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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 constant input to the arteries that keeps them somewhat constricted to maintain a basal level of blood pressure.






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






3. The allele in a heterozygou genotype that is not expressed; the phenotype resulting from possession of two recessive alleles (homozygous recessive).






4. A membrane lipid consisting of a glycerol molecule esteried to two fatty acid chains and a sugar molecule.






5. (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.






6. A pigmented membrane found just in from the lens of the eye. In the center of iris is the pupil - a hole through which light enters the eyeball. The iris regulates the diameter of the pupil in response to the brightness of light.






7. The final phase of the digestive tract - also called the colon. The primary funcion of the large intestine is to reabsorb water and to store the feces.






8. A chromosome that does not determine gender (is not a sex chromosome). Humans have two sex chromsomes and 22 autosomes.






9. The primary androgen (male sex steroid). Testosterone is a steroid hormone produced and secreted by the interstitial cells of the testes. It triggers the development of secondary male sex characteristics during puberty (including spermatogenesis) and






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






11. One of several vessels that carry oxygenated blood from the lungs to the left atrium of the heart.






12. The three small bones found in the middle ear (the malleus - the incus - and the stapes) that help to amplify the vibrations from sound waves. The malleus is atached to the tympanic membrane and the stapes is attached to the oval window of the cochle






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






14. An organism that can survive in the presence of oxygen (oxygen is not toxic) - but that does not use oxygen during metabolism (anaerobic metabolism only).






15. A small cell with extremely little cytoplasm that results from the unequal cytoplasmic divsion of the primary (produces the first polar body) and the secondary (produces the second polary body) oocytes during meiosis (oogenesis). The polar bodies deg






16. 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)






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






18. Also called thryoid hormone - thyroxine is produced and secreted by follicle cells in the thyroid gland. it targets all cells in the body and increases overall body metabolism.






19. An organism that cannot make its own food - and thus must ingest other organisms.






20. Gaps in the myelin sheath of the axons of peripheral neruons. Action potentials can 'hump' from node to node - thus increasing the speed of conduction (saltatory conduction).






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






22. The movement of a hydrophobic molecule across the plasma membrane of cell - down its concentration gradient. Since the molecule can esialy interact with the lipid bilayer - no additional help (such as a channel or pore) is required.






23. The portion of the ear consisting of the pinna and the external auditory canal. The outer ear is separated from the middle ear by the tympanic membrane (the eardrum).






24. All of the cell cycle except for mitosis. Interphase includes G1 - S phase - and G2.






25. A function of the reproductive system controlled by the sympathetic nervous system. In males - organs includes emission and ejaculation; in females it is mainly a series of rhythmic contraction of the pelvic floor muscles and the uterus.






26. A specific DNA nucleotide sequence where transcriptional regulatory proteins can bind.






27. 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






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






29. 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.






30. Enzymes secreted by the mucosal cells lining the intestine. The brush border enzymes are disaccharides adn dipeptidases taht digest the smallest peptides and carbohydrates into their respective monomers.






31. Something that acts to oppose the action of something else. For example - muscles that move a join in oppoiste direction are said to be antagonists.






32. Myelinated axons






33. 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






34. A long - whip - like filament that helps in cell motility. Many bacteria are flagellated - and sperm are flagellated.






35. Steroid hormones secreted from the adrenal cortex. The two major classes are teh mineralocorticoids and glucocorticoids. Aldosterone is the principal mineralocorticoid - and cortisol is the principal glucorcorticoid.






36. The sequence of nucleotides on a chromosome that activates RNA polymerase so that transcription can take place. The promoter is found upstream of the start site - the location where transcription actually takes place.






37. A sensory receptor that responds to specific chemicals. Some examples are gustatory (taste) receptors - olfactory (smell) receptors - and central chemoreceptors (responds to pH changes in teh cerebrospinal fluid).






38. A skeletal muscle cell - also known as a muscle fiber. Skeletal muscle cells are formed from the fusion of many smaller cells (during development) consequently they are very long and are multinucleate.






39. Earlier embryonic ducts that can develop into femal internal genitalia in the absence of testosteron.






40. 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.






41. A structure composed of two coils of DNA wrapped around an octet of histone proteins. The nucleosome is the primary form of packagin of eukaryotic DNA.






42. An insulating layer of membranes wrapped around the axons of almost all neurons in the body. Myelin is essentially the plasma membranes of specialized cells; Schwann cells in the peripheral nervous system - and oligodendrocytes in the central nervous






43. A clear area in a lawn of bacteria. Plaques represent an area where bacteria are lysing (dying) and usually caused by a lytic virus.






44. An organism that has two copies of its genome it each cell. The paired genomes are said to be homologous.






45. An incrase in the fragility of the membranes of sperm cells when exposed to the female reproductive tract. Capacitation is required sot aht the acrosomal enzymes can be relased to faciliate fertilization.






46. 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.






47. The clear portion of the tough outer layer of teh eye ball - found over the iris and pupil






48. Oil - forming glands found all over the body - especially on the face and neck. The product (sebum) is released to the skin surface through hair follicles.






49. The female primary sex organ. The ovary produces female gametes (ova) and secretes estrogen and progesterone.






50. 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.