Unit 3 pretest

The host range of a virus is determined by

.the proteins on its surface and that of the host.

A temperate phage goes dormant between which stages of the lytic cycle?

Entry and Synthesis

Powerhouse of the cell

Mitochondria

Protein synthesis

Ribosomes and Rough ER

These organelles are physically connected to each other

Rough ER and Smooth ER

Though plants, fungi, and prokaryotes all have cell walls, we place them in different taxa. Which of these observations comes closest to explaining the basis for placing these organisms in different taxa, well before relevant data from molecular systematics became available? A) a.Some closely resemble animals, which lack cell walls. B) b.Their cell walls are composed of very different biochemicals. C) c.Some have cell walls only for support. D) d.Some have cell walls only for protection from herbivores. E) e.Some have cell walls only to control osmotic balance.

b.Their cell walls are composed of very different biochemicals.

Bacteria perform each of the following ecological roles. Which role typically does not involve a symbiosis? A) a.skin commensalist B) b.decomposer C) c.aggregates with methane-consuming archaea D) d.gut mutualist E) e.pathogen

b.decomposer

Which of the following can be effective in preventing the onset of viral infection in humans? A) a.taking vitamins B) b.getting vaccinated C) c.taking antibiotics D) d.applying antiseptics E) e.taking nucleoside analogs that inhibit transcription

b.getting vaccinated

Which of the following locations would you find a intermediate filament A) a.Finger nail B) b.Spindle apparatus C) c.Cell cortex D) d.Cleavage furrow

a.Finger nail

Which of the following words is not a term that is associated with Actin A) a.Muscle B) b.Microvilli C) c.Microfilament D) d.Tension resisting E) e.Kinesin

e.Kinesin

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

extreme halophiles

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 sequences

When a membrane is freeze-fractured, the bilayer splits down the middle between the two layers of phospholipids. In an electron micrograph of a freeze-fractured membrane, the bumps seen on the fractured surface of the membrane are

integral proteins.

What kinds of molecules pass through a cell membrane most easily?

small and hydrophobic

After a membrane freezes and then thaws, it often becomes leaky to solutes. The most reasonable explanation for this is that

the integrity of the lipid bilayer is broken when the membrane freezes

Low pH of 5

Lysosome

The predatory bacterium, Bdellovibrio bacteriophorus, drills into a prey bacterium and, once inside, digests it. In an attack upon a gram-negative bacterium that has a slimy cell covering. What is the correct sequence of structures penetrated by B. bacteriophorus on its way to the prey's cytoplasm? 1. membrane composed mostly of lipopolysaccharide 2. plasma membrane 3. peptidoglycan 4. capsule

4, 1, 3, 2

Which of the following is characteristic of the lytic cycle?

A large number of phages are released at a time

The genome of a bacterial cell is sequenced and several remnants of phage DNA are uncovered. The most likely explanation is

A transduction has occurred

Mitochondria and Chloroplasts are similar in that...(mark all that apply) A) a.They both consist of just two membranes B) b.They are both found in all plants C) c.They are both found in all animals D) d.They both contain their own DNA E) e.They are both part of the endomembrane system

A,B,D

In a hypothetical situation, a bacterium lives on the surface of a leaf, where it obtains nutrition from the leaf's non-living, 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? Check those that apply. A) a. nutrient recycler B) b. mutualist C) c. commensal D) d. parasite E) e. primary producer

A,C,D,E

A prerequisite for undergoing conjugation is

An F factor

Which of the following organelles is NOT a member of the endomembrane system? A) a.nucleus B) b.golgi apparatus C) c.vacuoles D) d.peroxisomes E) e.lysosomes

D) d.peroxisomes

Which of the following is the most probable fate of a newly emerging virus that causes high mortality in its host? A) It is able to spread to a large number of new hosts quickly because the new hosts have no immunological memory of them. B) The new virus replicates quickly and undergoes rapid adaptation to a series of divergent hosts. C) A change in environmental conditions such as weather patterns quickly forces the new virus to invade new areas. D) Sporadic outbreaks will be followed almost immediately by a widespread pandemic. E) The newly emerging virus will die out rather quickly or will mutate to be far less lethal.

E) The newly emerging virus will die out rather quickly or will mutate to be far less lethal.

The best represented (most common) viral genome type is

Single Stranded RNA

Site of phospholipid synthesis

Smooth ER

Which statement about the domain Archaea is true? A) a.Genetic prospecting has recently revealed the existence of many previously unknown archaean species. B) b.No archaeans can reduce CO2 to methane. C) c.The genomes of archaeans are unique, containing no genes that originated within bacteria. D) d.No archaeans can inhabit solutions that are nearly 30% salt. E) e.No archaeans are adapted to waters with temperatures above the boiling point.

a.Genetic prospecting has recently revealed the existence of many previously unknown archaean species.

Which of these analogies best explains the difference between the cytosol and the cytoplasm A) a.The cytoplasm is like Atlantic Ocean and the cytosol is like the sea water in it B) b.The cytoplasm is like the sea water and the cytosol is like ships in the sea water C) c.The cytoplasm is like the beaches of an ocean and the cytosol is like the sea water D) d. The cytoplasm is like an island and the cytosol is the seawater that surrounds it

a.The cytoplasm is like Atlantic Ocean and the cytosol is like the sea water in it

Which of the following is a reasonable explanation for why unsaturated fatty acids help keep a membrane more fluid at lower temperatures? A) a.The double bonds form kinks in the fatty acid tails, forcing adjacent lipids to be further apart. B) b.Unsaturated fatty acids have a higher cholesterol content and therefore more cholesterol in membranes. C) c.Unsaturated fatty acids permit more water in the interior of the membrane. D) d.The double bonds block interaction among the hydrophilic head groups of the lipids. E) e.The double bonds result in shorter fatty acid tails and thinner membranes.

a.The double bonds form kinks in the fatty acid tails, forcing adjacent lipids to be further apart.

Which of the following span the phospholipids bilayer, usually a number of times? A) a.transmembrane proteins B) b.integral proteins C) c.peripheral proteins D) d.integrins E) e.glycoproteins

a.transmembrane proteins

This bacterium derives nutrition by digesting human intestinal contents (in other words, food) away from any air. Thus, this bacterium should be an

anaerobic chemoheterotroph

In general, what is the primary ecological role of prokaryotes?

breaking down organic matter

Which of the following is NOT an advantage of internal membranes? A) a. larger size B) b.Increased total membrane surface area C) c.Greater control of mobility D) d.Containment of toxic cellular reactions

c.Greater control of mobility

A researcher lyses a cell that contains nucleic acid molecules and capsomeres of tobacco mosaic virus (TMV). The cell contents are left in a covered test tube overnight. The next day this mixture is sprayed on tobacco plants. Which of the following would be expected to occur? A) a.The plants would develop some but not all of the symptoms of the TMV infection. B) b.The plants would develop symptoms typically produced by viroids. C) c.The plants would develop the typical symptoms of TMV infection. D) d.The plants would not show any disease symptoms. E) e.The plants would become infected, but the sap from these plants would be unable to infect other plants.

c.The plants would develop the typical symptoms of TMV infection.

An animal cell lacking oligosaccharides on the external surface of its plasma membrane would likely be impaired in which function?

cell-cell recognition

Which of the following filaments is made from adding smaller protein subunits together? A) a.Actin filaments B) b.Microtubule filaments C) c.Intermediate filaments D) d.All of the above

d.All of the above

Which of the following statements is not true? A) a.Archaea and bacteria have different membrane lipids B) b.Both archaea and bacteria generally lack membrane-enclosed organelles. C) c.The cell walls of archaea lack peptidoglycan. D) d.Only bacteria have histones associated with DNA. E) e.Only some archaea use CO2 to oxidize H2, releasing methane.

d.Only bacteria have histones associated with DNA.

Which statement about the genomes of prokaryotes is correct? A) a.Prokaryotic genomes are diploid throughout most of the cell cycle. B) b.Prokaryotic chromosomes are sometimes called plasmids. C) c.Prokaryotic cells have multiple chromosomes, "packed" with a relatively large amount of protein. D) d.The prokaryotic chromosome is not contained within a nucleus but, rather, is found at the nucleolus. E) e.Prokaryotic genomes are composed of circular DNA.

e.Prokaryotic genomes are composed of circular DNA.

Which of these are uniquely found in extracellular matrix or organelle lumen? A) a.transmembrane proteins B) b.integral proteins C) c.peripheral proteins D) d.integrins E) e.glycoproteins

e.glycoproteins

The presence of cholesterol in the plasma membranes of some animals

enables the membrane to stay fluid more easily when cell temperature drops.

Water passes quickly through cell membranes because

it moves through aquaporins in the membrane.