Exam 2

What are the three general regions of a cell?

membrane, the cytoplasm, and the nucleus.

What types of macromolecules compose the plasma membrane?

The plasma membrane is composed of lipids (phospholipids), sugars (glycolipids and glycoproteins), and proteins.

By what process does water enter and leave the cell?

Water enters and leaves the cell via osmosis.

Which transport process carries large macromolecules out of the cell?

Exocytosis carries large macromolecules out of the cell.

Which cellular organelles are involved with protein synthesis and packaging?

Ribosomes and rough ER produce proteins; the Golgi apparatus packages proteins.

Which organelle produces the energy needed for cellular activity?

11. The mitochondrion produces energy for cellular activity

Which organelle would be prevalent in a cell that specialized in phagocytosis?

A cell that specialized in phagocytosis would contain numerous lysosomes.

Which cytoskeletal element functions to resist tension and thus helps to keep the cell intact?

The intermediate filament resists tension.

What does the nucleolus produce?

The nucleolus produces ribosomal RNA and assembles the ribosomal subunits.

Which cytoplasmic organelle is continuous with the nuclear envelope?

Rough endoplasmic reticulum is continuous with the nuclear envelope.

How does the appearance of extended chromatin differ from that of condensed chromatin? What is the difference in function between these forms of chromatin?

Extended chromatin is thin Transverse colon Sigmoid colon Descending Ascending colon Rectum strings of chromatin that appear as beads (histones) on a string (DNA) in TEM. Extended chromatin is found in active regions of DNA where transcription is occurring. Condensed chromatin is thick, tightly coiled chromatin that is found in inactive regions of DNA.

In which phase of the cell life cycle does the cell spend most of its life?

Interphase

decipher the meaning of the terms anaphase, metaphase, and telophase? What is happening during each of these phases of mitosis?

poles of the cell during anaphase. Meta = between, transition; during metaphase, the chromosomes align in the midline of the cell. Telo = the end; in telophase, the nuclei of daughter cells reassemble, cytokinesis continues, cell division ends.

Which cellular structures would be abundant in cells that specialize in producing movement, such as muscle cells?

Muscle cells have abundant actin and myosin microfilaments.

Which organelles would be abundant in cells that produce and secrete hormones?

Cells that produce and secrete hormones contain abundant rough ER, mitochondria, and secretory granules.

According to which aging theory presented here can the aging process be altered by individual behavior?

According to the mitochondrial theory of aging, reducing caloric intake can increase life span.

All unit membranes

consist of a phospholipid bilayer and peripheral and integral proteins

In electronmicroscopy, unit membrane is described as trilaminar because it consists of 

a lighter layer bounded by two darker
layers

The cell membrane

(a) is also called the plasmalemma or plasma membrane (b) is a single unit membrane (c) encloses the cytosol (d) all of these 

The transport of a substance across the cell membrane is affected by the substance’s

(a) size (b) shape (c) electrical charge (d) lipid solubility (e) all of these

Some ? in the cell membrane form channels that allow substances of the right shape, size, or electrical charge to pass through.

integral proteins

Some _?_ in the cell membrane act as carrier molecules that can lock onto a particular substance and then change shape to move the substance from one side of the cell membrane to the other

integral proteins

The general term for the "bulk transport" of materials into the cell is _?_. 

endocytosis

"Bulk transport" moves materials that cannot cross the cell membrane because of their size, shape, electrical charge, or insolubility in lipids. Which of the following processes or structures is not involved in bulk transport ?

Diffusion

In receptor mediated endocytosis, coated vesicles add cell membrane receptor proteins to the endosome membrane. Pieces of the
endosome membrane containing these proteins bud off. Which of the following happens to them ?

They are returned to the plasmalemma.

Select the incorrect statement about pinocytosis and phagocytosis.

Both are forms of exocytosis

It is true that ?.]

(a) in general, the process of exocytosis is the reverse of endocytosis

The glycocalyx _?

(a) covers the outer surface of the cell membrane (b) consists of glycoproteins: carbohydrates attached to protein molecules
(c) consists of glycolipids: carbohydrates attached to lipid molecules : answer is D all the above

A network of microfilaments lines the inner surface of the cell membrane. The network both supports the membrane and changes its contours as
necessary. The microfilaments are composed of the contractile protein ?. (

Actin

A microvillus ?(a) is a projection of the cell membrane and cytoplasm (b) contains actin microfilaments (c) increases the cell surface area (d) all of these (e)

D- All of these

A cilium _? (a) is a projection of the cell membrane and cytoplasm (b) contains an array of 9 peripheral doublet microtubules and two central microtubules (c) is produced by a centriole (d) all of these 

d) all of these 

Cilia ? (a) are larger than microvilli (b) have effective and recovery strokes (c) move materials or propel cells (d) all of these

(d) all of these

Which cell-to-cell junction resembles a “spot weld” and involves a thickening of the cell membrane, intermediate filaments, and proteins called
cadherins ?

b) desmosome

Which cell-to-cell junction is formed by an array of plasmalemmal proteins called a connexon and forms a channel allowing the flow of materials
between the connected cells ?

Gap Junction

Which cell-to-cell junction resembles a beaded belt of proteins encircling the cell and connecting it to surrounding cells ?

tight Junction

A "working" ribosome _? (a) contains one small subunit + one large subunit (b) “reads” a molecule of mRNA (c) assembles amino acids into a
polypeptide or protein (d) all of these

D, all of these

It is not true that ribosomes ?

always synthesize the same polypeptide or protein

Polysomes (polyribosomes) ? (a) are groups of ribosomes reading the same mRNA molecule (b) may be attached to endoplasmic reticulum or
“free” in the cytoplasm (c) are efficient methods of making multiple copies of a protein. (d) all of these

(d) all of these

Smooth endoplasmic reticulum (s.e.r.) ?

is a cytoplasmic system of interconnected unit membrane tubules

The functions of the smooth endoplasmic reticulum vary with the type of cell. In various cells, it is known to ? a) produce steroid hormones (b)
process lipids (c) detoxify poisons (d) store and release calcium ions (e) all of these

(e) all of these

Rough or granular endoplasmic reticulum _?

is a system of unit membranes enclosing spaces called cisternae

Rough or granular endoplasmic reticulum produces all of the following except ?

autophagic vacuoles

Rough or granular endoplasmic reticulum _?_. (a) has connections with the nuclear envelope (b) has connections with smooth endoplasmic
reticulum (c) may increase or decrease in size (d) all of these

(d) all of these

The Golgi apparatus _? (a) is located in the nuclear compartment (b) is a system of unit membrane saccules or cisternae (c) has a concave cis
face and a convex trans face (d) all of these (e) none of these

(e) none of these

The Golgi apparatus processes ?. (a) hydrolases released as primary lysosomes (b) secretory proteins released as secretory vacuoles (c) cell
membrane proteins (d) all of these

D- all of these

Select the incorrect statement about lysosomes. (a) Lysosomes are unit membrane organelles containing acid hydrolases. (b) The acid hydrolases
are manufactured by g.e.r. ribosomes (c) The acid hydrolases are processed by the Golgi and released as unit membrane packages called primary
lysosomes. (d) Lysosomes are involved in autophagy and heterophagy. (e) Lysosomes are restricted to the nuclear compartment

(e) Lysosomes are restricted to the nuclear compartment

The hydrolytic enzymes in lysosomes _? (a) are proteins that break chemical bonds by adding the equivalent of a water molecule (b) can
digest carbohydrates, lipids, proteins, and nucleic acids (c) are called acid hydrolases because they are activated only in an acidic environment (d)
all of these

(d) all of these

Secretory vacuoles (droplets) (a) are unit membrane packages of proteins (b) contain proteins produced by the g.e.r. and modified and
packaged by the Golgi (c) release their contents by merging with the plasmalemma (d) all of these

(d) all of these

Select the incorrect statement. Peroxisomes ?. (a) are special types of lysosomes (b) contain oxidases that convert free radicals into hydrogen
peroxide (c) contain catalases that convert hydrogen peroxide to water and oxygen (d) are involved in lipid metabolism (e) are located in the
cytoplasmic compartment.

(a) are special types of lysosomes

The centrosome ?. (a) is the microtubule organizing center of the cell (b) contains a pair of centrioles (c) is located in the cytoplasm, usually
near the nucleus (d) all of these

(d) all of these

Select the incorrect statement. Centrioles ?. (a) are composed of nine sets of triplet microtubules and associated proteins (b) produce cilia and
flagella (c) produce the spindle apparatus of cell division (d) have the same microtubular structure as cilia (e) are located only in the cytoplasmic
compartmen

(e) are located only in the cytoplasmic
compartmen

In general, the cytoskeleton ?. (a) consists of proteins (b) is responsible for both maintaining and changing cell shape (c) forms a scaffolding for
the internal organization of the cell's organelles (d) all of these

(d) all of these

The cytoskeleton includes proteins organized to form ?. (a) microtubules (b) microfilaments (c) a variety of intermediate filaments (d) all
of these

(d) all of these

Select the incorrect statement about microtubules.

(c) The two ends of a microtubule are identical

Select the incorrect statement about microfilaments. (a) Microfilaments are larger than intermediate filaments. (b) Microfilaments are composed
of two twisted chains of the protein F-actin. (c) F-actin molecules are chains of G-actin molecules. (d) In non-muscle cells, actin interacts with
myosin to maintain or change cell shape, change plasmalemma contours, or move organelles

(a) Microfilaments are larger than intermediate filaments.

Mitochondria ?. (a) are composed of three unit membranes (b) enclose a chemical solution called the matrix (c) are located in both the
nucleus and the cytoplasm (d) all of these (e) none of these

(b) enclose a chemical solution called the matrix

Mitochondria ?. (a) are all the same size and shape (b) always have the same number of cristae (c) reproduce by dividing in half (d) probably
evolved from viruses that infected early cells (e) all of these

(c) reproduce by dividing in half

The mitochondrial matrix contains ?. (a) clusters of calcium ions or lipids called matrix granules (b) enzymes of the citric acid (Krebs) cycle (c)
circular mDNA molecules (d) mitochondrial ribosomes, which produce some mitochondrial proteins (e) all of these

(e) all of these

The inner mitochondrial membrane ?. (a) is thrown into cristae that increase its surface area (b) contains electron transport chain enzymes
(c) contains oxidative phosphorylases, enzymes that add a third phosphate to ADP (d) all of these

d) all of these

Mitochondrial enzymes "steal" the energy required for the production of ATP by breaking down small molecules derived from ?. (a) lipids (b)
proteins (c) carbohydrates (d) all of these (e) none of these

(d) all of these

After ATP is produced by a mitochondrion, it diffuses into the cytoplasm. In the cytoplasm, ?. (a) ATP is broken down to ADP and a phosphate
group and energy is released. (b) some of the energy is trapped and used to drive the metabolic reactions of the cell (c) some of the energy is lostt
as heat (d) all of these (e) none of these

(d) all of these

The ADP and phosphate groups produced by the cleavage of ATP in the cytoplasm, ?. (a) are destroyed by lysosomes (b) are collected by the
endoplasmic reticulum (c) diffuse back into mitochondria (d) are excreted from the cell (d) all of these (e) none of these

c) diffuse back into mitochondria

Select the incorrect statement about glycogen and lipids. (a) Glycogen is a storage form of glucose. (b) Glycogen is stored in glycosomes. (c)
Both glycosomes and lipid droplets are wrapped in unit membrane. (d) Glycogen and lipids are major energy sources

(c) Both glycosomes and lipid droplets are wrapped in unit membrane.

Select the incorrect statement. The nuclear envelope ?. (a) is manufactured by the nucleolus. (b) isolates the genetic material from the
cytoplasmic machinery of the cell (c) controls the flow of materials between the cytoplasmic and nuclear compartments (d) consists of two unit
membranes separated by a space called the perinuclear cisterna. (e) has connections with rough endoplasmic reticulum

(a) is manufactured by the nucleolus.

Nuclear pores ?. (a) are channels for materials entering or leaving the nucleus (b) are circular arrays of unit membrane proteins (c) span the
perinuclear cisterna (d) all of these

(d) all of these

Select the incorrect statement. Chromatin ?. (a) contains the genetic instructions of the cell (b) contains DNA molecules and histones (c) is
located in the nucleus and in mitochondria (d) in regions where genes are being "read," stains lightly and is called extended chromatin or
euchromatin (e) in regions where genes are not being "read," stains darkly and is called condensed chromatin or heterochromatin

(c) is located in the nucleus and in mitochondria

Nucleic acids, DNA and RNA, are polymers of ?

b) nucleotides

A nucleotide consists of ?. (a) a ribose or deoxyribose sugar molecule (b) a phosphate group (c) a base: adenine, thymine, cytosine, guanine
or uracil (d) all of these

d) all of these

Which two molecules are found in RNA, but not in DNA ? (a) ribose, uracil (b) deoxyribose, uracil (c) ribose, thymine (e) deoxyribose, thymine (e)
none of these

a) ribose, uracil

In DNA the two strands of nucleotides ?. (a) run in opposite directions (b) are held together by hydrogen bonds between the bases (c) are
twisted into a helix (d) all of these (e) none of these

d) all of these

A section of DNA wrapped around a group of eight histone molecules is called a ?. (a) beta helix (b) nucleosome (c) nucleotide (d) nucleolus (e)
nuclear cisterna

(b) nucleosome

A gene is a sequence of DNA that contains instructions for ? (a) protein synthesis (b) RNA synthesis (c) regulating the activity of other
genes (d) all of these (e) none of these

(d) all of these

Select the correct statement about protein synthesis. (a) Protein coding genes are sequences of bases in DNA molecules. (b) The copying of
genetic information from DNA to mRNA is called translation. (c) The instructions for assembling proteins are carried from DNA to ribosomes by
transfer RNA molecules. (d) Amino acids are transported to ribosomes by molecules of messenger RNA. (e) The assembly of proteins by a
ribosome - mRNA - tRNA complex is called transcription

(a) Protein coding genes are sequences of bases in DNA molecules.

Select the incorrect statement. The nucleolus ?. (a) is located in the centrosome (b) contains sections of DNA molecules coding for ribosomal
RNA. (c) contains RNA polymerases synthesizing rRNA molecules. (d) assembles ribosomal subunits (e) varies in size depending upon how much
protein the cell is producing

(a) is located in the centrosome

The following are steps in the process of reading a protein or RNA coding gene. Use the letters a – e to arrange them in the order of their
occurrence. ___The double helix in that section untwists. ___The nucleosomes in that section of a DNA molecule uncoil. ___ An RNA polymerase
attaches to the “start” signal of the gene. ___The hydrogen bonds between the bases in that section are broken. ___ An mRNA, tRNA, or rRNA
molecule is assembled.

2__The double helix in that section untwists. 3__The nucleosomes in that section of a DNA molecule uncoil.
1__ An RNA polymerase attaches to the "start" signal of the gene.
4__The hydrogen bonds between the bases in that section are broken.
5__ An mRNA, tRNA, or rRNA molecule is assembled.

The following are steps in the formation of a secretory protein. Use the letters a - e to arrange them in the order of their occurrence.
A__ Ribosome attaches to the g.e.r.
B__ Protein is transferred to the Golgi apparatus by a transfer vesicle.
C__ Protein is released into the g.e.r. cisterna.
D__ Ribosomal subunits combine with mRNA. E__Protein moves through the g.e.r. cisterna to the region of the Golgi apparatus

A
D
C
E
B

he following are steps in the formation of a secretory protein.
A__Secretory droplet is released from the cell by exocytosis.
B__The protein is released from the trans face of the Golgi apparatus wrapped in unit membrane. C__ The protein moves through the Golgi saccules
and is processed.
D__The protein enters the cis face of the Golgi
apparatus.

D, C, B, A

The following are steps in lysosomal action. Use the letters a - e to arrange them in the order of their occurrence.
A__Primary lysosome fuses with phagosome, pinocytotic vesicle, endosome, or autophagic
vacuole to form a secondary lysosome.
B__Primary lysosome is released from Golgi apparatus.
C__Lysosomal hydrolases are activated.
D__ Membrane proteins pump hydrogen ions into the secondary lysosome.
E__Digestion of lysosomal contents and formation of residual body.

B
A
D
C
E

The following are steps in the process of heterophagy. 
A__ Formation of a secondary lysosome. 
B__Formation of a phagosome or pinocytotic vesicle. 
C__Formation of a residual body. 
D__ Pinocytosis or phagocytosis. 
E__Hydrolytic digestion and resorption of useful
materials.

D
B
A
E
C

The following are steps in the process of autophagy.
A__ Formation of a residual body.
B__ Material is tagged with ubiquitin
C__Material is wrapped in unit membrane from the g.e.r. to form an autophagic vacuole.
D__ Hydrolytic digestion and resorption of useful materials.
E__ Formation of a secondary lysosome.

B, C, E, D, A

Epithelia ?. (a) are sheets of cells covering or lining body
surfaces (b) are supported by a basement membrane (c)
have free and basal surfaces (d) are normally avascular (e) all
of these

(e) all of these

The basement membrane ?. (a) provides mechanical
support and adhesion to surrounding materials (b) controls
the flow of some materials to and from the epithelial cells (c)
consists of a basal lamina produced by the epithelial cells
and a reticular lamina produced by connective tissue cells (d)
all of these (e) none of these

(d) all of these

Which type of cell-to-cell junction is responsible for the
polarization of epithelial cells ? (a) gap junction (b) tight
junction (c) desmosomes (d) all of these (e) none of these

 (b) tight junction 

The structural classification of epithelia does not describe
_?_. (a) cell shapes (b) cell free surface specializations (c)
numbers of cell layers (d) specific functional types of cells (e)
none of these

d) specific functional types of cells

If an epithelium is simple, then ?. (a) all of its cells contact
the basal lamina (b) its cells may be either squamous,
cuboidal, or columnar in shape (c) some of its cells may bear
cilia or microvilli (d) all of these (e) none of these

(d) all of these

Select the incorrect statement. If an eithelium is stratified,
then ?. (a) it contains two or more layers of cells (b) all of
its cells are the same shape (c) only the basal layer of cells
contacts the basal lamina (d) it may have one or more layers
of intermediate cells (e) only the shape of the surface layer of
cells is used for classification

(b) all of its cells are the same shape

If an epithelium lines a tube, then which is closest to the tube
lumen ? (a) its basal surface (b) its free surface (c)
basement membrane: basal lamina (d) basement
membrane: reticular lamina (e) none of these

(b) its free surface

Which epithelial cell shape most resembles a fried egg in
both surface and side views ? (a) columnar (b) squamous (c)
cuboidal (d) polygonal (e) polyhedral

(b) squamous

Cuboidal epithelial cells ?. (a) are taller than they are wide
(b) usually have a spherical nucleus (c) are found only in
simple epithelia (d) all of these (e) none of these

b) usually have a spherical nucleus

Columnar epithelial cells generally ?. (a) have an elongated
nucleus located toward the base of the cell (c) are
approximately equal in all dimensions (c) are found only in
pseudostratified epithelia (d) all of these (e) none of these

(a) have an elongated

Some epithelial cells of the inner ear and the epididymis bear
large, branching microvilli called ?. (a) stereocilia (b)
kinocilia (c) flagella (d) brush borders (e) striated borders

(a) stereocilia

In stratified squamous keratinized epithelia, the surface cells
_?_. (a) have no nucleus or organelles. (b) are packed with
intermediate filaments of keratin. (c) are dead. (d) all of these
(e) none of these

(d) all of these

Transitional epithelium ?. (a) is a stratified cuboidal
epithelium (b) lines parts of the urinary system subject to
stretching (c) looks like stratified squamous when stretched
(d) is also called uroepithelium (e) all of these

(e) all of these

The simple squamous epithelium that lines blood vessels is
called ?. (a) mesothelium (b) transitional epithelium (c)
endothelium (d) peritoneum (e) endoderm

(c) endothelium

The simple squamous epithelium that lines body cavities and
covers the organs projecting into them is called_?_. (a)
mesothelium (b) transitional epithelium (c) endothelium (d)
peritoneum (e) mesoderm

(a) mesothelium

The simple columnar epithelium that looks stratified because
its crowded cells are different heights is called ?. (a)
transitional (b) pseudostratified (c) keratinized (d)
mesothelium (e) pavement epithelium

(b) pseudostratified

A membrane that produces a watery fluid on its free surface
is called a ?. (a) mucosa (b) serosa (c) mesothelium (d)
endothelium (e) none of these

(b) serosa

The serous membranes surrounding the lungs are called ?
membranes. (a) pericardial (b) peritoneal (c) pleural (d) none
of these

(c) pleural

Both endothelium and mesothelium are derived from
embryonic ?. (a) mesoderm (b) endoderm (c) ectoderm (d)
all of these (e) none of these

a) mesoderm

Ciliated epithelia are involved in ?. (a) increasing cell
surface area for transmembrane transport (b) moving
materials through tubes (c) hearing and sperm maturation (d)
forming striated and brush borders (e) none of these

b) moving materials through tubes