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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. Aromatic bases found in DNa and RNA that have a single - ring structure. They include cytosine - thymine - and uracil.






2. Cranial nerve pair X. The vagus nerves are very large mixed nerves (They carry both sensory input and motor input) that innervate virtually every visceral organ. They are especially important in transmitting parasympathetic input to the heart and dig






3. 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






4. An ion channel that is opened or closed based on the binding of a specific ligand to teh channel. Once opened - the channel allows the ion to cross the plasma membrane according to its concentration gradient. An examples is the acetylcholine receptor






5. A tRNA with an amino acid attached. This is made by an animoacyl - tRNA synthetase specific to the amino acid being attache.d






6. A fluid - filled sphere formed about 5 days after fertilization of an ovum that is made up of an outer ring of cells and inner cell mass. THis is the structure that implants in the endometrium of the uterus.






7. A ductless gland that secretes a hormone into the blood






8. A period of time following an action potential during which no additional action potential can be evoked regardless of the level of stimulation. (usually because Na+ channel closed whle K+ efflux)






9. An organelle bounded by a double membrane (double lipid bilayer) called the nuclear envelope. The nucleus contains the genome and is the site of replication and transcription.






10. 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.






11. 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






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






13. 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






14. The stage of human development during which the organs are formed. Organogenesis begins after gastrulation and is completed by the eight week of gestation.






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






16. The first step in viral infection. Attachemen of a virus to its host is very specific and is also known as adsorption.






17. A precursor cell that undergoes mitosis during fetal development to produce more oogonium. These cells are then activated to produce primary oocytes - which remain dormant until stimulated to undergo meiosis I during some future menstrual cycle.






18. The formation of haploid gametes (sperm or ova) via meiosis.






19. Cells that form the walls of the seminiferous tubules and help in spermatogenesis Sertoli cells are also called susenacular cells.






20. A wave of contraction that sweeps along a muscular tube - pushing substances along the tube (e.g. - food through the digestive tract - urine through the ureters - etc.)






21. Photoreceptors in the retina of the eye that respond to dim light and provide us with black and white vision.






22. The amount of energy required to produce the transition state of a chemical reaction. If the activation energy for a reaction is very high - the reaction occurs very slowly. Enzymes (and other catalysts) increase reaction rates by reducing activation






23. A point mutation in which a pyrimidine is substitued for a purine - or vice versa.






24. 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.






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






26. A long projection off the cell body of a neruon down which an action potential can be propagated.






27. Molecules made by connecting amino acids via peptide bonds. Proteins are synthesized (translated) by ribosomes - and function as enzymes - carriers - structrual fibers - cell surface receptors - channels - porters - hormones - etc.






28. 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






29. The fraction of teh end - diastolic volume ejected from the ventricles in a single contraction of teh heart. THe ejection fraction is normally around 60% of the end diastolic volume.






30. Messenger RNA; the type of RNa that is read by a ribosome to synthesize protein.






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






32. The volume of blood pumped out of the heart in one minute (vol/min); the product of the stroke volume (vol/beat) and the heart rate (beat/min). Cardiac output is directly proportional to blood pressure**.






33. 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






34. The first (approximately 5%) of the small intestinte.






35. A network of membranes inside eukarytoic cells invovled in lipid synthesis (steroid in gonads) - detoxification (in liver cells) - and/or Ca2+ storage (muscle cells).






36. The primary female sex hormone. Estrogen stimulates the development of female secondary sex characteristics during puberty - maintains those characteristics during adulthood - stimulates the development of a new uterine lining after menstruation - an






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






38. A hormone released from the hypothalamus that triggers the anterior pituitary to secrete FSH and LH.






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






40. A type of mutation in DNa where a single base is substituted for another.






41. Hardy crystals consisting of calcium and phosphate that form the bone matrix.






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






43. A bacterium having a spiral shape (plural = spirochetes)






44. Anterior pituitary gland






45. An energy storage molecule used by muscle tissue. The phosphate from creatine phosphate can be removed and attached to an ADP to generate ATP quickly.






46. The smalles of all blodo vessles - typically having a diamtere just large neough for blood cells to pass through in single file. Capillaries have extremelyu thin walls to faciliate the exchange of material between the blood and the tissues.






47. An asexual method of bacterial reproduction that serves only to increase the size of the population; ther is no introduciton of gnetic diversity. THe bacterium simply grows in size until it has doubled its cellular components - then it replicates its






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






49. An organism that will use oxygen (aerobic metabolism) if it is available - and that can ferment (anaerobic metabolism) if it is not.






50. Major Histocompatability complex - a set of proteins found on the plasma membranes of cells that help display antigen to T cells. MHC I is found on all cells and displays bits of proteins from within the cell; this allows T cells to monitor cell cont