MCAT BIOLOGY

5-Cap

methylated guanine added to end of mRNA helps initiate translation

A - Band

band of sarcomere that extends to full length of the thick filament and includes thick and thin over lap

A - site

Arrival tRNA site on the ribosome where new AA is added

Accessory glands

three glands in the male reproductory system bulbourethral glands, prostate, and seminal vesicles

Accessory Organs

GI tract: gall bladder, pancreas, salivary glands

Reproductive: anything that’s not the ovaries or testes

acetylcholine (ACh)

neurotransmitter used throughout the parasympathetic nervous system and muscular junctions

Acetylcholinesterase

enzyme that breaks down Ach in synaptic cleft

acids hydrolase

enzyme that degrade molecules but require pH to work in lysosomes

acinar cells

cells part of exocrine glands and ducts pancreas and salivary glands

acrosome

region in the head of a sperm cell that contains digestive enzymes penetrate corona radiata

actin

contractile protein, thin filaments in muscle and cytoskeleton

active transport

movement of molecules against their concentration gradient that requires cellular input like ATP

Adenine

purine, 1H donor, 1H acceptor, binds to thymine

adenohypophysis

anterior pituitary gland

adipocyte

fat cell, stores as triglycerydes

adrenal medulla

inner region of adrenal gland that is part of the sympathetic nervous system and releases Epinephrine and norepinephrine.

adrenergic tone

constant stimulation to arteries that keep them somewhat constricted

Adrenocorticotropic hormone (ACTH)

anterior pituitary peptide hormone that targets the adrenal cortex to release cortisol and aldosterone

afferent arteriole

small artery that carries blood toward capillaries of glomerulus

afferent neuron

sensory neuron that carries info to the CNS

albumin

blood protein protein that helps maintain blood pressure through oncotic pressure

aldosterone

steroid hormone released from adrenal cortex that acts on the distal convoluted tubule to reabsorb more sodium

alimentary canal

digestive tract

Anti diuretic Hormone

also called vasopressin, produced in hypothalamus and secreted by the posterior pituitary, acts on collecting duct to increase water retention in the body

anitgen

a molecule that can trigger an immune response

antigen presenting cell

B cells and macrophages. display parts of ingested antigens to activate T cells

antiport

a carrier protein that transports one molecule in each direction

apoptosis

programmed cell death

aqueous humor

fluid in the anterior chamber of the eye

arousal

function of reproduction system controlled by the parasympathetic system including erection, dilation of arteries and lubrication

alveoli

sac that are sites of gas exchange in the lungs

amino acid activation

tRNA loading of AA

amnion

sac filled with fluid surrounding the embryo amniotic fluid

amylase

digest starches into disaccharides in saliva and secreted by pancreas

anabolism

building of complex structures out of simple precursors

anaphase

third phase of mitosis where sister chromatids are split and brought to opposite ends of the cell

Anaphase 1

third phase of meiosis 1 separation of homologous chromosomes. to each side of the cell

Anaphase 2 third phase of meiosis 2

now the homologous chromosomes are separated at the centromere so each cell gets a homologous chromatids

adrogens

males sex hormones Testosterone

anergic

immune cells that have become unresponsive and don’t go through apoptosis. B and T cells that recognize self antigens

angiotensinogen

precursor to RAAS system that acts to raise blood pressure through angiotensin 2 that vasoconstricts and releases aldosterone

antagonist

acts in opposite action of something else

antibody

also called immunoglobulins are proteins released by plasma cells that are highly specific proteins that bind to foreign proteins

artery

carries blood away from hard and have high pressure

Blood pressure

sys/dia. Done by going up to very high pressure when the beat is first heard that is systolic and when the beat is no longer heard that is diastolic

atrioventricular bundle

or bundle of his cardiac conduction fibers

AV valves

valves that separate atria and ventricles

attachment

first step in viral infection

auditory tube

or the eustachian tube connect the middle ear with the pharynx

autoimmune

immune reaction directed toward normal tissue

autonomic nervous system (ANS)

branch of the PNS that deal with involuntary innervation of organs with sub branches of the parasympathetic (rest and digest) and the sympathetic

autotroph

organism that makes its own food with CO2 as a source

auxotroph

an organism that cannot survive on the minimal amount of glucose because it cant synthesize a certain necessary compound

avascular

lacking blood supply

axon

long projection of cell body of neurons

B cell

lymphocyte that can recognize an antigen and secrete an antibody specific for that antigen. Mature into plasma cells or memory cells

bacillus

bacteria that has a rod shape

bacteriophage

is a virus that infects a bacteria

baroreceptor

sensory receptor that responds to pressure like blood pressure

basement membrane

layers of collagen that separate epithelium from connective tissue

basilar membrane

flexible membrane that supports the cochlea. Fibers are short and stiff at the entrance, to transduce high pitched/intensity sound. long and flexible at the end to traduces low pitch/intensity sound

bicarbonate

HCO3^- dissociation of H2CO3 carbonic acid and is the major buffer system for blood. Used to neutralize stomach acid secreted in the pancreas secretin

bicuspid valve

left AV valve also called mitral

bile

green fluid from the gall bladder that emulsifies fats for better digestion by lipases caused by CCK stimulation

binary fission

the asexual reproduction of bacteria that only serves to increase population there is no increase in genetic diversity

bipolar cells

connected directly to rods and cones and they play a crucial role in transmitting visual information from the light-detecting cells to the cells that transmit signals to the brain. 

blastocyst

fluid filled sphere formed 5 days after fertilization made of an outer ring of cells and an inner cell mass. Implants in the endometrium of the uterus

Bohr Effect

Right shift of hemoglobin oxygen saturation curve. Caused by acidosis, increased CO2, Increased bisphosphoglycerate, increased temp. more oxygen available to tissues

boiling point elevation

change in booiling point due to a change in solute

T=i*K*m

T=change in temp (K)

i= van hoff factor

K=boiling point elevation constant

m=molality mols/kg

Bone marrow

red bone marrow; site of blood cell production

yellow bone marrow: mostly fat and inactive

bownma’s capsule

region of nephron that surrounds the nephron

bronchioles

small tubes in the respiratory system. Terminal bronchioles end conducting zone and starts respiratory zone

brush border enzymes

enzymes secreted from the mucosal lining of the intestines and break molecules down to their smallest units

bulbourethral glands

secret alkaline fluid to combat the acidic environment of the vagina also lubricates

Calcitonin

produced by C cells in the thyroid and stimulates osteoblasts to deposit Ca into bones decreasing blood Ca concentration. Inhibits osteoclasts

Calcitriol

hormone derived from vitamin D that acts to produce serum calcium levels and inhibits blast and stimulates clasts. Product of PTH vitamin D activation

calmodulin

cytoplasmic Ca binding protein. important in smooth muscle cells

Cyclic AMP (cAMP)

a crucial intracellular signaling molecule that acts as a second messenger, relaying signals from extracellular stimuli into cells. plays a role in regulating various cellular processes, including metabolism, gene expression, and immune responses. Regulated by adenyl cyclase which is controlled by outside ligands.

capacitation

increased fragility of a sperm cell membrane when entering the uterine tract. This helps acrosome release

capillary

smallest diameter vessel and gas exchange

capsid

outer protein coat of a virus

carbonic anhydrase

enzyme in erythrocytes that converts H2O and CO2 into carbonic acid

Cardiac conduction system

SA node, AV node, bundle of his/AV bundle, purkinge fibers

Cardiac muscle

Striated, uninucleated, involuntary control

cardiac output

CO (L/min) = HR (Beats/min) * SV(Liters/Beat)

caridac sphincter

low esophageal sphincter

carrier protein

intermembrane protein that binds to the molecule it is moving and undergoes a conformational changes during movement. Ex symport, antiport, symport

cartilage

Elastic is the most flexible. Hyaline cartilage not as flexible and is present in the ribs for the respiratory cavity. fibrocartilage least flexible like the pubic synthesis and in between discs

caspases

family of proteases that carry out apoptosis

catalase

primary enzyme in peroxisomes that catalyze the hydrolysis of H2O2 into water and oxygen

cDNA

complementary DNA that is produced synthetically by reverse transcribing mRNA because of this cDNA has no introns do to splicing

cecum

first part of large intestine

cell theory

Robert Hooke proposed that all living things are composed of cells

central canal

hollow portion of an osteon that contains blood vessels and lymphatic vessels. the osteon is created around this central canal in layer call lamellae

central chemoreceptors

receptors in the CNS that monitor pH of cerebrospinal fluid and regulate ventilation rate

Central Nervous system

brain and spinal cord

centriole

cylindrical microtubule organizing centers and are duplicated in mitosis and organize the mitotic spindle

centromere

crimping of the eukaryotic chromatids that is attached to during mitosis

cerebellum

region of brain that coordinates and smoothes muscle movement

cerebral cortex

gray matter that is the conscious mind divided into the four lobes frontal, parietal, temporal, and occipital