Questions and Answers of Human Biology

Previous chapters have discussed various types of cloning, including the cloning of stem cells and of embryos. Dolly, the ewe shown with her first lamb in Figure 21.25, grew from a cloned cell. Is
How are the polypeptide chains of proteins that are specified by DNA assembled?
MRNA is produced by ______.a. Replicationb. Duplicationc. Transcriptiond. Translation
How does RNA differ from DNA?
______ carries coded instructions for an amino acid sequence to the ribosome.a. DNAb. RRNAc. MRNAd. TRNA
Name the three classes of RNA and describe their functions.
TRNA ______.a. Delivers amino acids to ribosomesb. Picks up genetic messages from rRNAc. Synthesizes mRNAd. All of the above
Distinguish between a codon and an anticodon.
An anticodon pairs with the bases of ______.a. MRNA codonsb. DNA codonsc. TRNA anticodonsd. Amino acids
Describe the three steps of translation.
The loading of mRNA onto the small ribosomal subunit occurs during ______.a. Initiation of transcriptionb. Transcript processingc. Translationd. Chain elongation
Use the genetic code (Figure 21.8) to translate the mRNA sequence AUGcgcaccucaggaugagau. (Human reading frames start with AUG.) Which amino acid sequence is being specified?a.
What is a restriction enzyme?
Match the terms related to protein building. alters genetic instructions codon transcription translation stages of transcription, translation a. initiation, elongation, termination b. conversion of
What is a “gene sequence”?
Rejoined cut DNA fragments from different organisms are best known as ______.a. Cloned genesb. Mapped genesc. Recombinant DNAd. Conjugated DNA
How are cancer cells structurally different from normal cells of the same tissue? What is the relevance of altered surface proteins to uncontrolled growth?
A tumor is _______.a. Malignant by definitionb. Always enclosed by connective tissuec. A mass of tissue that may be benign or malignantd. Always slow-growing
What are the differences between a benign tumor and a cancerous one?
A textbook on cancer contains the following statement: “Fundamentally, cancer is a failure of the immune system.” Why does this comment make sense?
Write a short paragraph that summarizes the roles of protooncogenes, oncogenes, and tumor suppressor genes in carcinogenesis.
The onset of cancer seems to require the activity of an oncogene plus the absence or mutation of at least one _______.
Ultimately, cancer kills because it spreads and disturbs homeostasis. Consider, for example, a kidney cancer that metastasizes to the lungs and liver. What are some specific aspects of homeostasis
List the four main categories of cancer tumors.
Chemical carcinogens _______.a. Include viral oncogenesb. Can damage DNA and cause a mutationc. Must be ingested in foodd. Are not found in foods
Over the last few months, your best friend, Mark, has noticed a small, black-brown, raised growth developing on his arm. When you suggest that he have it examined by his doctor, he says he’s going
What are the seven warning signs of cancer?
Some desperate cancer patients consume pills or other preparations containing shark cartilage, which the manufacturers tout as an anti-angiogenesis compound. The basis for these claims is the fact
Tumor suppressor genes _______.a. Occur normally in cellsb. Promote metastasisc. Are brought into cells by virusesd. Only rarely affect the development of cancer
The goal of immune therapy is to _______.a. Cause defective T cells in the thymus to disintegrateb. Activate cytotoxic T cellsc. Dramatically increase the numbers of circulating macrophagesd. Promote
Currently in the United States,_______ cancer is the leading cancer diagnosed among adult females;_______ cancer is the leading cancer most often diagnosed among adult males.a. Lung; colonb. Breast;
The cheetahs in Figure 23.26 are among the roughly 20,000 of these sleek, swift cats left in the world. One reason cheetahs have become endangered is that about 10,000 years ago cheetahs experienced
A _______ is a genetic unit consisting of one or more populations of organisms that usually closely resemble one another physically and physiologically.
Distinguish between microevolution and macroevolution.
The relative numbers of different genes (alleles) in a gene pool change as a result of four processes of microevolution:_______, _______, _______, and _______.
As shown in Figure 23.25, there is considerable variation in the facial features of humans. Explain this fact in terms of the concept of the gene pool.Figure 23.25
Humans can inherit various alleles for the liver enzyme ADH (alcohol dehydrogenase), which breaks down alcohol. People of Italian and Jewish descent commonly have a form of ADH that detoxifies
A difference in survival and reproduction among members of a population that vary in one or more traits is called _______.
In 1992 the frozen body of a Stone Age man was discovered in the Austrian Alps. Although the “Iceman” died about 5,300 years ago, his body is amazingly well preserved and researchers have
Explain how natural selection differs from adaptation.
The fossil record of evolution correlates with evidence from _______.a. The geologic recordb. Radiometric datingc. Comparing development patterns and morphologyd. Comparative biochemistrye. All of
Explain the difference betweena. Divergence and gene flowb. Homologous and analogous structures
Comparative biochemistry _______.a. Is based mainly on the fossil recordb. Often reveals similarities in embryonic development stages that indicate evolutionary relationshipsc. Is based on mutations
Comparative morphology _______.a. Is based mainly on the fossil recordb. Shows evidence of divergences and convergences in body parts among certain major groupsc. Compares the proteins and the DNA
Describe the chemical and physical environment in which the first living cells may have evolved.
In _______, new species of a lineage move into a wide range of habitats by way of bursts of microevolutionary events.a. An adaptive radiationb. Natural selectionc. Genetic driftd. Punctuated
The pivotal modification in hominin evolution was _______.a. The transition to bipedalismb. Hand modification that increased manipulative skillsc. A shift from omnivorous to specialized eating
Explain what an ecosystem is, and name the central roles that producers play in all ecosystems.
_______can be thought of as an ecosystem.a. A freshwater springb. A rain forestc. A cityd. All of the above
Imagine and describe a situation whereby you would be a link (not the top predator) in a food chain.
Explain the difference between an organism’s habitat and its niche.
Ecosystems have _______.a. Energy gains and lossesb. Nutrient cycling but not lossesc. One feeding leveld. A and b
The use of off-road recreational vehicles may double in the next 20 years. Enthusiasts would like increased access to government-owned deserts like the one shown in Figure 24.1A. Some argue that
Define and give examples of the different feeding levels in ecosystems. Which feeding level is most likely to include most humans?
_______is the study of how organisms interact with one another as well as with their physical and chemical environment.
If you were growing a vegetable garden, what variables might affect its net primary production?
Explain the difference between a food chain and a food web in an ecosystem.
Feeding levels can be described as _______.a. Structured feeding relationshipsb. Who eats whom in an ecosystemc. A hierarchy of energy transfersd. All of the above
Describe the reservoirs and organisms involved in the carbon cycle and the nitrogen cycle.
A feeding relationship that proceeds from algae to a fish, then to a fisherman, and then to a shark is _______.a. A food chainb. A food webc. A and b
Primary productivity is affected by _______.a. Photosynthesis and energy use by plantsb. How many plants are neither eaten nor decomposedc. Rainfalld. Temperaturese. All of the above
Match the following terms with the suitable description. ecological pyramid biogeochemical ecosystem parts primary a. water or nutrients moving from the cycle environment to organisms, then back b.
Describe at least two ways that human activities are altering air quality.
The map below shows the availability of direct solar energy in North America. Some areas are good candidates for solar heating systems and use of solar cells to produce electricity (see legend). What
The number of individuals that can be sustained indefinitely by the resources in a given region is the ________.a. Biotic potentialb. Carrying capacityc. Environmental resistanced. Density-dependent
Explain the difference between global warming and global climate change.
________ shields organisms against the sun’s UV wavelengths.a. A thermal inversionb. Acid rainc. The ozone layerd. The greenhouse effect
Some researchers and policymakers are proposing that we should protect entire ecosystems, such as forests, rather than just endangered species. Opponents say that this approach might endanger
Describe the greenhouse effect. Make a list of twenty agricultural and other products that you depend on. Are any implicated in global warming?
Acid rain is one outcome of ________.a. Coal burningb. Gas and oil burningc. Some industrial processesd. All of the above
What is deforestation, and how does large-scale deforestion damage an ecosystem?
Greenhouse gases ________.a. Slow the escape of heat from Earth into spaceb. Are produced by natural and human activitiesc. Are at higher levels than they were 100 years agod. All of the above
All the following are renewable energy sources except ________.a. Hydropowerb. Windc. Natural gasd. Solar energy
Earth’s biodiversity is threatened mainly by ________.a. The spread of disease organisms due to climate changeb. Habitat destruction by human activitiesc. Disasters such as wildfires and
________ production is continuous from puberty onward in males; ________ production is cyclic and intermittent in females.a. Egg; spermb. Sperm; eggc. Testosterone; spermd. Estrogen; egg
The inner layer of the eye includes the _______.a. Lens and choroidb. Sclera and corneac. Retinad. Start of optic nerve
How does the eye focus the light rays of an image? What do nearsighted and farsighted mean?
Your visual field is _______.a. A specific, small area of the retinab. What you actually “see”c. The area where color vision occursd. Where the optic nerve starts
_______ are molecules released from a signaling cell that have effects on target cells.a. Hormonesb. Neurotransmittersc. Local signaling moleculesd. Pheromonese. A and bf. All of the above
Which of the following stimulate the secretion of hormones?a. Neural signalsb. Local chemical changesc. Hormonal signals stimulate hormone secretiond. Environmental cuese. All of the above can
_______ lowers blood sugar levels;_______ raises the level of blood sugar.a. Glucagon; insulinb. Insulin; glucagonc. Gastrin; insulind. Gastrin; glucagon
The pituitary detects a rising hormone concentration in blood and inhibits the gland that is secreting the hormone. This is a _______ feedback loop.a. Positiveb. Negative
Match the hormone source with the closest description. adrenal cortex adrenal medulla thyroid gland parathyroids pancreatic islets pineal gland thymus a. affected by day length b. cortisol source c.
Match the endocrine control concepts. oxytocin ACTH ADH growth hormone estrogen a. released by the anterior pituitary and affects the adrenal gland b. influences extracellular fluid volume c. has
Distinguish between:a. Seminiferous tubule and vas deferensb. Sperm and semenc. Leydig cells and Sertoli cellsd. Primary oocyte and secondary oocytee. Follicle and corpus luteumf. The three phases of
Besides producing gametes (sperm and eggs), the primary male and female reproductive organs also produce sex hormones. The ________ and the pituitary gland control secretion of both.
Fertility specialists may advise a couple who wish to conceive a child to use an alkaline (basic) douche immediately before intercourse. What might the reasoning behind this advice be?
Which of the following statements about blood plasma is/are accurate?a. Blood plasma is mostly water.b. Blood plasma transports only a few substances, including blood cells, several proteins, and
A glass of whole milk contains lactose, protein, triglycerides (in butterfat), vitamins, and minerals. Explain what happens to each component when it passes through your digestive tract.
What are the main functions of the stomach? What roles do enzymes and hormones play?
Different regions of the digestive system specialize in _______ and _______ food and in _______ unabsorbed food residues.
Some nutritionists claim that the secret to long life is to be slightly underweight as an adult. If a person’s weight is related partly to diet, partly to activity level, and partly to genetics,
Explain the differences between the digestion roles of the small and large intestines. Does the appendix also have a digestive function?
Maintaining normal body weight requires that _______ intake be balanced by _______ output.
As a person ages, the number of body cells steadily decreases and energy needs decline. If you were planning an older person’s diet, what kind(s) of nutrients would you emphasize, and why? Which
List the organs and accessory organs of the digestive system. On a separate piece of paper, list the main functions of each organ.
The food label in Figure 11.28 lists the nutrients and other substances in a package of ready-to-eat macaroni and cheese. Based on your reading in this chapter, how would you rate this product’s
The preferred energy sources for the body are _______.
Along the lines of question 3, formulate a healthy diet for an actively growing 7-year-old.Question 3.As a person ages, the number of body cells steadily decreases and energy needs decline. If you
Define peristalsis, and list the regions of the GI tract where it occurs. Be sure to mention segmentation in your answer.

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