Bio/Biochem

Question 1

What are lacteals and where are they located?

Answer 1

Lacteals are in the intestines, they are associated with absorbing fat into the lymphatic system

Question 2

Given: Max volume in lungs 80 ml/kg, minimum volume is 15 ml/kg

Need: Difference btween max and min for 80 kg man?

Answer 2

This is a difference of 65 ml/kg, which, for an 80-kg man, amounts to (65 ml/kg)(80 kg) = 5200 ml, or 5.2 L.

Question 3

How do you find the Km for a Michaelis Menten graph?

Answer 3

Km, which is defined as the concentration of substrate that corresponds to half of Vmax. Km is important because it can be used as a rough measure of the affinity that an enzyme has for its substrate.

Question 4

Euchromatin

Answer 4

Less dense, transcriptionally active chromatin structure that appears under a light microscope.

Amino acids with positive charge allows for tight interactions, when deacylated it becomes neutral and promotes euchromatin structure (looser structure).

Question 5

In vivo

Answer 5

“In the living”. This refers to conditions found inside the living human body.

Question 6

Amino acid structure is written in which way?

Answer 6

N-terminus to C-terminus. T3 would be closer to N-terminus than T11. (T3 meaning threonine at position 3)

Question 7

Nociceptors

Answer 7

Sensory neurons that are activated by noxious stimuli mediates the perception of pain.

Question 8

Catecholamines

Answer 8

Class of molecules derived from tyrosine that include dopamine and norepinephrine

Question 9

Arachidonic acid, released by AEA hydrolysis, is a precursor for what classes of molecules?

Answer 9

Phospholipids (from ethanolamine)
Prostaglandins and thromboxane’s (eicosanoid signaling molecules)

Question 10

Known: Inhibitor A is hydronium ion. Inhibitor B is hydroxide ion. Both mixed in a beaker then added to rxn mixture, then lysozyme added. Where would the resulting enzyme kinetics land?

Answer 10

Inhibitor A is a strong acid (H3O+) and inhibitor B is a strong base (OH-). Since these inhibitors are mixed together before being added to the reaction mixture, they would simply neutralize each other and become water before having any effect at all. Thus, the enzyme kinetics would not be affected, and the curve would fall along line 1.

Question 11

What is the difference between eukaryotes and bacteria regarding introns?

Answer 11

Bacteria lack introns for the most part, whereas large eukaryotic genes usually contain several introns.

Question 12

What component of the cell membrane, when disrupted, is most likely to result in traffic complications similar to those of gap junction disorders?

Answer 12

Glycoproteins

Transmembrane proteins (many of which are glycoproteins) are the only components listed that pass all the way through the cell membrane and facilitate membrane transport.

Question 13

Haploid cells have how many chromosomes?

Answer 13

23

Question 14

Given that ΔG° is negative for a particular reaction, what can be said about the equilibrium constant K?

Answer 14

K is greater than 1

K is opposite of ΔG° (∆G° = -RT ln(K))

Question 15

Isoelectric

Answer 15

Having no net electric charge. For amino acids with acidic side chains, the isoelectric point is the average of the two most acidic (lowest) pKa values.

Question 16

Western blotting

Answer 16

Gives us information about the amount of protein expressed in a cell

Question 17

RT-PCR

Answer 17

Gives us information about the amount of RNA expressed

Question 18

Southern blotting

Answer 18

Used to probe DNA for specific sequences

Question 19

Nucleoside

Answer 19

Composed of a nitrogenous base and a five carbon sugar (ribose or deoxyribose)

Ex) Adenosine

Question 20

What is most likely to have selective protein channels in the blood brain barrier to facilitate passage?

Answer 20

BBB is highly selective and will choose things only essential for brain function and small enough to be transported through a channel (prefers small and nonpolar). An example of this would be amino acids. (glucose and fructose as well)

Question 21

Why is folate common supplement to prevent neural tube defects?

Answer 21

Neural tube defects are defects in the central nervous system. The nervous system is derived from the ectoderm. It can be concluded from the given information that folate is important for neurulation, or the induction of the ectoderm to differentiate into the nervous system.

Question 22

A sample of bacteria has a doubling time of 30 minutes. If a student begins with 1 g of the bacteria, at what time will the sample weigh 583.8 g?

Answer 22

Between 4.5 and 5 hours