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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. A neuron found completely within the central nervous system. Interneous typically connect sensory and motor neurons - especially in reflex arcs.






2. 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






3. A situation in which a heterozygote displays the phenotype associated with each of the alleles - e.g. - human blood type AB.






4. A virus with an RNA genome (e.g. HIV) that undergoes a lysogenic life cycle in a host with a double stranded DNA genome. In order to integrate its genome with the host cell genome - the virus must first reverse trasncribe its RNA genome to DNA.






5. The interior of a mitochondrion (the region bounded by the inner membrane). - The matrix is the site of action of pyruvate dehydroganse complex and the Krebs cycle.






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






7. A string of several hundred adenine nucletodies added to the 3' end of the eukaryotic mRNA.






8. Microscopic outward folds of the cells lining the small intestine; microvilli serve to increase the surface area of the small intestine for absorption.






9. The cells of the afferent artery at the juxtaglomerular apparatus. They are baroreceptors that secrete renin upon sensing a decrease in blood pressure.






10. The three small bones found in the middle ear (the malleus - the incus - and the stapes) that help to amplify the vibrations from sound waves. The malleus is atached to the tympanic membrane and the stapes is attached to the oval window of the cochle






11. A pair of replicated homologous chromosomes. Tetrads form during prophase I of meiosis so that homologous chromosomes can exchange DNA in a process known as 'crossing over.'






12. 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






13. 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.






14. Human Chorionic Gonadotropin - a hormone secreted by the trophoblast cells of a blasocyst (i.e. developing embryo) that prolongs the life of the corpus luteum - and thus increases the duration and amount of secreted progesterone. This helps to mainta






15. 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






16. The organ that carries out teh command sent along a particular motor neuron






17. An organism that has only a single copy of its genome in each of its cells. Haploid organisms possess no homolous chromosomes.






18. A point mutation in which a condon that specifies an amino acid is mutated into a stop (nonsense) codon.






19. Salivary amylase






20. An irritation of a tissue caused by infection or injury. Inflammation is characterized by four cardinal symptoms; redness (rubor) - swelling (tumor) - heat (calor) - and pain (dolor).






21. Heterogeneous nuclear RNA; the primary transcript made in eukaryotes before splicing.






22. MRNA that codes forsingle type of protein - such as is found in eukaryotic cells.






23. 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






24. An organism that can survive in the presence of oxygen (oxygen is not toxic) - but that does not use oxygen during metabolism (anaerobic metabolism only).






25. The basic functional and structural unit of the nervous system. The neuron is a highly specialized cell - designed to transmit action potentials.






26. Something that increases the rate of a chemical reaction by reducing the activation energy for that reaction. The free energy of reaction remains unchanged.






27. The outer layer of smooth muscle in the wall of the digestive tract. When the longitudinal muscle contracts the tube shortens.






28. The tube that carries urine from the bladder to the to outside of the body. In males it also carries semen and sperm during ejaculation.






29. A system of blood vessels where the blood passes from arteries to capillaries to veins - then through a second set of capillaries - and then through a final set of veins. THere are two portal systems in the body - the hepatic portal system and the hy






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






31. Proteins that bind to and stabilize the signle strands of DNA exposed when helicase unwinds the double helix in preparation for replication.






32. A type of lymphocyte. The major subtypes of T cells are the helper T cells (CD4) and the killer T cells (CD8 - or cytotoxic T cells). Helper T cells secrete chemicals that help killer Ts and B cells proliferate. Killer T cells destroy abnormal self -






33. A complex polymer of sugars and amino acids; the substance From which bacterial ell walls are made.






34. The period of time during which the ventricles of the heart are contracted.






35. A hormone produced by the C- cells of the thyroid gland that decreases serum calcium levels. It targets teh bones (stimulates osteoblasts) - the kidneys (reduces calcium reabsorption) - and the small intestine (decreases calcium absorption).






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






37. The inner region of an organ - e.g. - the renal medulla - the ovarian medulla - and the adrenal medulla - etc.






38. A function in the reproductive system - controlled by the parasympathetic nervous system - that includes erection (via dilation of erectile arteries) and lubrication.






39. Three loop - like structures in the inner ear that contain sensory receptors to monitor balance.






40. The bond formed between the carboxyl group of one amino acid and the amino group of another.






41. A hormone produced and secreted by teh adrenal medulla that prolongs and increases teh effects of the sympathetic nervous system.






42. The middle (approximtely 40%) of the small intestine.






43. The outermost layer of teh skin. The epidermis is made of epithelial tissue that is constantly dividing at the bottom; teh cells migrate to teh surface (dying along the way) to be sloughed off at the suface.






44. A statistical rule stating that the probability of two independent events occuring together is the product of their individual probabilities.






45. The first phase of meiosis I. During prophase I the replicated chromosomes condense - homologous chromsomes pair up - crossing over occurs between homologous chromosomes - the spindle is formed - and the nuclear envelope breaks apart into vesicles. P






46. Extremely small pseudo - cells in the blood - important for clotting. They are not true cells - but are broken - off bits of a larger cell (a megakaryocyte).






47. An organism that lacks a nucleus or any other memrane - bound organelles. All prokaytes belong to the Kingdom Monera (not protista!)






48. Also called vasopressin - this hormone is produced in the hypothalamus and secreted by teh posterior pituitary gland. It tartes teh kidney tubules - increasing their permeability to water - adn thus increasing water retention by the body. Also raises






49. The collection of fluid in the alveoli - particularly dangerous because it impedes gas exchange. Common causes of pulmonary edema are increased pulmonary blood pressure or infection of the respiratory system.






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