1) Which of the following statements about evolution is true? 1) ______
A) Organisms evolve structures in response to needs.
B) Evolution is directional.
C) Evolution is a passive process.
D) Evolution is deliberate and purposeful.
E) Individuals evolve within the span of their own lifetimes.
2) A diabetic, who does not utilize insulin properly, will metabolize fats instead of glucose. A condition called diabetic ketoacidosis is a common result of excessive fat metabolism, causing blood pH values of 7.1 or less (normal range = 7.35 — 7.45). What has happened to the blood pH and why? 2) ______
A) The pH is below normal (acidic) because the buffering capacity was exceeded.
B) The pH is above normal (basic) because the glucose is polar.
C) The pH is above normal (basic) because the ketones are too basic.
D) The pH is not affected because the blood buffers can absorb the excess H+.
E) The pH is below normal because buffers can donate OH+.
3) The molecular formula of most monosaccharides represents a multiple of 3) ______
A) CHO2.
B) CH3O.
C) CH2O.
D) CHO.
E) CHO3.
4) A basal body is 4) ______
A) identical in structure to flagella.
B) similar in structure to centrioles.
C) composed of nine microtubule doublets surrounding a central pair of microtubules.
D) identical in structure to cilia.
E) composed of nine microtubule triplets surrounding a central pair of microtubules.
5) Small, nonpolar, hydrophobic molecules such as fatty acids 5) ______
A) usually enter the cell via endocytosis.
B) require transport proteins to pass through a membrane's lipid bilayer.
C) are actively transported across cell membranes.
D) very slowly diffuse through a membrane's lipid bilayer.
E) easily pass through a membrane's lipid bilayer.
6) During which of the following phases of cellular respiration does substrate-level phosphorylation take place? 6) ______
A) "grooming" of pyruvate
B) glycolysis and the citric acid cycle
C) the citric acid cycle
D) glycolysis
E) oxidative phosphorylation
7) What is the likely origin of chloroplasts? 7) ______
A) prokaryotes with photosynthetic mitochondria
B) eukaryotes that engulfed photosynthetic fungi
C) mitochondria that had a mutation for photosynthesis
D) photosynthetic prokaryotes that lived inside eukaryotic cells
E) a combination of mitochondria and Golgi bodies
8) Asexual reproduction requires ________ individual(s). 8) ______
A) 0
B) 3
C) 2
D) 4
E) 1
9) The mechanism that "breaks" the linkage between linked genes is 9) ______
A) pleiotropy.
B) codominance.
C) crossing over.
D) independent assortment.
E) incomplete dominance.
10) Conjugation between a bacterium that lacks an F factor (F-) and a bacterium that has an F factor on its chromosome (F+) would typically produce which of the following results? 10) ______
A) The F+ bacterium ends up with a recombinant chromosome that carries some genes from the F- bacterium, and the F- bacterium ends up with a chromosome that lacks those genes.
B) The F- bacterium ends up with a recombinant chromosome that carries some genes from the F+ bacterium, and the F+ bacterium ends up with an unaltered chromosome.
C) The F+ bacterium ends up with a recombinant chromosome that carries some genes from the F- bacterium, and the F- bacterium ends up with an unaltered chromosome.
D) The F- bacterium ends up carrying one or more plasmids from the F+ bacterium; the F+ bacterium is unchanged.
E) The F- bacterium ends up with a recombinant chromosome that carries some genes from the F+ bacterium, and the F+ bacterium ends up with a chromosome that lacks those genes.
11) RNA splicing involves the 11) ______
A) addition of a nucleotide "tail" to the molecule.
B) addition of introns to the molecule.
C) addition of a nucleotide "cap" to the molecule.
D) removal of introns from the molecule.
E) removal of exons from the molecule.
12) The feature of "sticky ends" that makes them especially useful in DNA recombination is their ability to 12) ______
A) allow plasmids to attach to the main bacterial chromosome.
B) bind to DNA and thereby activate transcription.
C) insert a segment of RNA into a bacterial chromosome.
D) bind to ribosomes and thereby activate translation.
E) form hydrogen-bonded base pairs with complementary single-stranded stretches of DNA.
13) The advantage of being able to clone the gene for human insulin is that 13) ______
A) cow, pig, or horse insulin cannot keep a diabetic alive for more than three months.
B) using human insulin increases the probability that, in the future, the person suffering from diabetes can be weaned from a dependence on insulin.
C) there are too few cows, pigs, and horses to provide an adequate supply of their insulin.
D) human insulin is more variable than other sources of insulin, so cloning provides a greater chance of obtaining a form that can be used by the diabetic's muscles.
E) human insulin is less likely to provoke an allergic reaction than cow, pig, or horse insulin.
14) In order for gene therapy to be permanent, 14) ______
A) the defective gene must first be removed from all somatic cells.
B) the normal gene must be transferred to somatic cells that can continuously multiply.
C) the normal gene must first be treated with UV radiation to ensure noninfectivity.
D) the normal gene must be added to the germ line cells.
E) the defective gene must undergo restriction enzyme analysis first.
15) "Sticky ends" are 15) ______
A) produced by PCR.
B) DNA fragments with single-stranded ends.
C) used by mRNA to attach to ribosomes.
D) always long sequences of a single nucleotide.
E) produced by the action of DNA ligase.
16) Approximately what percentage of human DNA is noncoding? 16) ______
A) 98.5%
B) 37%
C) 99.9%
D) 49%
E) 79%
17) Enhancers are 17) ______
A) required to turn on gene expression when transcription factors are in short supply.
B) the site on DNA to which activators bind.
C) the products of transcription factors.
D) required to facilitate the binding of DNA polymerases.
E) adjacent to the gene that they regulate.
18) miRNA can be used by 18) ______
A) researchers to induce the production of more mRNA.
B) viruses to stop the production of new proteins.
C) researchers to artificially turn on gene expression.
D) researchers to stimulate the production of DNA.
E) cells to prevent infections from double-stranded RNA viruses.
19) Which of the following statements regarding cancer risk factors is false? 19) ______
A) Mutagens are usually not carcinogens.
B) Broccoli and cauliflower are thought to be especially rich in substances that help prevent cancer.
C) Eating 20-30 grams of plant fiber daily and reducing the intake of animal fat can reduce your risk of developing colon cancer.
D) X-rays and ultraviolet radiation are two of the most potent carcinogens.
E) Factors that alter DNA and make cells cancerous are called carcinogens.
20) The term "gene expression" refers to the 20) ______
A) fact that each individual of a species has a unique set of genes.
B) process by which genetic information flows from genes to proteins.
C) flow of information from parent to offspring.
D) fact that individuals of the same species have different phenotypes.
E) fact that certain genes are visible as dark stripes on a chromosome.