The main function of a DNA molecule is to ______. a. store heritable information b. carry a translatable message c. form peptide bonds between amino acids
> Immerse a human red blood cell in a hypotonic solution, and water _______. a. diffuses into the cell b. diffuses out of the cell c. shows no net movement d. moves in by endocytosis
> What accumulates inside the thylakoid compartment of chloroplasts during the light-dependent reactions? a. glucose b. hydrogen ions c. O2 d. CO2
> On the geologic time scale, life originated in the _______. a. Archaean b. Proterozoic c. Phanerozoic d. Cambrian
> A chromosome contains many different gene regions that are transcribed into different __________. a. proteins b. polypeptides c. RNAs d. a and b
> In the late 1970s, geologist Walter Alvarez was investigating the composition of the K–Pg boundary layer in different parts of the world. He asked his father, Nobel Prize–winning physicist Luis Alvarez, to help him ana
> The number of species on an island depends on the size of the island and its distance from a mainland. This statement would most likely be made by __________. a. an explorer b. a biogeographer c. a geologist d. a philosopher
> In the late 1970s, geologist Walter Alvarez was investigating the composition of the K–Pg boundary layer in different parts of the world. He asked his father, Nobel Prize–winning physicist Luis Alvarez, to help him ana
> Name one environmental factor that typically influences enzyme function.
> Dogs have a diploid chromosome number of 78. How many chromosomes do their gametes have? a. 39 b. 78 c. 156 d. 234
> Meiosis ______ the parental chromosome number. a. doubles b. halves c. maintains d. mixes up
> Crossing over happens during which phase of meiosis? a. prophase I b. prophase II c. anaphase I d. anaphase II
> Crossing over mixes up _______. a. chromosomes b. alleles c. zygotes d. gametes
> When DNA replication begins, ______. a. the two DNA strands unwind from each other b. the two DNA strands condense for base transfers c. old strands move to find new strands
> 1. Meiosis is a necessary part of sexual reproduction because it ______. a. divides two nuclei into four new nuclei b. reduces the chromosome number for gametes c. gives rise to new alleles 2. Meiosis ______. a. occurs only in animals b. supports growth
> One evolutionary advantage of sexual over asexual reproduction is that it produces ______. a. more offspring per individual b. more variation among offspring c. healthier offspring
> Researchers are designing and testing antisense drugs as therapies for a variety of diseases, including cancer, AIDS, diabetes, and muscular dystrophy. The drugs are also being tested to fight infection by deadly viruses such as Ebola. Antisense drugs co
> The diploid chromosome number for the body cells of a frog is 26. What would that number be after three generations if meiosis did not occur before gamete formation?
> ______ are always changed by participating in a reaction. (Choose all that are correct.) a. Enzymes c. Reactants b. Cofactors d. Coenzymes
> Catalase combines two hydrogen peroxide molecules (H2O2 + H2O2) to make two molecules of water. A gas also forms. What is the gas?
> ___ is life’s primary source of energy. a. Food b. Water c. Sunlight d. ATP
> The probability of a crossover occurring between two genes on the same chromosome _______. a. is unrelated to the distance between them b. decreases with the distance between them c. increases with the distance between them
> Refer to question 4. Assuming complete dominance, the F2 generation will show a phenotypic ratio of _______. a. 3:1 b. 9:1 c. 1:2:1 d. 9:3:3:1
> F1 offspring of the cross AA × aa are ________. a. all AA b. all aa c. all Aa d. 1/2 AA and 1/2 aa
>  The graph shown in FIGURE 8.5 is reproduced from an original 1952 publication by Hershey and Chase. Bacteriophage were labeled with radioactive tracers and allowed to infect bacteria. The virus–bacte
> An organism’s observable traits constitute its _______. a. phenotype b. variation c. genotype d. pedigree
> The enzyme trypsin is sold as a dietary enzyme supplement. Explain what happens to trypsin taken with food.
> Which of the following statements is not correct? a. Energy cannot be created or destroyed. b. Energy cannot change from one form to another. c. Energy tends to disperse spontaneously.
> Beginning physics students are often taught the basic concepts of thermodynamics with two phrases: First, you can’t win. Second, you can’t break even. Explain.
> Why would you think twice about ordering from a restaurant menu that lists the specific epithet but not the genus name of its offerings? Hint: Look up Homarus americanus, Ursus americanus, Ceanothus americanus, Bufo americanus, Lepus americanus, and Nicr
> Which of the following is a class of molecules that encompasses all of the other molecules listed? a. triglycerides b. fatty acids c. waxes e. lipids d. steroids f. phospholipids
> The photos shown above illustrate a case of synpolydactyly, a genetic abnormality characterized by two phenotypes: partially or completely duplicated fingers or toes, and webbing between fingers or toes. The same mutations that give rise to the human phe
> In the late 1800s, a biologist studying animal embryos coined the phrase “ontogeny recapitulates phylogeny,” meaning that the physical development of an animal embryo (ontogeny) seemed to retrace the species’ evolutionary history (phylogeny). Why would e
> ______ groups are the “acid” part of amino acids and fatty acids. a. Hydroxyl (−OH) b. Carboxyl (−COOH) c. Methyl (−CH3) d. Phosphate (−PO4)
> Steroids are among the lipids with no ______. a. double bonds b. fatty acid tails c. hydrogens d. carbons
> The graph shown in FIGURE 8.5 is reproduced from an original 1952 publication by Hershey and Chase. Bacteriophage were labeled with radioactive tracers and allowed to infect bacteria. The virus–bacteria mixtures
> Match the term with the best description. mitochondrial matrix a. needed for glycolysis b. inner space c. makes many ATP d. product of glycolysis e. reduced coenzyme f. no oxygen required -pyruvate NAD+ mitochondrion NADH anaerobic
> Is this statement true or false? Unlike saturated fats, all unsaturated fats are beneficial to health because their fatty acid tails kink and do not pack together.
> The main function of an mRNA molecule is to ______. a. store heritable information b. carry a translatable message c. form peptide bonds between amino acids
> A molecule into which a radioisotope has been incorporated can be used as a(n) ________. a. compound b. tracer c. salt d. acid
> In 2005, researcher Woo-suk Hwang reported that he had made immortal stem cells from human patients. His research was hailed as a breakthrough for people affected by degenerative diseases, because stem cells may be used to repair a person’s own damaged t
> DNA ______. a. guides form b. is the basis of traits c. is transmitted from and function parents to offspring d. all of the above
> Organisms require ______ and ______ to maintain themselves, grow, and reproduce. a. DNA; energy b. food; sunlight c. nutrients; energy d. DNA; cells
> The smallest unit of life is the ______. a. atom b. molecule c. cell d. organism
> Explain the difference between a one-celled organism and a single cell of a multi-celled organism.
> A cell with a Barr body is _________. a. a bacterium b. a sex cell c. from a female mammal d. infected by Barr virus
> Xeroderma pigmentosum is an inherited disorder characterized by rapid formation of many skin sores that develop into cancers. All forms of radiation trigger these symptoms, including fluorescent light, which contains UV light in the range of 320 to 400 n
> Proteins that influence gene expression by binding to DNA are called __________. a. promoters b. transcription factors c. operators d. all of the above
> In 2000, researchers measured the average amount of UV radiation received in more than fifty regions of the world, and correlated it with the average skin reflectance of people native to those regions (reflectance is a way to measure the amount of melani
> A recognized set of symptoms that characterize a genetic disorder is a(n) __________. a. syndrome b. disease c. abnormality
> In 2000, researchers measured the average amount of UV radiation received in more than fifty regions of the world, and correlated it with the average skin reflectance of people native to those regions (reflectance is a way to measure the amount of melani
> 1. _____ are fundamental building blocks of all matter. a. Atoms b. Molecules c. Cells d. Organisms 2. ___ is the transmission of DNA to offspring. a. Reproduction b. Development c. Homeostasis d. Inheritance 3. By sensing and responding to change, org
> A(n) ________ is a dome-shaped structure formed by mats of photosynthetic cells and sediments.
> A stromatolite is a structure ________. a. produced by endosymbiosis b. that forms when a meteorite hits the Earth c. consisting of layered bacteria and sediment d. that expels hot water from deep in the Earth
> Infoldings of the plasma membrane into the cytoplasm of some ancestral cells may have evolved into the __________. a. nuclear envelope b. ER membranes c. primary cell wall d. both a and b
> Among prokaryotes, only the cyanobacteria ________. a. live near hydrothermal vents b. produce oxygen during photosynthesis c. cannot tolerate oxygen d. have a nucleus-like structure
> The graph shown in FIGURE 8.5 is reproduced from an original 1952 publication by Hershey and Chase. Bacteriophage were labeled with radioactive tracers and allowed to infect bacteria. The virus–bacteria mixtures
> An RNA that functions as an enzyme is a ________. a. protein b. protocell c. ribosome d. ribozyme
> The prevalence of ________ in living organisms is taken as support for the idea that life arose near deep-sea vents. a. mitochondria b. iron–sulfide cofactors c. DNA d. a plasma membrane
> According to one hypothesis, negatively charged clay particles played a role in early _________. a. protein formation b. DNA replication c. photosynthesis d. oxygen declines
> How did the evolution of oxygen-releasing photosynthesis in cyanobacteria increase the likelihood that mitochondria would one day evolve?
> Translate the sequence of bases in the previous question, starting at the second base.
> The ______ and ______ have similar larvae. a. cnidarians/arthropods b. echinoderms/rotifers c. annelids/mollusks d. flatworms/roundworms
> A barnacle is a shelled ______. a. arthropod b. gastropod c. cephalopod d. crustacean
> A slug is a land-dwelling ______. a. arthropod b. gastropod c. cephalopod d. crustacean
> Which invertebrate phylum includes the most species? a. mollusks b. roundworms c. arthropods d. flatworms
> Annelids and ______ have a closed circulatory system. a. insects b. cephalopods c. flatworms d. sea stars
> After DNA replication, a eukaryotic chromosome ______. a. consists of two sister chromatids b. has a characteristic X shape d. all of the above c. is constricted at the centromere
> Earthworms are most closely related to ______. a. tapeworms b. roundworms c. planarians d. leeches
> ____ function(s) in the movement of cnidarians. a. A hydrostatic skeleton b. Tube feet c. Cnidocytes d. Malpighian tubules
> Horseshoe crab blood clots immediately upon exposure to bacterial toxins, so it can be used to test injectable drugs for the presence of dangerous bacteria. To keep horseshoe crab populations stable, blood is extracted from captured animals, which are th
> Horseshoe crab blood clots immediately upon exposure to bacterial toxins, so it can be used to test injectable drugs for the presence of dangerous bacteria. To keep horseshoe crab populations stable, blood is extracted from captured animals, which are th
> A rise in atmospheric carbon dioxide increases ocean acidity, making it harder for animals to build calcium carbonate parts. List some invertebrate animals that increased ocean acidity could harm in this way.
> Energy that drives translation is provided mainly by __________. a. ATP b. amino acids c. GTP d. all are correct
> True or false? Animal cells do not have walls.
> Â Horseshoe crab blood clots immediately upon exposure to bacterial toxins, so it can be used to test injectable drugs for the presence of dangerous bacteria. To keep horseshoe crab populations stable, blood is extracted from captured animals,
> A massive die-off of lobsters in the Long Island Sound was blamed on pesticides sprayed to control mosquitoes that carry West Nile virus. Why might a chemical designed to kill insects also harm lobsters but have no effect on sea stars?
> An abundance of ________ in Earth’s early atmosphere would have interfered with assembly of organic compounds. a. carbon dioxide b. ammonia c. water d. oxygen
> Some people think that many of our uniquely human traits arose by sexual selection. Over thousands of years, women attracted to charming, witty men perhaps prompted the development of human intellect beyond what was necessary for mere survival. Men attra
> The astronomer Carl Sagan once said, “We are made of star stuff.” Explain why this is true of all life on Earth.
> Researchers looking for fossils of the earliest life forms face many hurdles. For example, few sedimentary rocks date back more than 3 billion years. Review what you learned about plate tectonics (Section 16.7). Explain why so few remaining samples of th
> A person is declared dead upon the irreversible ceasing of spontaneous body functions: brain activity, blood circulation, and respiration. Only about 1 percent of a body’s cells have to die in order for all of these things to happen. How can a person be
> The graph shown in FIGURE 8.5 is reproduced from an original 1952 publication by Hershey and Chase. Bacteriophage were labeled with radioactive tracers and allowed to infect bacteria. The virus–bacteria mixtures
> 1. Electrophoresis separates fragments of DNA according to ______. a. sequence b. length c. species 2. PCR can be used __________. a. to increase the number of specific DNA fragments b. in DNA fingerprinting c. to modify a human genome d. a and b are co
> Formation of a(n) ______ allows some soil bacteria to survive adverse conditions. a. pilus b. nucleoid c. endospore d. plasmid
> Match the terms appropriately. club fungus a. first discovered in a chitin soil-dwelling sac fungus b. component of fungal cell walls - penicillin - sac fungus - zygote fungus lichen c. partnership between a fungus and one or more photoautotrophs d.
> 1. Unlike eukaryotic cells, prokaryotic cells ______. a. have no nucleus b. have RNA but not DNA c. have no ribosomes d. a and c 2. Enzymes contained in ______ break down worn-out organelles, bacteria, and other particles. a. lysosomes b. amyloplasts c.
> Budding is a mechanism of ______ in yeasts. a. extracellular digestion b. asexual reproduction c. defense d. toxin production
> All ______ form partnerships with plant roots. a. Glomeromycetes b. Chytrids c. Microsporidia d. Club fungi
> Fungal infections are most common in ______. a. plants b. insects c. mammals d. birds
> ______ are fungi that live as intracellular parasites. a. Glomeromycetes b. Chytrids c. Microsporidia d. Club fungi
> Some nitrogen-fixing cyanobacteria can partner with a fungus to form a ______. a. mycelium b. lichen c. mycorrhiza d. fruiting body
> are fungi that produce flagellated spores. a. Chytrids b. Sac fungi c. Zygote fungi d. Club fungi
> Two species of antelope, one from Africa, the other from Asia, are put into the same enclosure in a zoo. To the zookeeper’s surprise, individuals of the different species begin to mate and produce healthy, hybrid baby antelopes. Explain why a biologist m
> Spores released from a mushroom’s gills are ______. a. flagellated b. produced by mitosis c. dikaryotic d. haploid
> A mushroom is ______. a. a fungal digestive organ b. the only part of the fungal body made of hyphae c. a reproductive structure that releases sexual spores d. made of haploid hyphae
> The mycelium of a multicelled fungus is a mesh of filaments, each called a _______. a. septa b. hypha c. spore
> No animal cell has a ______. a. plasma membrane b. flagellum c. lysosome d. cell wall
> In most ______, an extensive dikaryotic mycelium is the longest-lived phase of the life cycle. a. chytrids b. zygote fungi c. sac fungi d. club fungi
> The yeasts whose fermentation reactions produce the carbon dioxide that makes bread rise are a type of _______. a. chytrid b. zygote fungus c. sac fungus d. club fungus
> Health professionals refer to fungal skin diseases as “tineas” and name them according to the region affected (TABLE 23.1). Fungal skin diseases are persistent, in part because fungi can penetrate deeper layers of skin
