BAPSY Biological Basis of Behavior 3 — Questions and Answers
Question 1: Which part of the neuron integrates incoming signals and initiates the action potential?
- Dendrites
- Cell body (soma)
- Axon hillock (Correct answer)
- Synaptic terminal
Correct answer: Axon hillock
The axon hillock sums excitatory and inhibitory postsynaptic potentials and fires an action potential when the threshold is reached.
Question 2: Heritability estimates in behavioral genetics reflect:
- The percentage of a trait caused by genetics in an individual
- The proportion of population variance in a trait attributable to genetic differences (Correct answer)
- Whether a trait is determined entirely by genes
- The probability a child will inherit a disorder from a parent
Correct answer: The proportion of population variance in a trait attributable to genetic differences
Heritability is a population statistic indicating what proportion of trait variability in a specific population is due to genetic variation.
Question 3: The reticular activating system (RAS) in the brainstem plays a key role in regulating:
- Voluntary motor control of limbs
- Arousal and states of consciousness (Correct answer)
- Procedural memory consolidation
- Spatial navigation and memory
Correct answer: Arousal and states of consciousness
The RAS modulates arousal, wakefulness, and attention by sending diffuse activating signals to the cortex.
Question 4: Which hormones are released by the adrenal medulla during acute stress?
- Cortisol and aldosterone
- Epinephrine and norepinephrine (Correct answer)
- Testosterone and estrogen
- Oxytocin and vasopressin
Correct answer: Epinephrine and norepinephrine
The adrenal medulla releases epinephrine (adrenaline) and norepinephrine in response to acute stress via sympathetic nervous system activation.
Question 5: In the context of genetics, a phenotype that appears only when two copies of a recessive allele are present is called:
- Codominant
- Autosomal dominant
- Polygenic
- Autosomal recessive (Correct answer)
Correct answer: Autosomal recessive
Autosomal recessive traits require homozygous recessive genotype (two copies of the recessive allele) to be expressed phenotypically.
Question 6: The cerebellum is primarily responsible for:
- Processing emotional memories and fear responses
- Coordinating movement, balance, and fine motor skills (Correct answer)
- Regulating hunger and thirst drives
- Producing and secreting pituitary hormones
Correct answer: Coordinating movement, balance, and fine motor skills
The cerebellum fine-tunes motor movements, maintains balance, and is essential for motor learning and coordination.
Question 7: When a neurotransmitter binds to an inhibitory postsynaptic receptor, the most common result is:
- Depolarization of the postsynaptic membrane toward threshold
- Hyperpolarization making the cell less likely to fire (Correct answer)
- Release of additional neurotransmitter from the presynaptic terminal
- Retrograde signaling back to the presynaptic neuron
Correct answer: Hyperpolarization making the cell less likely to fire
Inhibitory receptors typically open chloride channels or potassium channels, hyperpolarizing the membrane and reducing the probability of an action potential.
BAPSY Biological Basis of Behavior 3
Which part of the neuron integrates incoming signals and initiates the action potential?