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






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






3. The 3' end of a tRNA molecule that binds an amino acid. The nucleotide sequence at this end is CCA






4. One of the two small chambers in the heart that receive blood and pass it on to the ventricles. The right atrium receives deoxygenated blood from teh body through the superior and inferiro vena cavae - adn the left atrium receives oxygenated blood fr






5. Early embryonic ducts that can develop into male internal genitalia under the proper stimulation (testosterone).






6. 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.






7. A gene appearing in a single copy in diploid organisms - e.g. X- linked genes in human males.






8. All of the cell cycle except for mitosis. Interphase includes G1 - S phase - and G2.






9. The portion of the digestive tract that stores and grinds food. Limited digestion occurs in the somach - and it has the lowest pH in the body (1-2).






10. Movement across the membrane of a cell that does not require energy input from the cell. Passive transport relies on concentration gradients to provie the driving force for movement - and includes both simple and facilitated diffusion.






11. 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).






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






13. The third phase of meiosis I. During anaphase I the rplicated homologous chromosomes are separated (the tetrad is split) and pulled to opposite sides of the cell.






14. The process of reading a strand of mRNA to synthesize protein. Protein translation takes place on a ribosome.






15. Paired glands near the posterior side of the vaginal that secrete an alkaline mucus upon sexual arousal. The mucus helps to reduce the acidity of the vagina (which could be harmful to sperm) and lubricates the vagina to facilitate penetration.






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






17. One of the three primary (embryonic) germ layers formed during gastrulation. Endoderm ultimately forms internal structures - such as the inner lining of the GI tract and glandular organs.






18. 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






19. Receptors in the central nervous system that monitor the pH of cerebrospinal luid to help regulate ventilation rate.






20. A protein - based substance secreted by cells of the epiderms as they migrate outward. The keratin makes the cells tougher (better able to withstand abrasion) and helps make the skin waterproof.






21. An organism that requires the aid of a host organism to survive - and that harms the host in the process.






22. Bacteria that have a thick peptido glycan cell wall - and no outer membrane. They stain very darkly (purple) in Gram stain.






23. The portion of the ear consisting of the pinna and the external auditory canal. The outer ear is separated from the middle ear by the tympanic membrane (the eardrum).






24. One of the four aromatic bases found in DNA. Thymine is a pyrimidine; it pairs with adenine.






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






26. The reduced from (carries electrons) of FAD (flavin adenine dinucleotide). this is the other main electron carrier in cellular respiration (NADH is the most common).






27. A hormone secreted by the small intestine (duodenum) in response to low pH (e.g. - from stomach acid). It promotes the release of bicarbonate from the pancreas to act as a buffer.






28. The formatino of the nervous system during weeks 5-8 of gestation. Neuralation begins when a section of the ectoderm invaginates and pinches off to form the neural groove - which ultimately forms the neural tube - From which the brain and spinal cord






29. A genotype in which two different alleles are possessed for a given gene.






30. A form of evolution in which the same organism is placed into different environments with different selection pressures. This causes organisms to evolve differently - to diverge from their common ancestor. The resulting (new) species may share struct






31. The osmotic pressure in the blood vessels due only to plasma proteins (primarily albumin) --> causes water to rush back into capillaries at end.






32. A function of the reproductive system controlled by the sympathetic nervous system. In males - organs includes emission and ejaculation; in females it is mainly a series of rhythmic contraction of the pelvic floor muscles and the uterus.






33. A life cycle of animal viruses in which the mature viral particles bud from the host cell - acquiring an envelope (a coating of lipid bilayer) in the process.






34. 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.






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






36. The maintenance of relatively constant internal conditions (such as temperature - pressure - ion balance - pH - etc.) regardless of external conditions.






37. 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.






38. An enzyme whose transcription can be stimulated by an abundance of its substrate (as opposed to repressible enzyme). Usually in catabolism.






39. A point mutation in which a pyrimidine is susbstituted for a pyrimidine - or a purine is substituted for a purine.






40. (1) In the GI tract - organs that play a role in digestion but not directly part of the alimentary canal. These include the liver - the gallbladder - the pancreas - adn the salivary glands.






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






42. The failure of two separate genes to boey the Law of Independent Assortment - as might occur if the genes were found close together on the same chromosome.






43. The portion of theforebrain that includes the thalamus and hypothalamus.






44. An organism that can only survive in the absence of oxygen (anaerobic metabolism); oxygen is toxic to obligate anaerobes.






45. Transfer RNA; the type of RNA that carries an amino acid from the cytoplasm to the ribosome for incorporation into a growing protein.






46. A solid clump of cells resulting from cleavage in the early embryo. Because there is very little growth of these cells during cleavage - the morula is ony about as large as the original zygote.






47. A carrier protein that transports a single molecule across the plasma membrane.






48. A microscopic space between the axon of one neuron and the cell body or dendrites of a secon neruon - or between the axon of a neuron and an organ.






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






50. The cell body of a neuron.