Answers and Explanations - nelnetsolutions.com

1 CLEP is a registered trademark of the College Entrance Examination Board, whichwas not involved in the production of and does not endorse this and correct answer is (E). Because a family is more highly classified than kingdom, phylum,class, and order, organisms that share the samefamily must also share the same kingdom, phy-lum, class, and order. Only the genus of the twoorganisms may correct answer is (A). Plasma B cells arespecialized immune system cells that secreteantibodies, small Y-shaped proteins that can di-rectly attach to and agglutinate, or clump, in-vading bacteria. Attaching directly to cells is thejob of killer-T cells, and engulfing pathogens isthe job of macrophages. Clotting is done prima-rily by platelets and other protein correct answer is (B). Amphibians are char-acterized by their ability to breathe through moistskin (in addition to small lungs) and to walk onfour limbs.

2 The do not have rough, scaly skin orlay hard-shelled eggs like their reptile descen-dants, nor can they run quickly on land withmuscular limbs (also like reptiles). Mammals areset apart by their milk-producing correct answer is (C). The best evidenceto support the finding of fossils on widely sepa-rated land masses comes from continental drifttheory, which states that certain land areas hadbeen connected and slowly drifted apart thiswould allow for separation of what were oncecontinuous species ranges. It is highly unlikelythat a reptile species could have moved easilybetween continents or could have survived fro-zen seas during the Ice correct answer is (B). Different forms ofthe same gene are called alleles. For example, B(brown) and b (blue) are two different possibleeye color alleles in humans. No other answerchoices fit the definition of a factor that resultsin the expression of a certain correct answer is (C).

3 Carbon dioxide isneeded in the Calvin cycle to produce sugars,and there is no connection between the Calvincycle and the building of nitrogen-producingcompounds by a plant. The decrease in carbondioxide would most likely not result in the plant sdeath, but it might hurt the plant by decreasingits ability to produce sugars. Chlorophyll mol-ecules should be correct answer is (E). The oviduct, or fal-lopian tube, is the usual site of fertilization ofthe ovum. It is here, after being released fromthe ovary, that an egg is most likely to meet spermcells coming up from the correct answer is (C). When DNA is tran-scribed into messenger RNA, the base-pairingsare complementary but not identical. In addition,RNA has no thymine (T), only uracil (U). Thus,the correct complementary pairing would be A swith U s, T s with A s, and C s with G s orCGTAGT correct answer is (B).

4 Diabetics may suf-fer from a buildup of sugar in their bloodstreambecause their bodies produce too little insulin(which is normally responsible for pulling sugarout of the bloodstream and into cells), and/ortheir body s response to insulin is reduced (acondition known as insulin resistance). Althoughthe disease may cause damage to the kidneyseventually, the disease is not caused by any kid-ney correct answer is (A). The large intestineis responsible for the absorption of salts andwater from the digestive system. If damaged,excess water can remain in the digestive tractand cause watery stools, or 2004 Peterson sCLEP is a registered trademark of the College Entrance Examination Board, whichwas not involved in the production of and does not endorse this CLEP correct answer is (B). The mitochondrionis the organelle in which ATP is produced in eu-karyotic cells.

5 Most cells have multiple mitochon-dria to serve their energy needs. The letter C herepoints to a single mitochondrion within this correct answer is (E). The best conclusionhere is that the amount of carbon dioxide pro-duced per gram of body weight is the same for allspecies (CO2 production/Weight in grams = all species.). Be careful with choice D, be-cause although production of carbon dioxide forthe 24 gram lizard may be twice as great as thatof the 12 gram lizard, one cannot necessarily con-clude that the oxygen consumption of the largerlizard is exactly correct answer is (A). If DPIP is reduced(gains electrons) to lose its color, then the DPIP will show the greatest loss of color wherever thegreatest number of electrons are being knockedaround. Chlorophyll loses electrons when it isbombarded by photons of light. Thus, only chlo-roplasts in bright, white light will change DPIP greatly.

6 Boiled chloroplasts will be ineffective dueto enzyme denaturation, and chloroplasts in thedark or exposed only to green light will absorbfew photons if any. Chloroplasts have no directeffect on sugar production; thus being in a sugarsolution should not affect this reaction with DPIPin any correct answer is (A). Carbon dioxide pro-duced by the body s cells mixes with water in thebloodstream to form carbonic acid, which thendissociates into H+ and HCO3- (bicarbonate) hydrogen ions are complexed to hemoglo-bin in the red blood cells while the bicarbonateions generally remain in the plasma during thetrip to the correct answer is (E). Bacteria, which areprokaryotes, are classified as such due to theirlack of a nuclear membrane housing their addition, antibiotics are drugs used to kill bac-teria only and do not harm other living organ-isms or correct answer is (C).

7 Flowering plants, justlike other plants, should be expected to possesschloroplasts, mitochondria, cell walls, and largecentralized vacuoles. However, plant cells, un-like animal cells, have no centrioles to act as mi-crotubule organizing centers for cell correct answer is (B). The best evidencethat modern-day birds evolved from reptile lin-eages is that transitional fossils are fossils, such as the famous Archaeopteryx,show creatures with both reptilian and bird-likecharacteristics ( the claws and body shape ofa reptile with the feathers of a bird). correct answer is (D). Without workingpumps, the axon could not maintain a negativepotential inside compared to outside (accom-plished by the pumping out of 3 Na+ ions whilepumping in only 2 K+). Therefore, the axon itselfwould be unable to depolarize and transmit anaction potential. In addition, the Na-K pump isneeded to reverse the membrane potential alongthe axon once sodium ions have rushed inside.

8 Ifthis depolarization cannot be reversed, the neu-ron can no longer carry action correct answer is (B). Boiling most enzymeswill result in their denaturation loss of 3-D struc-ture. When denatured, enzymes lose their abilityto catalyze reactions. Additions or removals be-yond Substance C ( choice E) are unlikely toresult in any changes to the production of C, whichis upstream from the change. The addition ormixing of any enzymes is likely to increase Sub-stance C s correct answer is (A). The graph of apredator-prey interaction is usually depicted asa series of linked fluctuations. As the prey popu-lation rises, the predator population followswith a slight lag; as the predators eat too muchprey, the predator population falls with a slightlag behind the fall in the prey population. Thiswill continue as long as the survival of the preypopulation is linked to the size of the predator spopulation and 2004 Peterson sCLEP is a registered trademark of the College Entrance Examination Board, whichwas not involved in the production of and does not endorse this CLEP correct answer is (B).

9 FSH, known wellfor its role in the female menstrual cycle as theinducer of egg development, also induces sper-matogenesis, or sperm production. Prolactin isinvolved in female milk production; GnRHcauses the release of gonadotropins (FSH andLH) from the pituitary gland; aldosterone helpsthe kidneys in water balance; and, insulin de-creases blood glucose correct answer is (E). Digestion is the pro-cess of food breakdown, while ingestion is theact of taking the food into the body via the respiration refers only to the breakdown ofmacromolecules such as sugars within a cell smitochondria in order to produce ATP; and, de-hydration synthesis is the process of joiningsmaller molecules to make larger ones (as in thebuilding of a protein from individual amino ac-ids), and this is the opposite of hydrolysis, whichtakes place during correct answer is (B). The chloroplastsof plant cells are where the reactions of photo-synthesis take place.

10 This is where chlorophyllmolecules can be found within the chloroplastmembranes. The production of glucose andother sugars takes place within the stroma (in-ner fluid) of the correct answer is (A). In order to growtaller than a few centimeters, plants need vascu-lar tissues (xylem and phloem), which serve tocarry water and nutrients back and forth fromroots to leaves. Mosses are simple land plantsthat do not have these tissues and must live closeto the ground, where available water can diffuseinto key tissues. Mosses have chlorophyll (hencetheir green color) and spores. Whether or not acertain group of plants has a dominant gameto-phyte or sporophyte generation has nothing todo with how tall the plant can grow these aremerely designations to indicate whether or notthe plant we can see with our eyes (the domi-nant form) is diploid or correct answer is (D).