Prof. Shoeck Lectures 1-4

Question 1

Isotopes

Answer 1

• two isotopes have same # of protons but diff. number of neutrons

Question 2

Electronegativity

Answer 2

• it is how strong electrons are attracted to nucleus

Question 3

Why are buffers important?

Answer 3

• they are important for the function of many molecules

- keep pH constant

Question 4

What is advantage of biochemical unity?

Answer 4

• we obtain energy from eating and digesting other organisms

Question 5

Condensation

Answer 5

• formation of polymer linked by covalent bonds, releasing one water molecule w/ each monomer added

Question 6

Anabolic reaction

Answer 6

• reaction requires energy input

- DNA replication, making of starch ect.

Question 7

Hydrolysis

Answer 7

• Break down the covalent bonds w/ help of water to transform polymer into constituent monomers

Question 8

Catabolic

Answer 8

• digestion of food molecules for every generation

- releases energy

Question 9

Peptide bond formation

Answer 9

• Condensation reaction
• occurs between carboxyl group of one amino acid and the amino group
• amino acid starts w/ amino acid group [N-terminus] and ends w/ carboxyl group [C-terminus]

Question 10

Primary structure and secondary structure

Answer 10

• Primary: it is the # of amino acids and how they are arranged (requires energy)
• Secondary: alpha helix and beta pleated sheet (releases energy)
• Summary: primary structure is just sequence of amino acids, with each amino acid linked by peptide bonds. Some stretches of this polypeptide fold into alpha-helix or beta-pleated sheet, or remain unfolded at the first stage of folding.

Question 11

What is the only way to confirm the presence or absence of secondary structures within proteins?

Answer 11

Protein structure determination

Question 12

What is the purpose of the tertiary structure?

Answer 12

• finishes folding of polypeptide, mediated by side chain interactions

Question 13

What are the four types of interactions that contribute to tertiary structure formation? And which is most important?

Answer 13

1) Ionic bonds
2) hydrogen bonds
3) Disulphide bonds
4) hydrophobic interaction: most important for protein folding/tertiary structure

Question 14

Difference between tertiary and and quaternary structure?

Answer 14

• Tertiary: if both alpha helixes are from same polypeptide

- Quaternary: if two alpha helixes are from two different polypeptides

Question 15

What is the importance of amino acid sequence?

Answer 15

• single amino acid mutation in protein hemoglobin changes the shape - this results in red blood cells (sickled)
• the order of the sequence matters

Question 16

What are chaperones?

Answer 16

• Help proteins fold properly after synthesis or after stress-related unfolding

Question 17

Nucleotides

Answer 17

• nucleotides make RNA and DNA, serve function in signalling and energy storage as monomers
• made of 5-carbon sugar, nitrogenous base, phosphate group
• polymerize via phospdiester linkages w/ 3’ hydroxyl group of the polymer forming a covalent bond w/ 5’ phosphate group

Question 18

What direction is polymerization?

Answer 18

• it always occurs in 5’ to 3’ direction

Question 19

What comes first in evolution?

Answer 19

• RNA (stores and execute information)

Question 20

Stem-loop structure

Answer 20

• Important RNA structure found in many mRNA’s

- contributes to regulation of mRNA function