Biology 102 Exam 2
Where is an organism's evolutionary history documented?
using comparisons of nucleic acids or other molecules to deduce relatedness
True or false: studies of rRNA sequences indicate that fungi are more closely related to animals than to plants
homology is the result of speciation event and hence occurs between genes found in different species
results from gene duplication; hence, multiple copies of these genes have diverged from one another within a species
______ has to be there for orthologous genes to diverge
an approach for measuring the absolute time of evolutionary change based on the observation that some genes and other regions of genomes appear to evolve at constants rates
What are the 5 kingdoms
Protista (a diverse kingdom consisting mostly of unicellular organisms)
what are the three domains
What process actually increases the number of genes in an organism's genome?
Why do researchers use rRNA in investigations of relationships between taxa that diverged hundreds of millions of years ago?
DNA coding for rRNA changes relatively slowly.
The lakes of northern Minnesota are home to many similar species of damselflies of the genus Enallagma. These species have apparently undergone speciation from ancestral stock since the last glacial retreat about ten thousand years ago. Sequencing which of the following would probably be most useful in sorting out evolutionary relationships among these closely related species?
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
Molecular clocks are based on the idea that
on average neutral mutations arise at a constant rate
The most important feature that permits a gene to act as a molecular clock is
reliable average rate of mutation
Which of the following would, if it had acted upon a gene, prevent this gene from acting as a reliable molecular clock?
Based on cladistics, which eukaryotic kingdom is polyphyletic and, therefore, unacceptable?
Which eukaryotic kingdom includes members that are the result of endosymbioses that included an ancient aerobic bacterium and an ancient cyanobacterium?
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?
What is the function of fimbriae?
They are used to attach the cell to its substrate or to other prokaryotes
Jams, jellies, preserves, honey, and other foods with high sugar content hardly ever become contaminated by bacteria, even when the food containers are left open at room temperature. This is because bacteria that encounter such an environment ____.
undergo death as a result of water loss from the cell
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.
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,
1. nucleoid region
1, 2, and 4
Chloramphenicol is an antibiotic that targets prokaryotic (70S) ribosomes, but not eukaryotic (80S) ribosomes. Which of these questions stems from this observation, plus an understanding of eukaryotic origins?
If chloramphenicol inhibits prokaryotic ribosomes, should it not also inhibit mitochondrial ribosomes?
How does the large amount of genetic variation observed in prokaryotes arise?
They have extremely short generation times and large populations.
They can exchange DNA with many types of prokaryotes by way of horizontal gene transfer.
Genes for the resistance to antibiotics are usually located _
When a virus infects a bacterial cell, often new viruses are assembled and released when the host bacterial cell is lysed. If these new viruses go on to infect new bacterial cells the host cells may not be lysed. What is the most plausible explanation for this?
The virus has entered the genome of the bacterial cell and is in the lysogenic stage
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.`
Antibiotic-resistant bacteria are becoming an increasing problem. Some bacteria that were once killed by common antibiotics have acquired the ability to survive in the presence of those antibiotics. How can bacteria acquire antibiotic resistance?
Bacteria can pick up an antibiotic-resistance gene from the environment through transformation.
Bacteria can acquire random mutations that allow them to grow in the presence of antibiotics
Bacteria can acquire antibiotic-resistance genes by becoming infected with a virus that contains an antibiotic-resistance gene.
Bacteria can gain an antibiotic-resistance gene by conjugating with another species of bacteria.
Which of the following is true of generalized bacteriophage transduction?
The bacteriophage packages fragments of bacterial DNA into new phage particles.
Bacteria that live around deep-sea, hot-water vents obtain energy by oxidizing inorganic hydrogen sulfide belched out by the vents. They use this energy to build organic molecules from carbon obtained from the carbon dioxide in seawater. These bacteria are _____.
Which statement is true about obligate anaerobes?
They are poisoned by O2.
Biologists sometimes divide living organisms into two groups: autotrophs and heterotrophs. These two groups differ in _____.
their mode of nutrition
The prokaryotic organisms most likely to be found living in salt ponds are the
How are archaeans most similar to bacteria?
the shape of their chromosomes and plasmids
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?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.
You have found a new prokaryote. What line of evidence would support your hypothesis that the organism is a cyanobacterium?
It is able to form colonies and produce oxygen.
Which statement about the domain Archaea is true?
Genetic prospecting has recently revealed the existence of many previously unknown archaean species.
The thermoacidophile Sulfolobus acidocaldarius lacks
peptidoglycan, but still possesses a cell wall. What is likely to be
true of this species?
1. It is a bacterium.
2. It is an archaean.
3. The optimal pH of its enzymes will lie above pH 7.
4. The optimal pH of its enzymes will lie below pH 7.
5. It could inhabit certain hydrothermal springs.
6. It could inhabit alkaline hot springs
2, 4, and 5
An ecological relationship between organisms of different species that are in direct contact can best be described as _____
Bacteria perform each of the following ecological roles. Which role typically does NOT involve symbiosis?
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 adenosine triphosphate (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?
4. metabolic cooperation
1, 3, and 4
What is the goal of bioremediation?
to clean up areas polluted with toxic compounds by using bacteria
Which statement about endotoxins is true?
Endotoxins are released only when bacteria die and their cell walls break down.
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.
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
Genetic variation in bacterial populations cannot result from
Bacteria perform the following ecological roles. Which role typically does not involve symbiosis?
Plantlike photosynthesis that releases O2 occurs in
Which of the following processes contributes to genetic recombination in prokaryotes
Which of the following is true of secondary endosymbiosis?
An organism containing an endosymbiont is engulfed by another organism and becomes an endosymbiont.
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).
The chloroplasts of land plants are thought to have been derived according to which evolutionary sequence?
cyanobacteria → green algae → land plants
A particular species of protist has obtained a chloroplast via secondary endosymbiosis. You know this because the chloroplasts _____
have three or four membranes
All protists are ____
Consider the following data: (a) Most ancient eukaryotes are unicellular. (b) All eukaryotes alive today have a nucleus and cytoskeleton. (c) Most ancient eukaryotes lack a cell wall. Which of the following conclusions could reasonably follow the data presented? The first eukaryote may have been _____.
capable of phagocytosis
Green algae differ from land plants in that many green algae ___
_____ are eukaryotic autotrophs that float near the surface of water and are the basis of the food chain.Hints
Which of the following is a producer
Encouraging the growth (via nutrient fertilization) of photosynthetic protists in marine environments may help reduce global warming because _____.
photosynthetic protists fix atmospheric carbon dioxide, decreasing atmospheric carbon dioxide levels
Plastids that are surrounded by more than two membranes are evidence of
Biologists suspect that endosymbiosis gave rise to mitochondria before plastids partly because
all eukaryotes have mitochondria (or their remnants), whereas many eukaryotes do not have plastids.
Select the correct statement about photosynthesis by primary producers.
Photosynthetic protists and prokaryotes carry out the majority of the photosynthesis in aquatic communities.
Which of the following is a difference between plants and fungi?
Fungi are heterotrophic, and plants are autotrophic.
Fungi obtain nutrients through __
The body of most fungi consists of threadlike _____, which form a network called a _____.
hyphae ... mycelium
When a mycelium infiltrates an unexploited source of dead organic matter, what are most likely to appear within the food source soon thereafter?
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
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
The diploid phase of the life cycle is shortest in which of the following
What sexual processes in fungi generate genetic variation?
karyogamy and meiosis`
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
2 or 3
In most fungi, karyogamy does not immediately follow plasmogamy, which consequently ____
results in heterokaryotic or dikaryotic cells
An important example of interaction between fungi and certain other organisms is mycorrhizae, in which the fungal partners _____.
help plants take up nutrients and water
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 multicellular condition of animals and fungi seems to have arisen __
by convergent evolution
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 tough lignin, which cannot be harnessed for energy, to get to the more useful cellulose.
Which of the following is (are) unique to animals?
nervous system signal conduction and muscular movement
Both animals and fungi are heterotrophic. What distinguishes animal heterotrophy from fungal heterotrophy is that most animals derive their nutrition by _____.
What do animals ranging from corals to monkeys have in common?
presence of Hox genes
The evolution of animal species has been prolific (the estimates go into the millions and tens of millions). Much of this diversity is a result of the evolution of novel ways to _____.
sense, feed, and move
The last common ancestor of all animals was probably a _____.
Which of the following is radially symmetrical?
Gastrulation is the process that directly forms the __
primary germ layers
what are the two prokaryotes domains
bacteria and archaea
shapes of prokaryotic cells
spheres ( coccus)
rods ( bacillus)
what do most bacterial cell walls contain?
Archael cell walls contain....
variety of polysaccharides and proteins
can categorize many bacterial species according to differences in cell wall composition
bacteria have simpler walls with relatively large amount of peptidoglycan
bacteria have less peptidoglycan and are structurally more complex with an outer membrane that contains lipoplysaccharides
- more likely to be anibiotic resistant
a polysaccharide or protein layer is called
what is a fimbrae
hairlike appendages that are used to stick to their substrate or to one another
What is a pili
allow prokaryotes to exchange DNA
what is taxis
the ability to move toward or away from a stimulus
what is exaptation
where existing structures take on new functions through descent with modification
where are the chromosomes located on a prokaryote
What are plasmids?
small rings that contain DNA
how do prokaryotes reproduce?
How long does binary fission take?
what are the three factors that contribute to genetic diversity
what is genetic recombination
the combining of DNA from two sources
what is transformation
when a prokaryotic cell can take up and incorporate foreign DNA from the surrounding eniviroment
What i stransduction
the movement of genes between bacteria by bacteriophages
what is conjugation
the process where genetic material is transferred between prokaryotic cells
Where does the F factor exist
on a plasmid or a segment of DNA
what are R plasmids
carry genes for antibiotic resistance
Phototrophs get their energy from?
chemotrophs get their sunlight from
autotrophs require CO2 as...
a carbon dourece
what is obligate aerobes
must use O2 for cellular respiration
what is nitrogen fixation
when atmospheric nitrogen is converted to ammmonia
live in highly saline enviroments
live in very hot enivroments
release methance as a by-product of their unique ways of obtaining engery
ecological relationship which two species live in close contact
both organisms benefit
one organisms benefit while the other gets nothing
when one harms the host organsims
secreted and cause disease even if the prokaryotic that produce them are not present
released only when bacteria die and their cell walls break down
use of organisms to remove polluntants from soil,air or water
what is cynobacteria
photoautotrophs that generate O2