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MCAT Prep Biology

Subjects : mcat, science
Instructions:
  • Answer 50 questions in 30 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 mechanism of contraction in skeletal and cardiac muscl cells. It is a series of four repeated steps: (1) myosin binds actin - (2) myosin pull actin toward the center of the sarcomere (3) myosin releases actin - and (4) myosin resets to its high -






2. Small fragments of DNa produced on the lagging strand during DNa replication - joined later by DNA ligase to form a complete strand.






3. The muscle tissue of the heart Cardiac muscle is striated - uninucleate - and under involuntary control (controlled by teh autonomic nervous system). Note also that cardiac muscle is self - stimulatory - and autonomic control serves only to modify th






4. The movement of air out of the respiratory tract. Expiration can be passive (caused by relaxation of the diaphragm and elastic recoil of the lungs) or active (caused by contraction of the abdominal muscles - which increases intraabdominal pressure an






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






6. 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.






7. An organism that requires oxygen to survive (aerobic metabolism only).






8. An organs in the abdominal cavity with two roles. The first is an exocrine role: to produce digestive enzymes and bicarbonate - which are delivered to the small intestine via the pancreatic duct. The second is an endocrine role: to secrete insulin an






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






11. The first portion of the nephron tubuel after the glomerulus. THe PCT is the site of most reabsorption; all filtered nutrients are reabsorbed here as well as most of the filtered water.






12. The string between beads of DNA on histones. They are also wrapped around a single histone - called linker histone - may not really have to know..






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






14. A form of evolution in which different organisms are placed into the same environment and exposed to teh same selection pressures. This causes the organisms to evolve along similar lines. As a result - they may share functional - but not structural s






15. General - non - specific protection to the body - including the skin (barrier) - gastric acid - phagocytes - lysozyme - and complement.






16. An organelle bounded by a double membrane (double lipid bilayer) called the nuclear envelope. The nucleus contains the genome and is the site of replication and transcription.






17. The three glands in the male reproductive system that reproduce semen: the seminal vesicles - the prostate - and the






18. The valve that controls the release of feces from the recturm. It has an internal part made of smooth muscle (thus involuntary) and an external part made of skeletal muscle (thus voluntary).






19. A nucleoside with one or more phosphate gropus attached. Nucleoside triphosphates (NTPs) are the building blocks of RNA and are also used as energy molecules - especially ATP. Deoxynucleoside triphosphates (dNTPs) are the building blocks of DNA; in t






20. A protein channel in a cell membrane that is specific for a particular ion - such as Na+ or K+. Ion channels may be constitutively open (leak channels) - or regulated (voltage - gated or ligand - gated).






21. The theory that mitochondria and chloroplasts originated as independent unicellular organsims living in symbiosis with larger cells






22. 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






23. The portion of the nephron after the glomerulus and apsule; the region of the nephron where the filtrate is modified along its path to becoming urine.






24. A strong band of connective tissue that connets bones to one another.






25. A gland that secretes its product into a duct - which ultimately carries the product to the surface of the body or into a body cavity. Some examples of exocrine gland and their products are sweat glands (sweat) - gastric glands (acid - mucus - protea






26. The largest artery in teh body; the aorta carries oxygenated blood away from the left ventricle of the heart.






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






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






29. The reduced form of NAD+ (nicotinamide adenine dinucleotide). This is the most common electron carrier in cellular respiration.






30. An enzyme that connects two fragments of DNA to make a single fragment; also called DNA ligase. This enzyme is usedd during DNA replication and is also used in recombinant DNA research.






31. The region of teh brain that coordinates and smooth skeletal muscle activity.






32. The white portion of teh tough outer layer of the eyeball






33. 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






34. A triat determined by a gen on either the X or Y chromosomes (the sex chromosomes).






35. A rigid structure at the top of the trachea (so it is part of trachea - I assume) made completely out of cartilage. The larynx has three main functions: (1) its rigidness ensures that the trachea is held open (provides an open airway). (2) the epiglo






36. The cytoskeleton filaments with the smallest diameter. Microfilaments are composed of the contractile protein actin. They are dynamic filaments - constantly beig made and broken down as needed - and are responsible for events such as pseudopod format






37. 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.






38. The removal ( and usually the activation) of a viral genome from its host's genome.






39. A pigmented membrane found just in from the lens of the eye. In the center of iris is the pupil - a hole through which light enters the eyeball. The iris regulates the diameter of the pupil in response to the brightness of light.






40. A subphase of male orgasm - a reflex reaction triggered by the presence of semen in the urethra. Ejaculation is a series of rhythmic contractions of muscles near teh base of teh penis that increase pressure in the urethra - forcing the semen out.






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






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






43. The synthesis of blood cells (occurs in the red bone marrow)






44. 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






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






46. The second phase of meiosis I. During metaphase I the paired homologous chromsomes (tetrads) align at the center of the cell (the metaphase plate).






47. Muscle tissue found in the walls of hollow organs - e.g. - blood vessels - the digestive tract - the uterus - etc. Smooth muscle is non - striated - uninucleate - and under involuntary control (controlled by the autonomic nervous system).






48. Something that works together with another thing to augment the the second thing's activity. For example - a uscle that assists another muslce is said to be a syngergist. An enzyme that helps another enzyme is a synergist.






49. All the genetic information in an organism; all of an organism's chromosomes.






50. 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.