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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 pair of similar chromosomes that have the same genes in the same order - but may have different versions (alleles) of those genes. One of the pair of chromosomes came from Mom in an ovum - and the other came from Dad in a sperm. Humans have 23 pair






2. A dense grwoth of bacteria that covers the surface of a petri dish.






3. A group of sensory neuron cell bodies found just posterior to the spinal cord on either side. A pair of root ganglia exists for each spinal nerve that expands from the spinal cord. The ganglia are part of the peripheral nervous system (PNS).






4. 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






5. The volume of air inhaled and exhaled in a normla - resting breath - typically about 500 mL.






6. The burrowing of a blastocyst (a developing embryo) into the endometrium of the uterus - typically occuring about a week after fertilizaiton.






7. A region at the head of a sperm cell that contains digestive enzyems which - when released during the acrosome reaction - can facilitate penetration of the corona radiata of the egg - and subsequently - fertilization






8. 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.






9. A single piece of double - stranded DNA; part of the genome of an organism. Prokaryotes have circular chromosomes and eukaryotes have linear chromosomes.






10. Multiple sites of replication found on large - linear eukaryotic linear eukaryotie chromosomes.






11. Also called Leydig cells - these are teh cells within testes that produce and secrete testosteron. They are stimulated by luteinizing hormone (LH).






12. The tubes that carry urine from the kindeys to the bladder.






13. Unmyelinated neuron cell bodies and short unmyelinated axons.






14. A receptor that responds to light






15. A peptide hormone produced and secreted by the Beta cells of the pancreas. Insulin targets cells in the body - especially the liver and muscle - and allows them to take glucose out of gthe blood (thus lowering blood glucose levels).






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






17. Cytoskeletal filaments with a diameter in between that of the microtubule and the microfilament. Intermediate filaments are composed of many different proteins and tend to play structural roles in cells.






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






19. Specialized lymphatic capillaries in the intestines that take up lipids as well as lymph.






20. The 3D site of an enzyme where substrates (reactants) bind and a chemical reaction is facilitated.






21. A hormone released by the posterior pituitary that stimulates uterine contractions during childbirth and milk ejection during breastfeeding.






22. A red blood cell; they are filled with hemoglobin - and teh function of the erythrocytes is to carry oxygen in the blood.






23. A cytoplasmic protein that binds to a stop codon where it appears in the A- site of the ribosome. Release factors modify the peptidyl transferase activity of the ribosome - such that a water molecule is added to the end of the completed protein. This






24. The set of adult characteristics that develop during puberty under the control of the sex steroids. In males the secondary sex characteristics include enlargement and maturation of the genitalia - growth of facial - body - and pubic hair - increased






25. 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)






26. A protein channel in the nuclear envelope that llows the free passage of molecules smaller than 60 kD.






27. A thin - watery fluid found in teh anterior segment of the eye (between the lens and the cornea). THe aqueous humor is constantly produced and drained - adn helps to bring nutrients to the lesn and corena - as well as to remove metabolic wastes






28. The modifaction of enzyme activity through interactino of molecules with specific sites on the enzyme other than the active site (called allosteric sites)






29. 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.






30. A structure composed of a ribose molecule linked to one of the aromatic bases. In a deoxynucleoside - the ribose is replaced with deoxyribose.






31. A helical protein that winds around actin helices in skeletal and cardiac muscle cells to form the thin filament of the sarcomere. In the absence of Ca2+ - tropomyosin covers the myosin - binding sites on actin and prevents muscle contraction. When c






32. A set of vessels in the body that runs alongside the vessels of the circulatory system. It is a one - way system - with lymphatic capillaries beginning at the tissues and ultimately emptying into the large veins near the heart. It serves to return ex






33. A generic connective tissue cell that produces fibers; the progenitor of all other connective tissue cell types.






34. 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.






35. The division between neighboring cardiac muscle cells. Intercalcated discs include gap junctions - which allow the cells to function as a unit.






36. MRna that codes for several different proteins by utliizing different reading frames - nested genets - etc. Polycistronic mRNa is a characteristic of prokaryotes.






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






38. A group of three nucleotides taht is specific for a particular amino acid - or that specifies 'stop translating'






39. A ductless gland that secretes a hormone into the blood






40. Messenger RNA; the type of RNa that is read by a ribosome to synthesize protein.






41. 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






42. The rapid mitotic division of a zygot that being within 24-36 hours after fertilization






43. Paired glands near the posterior side of the vaginal that secrete an alkaline mucus upon sexual arousal. The mucus helps to reduce the acidity of the vagina (which could be harmful to sperm) and lubricates the vagina to facilitate penetration.






44. 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






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






46. The shaft of a long bone. The diaphysis is hollow and is made entirely from compact bone.






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






48. A contractile protein connecting microtubules in the '9+2- arrangement of cilia and eukaryotic flagella. The contraction of dynein produces the characteristic movement of these structures.






49. 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).






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