BIO102 Chapter 16-19 Test Review

Based on the figure from the section on HIV replication, why could researchers use PCR to amplify viral DNA from the chimp Marilyn's tissues?

HIV is converted to DNA and integrated into a cell's chromosome

Based on the figure, which of the following is true of HIV?

It is an enveloped virus

The human immunodeficiency virus (HIV) only affects a specific class of cells in the immune system called helper T cells, and not other types of T cells. Which is the best explanation for this observation?

Only helper T cells have the correct receptor on their cell surface

A layer of membrane outside the protein coat of some viruses is called a(n)

envelope

A reason given by scientists as to why viruses are not considered living organisms is that

viruses do not reproduce on their own

A site in nature where a virus exists is its

reservoir

A viral species is found to infect host fishes in isolated mountain lakes. The host range is

the one or more infected species of fishes that exhibit the viral disease symptoms

An infectious RNA molecule is a

viroid

An infectious protein is a

prion

Human immunodeficiency virus (HIV) is classified as

a retrovirus

Human influenza viruses are usually derived from influenza viruses that infect

birds and pigs

Oral infections with herpes simplex virus 1 can lie dormant in nerve cells for years. When a patient becomes stressed, the virus enters the active stage and forms cold sores on the lips. When the virus is inactive, or dormant, it is in the ________ stage.

latent

Our most effective weapon against viral infections is

vaccinations

Poliomyelitis is an RNA virus that can invade the nervous system and cause paralysis within a matter of hours. The nearly complete elimination of polio worldwide is due to

vaccinations

Rhinovirus is an RNA virus that causes the common cold and sinus infections. The virus does not contain an envelope. Which of the following is true of a rhinovirus?

It does not contain lipid

The correct sequence of the stages of viral replication is

attachment, penetration, synthesis, assembly, and then release

The enzyme that HIV uses to copy its RNA into DNA is

reverse transcriptase

The host range of a virus is determined by

specific receptors on cells it infects

The genetic information in viruses

can be DNA or RNA, and single- or double stranded

The host range of a virus is

the type of organisms or cells that a virus can infect

The influenza virus contains an RNA genome. Every year a flu vaccine is designed to protect against three different strains of the influenza virus. Why do scientists make a new vaccine each year?

The virus can rapidly mutate into new strains

The shape of a virus is determined by its

coat protein organization

The stage of viral replication in which the new viruses leave the host cell is

release

The stage of viral replication in which the virus binds a cell surface receptor is

attachment

The stage of viral replication in which viral nucleic acids and proteins are manufactured is

synthesis

The type of viral infection in which a virus enters a host cell, immediately replicates, and causes the host cell to burst is a ________ infection.

lytic

The virus structure indicated by the arrow labeled A is the

genetic material, DNA or RNA

The type of virus indicated by the arrow labeled B is a(n)

bacteriophage

The virus structure indicated by the arrow labeled C is the

the lipid-rich envelope

Viral DNA inserted into a chromosome of the host is a

prophage

Viruses always lack which of the following?

organelles

Viruses are not considered as alive, yet they share with living cells the ability to

evolve

Viruses are smaller than

All of the answer choices are correct

Viruses that infect bacteria are

bacteriophages

What is the genetic material found in HIV?

RNA

What type of cell does HIV infect?

helper T cells

Which of the following diseases is not caused by viruses?

diabetes

Why has it been difficult to generate drugs to treat AIDS?

HIV mutates rapidly among infected humans

________ aid in locomotion of some prokaryotes.

Flagella

A microbiologist Gram stains a bacterium and finds the bacterium to be blue to purple in color. This identifies the

bacterium as gram-positive

A prokaryote that occupies a habitat consisting of a low pH is a(n)

acidophile

A prokaryote that occupies a habitat that is characterized by extreme heat (above 50 degrees Celsius) is a(n)

thermophile

A prokaryote that occupies an extremely salty habitat is a(n)

halophile

A type of horizontal gene transfer in prokaryotes, in which a cell receives DNA from another cell through a sex pilus, is

conjugation

A type of horizontal gene transfer in prokaryotes, in which a cell receives bacterial DNA from a bacteriophage, is

transduction

A type of horizontal gene transfer in prokaryotes, in which a cell takes up naked DNA without cell-to-cell contact, is

transformation

An asexual process used by prokaryotes, in which replicated DNA and other cell parts are distributed into two daughter cells, is called

binary fission

An endospore is an important internal structure for some bacteria in that it

allows the organism to become dormant and survive harsh conditions

An organism to which oxygen is toxic is an obligate anaerobe.

True

Autotrophs must acquire carbon from organic molecules produced from other organisms.

False

Bacteria and archaea use the same four bases in their DNA as eukaryotes. This supports which of the following statements?

All three domains arose from a common ancestor

Because Archaea were first found in environments that lacked oxygen or were very hot, acidic, or salty, they were nicknamed "extremophiles."

True

Chloroplasts and mitochondria have relatively small, circular chromosomes. This observation is evidence which supports the endosymbiotic theory, proposing that chloroplasts and mitochondria arose from which of the following?

bacteria

Circular DNA that is apart from the chromosome DNA in some prokaryotes is called a(n)

plasmid

Clostridium tetani, the bacterium that causes tetanus, can only survive in soil away from oxygen. It is considered which of the following?

an obligate anaerobe

Clostridium tetani, the bacterium that causes tetanus, can survive in soil for up to 40 years. Forming which of the following structures would support its longevity?

an endospore

Cyanobacteria can derive nutritional carbon molecules by consuming those from other organisms, or by producing them from inorganic carbon (atmospheric CO2) through photosynthesis. In which of the following ecological groups would they also be considered?

both heterotrophic and autotrophic

Escherichia coli and Salmonella can live in our intestines in the presence or absence of oxygen. They are considered which of the following?

facultative anaerobes

Escherichia coli and Salmonella can remain in one location in our intestines. They would most likely contain which of the following?

pili

Heterotrophs must acquire carbon from organic molecules produced from other organisms.

True

In prokaryotes, the structure that assembles proteins is the

ribosome

Infections by Helicobacter pylori cause 90% of peptic ulcers in the United States. These bacteria have pili that are only expressed in acidic conditions. A characteristic of this organism should be an ability to

attach to cells in the host organism's stomach

Many prokaryotes play vital roles in global nutrient cycles.

True

Methicillin is a medicine that inhibits cell wall production. Why does this make it a suitable antibiotic for eliminating bacterial infections in humans?

Human cells do not have cell walls

Most bacteria inside and on the human body cause diseases.

False

Mycobacterium tuberculosis is an obligate aerobe. In which organ would you expect to find these bacteria?

lung

Of the following, which is found in eukaryotes but not found among prokaryotes, such as bacteria and archaea?

membrane-bound organelles

One way that antibiotic-resistant strains of bacteria arise is that patients do not follow the instructions for taking the drug. In a typical scenario, a drug may be prescribed for a week, but the patient may stop taking it after 2 to 3 days if they start to feel better. Then when the infection flares up again, they take the rest of their dose. Why would this scenario lead to drug resistance?

The first round of treatment does not kill the most resistant bacteria, which then increase in number.

Pili are bacterial structures used primarily for motility.

False

Prokaryotes lack which of the following?

a nucleus

Streptomyces are aerobic soil bacteria that produce over two-thirds of our antibiotics. Why might a bacterium produce antibiotics?

to kill competing bacteria of different species

Streptomyces are aerobic soil bacteria that produce over two-thirds of our antibiotics of natural origin. These antibiotics should also be effective in killing Streptomyces.

False

Streptomyces are obligate aerobic soil bacteria that infect many plant roots, causing scabs on their leaves. You would expect to find more Streptomyces near the surface of the soil.

True

The Gram stain distinguished bacteria into two types of cells. This stain is dependent on the amount of ________ in the cell wall.

peptidoglycan

The domains that contain prokaryotes are

Archaea and Bacteria

The rigid barrier that surrounds most prokaryotes is the

cell wall

The structures of prokaryotes that are used to transfer DNA from one cell to another are

sex pili

The three most common shapes of prokaryotes are

spherical, rod-shaped, and spiral

Using an electron microscope, you observe bacterial cells from an environmental sample. You view a region of the bacterial cells that contains the chromosome. You identify and label the region as the

nucleoid

Vibrio cholera is the cause of cholera, and has a single flagellum stretching off from one end. A characteristic of this organism should be an ability to

move within its liquid habitat

Which of the following is true of a gram-positive bacterium, and not of a gram-negative bacterium?

Its cell wall is made of a thick layer of peptidoglycan

A dinoflagellate has both a transverse flagellum and longitudinal flagellum.

True

A protective layer made of rigid or elastic protein strips surrounding the cell membrane of euglenoids is a

pellicle.

A substance produced by brown algae that is used as an emulsifying and thickening agent in many foods and other products is

algin.

African sleeping sickness is caused by Trypanosoma brucei, a unicellular flagellated protist that infects red blood cells after being injected into the bloodstream. Trypanosoma brucei is which of the following?

a protozoan

All protists are single-celled.

False

Alternation of generations means having alternating, multicelled haploid and diploid phases in a life cycle.

True

Based on the theory of endosymbiosis, which of the following would you expect to find in a chloroplast?

DNA

Chlamydomonas is multicellular, produces motile haploid sperm, and is photosynthetic. Chlamydomonas is which of the following?

a green alga

DNA sequence evidence suggests that plants, fungi, and animals arose from different lineages of unicellular protists. This suggests which of the following?

Protists arose before the other three kingdoms.

Diatoms are a type of algae, but with a hard silica shell. Which of the following structures would you expect to find directly underneath the silica shell?

a plasma membrane

Dictyostelium discoideum is an unusual organism, one that straddles the boundary between the unicellular and the multicellular. Its feeding phase consists of individual amoeba-like cells that move independently, feeding on bacteria by phagocytosis. When the food runs out, cells begin to aggregate into a multicelled structure that migrates toward light. The cells differentiate into a base, stalk, and spores; only the spores survive to colonize a new habitat. What is the advantage of forming spores?

Spores are smaller and can be transported to new habitats.

Entamoeba histolytica can cause amoebic dysentery. It moves using pseudopodia, can only feed by phagocytosis, and is unicellular. Entamoeba histolytica is classified as

a protozoan

Euglena and dinoflagellates have chloroplasts and flagella. This indicates they are

photosynthetic and mobile

Euglena have chloroplasts and can perform phagocytosis. Euglena would be considered which of the following?

autotrophs and heterotrophs

Foraminiferan shells are made of

calcium carbonate

From which source, is it thought, that chloroplasts in algae originated?

cyanobacteria

From which source, is it thought, that mitochondria in algae originated?

aerobic bacteria

Golden algae, diatoms, and brown algae contain yellowish pigments.

True

In malaria, Plasmodium falciparum grow inside human cells. Because they use the human cells for food, they are which of the following?

heterotrophs