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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. One of several different nutrietns that must be consumed in the diet - and generally not synthesized in the body. Vitamins can be hdyrophobic (fat - solube) or hydrophilic (water - soluble).






2. 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.






3. 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.






4. An enzyme present in erythrocytes (as well as in other places) that catalyzes the conversion of CO2 and H2O into carbonic acid (H2CO3).






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






6. The second phase of meiosis I. During metaphase I the paired homologous chromsomes (tetrads) align at the center of the cell (the metaphase plate).






7. A blood vessel that carries blood toward the heart chambers. Veins do not have muscular walls - have valves to ensure that blood flows in one direction only - and are typically low - pressure vessels.






8. A genetic cross between an organism displaying a recessive phenotype (homozygous recessive) and an organism displaying a dominant phenotype (for whic the genotype is unknown) - done to determine the unknown genotype.






9. The largest of the cytoplasmic filaments. Microtubules are composed of two types of protein - alpha tubulin and beta tubulin. They are dynamic fibers - constantly being built up and broken down - according to cellular needs. Microtubules form the mit






10. Unmyelinated neuron cell bodies and short unmyelinated axons.






11. The volume of air remaining in the lungs after a maximal forced exhalation - typically about 1200 mL.






12. The period of time during which the ventricles of the heart are contracted.






13. Globular protein that assist in DNA packaging in eukaryotes. Histones form octamers around which DNA is wound to form a nucleosome.






14. The 'blind spot' of the eye - this is where the axons of the ganglion cells exist the retinal to form the optic nerve. There are no photoreceptors in the optic disk.






15. A neuron with a single axon and a single dendrite - often projecting from opposite sides of the cell body. Bipolar neurons are typically associated with sensory organs; an example is the bipolar neuron in the retina of the eye. - note that one axon m






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






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






18. 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.






19. One of the four aromatic bases found in RNA. Uracil is pyrimidine; it pairs with adnenine.






20. A person with blood type AB+. Because this person's red blood cells possess all of the typical blood surface proteins - they will not display an immune reaction if transfused with any of the other blood types.






21. 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.






22. A mechanism by which the stroke volume of the heart is increased by increasing the venous return of the heart (thus stretching the ventricular muscle).






23. A cyclic version of adenosine monophosphate - where the phosphate is esterified to both the 5' and 3' carbons - forming a ring. Cyclic AMP is an important intracellular signaling moelcule - often called the 'second messenger.' It serves to activate c






24. A type of syanpse in which the cells are connected by gap junctions - allowing ions (and therefore an action potential) to spread easily from cell to cell - usually in smooth and cardiac muscle. - compared to chemical synapse.






25. The nerve extending from the back of teh eyeball to teh brain that carries visual information. The ptic nerve is made up of the axons of the ganglion cells of the retina.






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






27. Movement that is directed by chemical gradients - such as nutrients or toxins. (seen in some bacteria)






28. A non - bony material that fills the hollow spaces inside bones. Red bone marrow is found in regiosn of spongy bone and is the site of blood cell (red and white) production. Yellow bone marrow is found in the diaphysis (shaft) of long bones - is most






29. A region of specialized cardiac muscle cells in the right atrium of the heart that initiate the impules of heart contraction; for this reason the SA node is knownas the 'pacemaker' of the heart.






30. A blood protein produced by the liver. Albumin helps to mantain blood osmotic pressure (oncotic pressure)






31. The 'language' of a molecular biology that specifies which amino acid corresponds to which three - nucleotide group (codon).






32. A function the reproductive system (conrolled by the sympathetic nervous system) that returns the body to its normal resting state after sexual arousal and orgasm.






33. The volume of blood pumped out the heart in a single contraction.






34. 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.






35. The prokaryotic ribosome - binding site on mRNA - found 10 nucleotides 5' to the start codon.






36. The cerebral hemispheres.






37. 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.






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






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






40. 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] -






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






42. A long projection on a bacterial surface involved in an attachment - e.g. - the sex pilus attaches F+ and F- bacteria during conjugation.






43. The first branches of the trachea. There are two primary bronchi - one for each lung.






44. A protein complex foudn in the inner membrane of the mitochondira. It is essentially a channel that llows H+ ions to flow from teh intermembrane space to the matrix (down teh gradeint produced by the enyzmes complexes of the electron transport chain)






45. (1) The secretion of useful substances from a cell - either into the blood (endocrine secretin) or into a cavity or onto the body surface (exocrine secretion). (2) in the nephron - the movement of substances from the blood to the filtrate along the t






46. The principal glucocorticoid secreted from teh adrenal cortex. This steroid hormone is released ruing stress - causing increased blood glucose levels and reducing inflammation. The latter effect has led to a clinical use of cortisol as an anti - infl






47. A highly specific cellular uptake mechanism. The molecule to be taken up must bind to cell surface receptor found in a clathrin - coated pit.






48. The muscuar layer of the uterus. The myometrium is made of smooth muscles that retains its ability to divide in order to accomodate the massive size increases that occur during pregnancy. The myometrium is stimulated to contract during labor by the h






49. A neuron - to - neuron - neuron - to - organ - or muscle to cell - to - muscle cell junction.






50. The portion of the nephron where water reabsorption is regulated via antidiuretic hormone (ADH). Several nephrons empty into each collecting duct - and this is the final region through which urine must passon its way to the ureter.