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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 specific molecule that binds to a receptor.






2. Having the ability to become anything; a zygote is totipotent.






3. 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.






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






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






6. A projection of the cell body of a neuron that recieves a nerve impulse form a different neuron and send the impulse to the cell body. Neurons can have one or several dendrites!






7. The enzymes that catalyzes the phosphorylation of glucose to form glucose -6- phosphate in the first step of glycolysis. This is one of the ain regulatory steps of this pathway. Hexokinase is feedback - inhibited by glucose -6- P.






8. An ion channel that is oepend or closed based on the electrical potential across the plasma membrane. Once opened - the channel allows ions to cross the membrane according to their concentration gradients. Examples are the Na+ and K+ voltage - gated






9. 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.






10. Complementary DNA. DNA produced synthetically by reverse trascribing mRNA. Because of eukaryotic mRNA splicing - cDNA contains no inrons.






11. The hollow center of an osteon - also known as a Haversian canal. The central canal contains blood vessels - lymphatic vessels - lymphatic vessels - and nerves. Bone is laid down around the central canal in concentric rings called lamellae.






12. 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






13. The duplication of DNA






14. The membranes that line the surface of the lungs (visceral pleura) and the inside wall of the chest cavity (parietal pleura).






15. Muscle tissue that is attached to the bones. SKeletal muscle is striated multinucleate - and under voluntary control.






16. A bacterial extrachromosal elent that allows the bacterium to initati conjugation. Bacteria that possess teh F factor are known as F+ 'males'.






17. The mechanism that ensures tehat skeletal muscle contraction does not occur without neural stimulation (excitation). A trest - cytosolic [Calcium] is low - and the troponin - tropomyosin complex covers the myosin - binding sites on actin. When the mu






18. A blood clot that forms in an unbrokened blood vessel. Thrombi are dangerous they can break free and begin travelin in the bloodstream (become an embolus). Emboli ultimately become stuck in a small vessel and prevent adequate blood delivery to tissue






19. A steroid hormone produced by the corpus luteum in the ovary during the second half of the menstrual cycle Progesterone maintains and enhances the uterine lining for the possible implantation of a fertilized ovum. It is the primary hormone secreted d






20. A developing oocyte and all of its surrounding (supporting) cells.






21. A sensory receptor that responds to hcanges in pressure; for example - there are baroreceptors in the carotid arteries and the aortic ach that monitor blood pressure.






22. 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.






23. The primary androgen (male sex steroid). Testosterone is a steroid hormone produced and secreted by the interstitial cells of the testes. It triggers the development of secondary male sex characteristics during puberty (including spermatogenesis) and






24. Earlier embryonic ducts that can develop into femal internal genitalia in the absence of testosteron.






25. Myelinated axons






26. Movement of a hydrophilic molecuel across the plasma membrane of a cell - down its concentration gradient - through a channel - pore - or carrier molecule in the membrane. Because the hydrophilic nature of the molecule - it requires a special path th






27. The main air tube leading into the respiratory system. The trachea is made of alternating rings of cartilage and connective tissue.






28. A sensory receptor that responds to specific chemicals. Some examples are gustatory (taste) receptors - olfactory (smell) receptors - and central chemoreceptors (responds to pH changes in teh cerebrospinal fluid).






29. The duct that carries bile from the gallbladder and liver to the small intestine (duodenum).






30. Active transport that relies directly on the hydrolysis of ATP.






31. The perio of time during which the ventricles of the heart are relaxed.






32. The monomer of a carbohydrate. Monosaccharides have the general chemical formula CnH2nOn - and common monosaccharides include glucose - fructose - galactose - and ribose.






33. The cells of the distal tubule at the juxtaglomerular apparatus. They are receptors that monitor filtrate osmolarity as a means of regulatin filtration rate. If a drop is osmolarity is sensed - the macula densa dilates the afferent arteriole (to incr






34. A tropic hormone produced by the anterior pituitary gland that targets the gonads. In females LH triggers ovulation and the development of a corpus luteum during the menstrual cycle; in males - LH stimulates the production and release of testosteron.






35. The regino of the sarcomere made up only of thin filaments. The I band is bisected by a Z line. I bands alternate with A bands to give skeletal and cardiac muscle a striated appearance. I bands get shorter (and may disappear completely) during muscle






36. Bacteria that have a thin peptidoglycan cell wall covered by an outer plasma membrane. They stain very lightly (pink) in Gram stain. Gram - negative bacteria are typically more resistant to antibiotics than Gram - positive bacteria.






37. All parts of the nervous system except for the brain and spinal cord.






38. One of the four aromatic bases found in DNA and RNA. Guanine is a purine; it pairs with cytosine.






39. The region of teh brain that coordinates and smooth skeletal muscle activity.






40. A systme of ductless glands taht secrete chemical messengers (into) the blood - has to be into the blood.






41. 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.






42. The fertilization of an oocyte by more than one sperm. This occurs in some animals - but in humans - blocks to polyspermy exist (the fast block and the slow block) so that only a single sperm can penetrate the oocyte.






43. 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






44. The layer of epithelial tissue that lines body cavities in contact with the outside environment (respiratory - digestive - urinary - and reproductive tracts).






45. A group of sensory neuron cell bodies found just posterior to the spinal cord on either side. A pair of root ganglia exists for each spinal nerve that expands from the spinal cord. The ganglia are part of the peripheral nervous system (PNS).






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






47. The cytoskeleton filaments with the smallest diameter. Microfilaments are composed of the contractile protein actin. They are dynamic filaments - constantly beig made and broken down as needed - and are responsible for events such as pseudopod format






48. An integral membrane proteint hat binds extracellular signaling molecules - suchas hormones and peptides.






49. A blood pressure cuff






50. One of the three primary (embryonic) germ layers formed during gastrulation. Ectoderm ultimately forms external structures such as the skin - hair - nails - and inner linings of the mouth and anus - as well as the entire nervous system.