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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 combination of alleles of an organism carries. In a homozygous genotype - both alleles are the same - whereas in a heterozygous gentorype the alleles are different.






2. A looser - more porous type of bone tissue found at the inner core of the epiphyses in long bones and all other bone types. Spongy gone is filed with red bone marrow - important in blood cell formation.






3. 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






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






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






6. The main protease secreted by the pancreas; trypsin is activated (from trypsinogen) by enterokinase - and subsequently activates other pancreatic enzymes.






7. The darkly pigmented middle layer of the eyeball - found between teh sclera (outer layer) and the retina (inner layer).






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






9. The small artery that carries blood toward the capillaries of the glomerulus.






10. A period of time following an action potential during which no additional action potential can be evoked regardless of the level of stimulation. (usually because Na+ channel closed whle K+ efflux)






11. The division of the autonomic nervous system known as the 'resting and digesting' system. It causes a general decrease in body activities such as heart rate - respiratory rate - and blood pressure - and an increase in blood flow to the GI tract and d






12. 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.






13. A layer of cells surroudning the granulosa cells of the follicles in an ovary. Thecal cells help produce the estrogen secreted from the follicle during the first phase of the ovarian cycle.






14. 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.






15. A type of substrate binding to a multi - active site enzyme - in which the bnidng of one substrate molecule facilitates teh binding of subsequent substrate molecules. A graph of reaction rate vs. substrate concentration appears sigmoidal. Noe that co






16. The portion of the diencephalon involved in maintaining body homeostasis. the hypothalamus also controls the release of hormones from the pituitary gland.






17. The process of breaking down large molecules into smaller precursors - e.g. digesion of starch into glucose.






18. A hole in the center of the iris of the eye that allows light to enter the eyeball. The diameter of pupil is controlled by the iris in response to the brightness of the light.






19. The division of the inner cell mass of a blastocyst (developing embryo) into the three primary germ layers. Gastrulation occurs during weeks 2-4 of gestation.






20. 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).






21. The valve that controls the release of urine from the bladder. It has an internal part made of smooth muscle (thus involuntary) and an external part made of skeletal muscle (thus voluntary).






22. A normal component of the outer membrane of Gram - negative bacteria. Endotoxins produce extreme immune reactions (septic shock) - particularly when many of them enter the circulation at once.






23. The nervous system of the gastrointestinal tract. It controls secretion and motility within teh Gi tract - and is linked to the central nervous system.






24. 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






25. The cytoskeleton filaments with the smallest diameter. Microfilaments are composed of the contractile protein actin. They are dynamic filaments - constantly beig made and broken down as needed - and are responsible for events such as pseudopod format






26. A toxin that secreted by a bacterium into its surrounding medium that help the bacterium compete with other species. Some exotoxins cause serious disease in humans (botulism - tetanus - diptheria - toxic shock syndrome).






27. A bacteria having a round shape (plural = cocci)






28. Something that works together with another thing to augment the the second thing's activity. For example - a uscle that assists another muslce is said to be a syngergist. An enzyme that helps another enzyme is a synergist.






29. Also known as the Bundle of His - this is the first portion of the cardiac conduction system - after the AV node.






30. 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.






31. Proteins that bind to and stabilize the signle strands of DNA exposed when helicase unwinds the double helix in preparation for replication.






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






33. The percentage of individuals with a particular genotype that actually displays the phenotype associated with the genotype.






34. Strong bands of connective tissue that connect skeletal muscle to bone.






35. Also known as the cortical reaction - the slow block invovles an increase in intracellular [Ca2+] in the egg - which causes the release of cortical granules near the egg plasma membrane. This results in the hardening of the zona pellucida and its sep






36. A eukaryotic organelle filled with digestive enzymes (acid hydrolases) that is involved in digestion of macromolecules such as worng organelles or material ingested by phagocytosis.






37. A statistical rule stating that the probability of two independent events occuring together is the product of their individual probabilities.






38. The valve that regulates the passage of chyme from the stomach into the small intestine.






39. 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.






40. The structure in the cochlea of the inner ear made up of the basilar membrane - the auditory hair cells - and the tectorial membrane. The Organ of Corti is the site where auditory sensation is detected and transduced to action potentials.






41. The site(s) where the parental DNA double helix unwinds during replication.






42. An organism that has only a single copy of its genome in each of its cells. Haploid organisms possess no homolous chromosomes.






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






44. A series of enzyme complexes found along the inner mitochondrial membrane. NADH and FADH2 are oxidized by tehse enzymes; the electrons are shuttled down the chain and are ultimately passed to oxygen and to produce water. The electron energy is used t






45. The portion of the digestive tract that stores and grinds food. Limited digestion occurs in the somach - and it has the lowest pH in the body (1-2).






46. Also called simply - 'islet cells' these are the endocrine cells of the pancreas. Different cell types wihtin the inslets secrete insulin - glucagon - and somatostatin






47. The valvecontrolling release of bile and pancreatic juice into the bloodstream.






48. 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)






49. A mature - cartilage cell.






50. 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.