BSC1011 - Test 1

In a bacterium that possesses antibiotic resistance and the potential to persist through very adverse conditions, such as freezing, drying, or high temperatures, DNA should be located within, or be part of, which structure(s)? 1. nucleoid region 2. endospore 3. fimbriae 4. plasmids

1, 2, and 4

The termite gut protist, Mixotricha paradoxa, has at least two kinds of bacteria attached to its outer surface. One kind is a spirochete that propels its host through the termite gut. A second type of bacteria synthesizes ATP, some of which is used by the spirochetes. The locomotion provided by the spirochetes introduces the ATP-producing bacteria to new food sources. Which term(s) is (are) applicable to the relationship between the two kinds of bacteria? 1. mutualism 2. parasitism 3. symbiosis 4. metabolic cooperation

1, 3, and 4 mutualism, symbiosis, metabolic cooperation

If a single, diploid G2 nucleus in an ascus contains 400 nanograms (ng) of DNA, then a single mature ascospore of this species should contain ____ ng of DNA, carried on a total of ____ chromosomes.

100, carried on 7 chromosomes

In a hypothetical situation, a bacterium lives on the surface of a leaf, where it obtains nutrition from the leaf's nonliving, waxy covering while inhibiting the growth of other microbes that are plant pathogens. If this bacterium gains access to the inside of a leaf, however, it causes a fatal disease in the plant. Once the plant dies, the bacterium and its offspring decompose the plant. What is the correct sequence of ecological roles played by the bacterium in the situation described here? Use only those that apply. 1. nutrient recycler 2. mutualist 3. commensal 4. parasite 5. primary producer

2, 4, 1 mutualist, parasite, nutrient recycler

The most important feature that permits a gene to act as a molecular clock is _______.

A reliable average rate of mutation

In a comparison of bird and mammals, having four limbs is ____.

A shared ancestral character

For several decades now, amphibian species worldwide have been in decline. A significant proportion of the decline seems to be due to the spread of the chytrid fungus, Batrachochytrium dendrobatidis (Bd). Chytrid sporangia reside within the epidermal cells of infected animals, animals that consequently show areas of sloughed skin. They can also be lethargic, which is expressed through failure to hide and failure to flee. The infection cycle typically takes four to five days, at the end of which zoospores are released from sporangia into the environment. In some amphibian species, mortality rates approach 100%; other species seem able to survive the infection. If infection primarily involves the outermost layers of adult amphibian skin, and if the chytrids use the skin as their sole source of nutrition, then which term best applies to the chytrids?

Aerobic chemoheterotroph

Which of the following extremophiles might researchers most likely use as a model for the earliest organisms on Earth?

An anaerobic archaean species

The adaptive advantage associated with the filamentous nature of fungal mycelia is primarily related to _____.

An extensive surface area well suited for invasive growth and absorptive nutrition

A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan. This bacterium derives nutrition by digesting human intestinal contents (in other words, food). Thus, this bacterium should be an _______.

Anaerobic chemoheterotroph

The pathogenic prokaryotes that cause cholera are _____.

Bacteria that release an exotoxin.

Which of the following is LEAST associated with the others? : horizontal gene transfer conjugation transformation binary fission

Binary Fission

What do fungi and arthropods have in common?

Both groups use chitin for support.

A gelatinous seaweed that grows in shallow, cold water and undergoes heteromorphic alternation of generations is most probably what type of alga?

Brown

The multicellular condition of animals and fungi seems to have arisen _____.

By convergent evolution

Orchid seeds are tiny, with virtually no endosperm and with miniscule cotyledons. If such seeds are deposited in a dark, moist environment, then which of the following represents the most likely means by which fungi might assist in seed germination, given what the seeds lack?

By providing the embryos with some of the organic nutrients they have absorbed

While examining a rock surface, you have discovered an interesting new organism. Which of the following criteria will allow you to classify the organism as belonging to Bacteria but not Archaea or Eukarya?

Cell walls are made primarily of peptidoglycan

When a mosquito infected with Plasmodium first bites a human, the Plasmodium _____.

Cells infect the human liver cells

A phylogenetic tree constructed using sequence differences in mitochondrial DNA would be most valid for discerning the evolutionary relatedness of ____.

Chimpanzees and Humans

You observe the gametes of a fungal species under the microscope and realize that they resemble animal sperm. To which of the following group does the fungus belong?

Chytrids

Healthy individuals of Paramecium bursaria contain photosynthetic algal endosymbionts of the genus Chlorella. When within their hosts, the algae are referred to as zoochlorellae. In aquaria with light coming from only one side, P. bursaria gathers at the well-lit side, whereas other species of Paramecium gather at the opposite side. The zoochlorellae provide their hosts with glucose and oxygen, and P. bursaria provides its zoochlorellae with protection and motility. P. bursaria can lose its zoochlorellae: (1) if kept in darkness, the algae die, and (2) if prey items (mostly bacteria) are absent from its habitat, P. bursaria will digest its zoochlorellae. Which term most accurately describes the nutritional mode of healthy P. bursaria?

Commensalistic

Which process in Paramecium results in genetic recombination but no increase in population size?

Conjugation

Some beetles and flies have antler-like structures on their heads, much like male deer do. The existence of antlers in beetle, fly, and deer species with strong male-male competition is an example of _____.

Convergent Evolution

The chloroplasts of land plants are thought to have been derived according to which evolutionary sequence?

Cyanobacteria ----> Green Algae -----> Land Plants

A fungal spore germinates, giving rise to a mycelium that grows outward into the soil surrounding the site where the spore originally landed. Which of the following accounts for the fungal movement, as described here?

Cytoplasmic streaming in hyphae

Bacteria perform the following ecological roles. Which role typically does not involve symbiosis?

Decomposer

There is some evidence that reptiles called cynodonts may have had whisker-like hairs around their mouths. If true, then hair is a shared _____.

Derived Character of mammals, but only if cynodonts are reclassified as mammals

Which of the following is a producer?

Diatom

You are given the task of designing an aquatic protist that is a primary producer. It cannot swim on its own, yet must stay in well-lit surface waters. It must be resistant to physical damage from wave action. It should be most similar to a(n)

Diatom

Rose-picker's disease is caused by the yeast, Sporothrix schenkii. The yeast grows on the exteriors of rose-bush thorns. If a human gets pricked by such a thorn, the yeasts can be introduced under the skin. The yeasts then assume a hyphal morphology and grow along the interiors of lymphatic vessels until they reach a lymph node. This often results in the accumulation of pus in the lymph node, which subsequently ulcerates through the skin surface and then drains. The answer to which of these questions would be of most assistance to one who is attempting to assign the genus Sporothrix to the correct fungal phylum?

Does S. schenkii rely on animal infection to complete some part of its life cycle, or is the infection merely opportunistic?

Which of the following is responsible for nearly 100,000 human deaths worldwide every year?

Entamoeba Histolytica

All protists are

Eukaryotic

Sexual Reproduction in eukaryotes increases genetic variation. In prokaryotes, transformation, transduction, and conjugation are mechanisms that increase genetic variation. A fundamental difference between the generations of genetic variation in the two domains is:

Eukaryotic genetic variation occurs with vertical gene transfer while prokaryotic genetic variation occurs with horizontal gene transfer.

Previously understood similarities that seemed to connect slime molds and fungi are now considered to be _____.

Examples of Convergent Evolution

Assuming that each of these possesses a cell wall, which prokaryotes should be expected to be most strongly resistant to plasmolysis in hypertonic environments?

Extreme Halophiles

Which feature seen in chytrids supports the hypothesis that they diverged earliest in fungal evolution?

Flagellated Spores

When a mycelium infiltrates an unexploited source of dead organic matter, what are most likely to appear within the food source soon thereafter?

Fungal Enzymes

Why are mycorrhizal fungi superior to plants at acquiring mineral nutrition from the soil?

Fungi secrete extracellular enzymes that can break down large molecules

The reason that paralogous genes can diverge from each other within the same gene pool, whereas orthologous genes diverge only after gene pools are isolated from each other, is that _______.

Having an extra copy of a gene permits modifications to the copy without loss of the original gene product

Plasmogamy can directly result in which of the following? 1. cells with a single haploid nucleus 2. heterokaryotic cells 3. dikaryotic cells 4. cells with two diploid nuclei

Heterokaryotic cells or Dikaryotic cells

A large seaweed that floats freely on the surface of deep bodies of water would be expected to lack which of the following?

Holdfasts

The common ancestors of birds and mammals were very early (stem) reptiles, which almost certainly possessed 3-chambered hearts (2 atria, 1 ventricle). Birds and mammals, however, are alike in having 4-chambered hearts (2 atria, 2 ventricles). The 4-chambered hearts of birds and mammals are best described as ________.

Homoplasies

Which process could have allowed the nucleomorphs of chloroarchinophytes to be reduced, without the net loss of any genetic information?

Horizontal Gene Transfer

Which value(s) would be required to calculate how long ago the most recent ancestor of ungulates lived? I) the number of base pairs that differ among species in a certain genetic sequence II) the total number of base pairs in the genetic sequence examined III) the age of a fossil ancestor for calibration

I,II, and III

If we were to apply the most recent technique used to fight potato late blight to the fight against the malarial infection of humans, then we would _________.

Insert genes from a Plasmodium-resistant strain of mosquito from Anopheles mosquitoes

Giardia intestinalis can in several different mammalian species, including humans. Giardia organisms (G. intestinalis) that infect humans are similar morphologically to those that infect other mammals; thus they have been considered a single species. However, G. intestinalis has been divided into different subgroups based on their host and a few other characteristics. In 1999, a DNA sequence comparison study tested the hypothesis that these subgroups actually constitute different species. The following phylogenetic tree was constructed from the sequence comparison of rRNA from several subgroups of G. intestinalis and a few other morphologically distinct species of Giardia. The researchers concluded that the subgroups of Giardia are sufficiently different from one another genetically that they could be considered different species. (T. Monis et al. 1999. Molecular systematics of the parasitic protozoan Giardia intestinalis. Mol. Biol. Evol. 16[9]:1135-44.) By examining the phylogenetic tree diagrammed in the figure above, what conclusion can you draw about the species G. microti?

It is part of a monophyletic group that also includes G. intestinalis

Which of the following traits do archaeans and bacteria share?

Lack of a nuclear envelope and presence of plasma membrane

Mycorrhizae are to the roots of vascular plants as endophytes are to vascular plants ______.

Leaf Mesopyhyll

If haustoria from the fungal partner were to appear within the photosynthetic partner of a lichen, and if the growth rate of the photosynthetic partner consequently slowed substantially, then this would support the claim that ______.

Lichens are not purely mutualistic relationships

Assume that some members of an aquatic species of motile, photosynthetic protists evolve to become parasitic to fish. They gain the ability to live in the fish gut, absorbing nutrients as the fish digests food. Over time, which of the following phenotypic changes would you expect to observe in this population of protists?

Loss of Chloroplasts

Phylogenetic trees constructed from evidence from molecular systematics are based on similarities in _____.

Mutations to homologous genes

Some fungal species can kill herbivores while feeding off of sugars from its plant host. What type of relationship does this fungus have with its host?

Mutualistic

Which of the following would, if it had acted upon a gene, prevent this gene from acting as a reliable molecular clock?

Natural Selection

Concerning growth in genome size over evolutionary time, which of these is least associated with the others?

Orthogolous Genes

(Diagram Shown) Assuming chimps and gorillas are humans' closest relatives, removing humans from the great ape clade and placing them in a different clade has the effect of making the phylogenetic tree of the great apes ______.

Paraphyletic

Which of the following best describes the physical relationship of the partners involved in lichens?

Photosynthetic cells are surrounded by fungal hyphae

Linnaeus believed that species remained fixed in the form in which they had been created. Linnaeus would have been uncomfortable with _____.

Phylogenies

Which eukaryotic kingdom includes members that are the result of endosymbioses that included an ancient aerobic bacterium and an ancient cyanobacterium?

Plantae

Unikonta is a supergroup that includes all of the following except

Plants

Which two genera have members that can evade the human immune system by frequently changing their surface proteins? 1. Plasmodium 2. Trichomonas 3. Paramecium 4. Trypanosoma 5. Entamoeba

Plasmodium & Trypanosoma

Which of the following is (are) problematic when the goal is to construct phylogenies that accurately reflect evolutionary history?

Polyphetic taxa and Paraphyletic taxa

Some molecular data place the giant panda in the bear family (Ursidae) but place the lesser panda in the raccoon family (Procyonidae). Consequently, the morphological similarities of these two species are probably due to

Possession of analogous (convergent) traits

If all fungi in an environment that perform decomposition were to suddenly die, then which group of organisms should benefit most, due to the fact that their fungal competitors have been removed?

Prokaryotes

In prokaryotes new mutations accumulate quickly in populations while in eukaryotes new mutations accumulate much more slowly. The primary reasons for this are

Prokaryotes have short generation times and large population sizes

A biologist discovers an alga that is marine, multicellular, and lives at a depth reached only by blue light. This alga is most likely a type of _____.

Red Algae

The best classification system is that which most closely _____.

Reflects evolutionary history

In most fungi, karyogamy does not immediately follow plasmogamy, which consequently _____.

Results in heterokaryotic or dikaryotic cells

The legless condition that is observed in several groups of extant reptiles is the result of _____.

Several instances of the legless condition arising independently of each other

Which statement represents the best explanation for the observation that the nuclear DNA of wolves and domestic dogs has a very high degree of sequence homology? Dogs and wolves _____.

Share a very recent common ancestor

(Diagram Shown) In which of the following human mycoses should one expect to find a growth pattern most similar to that of the mycelium that produced the fairy ring?

Skin mycoses

A billionaire buys a sterile volcanic island that recently emerged from the sea. To speed the arrival of conditions necessary for plant growth, the billionaire might be advised to aerially sow what over the island?

Soredia

According to the endosymbiotic theory, why was it adaptive for the larger (host) cell to keep the engulfed cell alive, rather than digesting it as food?

The engulfed cell provided the host cell with Adenosine Triphosphate (ATP)

Fungi have an extremely high surface-area-to-volume ratio. What is the advantage of this to an organism that gets most of its nutrition through absorption?

The larger surface area allows for more material to be transported through the cell membrane.

The term homoplasy is most applicable to which of the following features?

The legless condition found in various lineages of extant lizards

Which of the following observations about flagella is true and is consistent with the scientific conclusion that the flagella from protists and bacteria evolved independently?

The protein structure and the mechanism of movement in protist flagella are different from those of bacteria flagella.

If all prokaryotes on Earth suddenly vanished, which of the following would be the most likely and most direct result?

The recycling of nutrients would be greatly reduced, at least initially.

The various taxonomic levels (for example, phyla, genera, classes) of the hierarchical classification system differ from each other on the basis of _____.

Their inclusiveness

Biologists sometimes divide living organisms into two groups: autotrophs and heterotrophs. These two groups differ in _____.

Their mode of nutrition

Which of the following is a characteristic of ciliates?

They are often multinucleate

Basidiomycetes are the only fungal group capable of synthesizing lignin peroxidase. What advantage does this group of fungi have over other fungi because of this capability?

This fungal group can break down the rough lignin, which cannot be harnessed for energy to get the more useful cellulose

Which of the following describe all existing bacteria?

Tiny, ubiquitous, metabolically diverse

Your professor wants you to construct a phylogenetic tree of orchids. She gives you tissue from seven orchid species and one lily. What is the most likely reason she gave you the lily?

To serve as an outgroup

(Graph Shown) In this eight-year experiment, 12 populations of E. coli, each begun from a single cell, were grown in low-glucose conditions for 20,000 generations. Each culture was introduced to fresh growth medium every 24 hours. Occasionally, samples were removed from the populations, and their fitness in low-glucose conditions was tested against that of members sampled from the ancestral (common ancestor) E. coli population. If new genetic variation in the experimental populations arose solely by spontaneous mutations, then the most effective process for subsequently increasing the prevalence of the beneficial mutations in the population over the course of generations is A) transduction. B) conjugation. C) transformation. D) binary fission.

Transformation

If you were using cladistics to build a phylogenetic tree of cats, which of the following would be the best outgroup?

Wolf

Neutral theory proposes that ________.

a significant proportion of mutations are not acted upon by natural selection

Deuteromycetes _____.

are the group of fungi that have no known sexual stage

Green algae differ from land plants in that many green algae __________.

are unicellular

(Diagram shown) We know the streamlined bodies shown in the figure above are examples of homoplasy. If the following groups also had streamlined bodies, which of the groupings would give the most support to this body type being homologous?

lizards, pterosaurs, dinosaurs, birds, synapsids, monotremes, marsupials, rodents, and primates

Dinoflagellates ______.

possess two flagella

What kind of evidence has recently made it necessary to assign the prokaryotes to either of two different domains, rather than assigning all prokaryotes to the same kingdom?

rRNA genes

What is the goal of bioremediation?

to clean up areas polluted with toxic compounds by using bacteria