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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. Oil - forming glands found all over the body - especially on the face and neck. The product (sebum) is released to the skin surface through hair follicles.






2. Cells found in gastric glands that secrete hydrochloric acid (for hydrolysis of ingested food) and gastric intrinsic factor (for absorption of vitamin B-12).






3. 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).






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






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






6. An ion channel that is opened or closed based on the binding of a specific ligand to teh channel. Once opened - the channel allows the ion to cross the plasma membrane according to its concentration gradient. An examples is the acetylcholine receptor






7. An enzyme that lyses bacterial cell walls. Lysozyme is produced in the end stages of the lytic cycle so that new viral particles can escape their hosst; it is also found in human tears and human saliva.






8. An incrase in the fragility of the membranes of sperm cells when exposed to the female reproductive tract. Capacitation is required sot aht the acrosomal enzymes can be relased to faciliate fertilization.






9. The step in the sliding filament theory during which yosin undergoes a conformaitonal change to its low energy state - in the process dragging the thin filaments (and the attached Z lines) toward the center fo the sarcomere. NOte that power stroke re






10. A point mutation in which a codon that specifies an amino acid is mutated into a new codon that specifies the same amion acid.






11. 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.






12. An activated B cell that is secreting antibody.






13. A normal blood protein produced by the liver - angiotensin is converted to angiotensim I by renin (secreted by kidney when blood pressur falls). Angiotensin I si further onverted to angiotensim II by ACE (angiotensin converting enzyme). Angiotensin I






14. The energy in a system that can be used to drive chemical reactions. If the change in free energy of a reaction (Delta G - the free energy of the products minus the free energy of the energy of the reactants) is negative - the reaction will occur spo






15. The regino of the digestive tract where virtually al digestion and absorption occur. It is subdivided into three regions: the duodenum - the jejunum - and the ileum.






16. A long projection on a bacterial surface involved in an attachment - e.g. - the sex pilus attaches F+ and F- bacteria during conjugation.






17. The flow of blood from the heart - through the lungs - and back to the heart.






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






19. Movement of a hydrophilic molecuel across the plasma membrane of a cell - down its concentration gradient - through a channel - pore - or carrier molecule in the membrane. Because the hydrophilic nature of the molecule - it requires a special path th






20. The tube that connects the middle ear acity with the pharynx; also known as the Eustachian tube. Its fucntion is to equalize midle ear pressure with atmospheric pressure so that pressure on boths sides of the tympanic membrane is the same.






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






22. 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






23. Partially digested - semiliquid food mixed with digestive enzymes and acids in the stomach.






24. 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.






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






26. 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






27. The synapse between a motor neuron and a muscle cell. At the NMJ - the muscle cel lmembrane is invaginated and the axon terminus is elongated so that a greater area of membrane can be depolarized at one time.






28. A neuron with a single axon and a single dendrite - often projecting from opposite sides of the cell body. Bipolar neurons are typically associated with sensory organs; an example is the bipolar neuron in the retina of the eye. - note that one axon m






29. A highly specific cellular uptake mechanism. The molecule to be taken up must bind to cell surface receptor found in a clathrin - coated pit.






30. The principal mineralocorticoid secreted by teh adrenal cortex. This steroid hormone targets the kidney tubules and increases renal reabsorption of sodium [and excretion of potassium]. (this causes ADH to be secreted & increased water comes out - inc






31. A region of specialized cardiac muscle cells in the right atrium of the heart that initiate the impules of heart contraction; for this reason the SA node is knownas the 'pacemaker' of the heart.






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






33. 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.






34. A substance secreted by embryonic testes that causes the regression of the Mullerian ducts.






35. A gland that secretes a waxy product - found in the external ear canal.






36. 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).






37. The portion of theforebrain that includes the thalamus and hypothalamus.






38. The blood vessel that carries deoxygenated from the right ventricle of the heart to the lungs.






39. A precursor cell that undergoes mitosis during fetal development to produce more oogonium. These cells are then activated to produce primary oocytes - which remain dormant until stimulated to undergo meiosis I during some future menstrual cycle.






40. The portion of the brain responsible for visual and auditory startle reflexes.






41. Something that acts to oppose the action of something else. For example - muscles that move a join in oppoiste direction are said to be antagonists.






42. The folds of the inner membrane of a mitochondrion






43. A concentrated region of white blood cells found along the vessels of the lympatic system.






44. An enzyme whose transcription can be stopped by an abundance of its product (as opposed to inducible enzymes). Usually part of anabolism of product.






45. One of several different nutrietns that must be consumed in the diet - and generally not synthesized in the body. Vitamins can be hdyrophobic (fat - solube) or hydrophilic (water - soluble).






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






47. The inside of the a hollow organ (e.g. - the somach - intestines - bladder - etc.) or a tube (e.g. - blood vessels - ureters - etc.)






48. One of the three primary (embryonic) germ layers formed during gastrulation. Mesoderm ultimately forms 'middle' structures such as bones - muscles - blood vessels - heart - kindeys - etc.






49. Also called vasopressin - this hormone is produced in the hypothalamus and secreted by teh posterior pituitary gland. It tartes teh kidney tubules - increasing their permeability to water - adn thus increasing water retention by the body. Also raises






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