MCAT Biology

a methylated guanine nucleotide added to the 5' end of eukaryotic mRNA. The cap is necessary to initiate translation of the mRNA.

the band of the sarcomere that extends the full length of the think filament.

a period of time following an action potential during which no additional action potential can be evoked regardless of the level of stimulation

• the 3 glands of the male reproductive system that produce semen:
• seminal vesicles, prostate, and bulbourethral glands

liver, gallbladder, pancreas, salivary glands

the first substrate in the Krebs cycle, produced primarily from the oxidation of pyruvate by the pyruvate dehydrogenase complex.

cells that make up exocrine glands, and that secrete their products into ducts

a region at the head of a sperm cell that contains digestive enzymes which, when released during the acrosome reaction, can facilitate penetration of the corona radiata of the oocyte and fertilization

a contractile protein. In skeletal and cardiac muscle, it polymerizes to form the thin filaments

On of the four aromatic bases found in DNA and RNA. It is a purine and pairs with thymine (DNA) and uracil (RNA)

releases epinephrine and norepinephrine

the small artery that carries blood toward the capillaries of the glomerulus

produced by the liver to help maintain blood osmotic pressure

the 3' end of a tRNA molecule that binds an amino acid

a tRNA with an amino acid attached; made by an aminoacyl-tRNA synthetase

an enzyme that digests starch into disaccharides. Secreted by salivary glands and pancreas

male sex hormones

aka "vasopressin", is produced by the hypothalamus and secreted by the posterior pituitary. Targets the kidney tubules to increase their permeability to water and thus increase water retention

Aminoacyl-tRNA site; the site on a ribosome where a new amino acid is added to a growing peptide

a bacterium that cannot survive on minimal medium(glucose alone), because they cannot synthesize a molecule needed to live

rod-like shaped bacteria

the transfer of DNA or proteins from an electrophoresis gel to a nitrocellulose filter

the tendency of certain factors to stabilize hemoglobin in the tense conformation, thus reducing its affinity for oxygen and enhancing the release of oxygen to the tissues

the region of the nephron that surrounds the glomerulus. It collects the plasma that is filtered from the capillaries in the glomerulus.

A cytoplasmic Ca²⁺ binding protein, important in smooth muscle cells

outer protein coat of a virus

an enzyme in eruthrocytes that catalyzes the conversion of CO₂ and H₂O into carbonic acid

pepsinogen-secreting cells found at the bottom of the gastric glands of the stomach

a hormone secreted by the small intestine in response to the presence of fats. It promotes the release of bile from the gallbladder and pancreatic juices from the pancreas

a round shaped bacteria

an inorganic molecule that associates non-covalently with an enzyme, and that is required for the proper functioning of the enzyme

a type of substrate binding to a multi-active site enzyme, in which the binding of one substrate molecule facilitates the binding of subsequent substrate molecules

a general cell junction, used primarily for adhesion

the enzyme that replicates DNA. Eukaryotes have a single version and Prokayotes have 3

ultimately forms external structures such as skin, hair, nails, inner lining of mouth and anus, and the nervous sytem

the small artery that carries blood away from the capillaries of the glomerulus

a biochemical technique that utilizes antigen-antibody interactions to determine the presence of either antigens of specific immunoglobulins in a sample

ultimately forms internal structures, such as the inner lining of the GI tract and some glandular organs

a hormone secreted by the small intestine in response to the presence of food.

a duodenal enzyme that activates trypsinogen to trypsin

the specific site on an antigenic molecule that binds to a T-cell receptor or to an antibody

DNA that is loosely packed around histones. DNA is more accessible to enzymes and can be activated if needed

an organism that will use oxygen to produce energy if it is available, and that can ferment if it is not

a blood protein essential to blood clotting

a hormone released by the G cells of the stomach in the presence of food. Promotes muscular activity of the stomach as well as secretion of hydrochloric acid, pepsinogen, and mucus

a prokaryotic enzyme used to twist the single circular chromosome of prokaryotes upon itself to form supercoils.

a hormone secreted by the trophoblast cells of a blastocyst that prolongs the life of the corpus luteum, and thus increases the duration and amount of progesterone. This helps to maintain the uterine lining.

enzyme that unwinds the double helix of DNA and separates the DNA strands in preparation of replication

enzyme that catalyzes the phosphorylation of glucose to form glucose-6-phosphate in the first step of glycolysis

globular proteins that assist in DNA packaging in eukaryotes

the region at the center of an A band of a sarcomere that is made up of myosin only. Gets shorter with muscle contraction

the region of a sarcomere made up only of the thin filaments. Alternate with A bands to give striation

a chemical secreted by a T cell that stimulates activation and proliferation of other immune system cells

an enzyme that transfers a phosphoryl group from ATP to other compounds

The substrate concentration required to reach 1/2 V_max

acetyl-CoA is combined with oxaloacetate to form citric acid. The citric acid is then decarboxylated twice and isomerized to recreate oxaloacetate

states that two alleles of a given gene will be separated from one another during gamete formation

an enzyme that connects two fragments of DNA to make a single fragment. Used during DNA replication

an enzyme that lyses bacteria by creating holes in their cell walls

the cells of the distal tubule at the juxtaglomerular apparatus

ultimately forms "middle" structures such as bones, muscles, blood vessels, heart, kidneys,....

small fragments of DNA produced on the lagging strand during DNA replication, joined later by DNA ligase to form a complete strand

an enzyme that removes a phosphoryl group from a compound

enzyme used in third step of glycolysis (main regulatory step). PFK is feeback-inhibited by ATP

site of most reabsorption in nephron; all filtered nutrients as well as most filtered water is reabsorbed here

• peptidyl-tRNA site;
• site of a ribosome where the growing peptide is found during translation

enzyme secreted by juxtaglomerular cells when BP decreases; Renin converts angiotensinogen to angiotensin I

a rise in blod pH due to hyperventilation and a resulting decrease in CO₂

an organism that feeds of dead plants and animals

hormone secreted by the small intestine in response to low pH. Promotes the release of bicarbonate from the pancreas to act as a buffer

phase of cell cycle during which the genome is replicated

spiral shaped bacteria

enzyme that cuts one or both strands of DNA to relieve the excess tension caused by the unwinding of the helix by helicase during replication

the ends of a sarcomere

uses CO₂ as carbon source

capsid

the activation of the sympathetic nervous system

exocrine gland

difference between systolic and diastolic BP

due to the decrease in the level of expression of β-galactosidase

secreted in response to high serum Ca²⁺; it inhibits osteoclast-mediated bone breakdown and increases osteoblast-mediated bone formation

both increase bone reabsorption and decrease bone formation

spongy bone of flat bones

to reduce surface tension

after fertilization, before egg and sperm nuclear membranes fuse

allows you to detect the presence of specific sequences within a heterogeneous sample of DNA. Also allows you to isolate and purify target sequences of DNA

same as southern blotting, except that mRNAs are separated via gel electrophoresis instead of DNA

allows you to detect the presence of certain proteins with a sample and also serves as a diagnostic tool