CHAP 4

In the mitochondria, the energy from "food" molecules (such as glucose) that are partially broken down in the cytosol are converted to

. ATP.

Which organelle is not enclosed by at least two membranes?

. Lysosome

What is the major distinction between a prokaryotic and a eukaryotic cell?

A prokaryotic cell does not have a nucleus, whereas a eukaryotic cell does.

Which of the following are not specialized cell junctions?

Cytoplasmic plaques

Chromatin is a series of entangled threads composed of

DNA and protein.

Which statement about animal cell junctions is false?

Gap junctions block communication between adjacent cells.

Which of the following organelles is found only in plant cells?

Glyoxysome

. Convert stored lipids to carbohydrates in plants

Glyoxysomes

Which of the following are two components of chloroplasts?

Grana and thylakoids

Which of the following is not a function of vacuoles?

Helping to anchor the cell in place

Which of the following structures is/are involved with maintaining the position of the organelles within a cell?

Intermediate filaments

Which statement about the plant cell wall is false?

It completely isolates adjacent cells from one another.

Generated by the Golgi; contain digestive enzymes to hydrolyze macromolecules

Lysosomes

Which statement about mitochondria is false?

Mitochondria are green because they contain chlorophyll.

Contain special enzymes to safely break down toxic by-products of oxidation

Peroxisomes

Generated by the plasma membrane; contain macromolecules

Phagosomes

. Which of the following is not a component of the endomembrane system?

Plastids

Ribosomes are made up of

RNA and proteins.

Translate mRNA into polypeptides

Ribosomes

Which of the following is/are found in prokaryotic cells?

Ribosomes

If all the lysosomes within a cell suddenly ruptured, what would be the most likely result?

The macromolecules in the cytosol would break down.

How does the surface area-to-volume ratio of a 1-mm cube compare to the surface area-to-volume ratio of a 3-mm cube?

The ratio decreases as the cube becomes larger.

Which of the following statements about lysosomes is true?

They are the sites where autophagy occurs.

What is the difference between "free" ribosomes and "attached" ribosomes?

a. Free ribosomes are in the cytoplasm, whereas attached ribosomes are anchored to the endoplasmic reticulum. b. Free ribosomes produce proteins in the cytosol, whereas attached ribosomes produce proteins that are inserted into the ER.

Which of the following statements about the nuclear envelope is true?

a. It contains pores for the passage of large molecules. b. It is composed of two membranes

Which of the following is a function of a plant cell vacuole?

a. Storage of toxic by-products and wastes b. Support for the cell c. Containment of animal-attracting pigments that aid in pollination d. Hydrolysis of seed proteins into plant embryo food

Desmosomes include or associate with

a. dense, plaque-like regions. b. keratin fibers. c. cell adhesion molecules.

In order to survive, cells must

a. obtain and process energy. b. convert genetic information into proteins. c. replicate.

The plasma membrane of a cell

a. separates the cell from its environment. b. regulates what goes into and out of the cell. c. helps maintain a constant internal environment. d. communicates with adjacent cells.

The type of cell that always lacks a cell wall is the _______ cell.

animal

Microfilaments

are composed of actin

Members of the domains Bacteria and Archaea

are prokaryotes.

Cilia

are shorter and more numerous than flagella.

Many proteins within the endomembrane system are transported to the correct location by means of

carbohydrate groups found on the packaged glycoproteins.

In some prokaryotic organisms, the plasma membrane folds to form an internal membrane system that is able to

carry on photosynthesis

A specialized structure found in most prokaryotes is the

cell wall

The semirigid structure that supports the plant cell and determines its shape is the

cell wall.

A vesicle containing proteins from the ER fuses with the _______ region of the Golgi complex.

cis

The folds of the inner mitochondrial membrane

create a large membrane surface for reactions within the mitochondrion.

The overall shape of a cell is determined by its

cytoskeleton.

Structures that contain networks of keratin fibers and provide mechanical stability to animal tissues are called

desmosomes

Lysosomes are important to eukaryotic cells because they contain

digestive enzymes

Ribosomes are not visible under a light microscope, but they can be seen with an electron microscope because

electron microscopes have more resolving power than light microscopes have.

Prokaryotic cells generally are smaller than eukaryotic cells because

eukaryotes have compartmentalization, which allows for specialization

The surface area-to-volume ratio of a cell

explains why cells are small

. An organelle with an internal cross section showing a characteristic "9 + 2" microtubule morphology is the

flagellum.

Some bacteria are able to propel themselves through liquid by means of a structure called the

flagellum.

The electric signal for a contraction passes rapidly from one heart muscle cell to the next by way of

gap junctions.

Ribosomes are the structures in which

genetic information is used to make proteins.

Cells that synthesize a large amount of protein, such as _______ cells, are packed with rough endoplasmic reticulum.

glandular

An organelle consisting of a series of flattened sacks stacked somewhat like saucers is the

golgi apparatus

The rough ER is the portion of the ER that

has ribosomes attached to it.

The extracellular matrix of animal cells

helps orient cell movements during embryonic development.

The role of organelles is to

increase the efficiency of cellular activities

A group of transmembrane proteins involved in maintaining cell structure via their interactions with the cytoskeletion and extracellular matrix are known as

integrins.

A secondary lysosome is a lysosome that

is a primary lysosome that has fused with a phagosome.

The cytosol

is composed largely of water.

. The DNA of mitochondria

is used to make proteins needed for mitochondrial function.

Hair and a major class of intermediate filament proteins are composed of

keratin protein family members

Most plant and animal cells are

large enough to be seen with a light microscope.

The surface area-to-volume ratio of an object can be decreased by

making it spherical

. Uniform concentrations of cytoplasmic materials are maintained between plant cells by

membrane-lined channels called plasmodesmata.

The cytoskeleton consists of

microtubules, intermediate filaments, and microfilaments.

The DNA of prokaryotic cells is found in the

nucleoid region

Of the following structures of an animal cell, the one with the largest volume is the

nucleus

A large organelle found in eukaryotic cells that genetically controls the cell's activities is the

nucleus.

The membranes of the endoplasmic reticulum are continuous with the membranes of the

nucleus.

A prokaryotic cell does not have a _______ or _______.

nucleus; membrane-bound organelles

One difference between plant cells and animal cells is that

only animal cells contain centrioles.

Chloroplasts are a kind of

plastid.

Which type of organelle is found in plants but not in animals?

plastids

The function of the nuclear pores is to

regulate movement of materials across the nuclear membrane.

All cellular membranes

regulate which materials can cross the membrane

The membrane surrounding each organelle

regulates movement into and out of the organelle.

. Which of the following is not a membrane-enclosed organelle?

ribosomes

Proteins that are transported in vesicles are made by

ribosomes on the rough endoplasmic reticulum

Cells that perform little protein synthesis but are involved with the modification of molecules that enter the body through the digestive system typically have large amounts of

smooth er

The DNA of a chloroplast is located in the

stroma.

Chloroplasts are the structures in which

sunlight energy is converted into chemical energy

Ribosomes are not found in

the Golgi apparatus.

Steroids such as cholesterol are synthesized by

the smooth ER.

The difference between tight junctions, desmosomes, and gap junctions is that

tight junctions and desmosomes have mechanical roles, whereas gap junctions facilitate communication between cells.

. Of the following plant cell structures, which is most likely to have the greatest volume?

vacuole

You would not expect to find RNA in which of the following structures?

vacuole

Microtubules are composed of monomers of

α- and β-tubulin