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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. Large conglomerations of proteins - fats - and cholesterol that transport lipids in the bloodstream. (chylomicrons are a type of lipoprotein).






2. 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.






3. The valve that controls the release of feces from the recturm. It has an internal part made of smooth muscle (thus involuntary) and an external part made of skeletal muscle (thus voluntary).






4. The outer ring of cells of a blastocyst. The trophoblast takes part in the formation of the placenta.






5. The constant inhibition provided to the heart by the vagus nerve. Vagal tone reduces the intrinsic firing rate of teh SA node from 120 beats/minute to around 80 beats/minute.






6. The three glands in the male reproductive system that reproduce semen: the seminal vesicles - the prostate - and the






7. A physiological catalyst. Enzymes are usually proteins - although some RNAs have catalytic activity.






8. An enzyme that polymerizes a strand of DNA by reading an RNA template (an RNA dependent DNa polymerase); used by retrovirus in order to integrate their genome with the host cell genome.






9. A toxin that secreted by a bacterium into its surrounding medium that help the bacterium compete with other species. Some exotoxins cause serious disease in humans (botulism - tetanus - diptheria - toxic shock syndrome).






10. 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






11. An organism that has two copies of its genome it each cell. The paired genomes are said to be homologous.






12. A mechanism for increasing tension (contractile length) in a muscle by activating more motor units.






13. A blood vessel that carries blood away from the heart chambers. Arteries have muscular walls to regulate blood flow and are typically high - pressure vessles.






14. An enzyme whose transcription can be stopped by an abundance of its product (as opposed to inducible enzymes). Usually part of anabolism of product.






15. Zygot - derived projections that extend into the endometrium of the uterus during pregnancy. Fetal capillaries grow into the placental villi - which are surrounded by a pool of maternal blood. THis facilitates nutrient and gas exchange between the mo






16. The muscle tissue of the heart Cardiac muscle is striated - uninucleate - and under involuntary control (controlled by teh autonomic nervous system). Note also that cardiac muscle is self - stimulatory - and autonomic control serves only to modify th






17. A structure composed of a ring of nine microtube triplets - found in pairs in the MTOC (microtubule organizing center) of a cell. The centrioles duplicate during the cell division - and serve as the organizing center for the mitotic spindle.






18. Partially digested - semiliquid food mixed with digestive enzymes and acids in the stomach.






19. An immune organ located near the heart. THe thymus is the site of T cell maturation and is larger in children and adolescents.






20. The fourth and final phase of meiosis II. Telophase II is identical to mitotic telophase - except that the number of chromosomes was reduced by half during meiosis. I.






21. The outer layer of an organ - e.g. the renal cortex - the ovarian cortex - the adrenal cortex - etc.






22. The second phase of meiosis II. Metaphase II is identical to mitotic metaphase - except that the number of chromosomes was reduced by half during meiosis I.






23. 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.






24. A diploid cell that can undergo mitosis to form more spermatogonium - and can also be triggered to undergo meiosis to form sperm.






25. The pressure in the (theoretical) space between the lung surface and the inner wall of the chest cavity.






26. A group of blood proteins that bind non - specifically to the surface proteins of foreign cells (such as bacteria) - ultimately leading to the destruction of the foreign cell - part of the innate immunity.






27. The maximum amount of air that can be forcibly exhaled from the lungs after filling them to their maximum level - typically about 4500 mL






28. A structure composed of a ribose molecule linked to one of the aromatic bases. In a deoxynucleoside - the ribose is replaced with deoxyribose.






29. A statistical rule stating that the probability of either of two indpendent (and mutually exclusive) events ocuring is the sum of their individual probabilities minus the probability of them both occuring together.






30. A contractile protein connecting microtubules in the '9+2- arrangement of cilia and eukaryotic flagella. The contraction of dynein produces the characteristic movement of these structures.






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






32. The valves in the heart that separte the atria from teh ventricles. The tricuspid valve separates teh right atrium from the right ventricel - and the bicuspid (mitral) valves separates the left atrium from the left ventricle. These valves close at th






33. The third phase of the uterin (endometrial) cycle - during which the rebuilt endometrium is enhanced with glycogen and lipid stores. The secretory phase is primarily under the controll of progestone and estrogen (secreted from the copus luteum during






34. The uptake of material into a cell - usually by invagination. See also 'phagocytosis' - pinocytosis - and receptor - mediated endocytosis..






35. The prokaryotic ribosome - binding site on mRNA - found 10 nucleotides 5' to the start codon.






36. A hormone made of amino acids (in some cases just a single - modified amino acid). Peptide hormones are generally hydrophilic and cannot cross the plasma membranes of cells - thus receptor for peptide hormones must be found on the cell surface. An ex






37. A subphase of male orgasm. Emission is the movement of sperm (via the vas deferens) and semen into the urtehra in prepartion for ejaculation.






38. A rapid from of action potential conduction along the axon of a neuron in which the action potential appears to jump from nodde of Ranvier to node of Ranvier.






39. A function the reproductive system (conrolled by the sympathetic nervous system) that returns the body to its normal resting state after sexual arousal and orgasm.






40. The flexible membrane in teh chochlea that supports the organ of Corti (structure which contains the hearing receptors). The fibers of the basilar membrane are short and stiff near the oval windown and long and fleaxible near the apex of the cochlea.






41. High frequency of recombination bacterium An F+ bacterium that has the fertility factor integrated into its chromosome. When conjugation takes place - it is able to transfer not only the F factor - but also its genomic DNA.






42. A thick - transpartent coating rich in glycoproteins that surrounds an oocyte.






43. A junction between cells - consisting of a protein channel called a connexon on each of the two cells that connect to form a single channel between teh cytoplasms of both cells. Gap junctions allow small molecules to flow between teh cells - and are






44. An incrase in the fragility of the membranes of sperm cells when exposed to the female reproductive tract. Capacitation is required sot aht the acrosomal enzymes can be relased to faciliate fertilization.






45. Specialized lymphatic capillaries in the intestines that take up lipids as well as lymph.






46. An activated B cell that is secreting antibody.






47. The valves in the heart that separate the ventricles from the arteries. The pulmonary semilunar valve separates the right ventricle from the pulmonary artery - and the aortic semilunar valve separates left ventricle from the aorta. These valves close






48. In skeleta and cardiac muscle tissue - a filament composed of actin - tropomyosin - and troponin. Thin filaments are attached to teh Z lines of the sarcomers and slide over thick filaments during muscle contraction.






49. A flexible piece of cartilage in the larynx that flips downward to seal teh trachea during swallowing.






50. The third phase of mitosis. During anaphase - replicated chromosmes are split apart at their centromeres (the sister chromatids are separated from each other) and moved to opposite sides of the cell.