caused by a mutation in hemoglobin that changes a charged amino acid to a hydrophobic aa.

Where in the protein would you expect to find this charged aa?

Answer 7

On the exterior of the protein

-proteins aggregate into a fiber, because the ability to carry oxygen has reduced due to the change from charged to hydrophobic.

Question 8

Nucleic Acids Function/Characteristics

Answer 8

Function: Storage, Transmission, and gene expression

-highly charged
-sugar-phosphate backbone
-base-pair
-directionality (3’ to 5’)

Question 9

Components of Nucleotides (3)

Answer 9

1.) Pentose Sugar
2.) Nitrogenous Base
3.) Phosphate Groups

Question 10

What is a nucleotide?

Answer 10

Monomer units of Nucleic Acids

Question 11

Nitrogenous Bases (2 types)

Answer 11

1.) Pyrimidines (CUT)
-Cytosine
-Uracil
-Thymine

2.) Purines (pure as AG)
-Adenine
-Guanine

Question 12

Clicker:
What is harder to break/separate apart?
a.) a DNA fragment with all CG base pairs
b.) alternating AT and CG
c.) Half AT Half CG
d.) One CG, the rest of the fragment AT

Answer 12

a. All CG

Why?:
C-G have three H-bonding regions
A-T have two H-bonding regions

(All C-G is hardest to melt/break/separate due to stronger intermolecular forces)

Question 13

Clicker:
What kind of AA would likely interact with the backbone of DNA

a. Polar
b. Non-polar
c. Positively Charged
d. Negatively Charged

Answer 13

c. Positively charged

DNA backbone is largely negatively charged (probably due to phosphate groups but idk)

Question 14

DNA

Answer 14

Deoxyribonucleic acid
CH2 on C2
OH on C3

Question 15

Ribose

Answer 15

OH on both C2 and C3
-less stable compared to DNA, degrades faster

Question 16

Clicker:
In the DNA of certain bacterial cells, 16% of the nucleotides are Adenine. What percentage of Guanin nucleotides would you expect to find?

a. 16%
b. 32%
c. 34%
d. More info needed

Answer 16

c. 34%

A+T=(0.162)=0.32
1-0.32=0.68/2=0.34100=34%