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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 point mutation in which a codon that specifies an amino acid is mutated into a codon that specifies a different amino acid.






2. The movement of a particle (the solute) in a solution from its region of high concentration to its region of low concentration ( or down it concentration gradient).






3. The failure of homologous chromosomes or sister chromatids to separate properly during cell division. This could ocur during anaphase I of meiosis (homologous chromosomes) [--> leaving 2 gametes w/ 2 copies and 2 gametes w/ no copies of chromosome] -






4. A hormone produced from vitamin D that acts in essentially the same manner as parathyroid hormone.






5. The law of conservation of energy; the energy of the universe is constant - thus if the energy of a system increases - the energy of its surroundings must decrease - and vice versa.






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






7. 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






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






9. An activated B cell that is secreting antibody.






10. A stack of membranes found near the rough ER in eukaryotic cells that is involved in the secretory pathway. The Golgi is involved in protein glycosylation (and other protein modification) and sorting and packagin proteins.






11. An organ that develops during pregnacy - derived in part from the mother and in part from the zygote. The placenta is the site of exchange of nutrients and gases between the mother's blood and the fetus' blood. The placenta is formed during the first






12. The second phase of the uterine (endometrial) cycle - during which the endometrium (shed off during menstration is rebuilt). This phase of the cycle is under the control of estrogen - secreted from the follicle developing in the ovary during this tim






13. The ball of capillaries at the beginning of the nephron where blood filtration takes place.






14. A viral enzyme that makes a strand of RNA by reading a strand of RNa . All prokaryotic and eukaryotic RNa polymerases are DNa dependent; they make a strand of RNa by reading a strand of DNA.






15. Also known as the gastrointestinal (GI) tract of the digestive tract - the alimentary canal is the long muscular 'tube' that includes the mouth esophagus - somatch - small intesitne - and large intestine.






16. The birth canal; the stretchy - muscular passageway through which a baby exits the uterus during childbirth.






17. A large multinucleate cell - typically formed by the fusion of many smaller cells during development (e.g. a skeletal muscle cell) - or formed by nuclear division in the absence of cellular division.






18. 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






19. A situation in which the expression of one gene prevents expression of all allelic forms of another gene - e.g. - the gene for male pattern baldness is epistatic to the hair color gene.






20. Toward the 3' end of an RNA transcript (the 3' end of the DNA coding strand). Stop codons and (in eukaryotes) the pol - A tail are found 'downstream.'






21. The division of the periperal nervsous system that innervates and cotnrols the visceral organs (everything but the skeletal muscles). It is also knowns as the involuntary nervous system and an be subdivided into the sympathetic and parasympathetic di






22. The phase of the cell cycle during which the genome is replicated.






23. The portion of an integral membrane protein that passes through the lipid bilayer.






24. A bacterial enzyme that recognizes a specific DNA nucleotide sequence and that cuts the double helix at a specific site within the sequence.






25. Cells that possess MHC II (B cells and macrophages) and are able to display bits of ingested antigen on their surface in order to activate T cells. See also 'MHC'






26. The outer protein coat of a virus (the whole coat)






27. The energy in a system that can be used to drive chemical reactions. If the change in free energy of a reaction (Delta G - the free energy of the products minus the free energy of the energy of the reactants) is negative - the reaction will occur spo






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






29. 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).






30. 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.






31. 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.






32. Also known as the neurohyophysis - the posterior pituitary is made of nervous tisssue and stores and secretes two hormones made by the hypothlamus; oxtytocin and ADH. The posterior pituitary is controlled by action potentials from the hypothalamus.






33. Anterior pituitary topic hormones FSH (follicle stimulating hormone) and LH (luteinizing homeon) that stimulates the gonads (testes and ovaries) to produce gametes and to secrete sex steroids.






34. A kinase in smooth muscle cells activated by calmodulin the presence of Ca2+. As its name implies - this kinase phosphorylates myosin - activating it so that muscle contraction can occur.






35. 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.






36. Cytoskeletal filaments with a diameter in between that of the microtubule and the microfilament. Intermediate filaments are composed of many different proteins and tend to play structural roles in cells.






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






38. A four - subunit protein found in red blood cells that binds oxygen. Each subunit contains a heme group - a large multi - ring molecule with an iron atom at its center. One hemoglobin molecule can bind four oxygen molecules in a cooperative manner.






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






40. Myelinated axons






41. The percentage of wholeblood made up of erythrocytes The typical hematocrit value is between 40-45%.






42. Muscle tissue found in the walls of hollow organs - e.g. - blood vessels - the digestive tract - the uterus - etc. Smooth muscle is non - striated - uninucleate - and under involuntary control (controlled by the autonomic nervous system).






43. Large conglomerations of proteins - fats - and cholesterol that transport lipids in the bloodstream. (chylomicrons are a type of lipoprotein).






44. An enzyme inhibitor that competes with substrate for binding at the active site of teh enzyme. When the inhibitor is bound - no product can be made.






45. A structure composed of a ribose molecule linked to one of the aromatic bases. In a deoxynucleoside - the ribose is replaced with deoxyribose.






46. The small artery that carries blood away from the capillaries of the glomerulus.






47. 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.






48. The region at the center of an A band of a sarcomere that is made up of myosin only. The H zone gets shorter (and may disappear) during muscle contraction.






49. 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






50. A structure made of two protein subunits and rRNA; this is the site of protein synthessis (translation) in a cell. Prokaryotic ribosomes (also known as 70S ribosomes) are smaller than eukaryotic ribosome (80S ribosomes). The S value refers to the sed