BIO 214 Midterm 1

Considering the amino acids that form hydrogen bonds with 2,3 BPG in ADULT hemoglobin; what characteristic(s) do these amino acids share?

- Positively Charged R Group - Polar R Group - Hydrophilic R Group

What term describes each of the following: 1. COOH 2. COO- 3. NH2 4. NH3+

1. Acid 2. Conjugate base 3. Base 4. Conjugate acid

Since the Tense state of hemoglobin only has __1___affinity for oxygen, conformational changes (that is, going from T conformation to R conformation) can only occur under __2__ oxygen concentrations

1. LOW 2. HIGH

What will cause the Oxygen-Hemoglobin dissociation curve to shift to the left?

2, 3-BPG

The central atom in an amino acid in which 4 substituents are bonded is known as:

Alpha Carbon

What makes up a peptide bond?

Bond between C-N(carboxyl group and amine group) between two amino acids

How do you determine between L and D form of an amino acid?

CORN

As you learned in lecture, myoglobin is a carrier molecule similar to hemoglobin, and they share many of the same characteristics. Considering the structures of both myoglobin and hemoglobin, which of the following characteristics do they not share?

Cooperativity

There is only one amino acid that lacks chirality. Which one do you think it is?

Glycine

Considering the oxygen affinity patterns for hemoglobin and myoglobin, which curve would depict myoglobin?

Myoglobin has a higher affinity for oxygen so it would be a higher affinity curve.

Choose one amino (pka 9) and one carboxyl group (pka 2) that can not simultaneously exist in an aqueous solution.

NH2 and COOH they can never both be neutral simultaneously

2,3 Bisphosphoglycerate stabilizes which conformation of hemoglobin?

Tense

Deoxygenated hemoglobin is found in which conformation?

Tense

What is the C terminus?

The Carboxyl group

What is the N terminus?

The amine group

What is the alpha carbon?

The center carbon that has the four groups off of it (amine, carboxyl, R, H)

What is a zwitterion?

When the amino acid has a net charge of zero due to the carboxyl group being negatively charged and the amine group being positively charged-- neutralizing the whole ion.

Which of the following explains what is happening when sodium chloride dissolves in water? a) More hydrogen bonds form between water molecules. b)Hydration shells form around the sodium and chloride ions. c)Covalent bonds are broken and re-formed. d)Nonpolar solute is dissolving into a polar solvent.

b Anions (sodium) and cations (chloride) are surrounded by hydration shells of polar water molecules, and pulled into solution. Anions are surrounded by water molecules in which the dipole is oriented with the oxygen (negative pole) facing the ion, while cations are surrounded by dipoles with the hydrogen (positive pole) towards the ion.

Which of the following is a feature shared by all these amino acids? a)Carbonyl group b)Carboxyl group c)Amide group d)Hydroxyl group

b Carboxyl group (-COOH) is the correct answer: Carbonyl group have a carbon covalently bound to oxygen with a double bond, (R-CO-R) and an amide group is a nitrogen bonded to a carbonyl group (R-CO-N-). These don't exist in amino acids, but are formed when amino acids are joined to each other by peptide bonds (here, R represents any other covalently bound atom, not an amino-acid side-chain). Hydroxyl groups (-COH) are present in some (Serine, Threonine, Tyrosine) but not all amino acids.

Which amino acid will disrupt the structure of an alpha helix? a. Cysteine b. alanine c. proline d. isoleucine e. phenylalnine

c. Proline

Which of these enzymes is responsible for unwinding DNA, and making it accessible to replication machinery? a. Endonuclease b. Ligase c. Topoisomerase d. Primase e. Helicase

e. Helicase