Chapter 24 Flashcards
(21 cards)
Prokaryotes lack the nucleus found in eukaryotic cells. As a result, prokaryotic cells lack what structure?
A. a nuclear membrane
B. DNA
C. one or more chromosomes
D. all of the above
A. a nuclear membrane
Which statement best describes most prokaryotes?
A. They are generally harmful.
B. They are limited to living in a few habitats.
C. They are very common in the environment.
D. They are responsible for the common cold.
C. They are very common in the environment.
Which feature of bacteria is not a defensive structure?
A. cell walls
B. endospores
C. capsules
D. R plasmids
E. F plasmids
E. F plasmids
What is(are) the feature(s) of prokaryotes that enable(s) them to adapt so quickly?
A. short generation time
B. genetic diversity in prokaryotes, which can possibly arise by transformation, transduction, or conjugation
C. ability to transfer advantageous alleles
D. rapid proliferation, which increases chance of mutation
E. All of the choices are correct.
E. All of the choices are correct.
What is true of archaeans?
A. They are the cause of many human diseases.
B. Structurally, they represent an intermediate form between bacteria cells and eukaryotic cells.
C. They are all extremophiles.
D. They have undergone horizontal gene transfer with bacteria and with eukaryotes.
E. They include Earth’s first aerobic photosynthesizers.
D. They have undergone horizontal gene transfer with bacteria and with eukaryotes.
Cyanobacteria that can perform nitrogen fixation
A. use this metabolic pathway to provide themselves with glucose.
B. cannot also perform aerobic photosynthesis.
C. provide both fixed nitrogen and fixed carbon dioxide to other organisms.
D. do so on membranes called thylakoids.
E. are part of the community of organisms at deep-sea vents.
C. provide both fixed nitrogen and fixed carbon dioxide to other organisms.
Which has the thickest layer of peptidoglycan in the cell wall?
A. bacillus
B. gram-negative bacteria
C. coccus
D. gram-positive bacteria
D. gram-positive bacteria
Which would be a great surprise if found in prokaryotes?
A. ribosome
B. endospore
C. nucleus
D. plasmid
C. nucleus
In what type of environment would you find extreme halophiles living?
A. ice
B. hot springs
C. very salty water
D. anoxic swamps
C. very salty water
Which gets its energy from sunlight and its carbon from ingesting other organisms?
A. photoautotroph
B. chemoautotroph
C. photoheterotroph
D. chemoheterotroph
C. photoheterotroph
In a 2008 test, researchers simulated a volcanic eruption and, using modern equipment, re-analyzed molecules from Miller’s 1953 experiment. The results
A. showed that fewer amino acids formed under conditions simulating a volcanic eruption.
B. showed that the mass of amino acids was greater in the original (1953) experiment.
C. were not valid based on the instruments used.
D. indicated that a reducing atmosphere may have produced more organic compounds than a neutral one.
D. indicated that a reducing atmosphere may have produced more organic compounds than a neutral one.
A protocell is
A. a stage in one scenario for the origin of simple cells.
B. a “package” that could maintain an internal chemistry different from that of its surroundings.
C. the result of chemical and physical processes on early Earth.
D. a droplet with membranes.
E. All of the choices are correct.
E. All of the choices are correct.
Which are layered rocks formed by certain prokaryotes?
A. vesicles
B. montmorillonites
C. protocells
D. stromatolites
E. ammonites
D. stromatolites
Since flagella of bacteria, archaea, and eukaryotes arose independently, they are considered _______ structures.
A. symbiotic
B. homologous
C. analogous
D. divergent
C. analogous
How many hours would it take for a single prokaryote, dividing every 20 minutes by binary fission in a favorable environment, to produce 512 of its kind?
A. 2
B. 3
C. 0
D. 180
E. none of the above
B. 3
The process of phages carrying prokaryotic genes from one host cell to another is called
A. conjugation.
B. transformation.
C. replication.
D. transduction.
E. induction.
D. transduction.
Which are the only bacteria lacking cell walls?
A. cyanobacteria
B. actinomycetes
C. mycoplasma
D. spirochetes
E. myxobacteria
C. mycoplasma
Why does the hydrothermal vent community not include photosynthetic organisms?
A. The community derives its energy from H2S.
B. Sunlight doesn’t penetrate to the vents.
C. The population is too dense.
D. The vent bacteria are thermophiles, which are non-photosynthetic.
B. Sunlight doesn’t penetrate to the vents.
What is true about bacterial endotoxins?
A. They cause the diseases cholera and botulism.
B. Some endotoxins can produce disease even when the bacterium that manufactures them isn’t present when
contaminated food is eaten.
C. They are made from lipopolysaccharide membrane components.
D. They are proteins secreted by certain bacteria and other organisms.
C. They are made from lipopolysaccharide membrane components.
CRISPR-Cas9
A. is used for bacterial defense against phages.
B. is a cell treatment in research on HIV.
C. is a tool for altering genes in virtually any organism.
D. must be used with concern for unintended consequences.
E. All of the choices are correct.
E. All of the choices are correct.
It is now thought that early life may have had genetic information encoded in
A. peptidoglycan.
B. protein.
C. DNA.
D. RNA.
D. RNA.
