An organism's genetic makeup is its genotype, while its observable inherited characteristics make up its phenotype.
Missing Word
phenotype
Phenotype refers to the traits that can be observed, such as eye color, which result from both genes and environment. It contrasts with genotype, the underlying genetic makeup.
Category: Genetics and Evolution
Question 2
A person who carries two identical alleles for a gene, such as BB or bb, is described as homozygous for that gene.
Missing Word
homozygous
Homozygous means both alleles for a gene are the same. A person with two different alleles, such as Bb, is heterozygous.
Category: Genetics and Evolution
Question 3
The field that studies how experiences and environment alter gene expression without changing the DNA sequence itself is called epigenetics.
Missing Word
epigenetics
Epigenetics explains how people with the same genotype, such as identical twins, can come to show different phenotypes as environmental factors switch genes on or off over a lifetime.
Category: Genetics and Evolution
Question 4
The cell body of a neuron, which contains the nucleus, is also known as the soma.
Missing Word
soma
The soma is the cell body of the neuron. It houses the nucleus, and the dendrites and axon extend from it.
Category: Neurons and Synapses
Question 5
The neurotransmitter released by motor neurons to make skeletal muscles contract, which is also important for memory, is acetylcholine.
Missing Word
acetylcholine
Acetylcholine carries the signal from motor neurons to muscle fibers and also plays a role in memory and cognition.
Category: Neurons and Synapses
Question 6
Many antipsychotic drugs block receptors for the neurotransmitter dopamine, reducing symptoms linked to excess activity of that chemical.
Missing Word
dopamine
Dopamine is involved in mood, reward and movement. Antipsychotics that act as dopamine antagonists are used to treat symptoms associated with too much dopamine activity.
Category: Neurons and Synapses
Question 7
In the peripheral nervous system, bundles of axons are called nerves.
Missing Word
nerves
Nerves are bundles of axons that connect the central nervous system to the muscles, organs and senses of the body.
Category: Nervous System Divisions
Question 8
The sympathetic and parasympathetic divisions work together to maintain homeostasis, a balanced state in which conditions such as body temperature stay at optimal levels.
Missing Word
homeostasis
Homeostasis is the body's maintenance of stable internal conditions. The two autonomic divisions have opposite effects, and their balance keeps the body in this state.
Category: Nervous System Divisions
Question 9
The hippocampus, a seahorse-shaped limbic structure in the temporal lobe, is essential for forming new long-term memories of facts and events.
Missing Word
hippocampus
The hippocampus is a limbic structure that is essential for forming new explicit memories. Damage to it, as in the patient H.M., leaves old memories and motor learning largely intact but blocks the storage of new facts and events.
Category: Brain Structures
Question 10
The hypothalamus regulates body temperature, appetite and blood pressure and links the nervous system to the endocrine system.
Missing Word
hypothalamus
The hypothalamus is a small forebrain structure that controls homeostatic functions and directs the pituitary gland, connecting brain and hormones.
Category: Brain Structures
Question 11
The hindbrain structure that coordinates balance and smooth movement and is linked to procedural memory is the cerebellum.
Missing Word
cerebellum
The cerebellum, at the back of the brain, fine-tunes movement and balance and supports skills such as riding a bicycle.
Category: Brain Structures
Question 12
The longitudinal fissure divides the brain into left and right halves, each called a cerebral hemisphere.
Missing Word
hemisphere
A cerebral hemisphere is one half of the cerebrum. The two hemispheres are separated by the longitudinal fissure and connected by the corpus callosum.
Category: Cerebral Cortex
Question 13
A PET scan tracks a radioactive tracer in the blood to show which brain regions are active.
Missing Word
PET
PET stands for positron emission tomography. It shows activity through blood flow to active regions but gives less detail and poorer timing than fMRI, and it involves radiation exposure.
Category: Brain Imaging
Question 14
Epinephrine and norepinephrine are released during the stress response by the adrenal glands, which sit atop the kidneys.
Missing Word
adrenal
The adrenal glands sit on top of the kidneys and secrete epinephrine and norepinephrine, hormones that increase arousal and metabolic activity during stress.
Category: Endocrine System
Question 15
The pancreas releases insulin to lower blood glucose and glucagon to raise it.
Missing Word
glucagon
Glucagon is a pancreatic hormone that raises blood sugar, working opposite to insulin so that blood glucose stays stable.
Category: Endocrine System