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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 type of eukaryotic mRNA processing in which introns are removed from the primary transcript and exons are ligated together. SPlicing of transcripts can be different in different tissues.






2. An ion channel that is oepend or closed based on the electrical potential across the plasma membrane. Once opened - the channel allows ions to cross the membrane according to their concentration gradients. Examples are the Na+ and K+ voltage - gated






3. The membrane surrounding the DNA in eukaryotic cells made of two lipid bilayers.






4. A neuron that arries information (action potentials) to the central nervous system; a sensory neuron.






5. A hydrophobic molecule - usually fomred from long hydrocarbon chains. The most common forms in which lipids are found in the body are as triglycerides (energy storage) - phospholipids (cell membranes) - and cholestero (cell membranes and steroid synt






6. An organism that lacks a nucleus or any other memrane - bound organelles. All prokaytes belong to the Kingdom Monera (not protista!)






7. A sequence of amino acids (usually basic) that directs a protein to the nuclear envelope - where it is imported by a specific transport mechanism.






8. 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.






9. Specialized tissue with a lot of space that can fill with blood upon proper stimulation - causing teh tissue to become firm. Erectile tissue is found in the penis - the clitoris - the labia - and the nipples.






10. Something that increases the rate of a chemical reaction by reducing the activation energy for that reaction. The free energy of reaction remains unchanged.






11. Fat cell






12. A diploid cell that can undergo mitosis to form more spermatogonium - and can also be triggered to undergo meiosis to form sperm.






13. The most common class of bone in the body - long bones have a well - defined shaft (the diaphysis) and two well - defined ends (the epiphyses).






14. The subdivision of the nervous system consisting of the brain and spinal cord.






15. A hormone secreted by the anterior pituitary that tarets the mammary glands stimulating them to produce breastmilk.






16. The process of bulidng complex structures out of simpler precursors - e.g. synthesizing protiens from amino acids.






17. The third phase of the uterin (endometrial) cycle - during which the rebuilt endometrium is enhanced with glycogen and lipid stores. The secretory phase is primarily under the controll of progestone and estrogen (secreted from the copus luteum during






18. 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






19. Amino - acyl tRNA site; the site on a ribosome where a new amino acid is added to a growing peptide.






20. The characteristics of amolecule that has both polar (hydrophilic) and non - polar hydrophobic) regions - e.g. phospholipids - bile - etc.






21. A short sequence of amino aids - usually found at the N- terminus of a protein being translated - that directs the ribosome and its associated mRNa to the membranes of the rough ER where trasnlation will be completed. Signal sequences are found on me






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






23. 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.






24. The allele in a heterozygous genotype that is expressed; the phenotype resulting from either a heterozygous genotype or a homozygous dominant genotype.






25. The non - specific uptake of liquid particles into a cell by invagination of the plasma membrane and subsequent 'pinching off' a small bit of the extracellular fluid.






26. The period of human development beginning at 8 weeks of gestation and lasting until birth (38-42 weeks of gestation). During this stage the organs formed in the embryonic stage grow and mature. The developing baby is known as a fetus during this time






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






28. Human Chorionic Gonadotropin - a hormone secreted by the trophoblast cells of a blasocyst (i.e. developing embryo) that prolongs the life of the corpus luteum - and thus increases the duration and amount of secreted progesterone. This helps to mainta






29. The stage of human development during which the organs are formed. Organogenesis begins after gastrulation and is completed by the eight week of gestation.






30. A hair - like structure on teh cell surface composed of microtubules ina '9+2' arrangement (nine pairs of microtubles surrounding 2 single microtubules in the center). Teh microtubules are conneted with a contractile protien called dynein. Cilia beat






31. An organism that can only survive in the absence of oxygen (anaerobic metabolism); oxygen is toxic to obligate anaerobes.






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






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






34. The second phase of meiosis II. Metaphase II is identical to mitotic metaphase - except that the number of chromosomes was reduced by half during meiosis I.






35. A form of genetic recombination in bacteria in which plasmid and/or genomic DNA is transferred from one bacterium to the toher through a conjugation bridge.






36. Cells that possess MHC II (B cells and macrophages) and are able to display bits of ingested antigen on their surface in order to activate T cells. See also 'MHC'






37. One of the main pancreatic proteases; it is activated (from chymotrypsinogen) by trypsin.






38. The membranes that line the surface of the lungs (visceral pleura) and the inside wall of the chest cavity (parietal pleura).






39. A point mutation in which a pyrimidine is substitued for a purine - or vice versa.






40. The movement of a substance across a membane via pressure. In the kidney - filtration refers specifically to the movement of plasma across the capillary walls fo the glomerulus - into the capsule and tubule of the neprhon. Filtration at teh glomerulu






41. A hormone produced from vitamin D that acts in essentially the same manner as parathyroid hormone.






42. A small - extrachromosomal (outside the genome) - circular DNA molecule found in prokaryotes.






43. A viral life cycle in which the host is turned into a 'virus factory' and ultimately lysed to release the new viral particles.






44. The uptake of material into a cell - usually by invagination. See also 'phagocytosis' - pinocytosis - and receptor - mediated endocytosis..






45. Integration by a postsynaptic neuron of inputs (EPSPs and IPSPs) from multiple sources.






46. 'Yellow body.' The remnants of an ovarian follicle after ovulation has occurred. The cells enlarge and begin secreting progesterone - the dominant female hormone during the second half of the menstrual cycle. Some estrogen is also secreted.






47. Complementary DNA. DNA produced synthetically by reverse trascribing mRNA. Because of eukaryotic mRNA splicing - cDNA contains no inrons.






48. 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






49. Muscles that help focus light on teh retin by controlling the curvature of the lens of the eye.






50. A bacterial structure formed in unfavorable growth conditions. Endospores have very rough outer shells made of peptidoglycan and can survive harsh conditions. The bacterium inside the endospore is essentially dormant and can become active (called ger