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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. High frequency of recombination bacterium An F+ bacterium that has the fertility factor integrated into its chromosome. When conjugation takes place - it is able to transfer not only the F factor - but also its genomic DNA.






2. 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.






3. (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.






4. 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






5. A type of white blood cell; leukocytes are either B or T cells and are involved in disease defense.






6. The constant inhibition provided to the heart by the vagus nerve. Vagal tone reduces the intrinsic firing rate of teh SA node from 120 beats/minute to around 80 beats/minute.






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






8. An organism that makes its own - typically using CO2 as a carbon source.






9. The period of human development beginning at 8 weeks of gestation and lasting until birth (38-42 weeks of gestation). During this stage the organs formed in the embryonic stage grow and mature. The developing baby is known as a fetus during this time






10. A virus that infects a bacterium.






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






12. Peptidyl - tRNA site; the stie on a ribosome where the growing peptide (attached to a tRNA) is found during translation.






13. The second phase of meiosis II. Metaphase II is identical to mitotic metaphase - except that the number of chromosomes was reduced by half during meiosis I.






14. 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






15. The return of membrane potential to normal resting values after a depolarization of hyperpolarization.






16. Specif ic defense of the body by antibodies - secreted into the blood by B- cells.






17. The fusion of a sperm with an ovum during sexual reproduction. Fertilization typically occurs in the uterine tubes and requires capacitation of the sperm and relase of the acrosomal enzymes. Fertilization is a species - specific process - requiring b






18. A genotype in which two identical alleles are possessed for a given gene. The allelles can both be dominant (homozygous dominant) or both be recessive (homozygous recessive)






19. The curled structure in the inner ear that contains the membranes and hair cells that transduce sound waves into action potentials.






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






21. An intracellular chemical signal (such as cAMP ) that relays instructions from the cell surface to enzymes in the cytosol.






22. A cell produced when a B cell is activated by antigen. Memory cells do not actively fight the current infection - but patrol the body in case of future infection with the same antigen. If the antigen should appear again the future - memory cells are






23. A cell characterized by the presence of a nucleus and other membrane - bound organelles. Eukaryotes can be unicellular (protists) or multicellular (fungi - plants and animals).






24. An abdominal organ that is considered part of the immune system. THe spleen has four functions: (1) it filters antigen from the blood (2) it is the site of B cell maturation - (3) it stors blood - and (4) it destroys old red blood cells.






25. The deliberate exposure of a person to an antigen in order to provoke the primary immune response and memory cell production. Typically the antigens are those normally associated with pathogens - thus if the live pathogen is encountered in the future






26. A set of veins that connect a capillary bed in the hypothalamus (the primary capillary plexus) with a capillary bed in the anterior pituitary gland (the secondary capillary bed). Releasing and inhibiting factors from the hypothalamus travel along the






27. The mechanism described by Charles Darwin that drives evolution. Through mutation - some organisms possess genes that make them better adapted to their environment. These organisms survive and reproduce more than those that do not possess the benefic






28. An enzyme that phosphorylates something else. Kinases are frequently used in regulatory pathways - phosphorylating other enzymes.






29. 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.






30. One of the contractie proteins in muscle tissue. In skeletal and cardiac muscles - myosin forms the thick filaments. Myosin has intrinsic ATPase activity and can exist in two conformation - either high energy or low energy.






31. Connective tissue that lacks great amount of collagen or elastic fibers (hence - loose) - e.g. - adipose tissue and areolar (general connective) tissue.






32. The period of human development from implantation through 8 weeks of gestation. Gastrulation - neurulation - and organogenesis occur during this time period. The developing baby is known as embryo during this time period.






33. An organism that requires oxygen to survive (aerobic metabolism only).






34. 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






35. 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.






36. A molecule composed of two monosaccharides. Common disaccharides include maltose - sucrose - and lactose.






37. The muscular femal organ - in which a baby develops during pregnancy.






38. The enzyme that catalyzes the phosphorylation of fructose -6- phosphate to form fructose -1-6- bisphosphate in the third step of glycolysis. This is the main regulatory step of glycolysis. PFK is feedback - inhibited by ATP.






39. Pain receptors. Nociceptors are found everywhere in the body except for the brain.






40. The movement of molecules through the plasma membrane against their concentration gradients. Active transport requires input of cellular energy - often in the form of ATP. An example is the Na+/K+ ATPase in the plasma membrane of all cells.






41. 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.






42. Muscles that help focus light on teh retin by controlling the curvature of the lens of the eye.






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






44. The portion of the cell membrane at the neuromusclar junction; essentially the postsynaptic membrane at the synapse.






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






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






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






48. 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






49. A mature - dormant osteoblast.






50. A sweat gland located in the dermis of the skin. Sweat consists of water and ions (including Na+ and urea) and is secreted with temperatures rise.