The pattern of inheritance (monohybrid, dihybrid, sex-linked, and genes linked on the
same chromosomes) can be predicted from data if one is given the parent or offspring
genotypes or phenotypes. Two organisms, with genotypes BbDD and BBDd, are mated.
Assuming independent assortment of the B/b and D/d genes, determine the genotypic
ratios in offspring that would occur.
A) 1/2 BBDD 1/2 bbdd
B) 1/4 BBDD 1/4 BbDD 1/4 BBDd 1/4 BbDd
C) 9/16 BBDD 3/16 BbDD 3/16 BBDd 1/16 bbdd
D) 1/4 BBDD 1/2 BbDd 1/4 bbdd
The individual with genotype AaBbCCDdEE can make many kinds of gametes. Which
of the following is the major reason?
A) recurrent mutations forming new alleles
B) crossing over during prophase I
C) different possible assortment of chromosomes into gametes
D) the tendency for dominant alleles to segregate together
Humans can digest starch but not cellulose because _____.
A) humans have enzymes that can hydrolyze the α-glycosidic linkages of starch but not
the β-glycosidic linkages of cellulose
B) starch monomers are joined by covalent bonds and cellulose monomers are joined by
ionic bonds
C) the monomer of starch is glucose, while the monomer of cellulose is galactose
D) the monomer of starch is fructose, while the monomer of cellulose is glucose
Catabolic pathways _____.
A) combine molecules into more energy-rich molecules
B) supply energy, primarily in the form of ATP, for the cell’s work
C) are endergonic
D) are spontaneous and do not need enzyme catalysis
An otherwise healthy student in your class is infected with EBV, the virus that causes
infectious mononucleosis. The same student had already been infected when she was a
child, at which time she had merely experienced a mild sore throat and swollen lymph
nodes in her neck. This time, though infected, she does not get sick.
Her immune system’s recognition of the second infection involves memory _____.
A) helper T cells
B) natural killer cells
C) plasma cells
D) cytotoxic T cells
Which of the following is a FALSE statement concerning amino groups? Amino groups
_____.
A) are basic with respect to pH
B) are found in amino acids
C) contain nitrogen
D) are nonpolar
The Bohr shift on the oxygen-hemoglobin dissociation curve is produced by changes in
_____.
A) the partial pressure of oxygen
B) hemoglobin concentration
C) temperature
D) pH
If Darwin had been aware of genes and their typical mode of transmission to
subsequent generations, with which statement would he most likely have been in
agreement?
A) If natural selection can change gene frequency in a population over generations,
given enough time and genetic diversity, then natural selection can cause sufficient
genetic change to produce new species from old ones.
B) If an organism’s somatic cell genes change during its lifetime, making it more fit,
then it will be able to pass these genes on to its offspring.
C) If an organism acquires new genes by engulfing, or being infected by, another
organism, then a new genetic species will result.
D) A single mutation in a single gene in a single gamete, if inherited by future
generations, will produce a new species.
Carotenoids are often found in foods that are considered to have antioxidant properties
in human nutrition. What related function do they have in plants?
A) They serve as accessory pigments to increase light absorption.
B) They protect against oxidative damage from excessive light energy.
C) They shield the sensitive chromosomes of the plant from harmful ultraviolet
radiation.
D) They reflect orange light and enhance red light absorption by chlorophyll.
If cell X enters meiosis, and nondisjunction of one chromosome occurs in one of its
daughter cells during meiosis II, what will be the result at the completion of meiosis?
A) All the gametes descended from cell X will be diploid.
B) Half of the gametes descended from cell X will be n + 1, and half will be n – 1.
C) 1/4 of the gametes descended from cell X will be n + 1, 1/4 will be n – 1, and 1/2
will be n.
D) Two of the four gametes descended from cell X will be haploid, and two will be
diploid.
Diatoms are encased in petri-platelike cases (valves) made of translucent hydrated silica
whose thickness can be varied. The material used to store excess calories can also be
varied. At certain times, diatoms store excess calories in the form of the liquid
polysaccharide, laminarin, and at other times as oil. The following are data concerning
the density (specific gravity) of various components of diatoms, and of their
environment.
Specific Gravities of Materials Relevant to Diatoms
Water’s density and, consequently, its buoyancy decrease at warmer temperatures.
Based on this consideration and using data from the table above, at which time of year
should one expect diatoms to be storing excess calories mostly as oil?
A) mid-winter
B) early spring
C) late summer
D) late fall
Which of the following has a coefficient of relatedness of 0.25?
A) a father to his daughter
B) an uncle to his nephew
C) a brother to his brother
D) a sister to her brother
Suppose two AaBbCc individuals are mated. Assuming that the genes are not linked,
what fraction of the offspring are expected to be homozygous recessive for the three
traits?
A) 1/4
B) 1/8
C) 1/16
D) 1/64
In general, liverworts have a cuticle and pores. However, some species do not have
pores. What would you predict concerning the cuticle of these species and why?
A) The cuticle would be the same as in those species with pores.
B) The cuticle would be thicker than in those species with pores.
C) The cuticle would be thinner than in those species with pores.
You briefly expose bacteria undergoing DNA replication to radioactively labeled
nucleotides. When you centrifuge the DNA isolated from the bacteria, the DNA
separates into two classes. One class of labeled DNA includes very large molecules
(thousands or even millions of nucleotides long), and the other includes short stretches
of DNA (several hundred to a few thousand nucleotides in length). These two classes of
DNA probably represent _____.
A) leading strands and Okazaki fragments
B) lagging strands and Okazaki fragments
C) Okazaki fragments and RNA primers
D) leading strands and RNA primers
Which of the following statements comparing respiration in fish and in mammals is
correct?
A) The respiratory medium for fish carries more oxygen than the respiratory medium of
mammals.
B) A countercurrent exchange mechanism between the respiratory medium and blood
flow is seen in mammals but not in fish.
C) The movement of the respiratory medium in mammals is bidirectional, but in fish it
is unidirectional.
D) In blood, oxygen is primarily transported by plasma in fish, but by red blood cells in
mammals.
Scientists isolate cells in various phases of the cell cycle. They find a group of cells that
have times more DNA than G1 phase cells. The cells of this group are _____.
A) between the G1 and S phases in the cell cycle
B) in the G2 phase of the cell cycle
C) in the M phase of the cell cycle
D) in the S phase of the cell cycle
If a portion of the pancreas is surgically removed from a rat and the rat subsequently
loses its appetite, one explanation is that the removed portion contains cells that secrete
a chemical signal that somehow stimulates appetite. Given this scenario, what type of
chemical signaling is occurring?
A) autocrine
B) paracrine
C) endocrine
D) neuroendocrine
Phylogenetic trees constructed from evidence from molecular systematics are based on
similarities in _____.
A) morphology
B) the pattern of embryological development
C) biochemical pathways
D) mutations to homologous genes
A plant developed a mineral deficiency after being treated with a fungicide. What is the
most probable cause of the deficiency?
A) Mineral receptor proteins in the plant membrane were not functioning.
B) Mycorrhizal fungi were killed.
C) Active transport of minerals was inhibited.
D) The genes for the synthesis of transport proteins were destroyed.
Looking at the figure above, what can you conclude about the data?
A) As species richness changes, plant biomass remains consistent.
B) As species richness increases, plant biomass increases.
C) As species richness increases, plant biomass increases and then levels off.
D) As species richness decreases, plant biomass increases.
A dietary Calorie equals 1 kilocalorie. Which of the following statements correctly
defines 1 kilocalorie? One kilocalorie equals _____.
A) 1000 calories, or the amount of heat required to raise the temperature of 1 g of water
by 1°C
B) 10,000 calories, or the amount of heat required to raise the temperature of 1 kg of
water by 1°F
C) 1000 calories, or the amount of heat required to raise the temperature of 1 kg of
water by 1°C
D) 1000 calories, or the amount of heat required to raise the temperature of 100 g of
water by 100°C
Exposing inner mitochondrial membranes to ultrasonic vibrations will disrupt the
membranes. However, the fragments will reseal “inside out.” The little vesicles that
result can still transfer electrons from NADH to oxygen and synthesize ATP.
After the disruption, when electron transfer and ATP synthesis still occur, what must be
present?
A) all of the electron transport proteins and ATP synthase
B) all of the electron transport system and the ability to add CoA to acetyl groups
C) the ATP synthase system
D) the electron transport system
Which of the following genetic processes may be most helpful in accounting for the
Cambrian explosion?
A) binary fission
B) random segregation
C) gene duplication
D) chromosomal condensation
Scientific theories _____.
A) are nearly the same things as hypotheses
B) are supported by, and make sense of, many observations
C) cannot be tested because the described events occurred only once
D) are predictions of future events
Which of the following statements is true?
A) A band of ribosomes determines where a cell plate will form in a dividing plant cell.
B) The way in which a plant cell differentiates is determined by the position of the
nucleus in the developing plant cell.
C) Homeotic genes often control morphogenesis.
D) Plant cells differentiate because the cytoskeleton determines which genes will be
turned “on” and “off.”
Two students studying physiology taste a known “bitter” substance, and both report
sensing bitterness. They then sample another substance. Student A reports sensing both
a bitter taste and a salty taste, but student B reports only a salty taste. What is the most
logical explanation?
A) Student A had an allergic reaction to the food, causing him to perceive the food as
being bitter.
B) Student A has normal “bitter” taste buds; student B has defective “bitter” taste buds
that result in lower sensitivity to bitterness.
C) Student A has a protein receptor capable of detecting a bitter molecule found in that
substance, whereas student B lacks that particular protein receptor.
D) Student A has normal saliva, whereas student B’s saliva is more alkaline than
normal.
Rhodopsins are light-sensitive molecules composed of a protein (opsin) and retinal
(derivative of vitamin A). Opsin is a membrane protein with several α-helical segments
that loop back and forth through the plasma membrane. There are two classes of
rhodopsins. According to Oded Beje, one class has relatively slow dynamics (a
photocycle of approximately 0.5 second) and is well suited for light detection. The
second class has faster dynamics (a photocycle of approximately 0.02 seconds) and is
well suited for chemiosmosis: pumping of protons or chloride ions across cell
membranes. Oded Beje was the first, in September 2000, to report on a rhodopsin
(proteorhodopsin) found in the domain Bacteria. [SOURCE: O. Beje et al., Science 289
(2000): 1902.]
Proteorhodopsin consists of a single polypeptide chain. What is the highest level of
structure found in this protein?
A) primary
B) secondary
C) tertiary
D) quaternary
White blood cells engulf bacteria using _____.
A) phagocytosis
B) pinocytosis
C) osmosis
D) receptor-mediated exocytosis
Large numbers of ribosomes are present in cells that specialize in producing which of
the following molecules?
A) lipids
B) glycogen
C) proteins
D) nucleic acids
Most of the neurons in the human brain are _____.
A) sensory neurons
B) motor neurons
C) interneurons
D) peripheral neurons