Biological and Biochemical Foundations of Living Systems

Question 1

What is the body’s physiological response to reduced leptin?

Answer 1

A starvation response (increased cortisol, appetite, insulin resistance).

Question 2

How are blood calcium levels increased?

Answer 2

By stimulating osteoClasts to Catabolize bone, releasing calcium.

Question 3

How many molecules of ATP are produced per molecule of glucose by an aerobic organism?

Answer 3

36 ATP/glucose.

Question 4

How many molecules of ATP are produced per molecule of glucose by an obligate anaerobic organism?

Answer 4

2 ATP/glucose.

Question 5

Water forms a solvation layer around non-polar groups, but what about polar groups?

Answer 5

Still forms a solvation layer, but to a lesser extent.

Question 6

How is the secondary structure of proteins determined?

Answer 6

By hydrogen bonding.

Question 7

_________ play an important role in the tertiary and quaternary structures of proteins.

Answer 7

Hydrophobic interactions.

Question 8

A man with type AB blood and a woman with type O blood have children. What blood types might their children inherit?

Answer 8

Either type A or type B (think mendelian genetics where A and B are dominant and O is recessive).

Question 9

What part of an RNA strand gets bound by the repressor when no inducer is present?

Answer 9

The repressor binds the operator, preventing transcription.

Question 10

How many hydrogen bonds do Adenine and Thymine form with each other? What about Guanines and Cytosines?

Answer 10

AT = 2 H bonds (will denature faster)
GC = 3 H bonds

Question 11

Denaturation of DNA is ________ while renaturation is ________.

Answer 11

Endothermic. Exothermic.

Question 12

What are the centrioles composed of?

Answer 12

Microtubules.

Question 13

Microtubules attach to chromosomes at ______.

Answer 13

Centromeres.

Question 14

What are the products of the citric acid cycle?

Answer 14

1 GTP
3 NADH
1 FADH₂
2 CO₂
Oxaloacetate

Question 15

What is the function of sodium-potassium pumps during propagation of an action potential?

Answer 15

To pump sodium out of the cell after depolarization. Repolarizes the cell for future action potentials.

Question 16

During glycolysis, how many molecules of ATP are produced per molecule of glucose?

Answer 16

2 molecules ATP per glucose.

Question 17

______ _______ in proliferating ______ cells can lead to cancer.

Answer 17

Genetic mutations. Somatic.

Question 18

Why might host antibodies fail to recognize a bacterial infection in the stomach?

Answer 18

Because the antibodies are denatured by the acidic environment and can’t function.

Question 19

Leukocytes in the body migrate to sites of _________.

Answer 19

Inflammation.

Question 20

What is the primary reason for losing water through the skin?

Answer 20

To regulate body temperature.

Question 21

What is the function of a lipase?

Answer 21

To catalyze the hydrolysis of fats AND other stuff that has a carboxylic acid ester linkage.

Question 22

During bacterial reproduction, what process is associated with the F factor plasmid?

Answer 22

Conjugation.

Question 23

If some genes in a bacteria are located apart from the chromosomes, what does this imply?

Answer 23

That the separated genes are self-replicating.

Question 24

When vertebrate oocytes undergo meiosis, most of the cytoplasm goes to the ____ while very little goes to the ____ ____.

Answer 24

Ovum. Polar bodies (/nurse cells?).

Question 25

Which "replication" process is mRNA (messenger RNA) directly involved in?

Answer 25

RNA translation.

Question 26

How do bacteria become resistant to antibiotics?

Answer 26

Some bacteria in a population are already resistant. When all their competition is killed off, these flourish. Antibiotics do not "cause" the bacteria to mutate and develop resistance.

Question 27

What process causes norepinephrine to be released into the synapse?

Answer 27

An action potential opens calcium channels which floods the synapse with calcium, triggering a series of events which culminate in norepinephrine release.

Question 28

What blood component is not expected to be filtered out by the kidneys?

Answer 28

Proteins, which are too big to exit the fenestrated capillaries in the glomerulus.

Question 29

When during mitosis do the tubulin polymers shorten? What event is occurring during this time?

Answer 29

During anaphase, when the chromosomes are pulled towards the poles of the cells.

Question 30

Where does calcium bind in the muscle cells to allow muscle contraction?

Answer 30

Binds to the troponin complex, allowing tropomyosin to expose the myosin-binding sites on actin.

Question 31

How is blood glucose conserved by the kidney?

Answer 31

It gets filtered out in the glomerulus and then reabsorbed in the proximal convoluted tubule.

Question 32

Why might a researcher choose erythrocytes if they wanted to study only plasma membrane proteins?

Answer 32

Erythrocytes lack organelles, so when broken down all you get is plasma membrane proteins and not organelle membrane proteins.

Question 33

Which type of bond is formed to link a lengthening glycogen polymer?

Answer 33

α-1,4-Glycosidic bonds.

Question 34

Serotonin is released from the neuron via what transport mechanism?

Answer 34

Exocytosis.

Question 35

_____ molecules generally have difficulty diffusing across cell membranes.

Answer 35

Polar.

Question 36

For a monomeric enzyme, what level of protein structure is the most important for functioning?

Answer 36

Tertiary structure.

Question 37

What occurs to sperm mitochondria when they enter the egg? What is the result of this?

Answer 37

All sperm mitochondria disintegrate. Therefore, they are not replicated and all future mitochondria come from the mother's gene line.

Question 38

What is the defining feature of purine structure? What about pyrimidine structure?

Answer 38

Purine: double ring Pyrimidine: single ring.

Question 39

Describe commensalism.

Answer 39

One species benefits, the other neither benefits nor suffers.

Question 40

Where do normal gut flora "hang out"? What does this allow them to do?

Answer 40

In the cecum, the outpouching of the large intestine (right after the small intestine). This allows them to re-colonize the gut after the gut has been cleansed of bacteria.

Question 41

Which enzyme is responsible for the last step in DNA repair? What does it act alongside?

Answer 41

DNA ligase links the new bases back together after the faulty ones are replaced by polymerase.

Question 42

What is the most prevalent protein in the human body?

Answer 42

Collagen.

Question 43

What are the 3 stop codons?

Answer 43

1. UAA (U are away) 2. UGA (U go away) 3. UAG (U are gone)

Question 44

What is the formula for osmotic pressure?

Answer 44

P = iMRT where P is pressure, i is the # of particles in solution after dissociation, R is the gas constant, T is temp in Kelvin, and M is molarity

Question 45

What are the X steps of glycolysis?

Answer 45

1. Glucose 2. G6P 3. F6P 4. F1,6bP 5. DHAP and G3P 6. 1,3 bPG 7. ATP and 3P 8. Pyruvate and ATP

Question 46

How many molecules of ATP are produced by glycolysis?

Answer 46

4 produced but 2 used, so net +2 ATP.

Question 47

Hemoglobin exhibits what kind of enzyme characteristic?

Answer 47

Allosteric effects (cooperativity) whereby the binding of oxygen increases the ability of subsequent oxygen to bind.

Question 48

What differentiates epimers?

Answer 48

They differ in structure/orientation at only one carbon (think of a fischer projection).

Question 49

What term is used to describe a signalling cascade in development which changes the structure/function of developing tissues through chemical mediators?

Answer 49

Induction. (blah INDUCES blah).

Question 50

At what point do cells in the embryo lose totipotency?

Answer 50

Very early on in development when we're still talking about the "X-cell stages".