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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 first phase of mitosis. During prophase the replicated chromosomes condense - the spindle is formed - and the nuclear envelope breaks apart into vessicles.






2. 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.






3. A nucleotide sequence on DNA that contians three elemtns: a coding sequence for one or more enzymes - *a coding sequence for a regulatory protein - and upstream regulatory sequences where the regulatory proteins can bind. An example is the lac operon






4. A pathway through a plasma membrane that restrics passage based only on the size of the molecules. Pore are made from porin proteins.






5. A subphase of male orgasm - a reflex reaction triggered by the presence of semen in the urethra. Ejaculation is a series of rhythmic contractions of muscles near teh base of teh penis that increase pressure in the urethra - forcing the semen out.






6. A globular protein found in muscle tissue that has the ability to bind oxygen. Myoglobin helps to store oxygen in the muscle for use in aerobic respiration (it does not move - just stays there). Muscles that participate in endurance activities (inclu






7. A protein channel in a cell membrane that is specific for a particular ion - such as Na+ or K+. Ion channels may be constitutively open (leak channels) - or regulated (voltage - gated or ligand - gated).






8. 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.






9. A diploid cell formed by the fusion of two gametes during sexual reproduction.






10. The inside of the a hollow organ (e.g. - the somach - intestines - bladder - etc.) or a tube (e.g. - blood vessels - ureters - etc.)






11. Heterogeneous nuclear RNA; the primary transcript made in eukaryotes before splicing.






12. The primary enzyme in peroxisomes; catalse catalyzes the hydrolysis of hydrogen peroxide (H2O2) into water and oxygen.






13. The first portion of the nephron tubuel after the glomerulus. THe PCT is the site of most reabsorption; all filtered nutrients are reabsorbed here as well as most of the filtered water.






14. 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






15. A pair of replicated homologous chromosomes. Tetrads form during prophase I of meiosis so that homologous chromosomes can exchange DNA in a process known as 'crossing over.'






16. Three loop - like structures in the inner ear that contain sensory receptors to monitor balance.






17. A lipid bilayer that surrounds the capsid of an animal virus. the envelope is acquired as teh virus buds out through the plasma membrane of its host cell. Not all annimal viruses possess and envelope.






18. 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






19. Pepsinogen - secreting cells foudn at teh bottom of the gastric glands






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






21. 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.)






22. Toward the 5' end of an Rna transcript (the 5' end of the DNA coding strand). The promoter and start sites are upstream.






23. The ends of a saromere.






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






25. An enzyme that unwinds the double helix of DNA and separates the DNA strands in preparation for DNA replication.






26. 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.






27. DNA replication in prokaryotes - so named because as replication proceeds around the single - circular chromosome - it takes on the appearnce of the Greek letter theta.






28. The membrane that separates the middle ear from the inner ear.






29. One of the four basic tissue types in the body (epithelial - connective - muscle - and nervous). Epithelial tissue is a lining and covering tissue (e.g. skin - the lining of the stomach and intestines - the lining of the urinary tract - etc. ) or a g






30. An RNA polymerase that creates a primer (made of RNA) initiate DNa replication. DNA pol binds to the primer and elongates it.






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






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






33. 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.






34. The cells of the afferent artery at the juxtaglomerular apparatus. They are baroreceptors that secrete renin upon sensing a decrease in blood pressure.






35. 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).






36. The fourth (and final) phase of mitosis. During telophase the nuclear envelope reforms - chromosomes decondense - and the mitotic spindle is disassembled.






37. The flow of blood from the heart - through the body (not including the lungs) - and back to the heart.






38. 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.






39. A chemical released by the axon of a neuron in response to an action potential that binds to receptors on a postsynaptic cell and causes that cell to either depolarize slightlly (EPSP) or hyperpolarize slightly (IPSP). Examples are acetylcholine - no






40. 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.






41. 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






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. An organelle surrounded by a double=membrane (two lipid bilayers) where ATP production takes place. The interior (matrix) is where PDC and the Krebs cycle occur - and the inner membrane contains the enzymes of the electron trasport chain and ATP synt






44. A substance secreted by embryonic testes that causes the regression of the Mullerian ducts.






45. An enzyme that lyses bacterial cell walls. Lysozyme is produced in the end stages of the lytic cycle so that new viral particles can escape their hosst; it is also found in human tears and human saliva.






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






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






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. The first phase of the uterine (endometrial) cycle - during which the endometrium from the previous cycle is shed off. Estrogen and progesterone levels are low during this time period. Menstruation typically lasts from day 1 to day 5 of the cycle.






50. 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