Biology Exam 2 Flashcards

Chapter 29 + Chapter 33 + Chapter 34 + Chapter 35

Chemicals, secreted by soil fungi, which inhibit the growth of bacteria are known as

antibiotics

Which of the following is an important role for fungi in the carbon cycle?

Fungi release fixed carbon back to the environment for other plants and photosynthetic organisms to utilize

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

Fungi that absorb nutrients from decaying plant matter are called

saprobes

All fungi are

heterotrophic

Which of the following is major characteristic of fungi that distinguishes them from other eukaryotes?

Nutrient acquisition via external digestion

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 protein function

Long, branching fungal filaments are called

hyphae

The vegetative (nutritionally active) bodies of most fungi are:

I. composed of hyphae
II. referred to as a mycelium
III. usually underground

I, II, and III

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 fungal hyphae are connected by pores that allow passage of cytoplasm from cell to cell.

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

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

Fungi with hyphae

are adapted for rapid directional growth to new food sources

Which of the following characteristics is unique to chytrids compared to other groups of fungi?

Flagellated spores

Apart from direct amphibian-to-amphibian contact, what is the most likely means by which the zoospores spread from one free-living amphibian to another?

By flagella

The adaptive advantage associated with the filamentous nature of fungal mycelia is primarily
related to

an extensive surface area well suited for absorptive nutrition

It has been hypothesized that fungi and plants have a mutualistic relationship because fungi
provide critical nitrogen for the plants' use. How do we know this happens? In experiments using
radioactively labeled

nitrogen, plants acquired more radioactive nitrogen when they were associated with fungi

Why are mycorrhizal fungi superior to plants at acquiring mineral nutrition from the soil?

Fungi secrete extracellular enzymes that can break down large molecules.

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.

Why is it important that ectomycorrhizal fungi (EMF) have peptidase enzymes?

These enzymes are needed to release nitrogen from dead plant material.

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?

Arbuscular mycorrhizal fungi

Some fungal species can kill herbivores while feeding off of sugars from its plant host. What type of relationship does this fungus have with its host?

Mutualistic

Which of the following terms refers to symbiotic relationships involving fungi living between the cells in plant leaves?

Endophytes

In both lichens and mycorrhizae, what does the fungal partner provide to its photosynthetic partner?

Water and minerals

Microsporidians are considered parasitic because of the ability to penetrate their host cells using

a polar tube

Many amphibian populations have been decimated by a parasitic fungus classified as a member of the

Chytridiomycota

Lichens are symbiotic associations of fungi and

cyanobacteria or algae

Which of the following best describes the physical relationship of the partners involved in lichens?

Photosynthetic cells are surrounded by fungal hyphae.

________ form ectomycorrhizal relationships with temperate forest trees while ________
form arbuscular (endomycorrhizal) relationships with plants in grasslands and tropical forests.

Basidiomycetes; glomeromycetes

Some fungi have been instrumental in the development of human culture, including __________ in the phylum ________ as they have been in use for hundreds of years in producing beer and bread.

yeasts; Ascomycota

Which of the following characteristics, structures, or processes is common to bacteria and viruses?

Genetic material composed of nucleic acids

Which of the following supports the argument that viruses are nonliving?

They are not cellular.

Viruses ________.

use the host cell to copy themselves and make viral proteins

When people die from HIV infections, it is usually because they ________.

have too few T cells to adequately fight infection

What is the difference between an epidemic and a pandemic?

An epidemic is restricted to a local region; a pandemic is global.

Which of the following statements does NOT explain the reason populations have been so adversely affected by pandemics such as the influenza pandemic of 1918 or the current AIDs pandemic?

Both viruses are very virulent and kill their hosts very rapidly.

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.

Which of the following is characteristic of the lytic cycle?

A large number of phages are released at a time.

Which of the following can be effective in preventing the onset of viral infection in humans?

Getting vaccinated

Effective antiviral drugs are usually associated with which of the following properties?

Interference with viral replication

Which of the three types of viruses shown in the accompanying figure has a capsid?

I, II, and III

In the accompanying figure, at the arrow marked II, what enzyme(s) is (are) being utilized?

Host cell DNA polymerase

In the figure, when new viruses are being assembled at the point marked IV, what mediates the assembly?

The viral components interact spontaneously and self-assemble.

You just discovered a new virus. This virus infects the 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 the receptor this virus uses and develop a drug that blocks the receptor

What is the main structural difference between enveloped and nonenveloped viruses?

Enveloped viruses have a phospholipid membrane outside their capsid, whereas nonenveloped viruses do not have a phospholipid membrane

The virus genome and viral proteins are assembled into virions (virus particles) during ________.

the lytic cycle only

What would the result be if a drug that blocks the action of RNA polymerase was introduced into a virus-infected organism?

The viral proteins would not be made, and the virus would not be able to reproduce.

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 viral genome has genes coding for enzymes needed for its own reproduction.

The first class of drugs developed to treat AIDS, such as AZT, were known as reverse transcriptase inhibitors. They worked because they

bonded to the viral reverse transcriptase enzyme, thus preventing the virus from making a DNA copy of its RNA genome

A population of viruses with similar characteristics is called a

strain

Which of the following human diseases is caused by a virus that requires reverse transcriptase to transcribe its genome inside the host cell?

AIDS

A fully formed virus that can cause an infection in a host cell is called a virion.

true

Spikes are glycoproteins that can be found projecting from the viral capsid

true

Viruses exhibit all the following except

metabolism

Helical and icosahedral are terms used to describe the shape of a viral

capsid

A/an _______ is the protein shell around the nucleic acid core of a virus

capsid

One of the principal viral capsid shapes is a 20-sided figure with 12 evenly spaced corners
referred to as a/an _______ capsid.

icosahedral

A naked virus only has an

nucleocapsid

Which of the following is not a typical capsid shape?

Complex

All of the following pertain to virus envelopes except

located between the capsid and nucleic acid

Viral spikes

are always present on enveloped viruses

The core of every virus particle always contains

either DNA or RNA

Which of the following is not associated with every virus?

Envelope

Viral nucleic acid types include which of the following?

1. Double-stranded DNA

2. Single-stranded DNA

3. Double-stranded RNA

4. Single-stranded RNA

Compared to most animals, the growth of most plant structure is best described as

indeterminate

Loss of water from the aerial parts of plants is called

transpiration

The surface area of a plant's root system is substantially larger than the surface area of its
shoot system. The extensive surface area of roots is an adaptation associated with

contact with soil particles for mineral and water absorption

When comparing root systems of corn plants growing on a square foot in a fertilized and
irrigated cornfield with the root systems of natural prairie plants growing in a meadow, what
result do you expect to see?

The mass and length of roots on a meadow will be higher because soil is poorer, and there is a
higher diversity of plants.

While walking a cornfield, you notice roots emerging from the corn stalks themselves, and you suspect that these roots are helping to hold the plants upright. These roots belong to a category of roots known as

adventitious roots

How would you expect the root system of a plant grown by hydroponics to compare to the root system of a plant grown in poor soil? The root system of a plant grown by hydroponics would be

less developed

Which type of modified stems grow horizontally belowground and produce new plants at nodes?

Rhizomes

A potato is a type of ________ known as a ________.

modified stem; tuber

Strolling in the Sonoran Desert, you come upon a stately Saguaro cactus. The large central
"trunks" of this cactus are covered with numerous smaller spines. The central stalks are modified
________ used for water storage and spines are modified ________ used for protection.

stems; leaves

Pines have needlelike leaves, with the adaptive advantage of

decreased surface area, reducing water loss

What is a disadvantage of having small, needlelike leaves?

Decreased efficiency of light capture

Plants that have leaves arranged in a rosette

have greatly shortened internodes

Axillary buds

have dormant meristematic cells

Some botanists argue that the entire plant should be considered as a single unit rather than a
composite of many individual cells. Which of the following cellular structures best supports this
view?

Plasmodesmata

One important difference between the anatomy of roots and the anatomy of leaves is that
________.

a waxy cuticle covers leaves but is absent from roots

Trichomes

repel or trap insects

Carbon dioxide enters the inner spaces of the leaf through the

stoma

You find a plant unfamiliar to you and observe that it has vascular bundles scattered throughout the stem cross-section. What do you conclude about the plant?

It is probably a monocot.

A student examining leaf cross sections under a microscope finds many loosely packed cells
with relatively thin cell walls. The cells have numerous chloroplasts. What type of cells are they?

Parenchyma

Which part of a plant absorbs most of the water and minerals taken up from the soil?

Root hairs

Which of the following is derived from the ground tissue system?

Pith

Which of the following have unevenly thickened primary walls that support young, growing parts of the plant?

Collenchyma cells

Choose the option that best describes the relationship between the cell wall thickness of parenchyma cells and sclerenchyma cells.

The cell walls of parenchyma cells are thinner than those of sclerenchyma cells

The veins of leaves are

I. composed of xylem and phloem
II. continuous with vascular bundles in the stem and roots
III. finely branched to be in close contact with photosynthesizing cells

I, II, and III

Which structure is correctly paired with its tissue system?

Tracheid, vascular tissue

Which of the following cells primarily transport sugars over long distances?

Tracheids and vessel elements

Which of the following is correctly paired with its structure and function?

Sclerenchyma, supporting cells with thick secondary walls

The following questions are based on the drawings of root or stem cross sections shown in the accompanying figure.

A monocot stem is represented by

A round circle with shaded circles within it covered in tiny dots all throughout and smaller circles.

Plants contain meristems whose major function is to

produce more cells

When you eat Brussels sprouts, you are eating

large axillary buds

Which of the following arise, directly or indirectly, from meristematic activity?

Secondary xylem, leaves, dermal tissue, and tubers

Which of the following cell types retains the ability to undergo cell division?

A parenchyma cell near the root tip

Which of the following is the correct sequence from the growing tip of a primary root back toward its base?

Root cap, Apical meristem, Zone of cellular division, Zone of cellular elongation, and Zone of
cellular maturation

Shoot elongation in a growing bud is due primarily to ________

cell elongation localized in each internode

________ is to xylem as ________ is to phloem.

Vessel element; sieve-tube member

A plant has the following characteristics: a taproot system, several growth rings evident in a
cross section of the stem, and a layer of bark around the outside. Which of the following best describes the plant?

Woody eudicot