Test your basic knowledge |

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. The attachment of an amino acid to a tRNA (not that this a specific interaction). tRNa loading requires two high - energy phosphate bonds.






2. A type of substrate binding to a multi - active site enzyme - in which the bnidng of one substrate molecule facilitates teh binding of subsequent substrate molecules. A graph of reaction rate vs. substrate concentration appears sigmoidal. Noe that co






3. Small paired gland found inferior to the prostate in males and at the posterior end of the penile urethra. They secrete an alkaline mucus on sexual arousal that helps toneutralize any traces of acidic urine the urethra that might be harmful to sperm.






4. The liquid portion of blood; plasma contains water - ions - buffers - sugars - proteins - etc. Anything that dissolves in blood dissolves in the plasma portion.






5. 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.






6. The sequence of nucleotides on a chromosome that activates RNA polymerase so that transcription can take place. The promoter is found upstream of the start site - the location where transcription actually takes place.






7. The volume of blood pumped out of the heart in one minute (vol/min); the product of the stroke volume (vol/beat) and the heart rate (beat/min). Cardiac output is directly proportional to blood pressure**.






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






9. 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






10. A membrane lipid consisting of a glycerol molecule esteried to two fatty acid chains and a sugar molecule.






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






12. The first encounter with an antigen - resuling in activated B cells (antibody secretion) and T cells (cellular lysis and lymphocyte proliferation). The primary immune response takes approximately ten days - which long enough for symptoms of the infec






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






14. The flow of blood from the heart - through the body (not including the lungs) - and back to the heart.






15. A clump of gray matter (unmyelinated neuron cell bodies) found in the peripheral nervous system.






16. A version of a gene. For example - the gene may be for eye color - and the allels include those for brown eyes - those for blu e eyes - those green eyes - etc. At most - dploid organsims can posses only two alleles for a given gene - one on each of t






17. The division of the inner cell mass of a blastocyst (developing embryo) into the three primary germ layers. Gastrulation occurs during weeks 2-4 of gestation.






18. A function in the reproductive system - controlled by the parasympathetic nervous system - that includes erection (via dilation of erectile arteries) and lubrication.






19. The monomer of a carbohydrate. Monosaccharides have the general chemical formula CnH2nOn - and common monosaccharides include glucose - fructose - galactose - and ribose.






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






21. Plasma with the clotting factors removed. Serum is often used in diagnostic tests because it does not clot.






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






23. 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






24. 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






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






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






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






28. One of two large vessels (superior and inferior) that return deoxygenated blood to the right atrium of the heart.






29. A blood vessel that carries blood away from the heart chambers. Arteries have muscular walls to regulate blood flow and are typically high - pressure vessles.






30. A genotype in which two identical alleles are possessed for a given gene. The allelles can both be dominant (homozygous dominant) or both be recessive (homozygous recessive)






31. The primary muscle of inspiration. The diaphragm is stimulated to contract at regular intervals by the respiratory center in the medulla oblongata (via the phrenic nerve). Although it is made of skeletal muscle (and can therefore be voluntary control






32. The constant inhibition provided to the heart by the vagus nerve. Vagal tone reduces the intrinsic firing rate of teh SA node from 120 beats/minute to around 80 beats/minute.






33. The folds of the inner membrane of a mitochondrion






34. Chemoreceptors in the upper nasal cavity that respond to odo chemicals.






35. 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






36. Also known as the adenohypophysis - the anterior pituitary is made of gland tissue and makes and secretes six different homrones: FSH - LH - ACTH - prolactin - TSH - and growth hormone. The anterior pituitary is controlled b yreleasing and inhibiting






37. The ends of a saromere.






38. Early embryonic ducts that can develop into male internal genitalia under the proper stimulation (testosterone).






39. The pressure measured in the arteries during contraction of the ventricles (during systole).






40. Summation by a postsynaptic cell of input (EPSPs or IPSPs) from a single source over time.






41. 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






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






43. Anterior pituitary gland






44. The inner layer of smooth muscle in the wall of the digestive tract. When the circular muscle contracts - the tube diameter is reduced. Certain areas of the circular muscle are thickened to act as valves (sphincters).






45. The plasma membrane of a muscle cell.






46. The portion of the cell membrane at the neuromusclar junction; essentially the postsynaptic membrane at the synapse.






47. A green fluid made from cholesterol and secreted by teh liver. It is stored and concentrated in the gallbladder. Bile isn an amphipathic molecule that is secreted itno the small intestine when fats are present - adn serves to emulsify the fats for be






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






49. A hormone produced by the C- cells of the thyroid gland that decreases serum calcium levels. It targets teh bones (stimulates osteoblasts) - the kidneys (reduces calcium reabsorption) - and the small intestine (decreases calcium absorption).






50. 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