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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. The fusion of a sperm with an ovum during sexual reproduction. Fertilization typically occurs in the uterine tubes and requires capacitation of the sperm and relase of the acrosomal enzymes. Fertilization is a species - specific process - requiring b






2. A layer of connective tissue underneath the epidermis of the skin. The dermis contains blood vessels - lymphatic vessels - nerves - sensory receptors - and glands.






3. A short period of time **prior to exponential growth of a bacterial population during which no - or very limited - cell division occurs.






4. An enzyme that unwinds the double helix of DNA and separates the DNA strands in preparation for DNA replication.






5. The portion of the brain responsible for visual and auditory startle reflexes.






6. The stoppage of bleeding; blood clotting.






7. A lubricating - nourishing fluid found in joint capsules.






8. A peptide hormone produced and secreted by the Beta cells of the pancreas. Insulin targets cells in the body - especially the liver and muscle - and allows them to take glucose out of gthe blood (thus lowering blood glucose levels).






9. The final portion of the large intestine.






10. An insulating layer of membranes wrapped around the axons of almost all neurons in the body. Myelin is essentially the plasma membranes of specialized cells; Schwann cells in the peripheral nervous system - and oligodendrocytes in the central nervous






11. The cord that connects the embryo of a developing mammal to the placenta in the uterus of the mother. The umbilical cord contains fetal arteries (carry blood toward the placenta) and veins (carry blood away from the placenta). The umbilical vessels d






12. The regino of the digestive tract where virtually al digestion and absorption occur. It is subdivided into three regions: the duodenum - the jejunum - and the ileum.






13. A red blood cell; they are filled with hemoglobin - and teh function of the erythrocytes is to carry oxygen in the blood.






14. The female primary sex organ. The ovary produces female gametes (ova) and secretes estrogen and progesterone.






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






16. The intracellular process triggered by the binding of a ligand to its receptor on the cell surface. Typically this activates seond messenger pathways.






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






18. The enzyme that breaks down acetylcholine in the synaptic cleft.






19. A genetic cross between an organism displaying a recessive phenotype (homozygous recessive) and an organism displaying a dominant phenotype (for whic the genotype is unknown) - done to determine the unknown genotype.






20. A large - ring shaped lipid found in cell membranes. Cholesterol is the precursor for steroid hormones - and is used to manufacture bile salts.






21. The sum of all genetic material in a population.






22. A cell characterized by the presence of a nucleus and other membrane - bound organelles. Eukaryotes can be unicellular (protists) or multicellular (fungi - plants and animals).






23. A molecule formed by joining many monosaccharides together. POlysaccharides are typically energy- storage molecules (glycogen in animals - starch in plants) or structural molecules (cellulose in plants - chitin in exoskeletons).






24. The release of milk from the mammary glands via contraction of ducts within the glands. Contraction is stimulated by oxytocin - which is released from the posterior pituitary when the baby begins nursing.






25. The string between beads of DNA on histones. They are also wrapped around a single histone - called linker histone - may not really have to know..






26. An integral membrane protein that undergoes a conformational change to move a molecule from one side of the membrane to another. See also 'uniporter' - 'antiporter' - and 'symporter'.






27. An enzyme inhibitor that binds at a site other than the active sit of an enzyme (binds at an allosteric site). THis changes the three - dimensional shape of the enzyme such that it can no longer catalyze the reaction






28. 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.






29. Also called occluding junctions - tight junctions form a seal between cells that prevents the movement of substances across the cell layer - except by diffusion through the cell membranes themselves. Tight junctions are found between the epithelial c






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






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






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. A contact point between the afferent arteriole of the glomerulus and the distal convoluted tubule of the nephron. It is involved in regulating blood pressure.






34. The deliberate exposure of a person to an antigen in order to provoke the primary immune response and memory cell production. Typically the antigens are those normally associated with pathogens - thus if the live pathogen is encountered in the future






35. A constant input to the arteries that keeps them somewhat constricted to maintain a basal level of blood pressure.






36. Paired masses of lymphatic tissue near the back of the throat that help trap inhaled or swallowed pathogens.






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






38. The portion of the nephron after the glomerulus and apsule; the region of the nephron where the filtrate is modified along its path to becoming urine.






39. (1) The integration of input (EPSPs and IPSPs) from many presynaptic neruons by a single postsynaptic neuron - either temporaly or spatially. Summation of al input can either stimulate the postsynaptic neuron and possibly lead to an action potential






40. 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.






41. 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






42. The phase of mitosis during which the cell physically splits into two daugter cells. Cytokinesis begins near the end of anaphase - and is completed during telophase.






43. The second most common of the five classes of leukocytes. Lymphocytes are involved in specific immunity and include two cell types - B- cells and T cells. B- cells produce and secrete antibodies and T- cells are invovled in cellular immunity.






44. The process of breaking down large molecules into smaller precursors - e.g. digesion of starch into glucose.






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






46. The first branches of the trachea. There are two primary bronchi - one for each lung.






47. The inside of the a hollow organ (e.g. - the somach - intestines - bladder - etc.) or a tube (e.g. - blood vessels - ureters - etc.)






48. The pressure measured in the arteries while the ventricles are relaxed (during diastole).






49. A viral life cycle in which the viral genome is incorporated into the host genome where it can remain dormant for an unspecified period of time. Upon activation - the viral genome is excised from the host genome and typically enters the lytic cycle.






50. 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).