mcat - content review gaps

define variable penetrance

Variable penetrance refers to the percentage of individuals with a particular genotype who actually express the associated phenotype

• “all or nothing”

define variable expressivity

Variable expressivity refers to the degree/intensity to which a genotype is expressed in an individual's phenotype

define stabilizing selection

Stabilizing selection is a type of natural selection that favors intermediate phenotypes and acts against extreme variations, leading to a reduction in variability.

• babies’ average birth weight and mortality rates

define directional selection

Directional selection is a type of natural selection that favors one extreme phenotype over the mean or other extreme, resulting in a shift in the population's trait distribution over time.

• thick furred wooly mammoths

define disruptive selection

Disruptive selection is a type of natural selection that favors extreme phenotypes at both ends of the spectrum, leading to increased variability and potentially the formation of two or more distinct species.

• rock pocket mice

define speciation selection

Speciation selection is the process through which new species arise due to evolutionary pressures, often involving mechanisms such as genetic divergence, reproductive isolation, and varying ecological niches.

• darwin’s finches

this subatomic particle is used to determine an element’s identity

the proton

this subatomic particle is used to determine the isotope of an element

the neutron

this subatomic particle is used to determine the charge of an atom

the electron

if a neutral atom loses an electron, it becomes

a cation (loses negativity)

if a neutral atom gains an electron, it becomes

an anion (gains negativity)

describe the basic steps and structures involved in a neural reflex arc (5)

a sensory receptor that detects a stimulus

a sensory [afferent] neuron that transmits the signal to the spinal cord

an interneuron that processes the information

a motor [efferent] neuron that carries the response signal to an effector muscle or gland

and the effector itself that executes the response (muscle, gland, etc)

what is the role of the hypothalamus in the endocrine system

The hypothalamus regulates the release of hormones from the pituitary gland and produces ADH & oxytocin

• the control center

what is the role of the pituitary gland

The pituitary gland secretes hormones that regulate various body functions and controls other endocrine glands such as the thyroid

• the master gland of the endocrine system.

what is the role of the thyroid gland

The thyroid gland produces hormones that regulate metabolism, growth, and development (T3/T4)

what is the role of the parathyroid

regulate calcium levels in the blood and bones by secreting parathyroid hormone (PTH)

what is the role of the adrenal cortex

The adrenal cortex produces hormones such as cortisol, aldosterone, and androgens (steroids)

what is the role of the adrenal medulla

The adrenal medulla produces catecholamines, such as Epi and NE, which are involved in the body's fight-or-flight response.

what is the role of the gonads

produce sex hormones, such as testosterone and estrogen, and are involved in reproduction.

what is the role of the pancreas

The pancreas produces digestive enzymes and hormones, such as insulin and glucagon, that regulate blood sugar levels.

what are the common state functions

Temperature, volume, enthalpy, internal energy, gibbs free energy and entropy

• TV HUGS

define conduction heat transfer

the process of thermal energy transfer through direct contact between materials, where heat moves from a hotter object to a cooler one

define convection heat transfer

the transfer of heat by the movement of fluids, where warmer areas rise and cooler areas sink, creating a circulation of fluid.

define adiabatic

A process in which no heat is transferred to or from the system, typically occurring in a perfectly insulated environment.

what differentiates a major depressive disorder diagnosis from persistent depression disorder

Major depressive disorder is characterized by one major depressive episode

Persistent depression disorder (dysthymia) involves chronic symptoms lasting for at least two years, that are not severe enough to be classified as MDD

what is the major difference between bipolar I and bipolar II

Bipolar I disorder involves at least one manic episode, while Bipolar II disorder is characterized by at least one major depressive episode and at least one hypomanic episode without a full manic episode.

define agoraphobia

An anxiety disorder characterized by an intense fear of being in situations where escape may be difficult, often leading to avoidance of public places or situations.

differentiate the three clusters found within personality disorders

Personality disorders are categorized into three clusters:

Cluster A (odd, eccentric behaviors)
Cluster B (dramatic, emotional, erratic behaviors)
Cluster C (anxious, fearful behaviors).

• weird, worried, wild

what is the difference between a nerve and a tract

A nerve is a bundle of axons in the peripheral nervous system that carries many types of information, while a tract is a bundle of axons in the central nervous system that only carries one type of info.

where in the spinal cord do afferent neurons enter

Afferent neurons enter the spinal cord at the dorsal roots.

where in the spinal cord do efferent neurons exit

Efferent neurons exit the spinal cord at the ventral roots.

where in the spinal cord do autonomic neurons exit

Efferent neurons exit the spinal cord at the ventral roots to the lateral horn.

which amino acids are common targets for phosphorylation

Serine, threonine, and tyrosine are common targets for phosphorylation.

what are the products of a strong acid and a strong base

The products of a strong acid and a strong base are water and a neutral salt, typically formed through a neutralization reaction.

what are the products of a strong acid and a weak base

The products of a strong acid and a weak base are an acidic solution and an acidic salt

what are the products of a weak acid and a strong base

The products of a weak acid and a strong base are a basic solution and a basic salt