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MCAT Prep Biology

Subjects : mcat, science
Instructions:
  • Answer 50 questions in 15 minutes.
  • If you are not ready to take this test, you can study here.
  • Match each statement with the correct term.
  • Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. An organism (such as a fungus) that feeds of dead plants and animals.






2. The smalles of all blodo vessles - typically having a diamtere just large neough for blood cells to pass through in single file. Capillaries have extremelyu thin walls to faciliate the exchange of material between the blood and the tissues.






3. A clump of gray matter (unmyelinated neuron cell bodies) found in the peripheral nervous system.






4. A point mutation in which a codon that specifies an amino acid is mutated into a codon that specifies a different amino acid.






5. The amount of blood returned to heart by the vena cavae.






6. The characteristics of amolecule that has both polar (hydrophilic) and non - polar hydrophobic) regions - e.g. phospholipids - bile - etc.






7. A relatively direct connection between a sensory neuron and a motor neuron that allows an extremely rapid response to a stimulus - often without conscious brain involvement.






8. An enzyme present in erythrocytes (as well as in other places) that catalyzes the conversion of CO2 and H2O into carbonic acid (H2CO3).






9. The resistance to blood flow in the systemic circulation. Peripheral resistance increases if arteries constrict (diameter decreases) - and an increase in peripheral resistance leads t o an increase in blood pressure.






10. One of the four aromatic bases found in DNA and RNA. Cytosine is a pyrimidine; it pairs with guanine.






11. Movement that is directed by chemical gradients - such as nutrients or toxins. (seen in some bacteria)






12. An enzyme secreted by the juxtaglomerular cells when blood pressure decreases. Renin onverts angiotensinogen to angiotensin I.






13. A cell that produces bone.






14. An 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.






15. The clear portion of the tough outer layer of teh eye ball - found over the iris and pupil






16. A fibrous - connective - tissue protein taht has the ability to recoil to its original shape after being stretche.d Elastin is found in great amounts in lung tissue - arterial tissue - skin - and the epiglottis.






17. A neuron - to - neuron - neuron - to - organ - or muscle to cell - to - muscle cell junction.






18. (1) The secretion of useful substances from a cell - either into the blood (endocrine secretin) or into a cavity or onto the body surface (exocrine secretion). (2) in the nephron - the movement of substances from the blood to the filtrate along the t






19. Small organelles that contain the hydrogen peroxide produced as a byproduct of lipid metabolism. Peroxisomes convert hydrogen peroxide to water and oxygen by way of the enzyme catalase.






20. The monomer of a protein; amino acids hae an amio group on one end fo the molecule and a carboxylic acid group on the other - and of the of 2 different side chains.






21. The theory that mitochondria and chloroplasts originated as independent unicellular organsims living in symbiosis with larger cells






22. A small - extrachromosomal (outside the genome) - circular DNA molecule found in prokaryotes.






23. The loop of the nephron that dips downward into the renal medulla. The loop of Henle sets up a concentration gradient in the kidney such that from the cortex to the renal pelvis osmolarity increases. The descending limb of the loop of Henle is permea






24. A network of membranes inside eukarytoic cells invovled in lipid synthesis (steroid in gonads) - detoxification (in liver cells) - and/or Ca2+ storage (muscle cells).






25. One of the four basic tissue types in the body (epithelial - connective - muscle - and nervous). Epithelial tissue is a lining and covering tissue (e.g. skin - the lining of the stomach and intestines - the lining of the urinary tract - etc. ) or a g






26. Specif ic defense of the body by antibodies - secreted into the blood by B- cells.






27. A chemical secreted by a T cell (usually the helper Ts) that stimulates activation and proliferation of other immune system cells.






28. The portion of an integral membrane protein that passes through the lipid bilayer.






29. The sphincter that separates the final part of the small intestine (the ileum) from the fron part of the large intestine (the cecum). It is typically kept contracted (closed) so that chyme can remain in the small intestine as long as possible. The il






30. The attachment of an amino acid to a tRNA (not that this a specific interaction). tRNa loading requires two high - energy phosphate bonds.






31. A protein - digesting enzyme secreted by the chief cells of the gastric glands. Pepsin is secreted in its inactive form (pepsinogen) and is activated by gastric acid. It is unusual in that its pH optimum is around 1-2; most of these enzymes in the bo






32. A neuron with a single axon and multiple dendrites; the most common type of neuron in the nervous system.






33. A dense grwoth of bacteria that covers the surface of a petri dish.






34. A sac filled with fluid (aminotic fluid) that surroudns and protects a developing embryo.






35. The rapid mitotic division of a zygot that being within 24-36 hours after fertilization






36. A non - protein - but organic - molecule (such as vitamin) that is covalently bound to an enzyme as part of the active site.






37. A set of veins that connect a capillary bed in the hypothalamus (the primary capillary plexus) with a capillary bed in the anterior pituitary gland (the secondary capillary bed). Releasing and inhibiting factors from the hypothalamus travel along the






38. A subsequent immune response to previously encountered antigen that results in antibody production and T cell activation. The secondary immune response is mediated by memory cells (produced during the primary immune respone) and is much faster and st






39. The inner region of the adrenal gland. The adrenal medulla is part of the sympathetic nervous systme - and releases epinephrine (adrenaline) and norepinephrine into the blood when stimuated. These hormones augment and prolon the effects of sympatheti






40. The process by which neighboring cells can influence the determination (and subsequent differentiation) of a cell.






41. A law of population genetics that states that the frequencies of alleles in a given gene pool do not change over time. There are five assumptions required for this law to hold true: there must be no mutation - there must be no migration - there must






42. The second phase of meiosis I. During metaphase I the paired homologous chromsomes (tetrads) align at the center of the cell (the metaphase plate).






43. The portion of the diencephalon involved in maintaining body homeostasis. the hypothalamus also controls the release of hormones from the pituitary gland.






44. The neurotransmitter used throughout the parasympathetic nervous system as well as the neuromuscular junction.






45. The darkly pigmented middle layer of the eyeball - found between teh sclera (outer layer) and the retina (inner layer).






46. A person with blood type AB+. Because this person's red blood cells possess all of the typical blood surface proteins - they will not display an immune reaction if transfused with any of the other blood types.






47. A thick muscular tube that connects the epididymis of the testes to the urethra. Muscular contractions of the vas deferns during ejaculation ehp propel the sperm outward. Severing of the vas deferens (vasectomy) results in sterility of the male.






48. A group of nucleotides that does not specify a particular amino acid - but instead serves to notify the ribosome that the protein being translated is complete. The stop codons are UAA - UGA - and UAG. They are also known as nonsense codons.






49. A tRNA with an amino acid attached. This is made by an animoacyl - tRNA synthetase specific to the amino acid being attache.d






50. The allele in a heterozygous genotype that is expressed; the phenotype resulting from either a heterozygous genotype or a homozygous dominant genotype.