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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 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.






2. The movement of teh membrane potential of a cell away from rest potential in a more positive direction.






3. Paired masses of lymphatic tissue near the back of the throat that help trap inhaled or swallowed pathogens.






4. The loop of the nephron that dips downward into the renal medulla. The loop of Henle sets up a concentration gradient in the kidney such that from the cortex to the renal pelvis osmolarity increases. The descending limb of the loop of Henle is permea






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






6. A sensory receptor that responds to hcanges in pressure; for example - there are baroreceptors in the carotid arteries and the aortic ach that monitor blood pressure.






7. A mass of lymphatic tissue at the befenning of the large intestine that helps trap ingested pathogens.






8. A cell characterized by the presence of a nucleus and other membrane - bound organelles. Eukaryotes can be unicellular (protists) or multicellular (fungi - plants and animals).






9. A point mutation in which a pyrimidine is susbstituted for a pyrimidine - or a purine is substituted for a purine.






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






11. Heterogeneous nuclear RNA; the primary transcript made in eukaryotes before splicing.






12. The region at the center of an A band of a sarcomere that is made up of myosin only. The H zone gets shorter (and may disappear) during muscle contraction.






13. The organ that carries out teh command sent along a particular motor neuron






14. 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).






15. 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






16. A receptor that responds to changes in body position - such as stretch on a tendon - or contraction of a muscle. These receptor allow us to be consciously aware of the position of our body parts.






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






18. A drop in blood pH due to hypoventilation (too little breathing) and a resulting accumulation of Co2.






19. Pain receptors. Nociceptors are found everywhere in the body except for the brain.






20. A group of three enzymes that decarboxylates pyruvate - creating an acetyl group and carbon dioxide. The acetyl group is then attached to coenzyme A to produce acetyl - CoA - a substrate in the Krebs cycle. In the process - NAD+ is reduced to NADH. T






21. 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.






22. Also known as the gastrointestinal (GI) tract of the digestive tract - the alimentary canal is the long muscular 'tube' that includes the mouth esophagus - somatch - small intesitne - and large intestine.






23. 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






24. A group of blood proteins that bind non - specifically to the surface proteins of foreign cells (such as bacteria) - ultimately leading to the destruction of the foreign cell - part of the innate immunity.






25. The reactants in an enzyme - catalyzed reaction. Substrate binds at the active site of an enzyme.






26. A phase in the cycle between mitosis and S phase (G1) or between S phase and mitosis (G2). During gap phases the cell undergoes normal activity and growth; G1 may include preparation for DNA replication and G2 includes preparation for mitosis. Note t






27. A rapid from of action potential conduction along the axon of a neuron in which the action potential appears to jump from nodde of Ranvier to node of Ranvier.






28. Pairing of homologus chromosomes in a diploid cell - as occurs during prophase I of meiosis.






29. The ability of tissues to regulate their own blood flow in the absence of neural stiulation. THis is generally accomplished via metabolic wastes (such as CO2) that act as vasodilators.






30. 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.






31. A clear fluid the circulates around through the brain and spinal cord that helps to physially support teh brain and act as a shock absorber - and taht also exchanges nutrients and wastes with teh brain and spinal cord.






32. The reduced from (carries electrons) of FAD (flavin adenine dinucleotide). this is the other main electron carrier in cellular respiration (NADH is the most common).






33. 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






34. Also called DNA pol - this is the enzyme that replicates DNA. Eukaryotes have a single version of the enzyme - simply called DNA pol (not need to know much detail); prokaryotes have three versions - called DNA pol I - DNA pol II - and DNA pol III.






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






36. The release of milk from the mammary glands via contraction of ducts within the glands. Contraction is stimulated by oxytocin - which is released from the posterior pituitary when the baby begins nursing.






37. The first phase of meiosis I. During prophase I the replicated chromosomes condense - homologous chromsomes pair up - crossing over occurs between homologous chromosomes - the spindle is formed - and the nuclear envelope breaks apart into vesicles. P






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






39. 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.






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






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






42. 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






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






44. A digestive accessory organ near the liver. The gallbladder stores and concentrates bile produced by the liver - and is stimulated to contrat by cholecystokin (CCK).






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






46. A thin (4 mm) layer of gray matter on the surface of the cerebral hemispheres. The cerebral cortex is the conscious mind - and is functionally divided into four pairs of lobes: the frontal lobes - the parietal lobes - the temporal lobes - and the occ






47. A blood pressure cuff






48. A physiological catalyst. Enzymes are usually proteins - although some RNAs have catalytic activity.






49. The return of membrane potential to normal resting values after a depolarization of hyperpolarization.






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