問題一覧
1
Which traits do archaea and bacteria share?
lack of nucleus envelope and presence of plasma membrane
2
Prokaryotes are classified as belonging to two different domains. What are the domains?
bacteria and archaea
3
What organisms are most numerous on Earth?
prokaryotes
4
What is the goal of bioremediation?
to clean up areas polluted with toxic compounds by using bacteria.
5
To establish a link between a specific bacterium and a skin disease, researchers have shown that the bacterium was present in sick persons but not in healthy individuals. They isolated the bacterium in a pure culture and demonstrated that experimental healthy animals injected with this culture became sick. What other experiment do researchers need to perform to be absolutely sure that the bacterium is responsible for the disease?
isolate bacterium from an infected sick animal and demonstrate that it is the same bacterium as the one used for infection
6
Some researchers have begun attempting to clean up oil spills by adding nonindigenous microbial hydrocarbon degraders to the spill, in the hope that these bacteria will neutralize the dangerous chemicals in the spill. What is this an example of ?
seeding
7
Chemicals, secreted by soil fungi, which inhibit the growth of bacteria, are known as?
antibiotics
8
Microbiologists use the Gram stain to aid in the identification of bacteria. What is the major difference between Gram-positive and Gram-negative bacteria?
presence or absence of that outer plasma membrane
9
Biologists sometimes divide living organisms into two groups: autotrophs and heterotrophs. How do these two groups differ?
they use different sources of carbon
10
Carl Woese and collaborators identified two major branches of prokaryotic evolution. What was the basis for dividing prokaryotes into two domains?
genetic characteristics such as ribosomal RNA sequence
11
Imagine that you are given some chemoorganotrophic bacteria to grow. What should you use as a source of energy for this type of bacteria? And this question can be modified for other types of prokaryote…Imagine that you are given some chemoorganotrophic bacteria to grow.
sugar
12
You might be interested to know how many different types of bacteria live on the shower curtain in your bathroom. What is the most efficient method for finding out?
direct sequencing
13
A prokaryote that obtains energy from light is a(n)?
phototrophs
14
A prokaryote that obtains energy and carbon as it decomposes dead organisms is a(n)?
heterotroph and chemotroph
15
Among the bacteria, plantlike photosynthesis that releases oxygen (O2) occurs in?
Cyanobacteria
16
A prokaryote that obtains carbon and energy by ingesting prey is a(n)
heterotroph and chemotroph or chemoheterotroph
17
The purple nonsulfur bacterium Rhodospirillum grows best as a photoheterotroph. What are the most favorable sources of energy and carbon for this bacterium?
Fructose and light
18
A newly discovered organism is found to use sulfide (S2−) for aerobic respiration and carbon dioxide (CO2) from the air as a source of carbon, much like a plant. What must this organism be?
chemolithotrauphs
19
Multicellularity and large body size of eukaryotic organisms require high metabolic rates and efficient ATP production by aerobic respiration. How did bacteria change Earth's atmosphere to enable aerobic respiration?
Oxygenic photosynthesis by Cyanobacteria significantly increased the amount of oxygen in the atmosphere
20
A water sample from a hot thermal vent contained a single-celled organism that had a cell wall but lacked a nucleus. What is its most likely classification?
archaea
21
Which of the following describe all existing bacteria?
tiny,ubiquitous,metabolically diverse
22
Which of the following obtain energy by oxidizing inorganic substances to obtain energy that is used, in part, to fix carbon dioxide?
chemoautotrophs
23
What is an example of a eukaryote pathogens that infects humans?
malaria/Plasmodium
24
Why are protists and bacteria grouped into different domains?
protist have a membrane bound nucleus ,which bacterial cells lack
25
Why are protists considered to be a paraphyletic group?
include some but not all descendants of their most recent common ancestry
26
Which of the following statements best describes the term synapomorphy?
a trait common in a single monophyletic group but not generally found outside of the group
27
Why might encouraging the growth (via nutrient fertilization) of photosynthetic protists in marine environments help reduce global warming?
photosynthesis protist fix atmosphere carbon dioxide, decreasing atmospheric carbon dioxide levels
28
A particular species of protist has obtained a chloroplast via secondary endosymbiosis. How would you know this?
have nuclear and Cyanobacterial genes
29
Which major eukaryotic lineages form the Bikonta, a monophyletic group characterized by two flagella as a synapomorphy?
Alveolata, Stramenpila, Rhizaria, plantae, excavata
30
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
31
According to the endosymbiosis theory of the origin of eukaryotic cells, how did mitochondria originate?
from engulfed , originally free living proteobcteria
32
Which eukaryote organelle was derived from an ancestral cyanobacterium?
chloroplast
33
What are some of the organelles or cellular structures that all protists share?
nucleus , mitochondria, vacuole, Golgi body , chrloroplast and endoplasmic reticulum
34
What places in a eukaryotic cell contain genomes?
nucleus or mitochondria and chloroplast
35
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 phenotypic changes would you expect to observe in this population of protists?
loss of chloroplast
36
What is the leading hypothesis on the origin of the nucleus?
the nucleus was formed through in folding of the plasma membrane
37
Transcriptional regulation in eukaryotes includes processes such as alternative splicing that are not observed in bacteria or archaea. What changes occurred in the eukaryotic cell to make alternative splicing possible?
spatial separation of transcription and translation-transcription occurs in the nucleus and translation occurs in cytoplasm
38
In the past decade, many new species of eukaryotic "picoplankton" have been discovered. What technique has enabled their discovery?
direct sequencing of environmental samples
39
Among protists, what term describes feeding by engulfing then digesting prey?
ingestive feeding, or phagocytosis
40
Are all protists unicellular?
no not all protist are unicellular
41
Encouraging the growth (via nutrient fertilization) of photosynthetic protists in marine environments may help reduce global warming because?
photosynthetic protist fix atmospheric carbon dioxide, decreasing atmospheric carbon dioxide levels
42
What characteristics, structures, or processes is common to bacteria and viruses?
genetic material composed of nucleus acids
43
HIV is inactivated in the laboratory after a few minutes of sitting at room temperature, but the flu virus is still active after sitting for several hours. What are the practical consequences of these findings?
The flu virus can be transmitted more easily from person to person than HIV
44
What is the function of reverse transcriptase in retroviruses?What is the function of reverse transcriptase in retroviruses?
uses viral RNA as a template for DNA synthesis to replicate itself
45
Effective antiviral drugs are usually associated with which properties?
interference with viral replication
46
Why do RNA viruses require their own supply of certain enzymes?
host cells lack the enzymes that can replicate the viral genome
47
You just discovered a new virus. This virus infects heart muscle, where it causes inflammation, and has a very high mutation rate. Which of the following is the best strategy for finding a treatment for this virus?
identify a receptor for virus and develop a drug that stops / blocking receptors
48
What would the result be if a drug that blocks the action of RNA polymerase was introduced into a virus-infected organism?
viral proteins would not be made, rendering the virus unable to reproduce
49
Viruses use the host's machinery to make copies of themselves. However, some human viruses require a type of replication that humans do not normally have. For example, humans normally do not have the ability to convert RNA into DNA. How can these types of viruses infect humans, when human cells cannot perform a particular role that the virus requires?
the virus has its own genome the code for any specialized host does not have
50
Which of the following viruses would most likely have reverse transcriptase?
an RNA-based lysogenic virus
51
What are the arguments for considering viruses non-living?
they do not carry metabolic processes
52
What is the difference between an epidemic and a pandemic?
an epidemic is a wide spread occurrence of n infectious disease in a community t a particular time a pandaemic when it spreads beyond a region to infect large numbers of people world wide
53
What is the main structural difference between enveloped and nonenveloped viruses?
envelope viruses have a phospholipid membrane outside their capsid,whearas neneveloped viruses do not have a phospholipid membrane
54
The HIV protease has been the target of several anti-HIV medications called protease inhibitors. Why is this antiviral strategy possible?
because protease inhibitors prevent the formation of active viral proteins
55
Viruses?
biological entities that use host cells to copy themselves
56
Fungi that absorb nutrients from decaying plant matter are called _____
saprobs / saprotrophic
57
Which of the following is major characteristic of fungi that distinguishes them from most other eukaryotes?
nutrient acquisition via external digestion
58
Why is it more difficult to treat fungal infections than bacterial infections in humans?
fungal and animal cells and proteins are similar. Thus drugs that disrupt fungal cell or protein function may also disrupt human cell or protien fuction
59
Long, branching fungal filaments are called __
Hyphae
60
Which of these fungal features supports the phylogenetic conclusion that fungi are more closely related to animals than to plants?
chitin, cell walls are made of it
61
In septate fungi, what structures allow cytoplasmic streaming to distribute needed nutrients, synthesized compounds, and organelles throughout the hyphae?
tiny holes (pores) in cross walls
62
It has been hypothesized that fungi and plants have a mutualistic relationship because plants make sugars available for the fungi's use. What is the best evidence in support of this hypothesis?
radioactively labeled sugars produced by plants eventually show up in the fungi with which they are associated
63
What group of fungi has the ability to penetrate its host's cell wall, thus increasing the efficiency with which materials are passed from fungus to host?
ectomycorrhizal fungi
64
When pathogenic fungi are found growing on the roots of grape vines, grape farmers sometimes respond by covering the ground around their vines with plastic sheeting and pumping a gaseous fungicide into the soil. The most important concern of grape farmers who engage in this practice should be that the
fungicide might also kill mycorrhizae
65
Why is it important that ectomycorrhizal fungi (EMF) have peptidase enzymes?
these enzymes are needed to release nitrogen from dead plant material in colder environments
66
Which of the following is an important role for fungi in the carbon cycle?
fungi help release fixed carbon back into the environment for plants and other photosynthetic organisms to use
67
Among the organisms listed here, which are thought to be the closest relatives of fungi among the Eukaryotes?
animals
68
Studies have shown that in some forest ecosystems carbon can move from one tree to another via mycorrhizal fungi. Which of the following features of fungal biology enables this?
the cells of fungi hyphae are connected by pores that allow passage of cytoplasm from cell to cell
69
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
70
Why are mycorrhizal fungi superior to plants at acquiring mineral nutrition from the soil?
fungi secretes extracellular enzymes that can break down large molecules