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Which of the following is an example of a commensalism?
A) fungi residing in plant roots, such as endomycorrhizae
B) bacteria fixing nitrogen in plants
C) rancher ants that protect aphids in exchange for sugar-rich honeydew
D) cattle egrets eating insects stirred up by grazing bison
The Hubbard Brook watershed deforestation experiment revealed that _____.
I) deforestation increased water runoff
II) nitrate concentration in waters draining the deforested area became dangerously high
III) calcium levels remained high in the soil of deforested areas
A) only I
B) only II
C) only III
D) only I and II
The structural integrity of bacteria is to peptidoglycan as the structural integrity of plant
spores is to _____.
A) lignin
B) cellulose
C) secondary compounds
D) sporopollenin
Suppose that S. schenkii had initially been classified as a deuteromycete. Asci were later
discovered in the pus that oozed from an ulcerated lymph node, and the spores therein
germinated, giving rise to S. schenkii yeasts. Which two of these are conclusions make
sense on the basis of this information?
1. S. schenkii produces asexual spores within lymph nodes.
2. S. schenkii should be reclassified.
3. S. schenkii continues to have no known sexual stage.
4. The hyphae growing in lymphatic vessels probably belonged to a different fungal
species.
5. S. schenkii yeasts belonging to two different mating strains were introduced by the
same thorn prick.
A) 1 and 3
B) 1 and 5
C) 2 and 5
D) 4 and 5
Which of the following statements about action potentials is correct?
A) Action potentials for a given neuron vary in magnitude.
B) Action potentials for a given neuron vary in duration.
C) Action potentials are propagated down the length of the axon.
D) Movement of ions during the action potential occurs mostly through the sodium
pump.
Trichoplax adhaerens (Tp) is the only living species in the phylum Placozoa.
Individuals are about 1 mm wide and only 27 μm high, are irregularly shaped, and
consist of a total of about 2000 cells, which are diploid (2n = 12). There are four types
of cells, none of which are nerve or muscle cells, and none of which have cell walls.
They move using cilia, and any "edge" can lead. Tp feeds on marine microbes, mostly
unicellular green algae, by crawling atop the algae and trapping it between its ventral
surface and the substrate. Enzymes are then secreted onto the algae, and the resulting
nutrients are absorbed. Tp sperm cells have never been observed, nor have embryos
past the 64-cell (blastula) stage.
Which of the following Tp traits is different from all other known animals?
A) Tp is multicellular.
B) Tp lacks muscle and nerve cells.
C) Tp has cilia.
D) Tp lacks cell walls.
Seed packets give a recommended planting depth for the enclosed seeds. The most
likely reason some seeds are to be covered with only -inch of soil is that the_____.
A) seedlings do not have an etiolation response
B) seeds require light to germinate
C) seeds require a higher temperature to germinate
D) seeds are very sensitive to waterlogging
When gene duplication occurs to its ultimate extent by doubling all genes in a genome,
what has occurred?
A) pseudogene creation
B) creation of a gene cluster
C) creation of a polyploid
D) creation of a diploid
Vinblastine, a drug that inhibits microtubule polymerization, is used to treat some forms
of cancer. Cancer cells given vinblastine would be unable to _____.
A) form cleavage furrows during cell division
B) migrate by amoeboid movement
C) separate chromosomes during cell division
D) maintain the shape of the nucleus
In order for an ovule (egg cell) in a flower to be fertilized and form a viable seed,
pollination must occur. In this process, a sperm cell is delivered to the ovule when the
pollen grain lands on the stigma and grows a tube, which enters the ovary and
discharges the sperm cell to form a diploid zygote when it fuses with the egg cell.
Although it only takes one pollen grain to successfully deliver sperm to the egg,
numerous pollen grains are generally transferred to the stigma during insect pollination
of flowering plants. Which phenotypic traits of pollen would you predict to be selected
upon to promote survival and fitness within an insect-pollinated flowering plant?
A) High pollen tube growth rate and ability to detect chemicals from cells surrounding
the egg.
B) Ability to produce the most cells during mitotic growth of the pollen tube.
C) Elaborate and striking UV "nectary guides" on the petals to guide an insect to the
stigma.
D) Larger pollen in order to carry the tube that is necessary for delivery of the sperm
cells.
Super cells characteristic of plasmodial slime molds result when which one of the
following common cellular processes does not occur?
A) mitosis
B) cytokinesis
C) aerobic metabolism
D) endocytosis
A fasting animal whose energy needs exceed those provided in its diet draws on its
stored resources in which order?
A) fat, then glycogen, then protein
B) glycogen, then protein, then fat
C) liver glycogen, then muscle glycogen, then fat
D) muscle glycogen, then fat, then liver glycogen
Increased atmospheric CO2 concentrations might have what effect on seawater?
A) Seawater will become more alkaline, and carbonate concentrations will decrease.
B) There will be no change in the pH of seawater, because carbonate will turn to
bicarbonate.
C) Seawater will become more acidic, and carbonate concentrations will decrease.
D) Seawater will become more acidic, and carbonate concentrations will increase.
Circulatory systems compensate for _____.
A) temperature differences between the lungs and the active tissue
B) the slow rate at which diffusion occurs over large distances
C) the problem of communication systems involving only the nervous system
D) the need to cushion animals from trauma
Which of the following allows water to move much faster across cell membranes?
A) the sodium-potassium pump
B) ATP
C) peripheral proteins
D) aquaporins
In positive control of several sugar-metabolism-related operons, the catabolite activator
protein (CAP) binds to DNA to stimulate transcription. What causes an increase in CAP
activity in stimulating transcription?
A) an increase in glucose and an increase in cAMP
B) a decrease in glucose and an increase in cAMP
C) an increase in glucose and a decrease in cAMP
D) a decrease in glucose and a decrease in the repressor
Most of the exchange surfaces of multicellular animals are lined with _____.
A) connective tissue
B) smooth muscle cells
C) neural tissue
D) epithelial tissue
Which of the following is an important feature of most terrestrial biomes?
A) annual average rainfall in excess of 250 centimeters
B) a distribution predicted almost entirely by rock and soil patterns
C) clear boundaries between adjacent biomes
D) vegetation demonstrating vertical layering
Which of the following techniques would be most appropriate to test the hypothesis that
humans and chimps differ in the expression of a large set of shared genes?
A) DNA microarray analysis
B) polymerase chain reactin (PCR)
C) DNA sequencing
D) protein-protein interaction assays
Even in the absence of sperm, metabolic activity in an egg can be artificially activated
by _____.
A) abnormally high levels of carbonic acid in the cytosol
B) abnormally low levels of extracellular oxygen
C) injection of calcium ions into the cytosol
D) depletion of its ATP supplies
The motor (somatic nervous) system can alter the activities of its targets, the skeletal
muscle fibers, because _____.
A) it is electrically coupled by gap junctions to the muscles
B) its signals bind to receptor proteins on the muscles
C) its signals reach the muscles via the blood
D) it is connected to the internal neural network of the muscles
Myasthenia gravis is a form of muscle paralysis in which _____.
A) motor neurons lose their myelination and the ability to rapidly fire action potentials
B) acetylcholine receptors are destroyed by an overactive immune system
C) ATP production becomes uncoupled from mitochondrial electron transport
D) troponin molecules become unable to bind calcium ions
According to the fossil record, plants colonized terrestrial habitats _____.
A) in conjunction with insects that pollinated them
B) in conjunction with fungi that helped provide them with nutrients from the soil
C) to escape abundant herbivores in the oceans
D) only about 150 million years ago
In response to stress, the adrenal gland promotes the synthesis of glucose from
non-carbohydrate substrates via the action of the steroid hormone _____.
A) glucagon
B) cortisol
C) thyroxine
D) adrenocorticotropic hormone (ACTH)
Parasitism is one of the most widespread life strategies ever to evolve. Which of the
following is consistent with this finding?
A) Parasites almost always predigest their hosts' tissues and, therefore, spend less
energy and require fewer structural adaptations.
B) Parasites, unlike predators, feed on almost all the tissues of their host.
C) Parasites do not generally kill their hosts; thus they can feed on the same host
throughout the host's normal life span and do not have competition from decomposers.
D) Parasites generally kill their host and can feed for a very long time because they are
much smaller than their host.
Cotton-topped tamarins are small primates with tufts of long white hair on their heads.
While studying these creatures, you notice that males with longer hair get more
opportunities to mate and father more offspring. To test the hypothesis that having
longer hair is adaptive in these males, you should _____.
A) test whether other traits in these males are also adaptive
B) look for evidence of hair in ancestors of tamarins
C) determine if hair length is heritable
D) test whether males with shaved heads are still able to mate
Generally speaking, deserts are located in places where air masses are usually _____.
A) tropical
B) humid
C) rising
D) descending
Which of the following is a difference between B cells and T cells?
A) One has a major role in antibody production, while the other has a major role in
cytotoxicity.
B) One binds a receptor called BCR (B-cell receptor), while the other recognizes a
receptor called TCR (T-cell receptor).
C) B cells are activated by free-floating antigens in the blood or lymph. T cells are
activated by membrane-bound antigens.
D) T cells are produced in the thymus and B cells are produced in the bone marrow.
The symbols +, -, and o are to be used to show the results of interactions between
individuals and groups of individuals in the examples that follow. The symbol + denotes
a positive interaction, - denotes a negative interaction, and o denotes where individuals
are not affected by interacting. The first symbol refers to the first organism mentioned.
What interactions exist between a lion pride and a hyena pack?
A) +/+
B) +/-
C) o/o
D) -/-
A young dog has never had much energy. He is brought to a veterinarian for help and
she decides to conduct several diagnostic tests. She discovers that the dog's
mitochondria can use only fatty acids and amino acids for respiration, and his cells
produce more lactate than normal. Of the following, which is the best explanation of the
dog's condition?
A) His mitochondria lack the transport protein that moves pyruvate across the outer
mitochondrial membrane.
B) His cells cannot move NADH from glycolysis into the mitochondria.
C) His cells lack the enzyme in glycolysis that forms pyruvate.
D) His cells have a defective electron transport chain, so glucose goes to lactate instead
of to acetyl CoA.
