Biology

Question 1

Hardy-Weinberg Equation

Answer 1

p + q = 1, p = frequency of S, q = frequency of s
p^2 + 2pq + q^2 = 1
p^2 = SS, 2pq = Ss, q^2 = ss

Question 2

SRY Gene

Answer 2

mammalian sex-determining gene, found on Y chromosome (male) its expression induces development of the testes–absence of the SRY protein = female

Question 3

A subset of aggressive cancers has a relatively high growth rate, leading to formation of large tumors. An effective drug against fast-growing tumors would most likely NOT target which stage of the cell cycle?

Answer 3

G0–cells within tumors are actively dividing, can be assumed that majority of the cells are in interphase and not arrested in G0

Question 4

What do kinesin motors do?

Answer 4

transport mitochondria and other intracellular cargo along microtubules in anterograde axonal transport (away from nucleus)

Question 5

Dynein

Answer 5

participates in retrograde axonal transport of intracellular cargo (towards nucleus)

Question 6

Mature egg and sperm

Answer 6

are both haploid (1N), they each contain 22 unpaired autosomes and 1 sex chromosome, resulting in 23 chromosomes

Question 7

Southern Blot

Answer 7

used to detect a particular sequence of DNA, can determine relative gene count

Question 8

Northern Blot

Answer 8

detects a particular sequence of RNA, cannot determine relative gene count

Question 9

Menopause

Answer 9

production of estrogen and progesterone within the ovaries declines substantially, leading to numerous physiological changes

Question 10

Vasoconstriction

Answer 10

smaller blood vessel diameter, less blood flow, higher BP

Question 11

Vasodilation

Answer 11

larger blood vessel diameter, increased blood flow, lower BP

Question 12

The genetic code is said to be degenerate because there are 64 different codons, but translation produces only 20 unique AAs. The degeneracy of the genetic code is due to which mechanism?

Answer 12

nontraditional base pairing of the anticodon with the third base of the codon

Question 13

What helps maintain the resting membrane potential of a neuron?

Answer 13

passive transport, adenosine triphosphate, membrane selective permeability

Question 14

Bacteriophages

Answer 14

viruses that exclusively infect bacteria, life cycle can be lytic or lysogenic

Question 15

Lytic Life Cycle

Answer 15

1. Attachment
2. Viral Genome Entry
3. Host Genome Degradation
4. Synthesis
5. Release

Question 16

Archaea

Answer 16

unicellular, have a circular chromosome, have no membrane-bound organelles or nucleus, and reproduce asexually via binary fission (do not have peptidoglycan cell wall)

Question 17

During a parasitic infection, which of the following would most likely be responsible for phagocytosis of organisms and the release of histamine, respectively?

Answer 17

Macrophages, basophils

Question 18

Basophils

Answer 18

release chemical mediators, such as histamine, enhance immune response

Question 19

Mast cells

Answer 19

release chemical mediators, such as histamine, modulate allergic reactions

Question 20

Neutrophils

Answer 20

kill and phagocytize bacterial cells

Question 21

Eosinophils

Answer 21

defend against parasitic infections and modulate immune responses during allergic rxns

Question 22

NK cells

Answer 22

release toxins to destroy virus-infected body cells

Question 23

B cells

Answer 23

identify foreign pathogens, antigen presenting, and producing antibodies

Question 24

T cells

Answer 24

mediate a number of immune responses, including those against viruses, bacteria and parasites

Question 25

WT1 and c-Myc most likely alter TERT transcription levels by doing which of the following at the TERT gene promoter?

Answer 25

inhibit and facilitate RNA polymerase binding, respectively

Question 26

Alternate Splicing

Answer 26

produces multiple protein products from the same gene, not multiple similar genes

Question 27

Conjugation

Answer 27

exchange of genetic info between prokaryotes, typically in form of plasmid DNA

Question 28

Transformation

Answer 28

occurs when prokaryotes pick up foreign genetic material from their surroundings

Question 29

Hormones secreted by the adrenal medulla most likely influence energy metabolism by:

Answer 29

inhibiting proteins that mediate glycogen synthesis

Question 30

Endocytosis

Answer 30

a type of transport in which molecules that can’t cross the plasma membrane enter through vesicles (endosomes) formed by the plasma membrane

Question 31

Receptor-mediated Endocytosis

Answer 31

highly specific, a particular extracellular molecule binds to its corresponding receptor on the cell surface—binding triggers invagination of plasma membrane

Question 32

Spleen

Answer 32

filters aged/damaged red blood cells (RBCs), reservoir for blood, immune response (B cell activation site, housing macrophages)

Question 33

Sodium Dodecyl Sulfate (SDS)

Answer 33

strong anionic detergent that denatures and confers a net negative charge on the protein, eliminating its shape and charge as separation factors (SDS disrupts only noncovalent bonds)

Question 34

2-mercaptoethanol

Answer 34

added to disrupt disulfide bridges, allowing each subunit to separate as individual polypeptides

Question 35

What are the functions of liver cells?

Answer 35

regulate blood glucose, storage of glycogen, synthesis of macromolecules, production and secretion of bile, breakdown/detoxification of numerous drugs and metabolic waste products

Question 36

What are functions of the liver?

Answer 36

Ketogenesis (synthesis of ketone bodies) if glycogen stores are depleted, detoxification of drugs, synthesis of plasma proteins

Question 37

Compared with blood in the pulmonary veins, blood in the pulmonary arteries has higher concentrations of:

Answer 37

H+ and CO2 than O2

Question 38

Which cellular process would most likely lead to increased genetic diversity in a population of organisms?

Answer 38

synapsis involving two homologous chromosomes—in prophase I of meiosis, homologous chromosomes recognize each other and line up side by side

Question 39

Alternative Splicing

Answer 39

a single gene transcript is processed to produce various mRNA molecules that encode different proteins, depending on the inclusion or exclusion of particular exons

Question 40

Fluid Mosaic Model

Answer 40

all components can migrate laterally through the membrane

Question 41

Peroxisome

Answer 41

contain various oxidoreductase enzymes and function to help maintain the proper oxidation state within cells

Question 42

Protons from the cytosol most likely enter the endosomal lumen by which of the following processes?

Answer 42

active transport; energy is required to pump protons into lumen against the concentration gradient (cytosol has low H+, high pH)

Question 43

Capsid

Answer 43

ALL viruses contain this protective protein coat

Question 44

Enveloped Viruses

Answer 44

have an additional phospholipid bilayer surrounding the capsid

Question 45

Non-enveloped Viruses

Answer 45

aka naked viruses, have only a capsid, but are more resistant to heat, detergents, and changes in moisture

Question 46

Prion

Answer 46

a misfolded protein that acts as an infectious agent by inducing other normal proteins to change their secondary structure and become misfolded; become less soluble, aggregate and can cause disease, do not contain genetic material and cannot transform bacteria

Question 47

Viroids

Answer 47

pathogenic, circular, single-stranded RNA molecules lacking protein coats and primarily affect plants—silence expression of specific genes and inhibit protein synthesis by binding RNA sequences; they hide inside viruses or damaged tissue

Question 48

The neuroendocrine signaling cascade that induces adrenal hyperplasia involves coordinated activity among:

Answer 48

hypothalamus, pituitary gland, adrenal glands, respectively

Question 49

How is the serum level of glucose regulated?

Answer 49

the hormones insulin, glucagon, epinephrine, norepinephrine, and the glucocorticoids

Question 50

Why is aldosterone secreted by the adrenal cortex?

Answer 50

in response to elevated plasma potassium and decreased blood pressure—acts on kidneys to increase reabsorption of sodium and water and ultimately blood volume and pressure

Question 51

Pyrimidines

Answer 51

one-ringed bases (C and T)

Question 52

Purines

Answer 52

two-ringed bases (A and G) for RNA it is (A and U)

Question 53

Hormones secreted from the posterior pituitary are synthesized in the:

Answer 53

hypothalamus

Question 54

Human cardiac muscle differs from skeletal muscle because it:

Answer 54

contains intercalated discs

Question 55

The gustatory-salivary reflex can be modulated by input from higher centers in the CNS. To modulate the salivary response, descending pathways from the brain would most likely synapse onto which part of the reflex arc?

Answer 55

the preganglionic neuron—reflexes are involuntary responses to stimuli that don’t require input from brain

Question 56

Somatic Nervous System

Answer 56

voluntary motor nerve fibers transmit impulses form CNS to skeletal muscles

Question 57

During periods of stress, many individuals experience dry mouth caused by decreased salivation. Which of the following functions would also be expected to decrease during periods of stress?

Answer 57

digestive peristalsis