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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 released from the hypothalamus that triggers the anterior pituitary to secrete FSH and LH.






2. The function unit of the kidney. Each kidney has about a million nehprons; this is where blood filtration and subsequent modification of the filtrate occurs. The nephron empties into collecting ducts - which empty into the ureter.






3. Also called transverse tubules - these are deep invaginations of the plasma membrane found in skeletal and cardiac muscle cells. These invaginations allow depolarization of the membrane to quickly penetrate to the interior of the cell.






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






5. Anterior pituitary topic hormones FSH (follicle stimulating hormone) and LH (luteinizing homeon) that stimulates the gonads (testes and ovaries) to produce gametes and to secrete sex steroids.






6. A virus with an RNA genome (e.g. HIV) that undergoes a lysogenic life cycle in a host with a double stranded DNA genome. In order to integrate its genome with the host cell genome - the virus must first reverse trasncribe its RNA genome to DNA.






7. 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.






8. A hormone secreted by the samll intestine (duodenum) in response to the presence of fats. It promotes release of bile from the gallbladder and pancreatic juice from the pancreas - and reduces stomach motility.






9. The transfre by a lysogenic virus of a portion of a host cell genome to a new host.






10. The division of the peripheral nervous system that innervates and controls the skeletal muscles; also known as the voluntary nervous system.






11. Muscle tissue that is attached to the bones. SKeletal muscle is striated multinucleate - and under voluntary control.






12. A viral life cycle in which the viral genome is incorporated into the host genome where it can remain dormant for an unspecified period of time. Upon activation - the viral genome is excised from the host genome and typically enters the lytic cycle.






13. An enzyme that transcribes RNa. Prokaryotes have a single RNA pol - while eukaryotes have three; in eukaryotes - RNA pol I transcribes rRNA - RNA pol II transcribes mRNA - and RNA pol III transcribes tRNA.






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






15. 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.






16. The sphincter that separates the final part of the small intestine (the ileum) from the fron part of the large intestine (the cecum). It is typically kept contracted (closed) so that chyme can remain in the small intestine as long as possible. The il






17. 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.






18. A bacterium having a rod - like shaped (plural = bacilli).






19. An inactive precursor of an enzyme - activated by various methods (acid hydrolysis - cleavage by another enzyme - etc.)






20. Muscles located in between the ribs that play a role in ventilation.






21. A contractile protein. In skeletal and cardiac muscle - actin polymerizes (along with other proteins) to form the thin filaments. Actin is involved in many contractile activities - such as cyotkinesis - pseudopod formation - and muscle contraction.






22. 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






23. The largest organ in the abdominal cavity. The liver has many roles - including procesing of carbohydrates and fats - synthesis of urea - production of blood proteins - production of bile - recycling heme - and storage of vitamins.






24. Mendel's seond law. States that genes found on different chromosomes - or genes found very far apart on the same chromosome (i.e. - unlinked genes) sort independently of one another during gamete formation (meiosis).






25. A cell surface receptor associated with an intracellular protein that binds and hydrolyzes GTP. When GTP is bound - the protein is active - and can regulate the activity of adenylyl cyclease; this modifies the intracellular levels of second messenger






26. The formation of haploid gametes (sperm or ova) via meiosis.






27. 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






28. Also called occluding junctions - tight junctions form a seal between cells that prevents the movement of substances across the cell layer - except by diffusion through the cell membranes themselves. Tight junctions are found between the epithelial c






29. The outermost layer of teh skin. The epidermis is made of epithelial tissue that is constantly dividing at the bottom; teh cells migrate to teh surface (dying along the way) to be sloughed off at the suface.






30. 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.






31. The point during development at which a cell becomes committed to a particular fate (sensory - other - etc.). Note that the cell is not differentiated at this point; determination comes before differentiation. Determination can be due to cytoplasmic






32. The duct that carries bile from the gallbladder and liver to the small intestine (duodenum).






33. An electrical potential established across the plasma membrane of all cells by the Na+/K+ ATPase and the K+ leak channels. In most cells - the resting membrane potential is approximately -70 mV with respect to the outside of the cell.






34. (1) The secretion of useful substances from a cell - either into the blood (endocrine secretin) or into a cavity or onto the body surface (exocrine secretion). (2) in the nephron - the movement of substances from the blood to the filtrate along the t






35. The first phase of mitosis. During prophase the replicated chromosomes condense - the spindle is formed - and the nuclear envelope breaks apart into vessicles.






36. 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






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






38. A diploid cell formed by the fusion of two gametes during sexual reproduction.






39. 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.






40. The enzymes that catalyzes the phosphorylation of glucose to form glucose -6- phosphate in the first step of glycolysis. This is one of the ain regulatory steps of this pathway. Hexokinase is feedback - inhibited by glucose -6- P.






41. The phase of the cell cycle during which the genome is replicated.






42. A hormone derived from cholesterol. Steroids are generally hydrophobic and can easily cross the plasma membrane of cells - thus receptors for steroids are found intracellularly. Once this steroid binds to its receptor - the receptor - steroid complex






43. 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'






44. 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.






45. 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






46. An enzyme whose transcription can be stimulated by an abundance of its substrate (as opposed to repressible enzyme). Usually in catabolism.






47. The primary membrane lipid. Phospholipids consist of a glycerol molecule esterified to two fatty acid chains and a phosphate molecule. Additional - highly hyrohpilic groups are attached to the phosphate - making this molecule extremely amphipathic.






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






49. Connective tissue with large amounts of either collagen fibers (making them strong) or elastic fibers - or both. Dense tissues are typically strong (e.g. bone - cartilage - tendons - etc.)






50. 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.