Deck 7: Apoptosis

Question 1

The process of apoptosis

A) is a result of damage or disease.
B) does not occur in the brain.
C) is a natural process during normal development.
D) does not occur in ducks.

Answer 1

C

Question 2

The appearance of an apoptotic neuron is referred to as

A) pyknotic.
B) microglial.
C) pathological.
D) neurotrophic.

Answer 2

A

Question 3

_______ are responsible for "cleaning up" dead cells in vertebrate nervous systems.

A) Schwann cells
B) Oligodendrocytes
C) Pyknotic cells
D) Microglia

Answer 3

D

Question 4

The decline in the number of motor neurons coincides with the appearance of pyknotic cells, which indicates that

A) only damaged motor neurons die.
B) motor neurons die during normal development.
C) neurogenesis of motor neurons occurs throughout life.
D) motor neurons do not normally die during development.

Question 5

In addition to affecting the number of motor neurons, manipulating the number of limb buds in chick embryos also affects the

A) size of individual dorsal root ganglion cells.
B) size of individual motor neurons.
C) number of dorsal root ganglion cells.
D) number of sympathetic ganglia.

Question 6

Which neurotrophic factor prevents apoptosis in sympathetic and dorsal root ganglia?

A) Brain-derived neurotrophic factor
B) Nerve growth factor
C) Ciliary neurotrophic factor
D) Neurotrophin-3

Question 7

NGF is transported _______ in a neuron to _______ apoptosis.

A) retrogradely; promote
B) anterogradely; promote
C) retrogradely; prevent
D) anterogradely; prevent

Question 8

What is the primary high-affinity receptor for NGF?

A) TrkB
B) TrkC
C) Robo
D) TrkA

Question 9

The p75 receptor differs from Trk receptors in that it

A) can promote cell death.
B) has high affinity for all neurotrophins.
C) only binds a particular type of neurotrophin.
D) can bind NGF to promote cell survival.

Question 10

Which C. elegans gene signals phagocytes to engulf dead cells?

A) ced-1
B) ced-2
C) ced-3
D) ced-4

Question 11

Which C. elegans gene functions within a phagocyte?

A) ced-1
B) ced-2
C) ced-3
D) ced-4

Question 12

What would happen if the C. elegans gene ced-3 was not functional?

A) Too many cells would die
B) Phagocytes would not be able to clean up debris
C) Proteins within a cell would get dismantled prematurely
D) Cells that are supposed to die would not be able to die

Question 13

Which vertebrate enzyme initiates the apoptotic cascade?

A) Caspase-1
B) Caspase-3
C) Caspase-6
D) Caspase-9

Question 14

Which vertebrate proteins have opposing effects on apoptosis?

A) Diablo and Bax
B) Bcl-2 and Bax
C) IAPs and Bcl-2
D) Diablo and caspase-9

Question 15

A mutation in the antioxidant protein superoxide dismutase can lead to ALS by

A) failing to get rid of free radicals.
B) clearing away too many free radicals.
C) introducing a toxic gain of function.
D) acting in the motor neuron itself to kill it.

Question 16

If the superoxide dismutase gene is knocked out in mice, they will

A) develop ALS.
B) have a shortened lifespan but not develop ALS.
C) die at birth.
D) have a normal, healthy lifespan.

Question 17

Sexual differentiation is the process of

A) changing from one sex to another.
B) males and females mating.
C) gamete formation.
D) males and females taking different developmental pathways.

Question 18

What drives the developing mammalian gonads to form testes?

A) The presence of a Y chromosome
B) Anti-Müllerian hormone
C) Testosterone production
D) The absence of two X chromosomes

Question 19

A person born with testes who appears female/feminine externally most likely has

A) no Y chromosome.
B) an extra X chromosome.
C) a dysfunctional androgen receptor.
D) little to no testosterone production.

Question 20

In rodent development, what would happen if there was no α-fetoprotein to bind the circulating estrogen that comes from the mother's ovaries?

A) Testosterone would not be converted into estradiol.
B) All rats would develop into females.
C) Males would be feminized in behavior.
D) Females would be masculinized in behavior.

Question 21

A songbird species in which males have larger forebrain regions than females is an example of a(n)

A) sexual dimorphism.
B) mutation.
C) gyandromorph.
D) activational effect.

Question 22

Which brain nucleus is larger in female rats compared to male rats?

A) Anteroventral periventricular nucleus (AVPV)
B) Sexually dimorphic nucleus of the preoptic area (SDN-POA)
C) Spinal nucleus of the bulbocavernosus (SNB)
D) Posterodorsal nucleus of the media amygdala (MePD)

Question 23

In rats, the spinal nucleus of the bulbocavernosus undergoes greater _______ in _______.

A) apoptosis; females
B) apoptosis; males
C) neurogenesis; males
D) neurogenesis; females

Question 24

The muscles of Lawrence in fruit flies take on a masculine phenotype as long as the _______ have a male genotype.

A) muscle cells
B) wings
C) motor neurons
D) abdominal ganglia

Question 25

The fraternal birth order effect, in which the number of brothers a boy's mother carried before him influences his likelihood of growing up to be gay, is

A) the result of social influences from the older brothers.
B) the result of a genetic mutation.
C) proof that sexual orientation is a matter of choice.
D) only apparent in boys who are right-handed.

Question 26

Viktor Hamburger found that removing the limb bud from one side of a chick embryo resulted in fewer motor neurons on that side of the spinal cord at hatching. What are two possible mechanisms by which limb bud removal could decrease the motor neuron pool? What follow-up experiment was designed to clarify this result, and what did it find? What are two possible mechanisms that could explain the result of this follow-up experiment?

Question 27

What is the difference between a tropic effect and a trophic effect?

Question 28

Refer to the figure.
Two neurotrophic factors (A and B) were applied to either dorsal root (left column) or sympathetic (right column) ganglia. Which neurotrophic factor is represented by A and which is represented by B, and what do you know about the effects of each factor that support your conclusion?

Question 29

Why is the vertebrate enzyme caspase-3 referred to as the "executioner"? What information can be gathered from using immunohistochemistry to label caspase-3 in cells?

Question 30

Describe how testosterone has both activational and permissive effects on male rodent mating behavior.

Question 31

Refer to the figure.
Describe the sexual dimorphism is apparent in normal male and female rats, and what might have caused this (A and B in the figure)? How does the experimental manipulation (C and D in the figure) illustrate the organizational hypothesis of sexual differentiation?

Question 32

Adult male, but not female, rodents have SNB motor neurons and muscles. Research has shown that androgens spare the death of SNB motor neurons in male rodents, and this effect is dependent on a functional androgen receptor. Developing females treated with androgens before these cells died retained the SNB motor neurons and muscles for life. What evidence indicated that this was not a cell-autonomous effect? What naturally occurring phenomenon did researchers exploit to make this determination? (Hint: The gene for androgen receptors is on the X chromosome.)

Question 33

What is it about Drosophila sexual differentiation that makes it possible for an individual fly to be fully masculine in some parts of the body and fully feminine in other parts? What is the term that refers to these types of individuals?

Question 34

What are the major ways that sexual differentiation differs between mammals and Drosophila? What is one way sexual differentiation is similar in mammals and Drosophila?

Question 35

Why might the evidence that some fruitless gene mutations cause same-sex courting behavior in Drosophila not be relevant to human sexual orientation?