BIOL231 - Ch2 Test

Which letter indicates the DNA molecule? A) A B) B C) C D) D E) E

A) A

Which letter indicates the chromatid? A) A B) B C) C D) D E) E

D) D

Which letter indicates the Golgi apparatus? A) A B) B C) C D) D E) E

E) E

This is an inherited disease that leads to an accumulation of undigested glycolipids especially in the lysosomes of neurons.

Tay-Sachs disease

Of the following, the only organelle that has a double membrane structure is the A) centriole. B) Golgi apparatus. C) endoplasmic reticulum. D) mitochondrion.

D) mitochondrion.

The cell that gathers information and controls body functions is a A) macrophage. B) fat cell. C) sperm cell. D) neuron.

D) neuron.

Which organelle is important in neutralizing free radicals? A) Golgi apparatus B) lysosome C) mitochondrion D) peroxisome

D) peroxisome

Which type of endocytosis ingests the most specific type of molecule? A) fluid-phase endocytosis B) phagocytosis C) pinocytosis D) receptor-mediated endocytosis

D) receptor-mediated endocytosis

Ribosomes may be either free within the cytoplasm or bound to a membrane system known as the A) Golgi apparatus. B) microtubule organizing center. C) cytoskeleton. D) rough endoplasmic reticulum.

D) rough endoplasmic reticulum.

The temporary structures in the cytoplasm include all of the following except A) pigments. B) glycosomes. C) lipid droplets. D) the Golgi apparatus.

D) the Golgi apparatus.

This organelle has both a cis and a trans face. A) Golgi apparatus B) lysosome C) rough endoplasmic reticulum D) mitochondria E) peroxisome

A) Golgi apparatus

This organelle primarily modifies products from the rough ER, and it resembles a stack of hollow saucers, one cupped inside the next. A) Golgi apparatus B) lysosome C) rough endoplasmic reticulum D) mitochondria E) peroxisome

A) Golgi apparatus

During anaphase, motor proteins attached to mitotic spindle fibers serve to A) pull the chromosomes to opposite poles of the cell. B) pull together the replicated chromosomal strands. C) re-form the nuclear envelope. D) form the aster.

A) pull the chromosomes to opposite poles of the cell.

Which of the following statements accurately describes the function of the nuclear envelope? A) separation of nucleoplasm and cytoplasm B) regulation of passage of substances into and out of the cell membrane C) transcription of DNA D) protein synthesis

A) separation of nucleoplasm and cytoplasm

Which letter indicates histones? A) A B) B C) C D) D E) E

B) B

Which letter indicates the mitochondrion? A) A B) B C) C D) D E) E

B) B

Dyneins and kinesins are motor proteins that ________. A) enable a cell to send out and retract extensions called pseudopods. B) move organelles along microtubules through the cytoplasm. C) are molecular components of telomeres D) resist pulling forces that are placed on cells.

B) move organelles along microtubules through the cytoplasm.

The endocytotic process in which small vesicles of fluid are brought into the cell is called A) phagocytosis. B) pinocytosis. C) exocytosis. D) xenocytosis.

B) pinocytosis.

Which letter indicates a nucleosome? A) A B) B C) C D) D E) E

C) C

Which letter indicates the microvilli? A) A B) B C) C D) D E) E

C) C

Materials that are to be exocytosed by cells are enclosed in vesicles synthesized by the A) nucleosome. B) ribosome. C) Golgi apparatus. D) mitochondrion.

C) Golgi apparatus.

Which of the following statements about the rough endoplasmic reticulum is false? A) It consists of stacked envelopes called cisternae. B) It makes the digestive enzymes contained in the lysosomes. C) It stores lipids as inclusions. D) It makes the integral proteins of the cell membrane.

C) It stores lipids as inclusions.

The mitotic spindle forms from the A) nucleus. B) Golgi apparatus. C) centrosome matrix. D) nucleolus.

C) centrosome matrix.

Mitosis refers only to nuclear division. Separation of the entire cell following mitosis is A) meiosis. B) karyokinesis. C) cytokinesis. D) telophase.

C) cytokinesis.

Hormones are secreted by A) phagocytosis. B) pinocytosis. C) exocytosis. D) osmosis.

C) exocytosis.

Which letter indicates the rough endoplasmic reticulum? A) A B) B C) C D) D E) E

D) D

Which type of proteins are required for exocytosis? A) caveolin B) coatomer proteins C) clathrin D) SNARE proteins

D) SNARE proteins

Which letter indicates the metaphase chromosome? A) A B) B C) C D) D E) E

E) E

This organelle detoxifies a number of toxic substances. A) Golgi apparatus B) lysosome C) rough endoplasmic reticulum D) mitochondria E) peroxisome

E) peroxisome

This organelle is numerous in liver and kidney cells. A) Golgi apparatus B) lysosome C) rough endoplasmic reticulum D) mitochondria E) peroxisome

E) peroxisome

This is the phase in which a cell grows and carries on all its usual metabolic activities.

G1 phase of interphase

Describe the three major types of cytoskeletal elements.

Microtubules are the largest in diameter and are formed by the protein tubulin. They are stiff, but bendable. Microtubules are important in the trafficking of organelles within the cytoplasm. Microfilaments are the smallest in diameter. They are strands of the protein actin, are contractile proteins, which are typically very labile. Intermediate filaments are of intermediate diameter. They are very stabile and permanent, functioning to resist shearing forces within and between adjacent cells.

The phospholipid molecules of the plasma membrane are primarily composed of ________.

a non-polar tail comprised of 2 fatty acid chains attached to a polar head

What would extended chromatin wrapped around a group of eight histones be called?

a nucleosome

These are the smallest living units in the body.

cells

This is the mechanism by which large particles and macromolecules enter a cell.

endocytosis

What is the transport mechanism by which substances move from the cytoplasm to the outside of the cell?

exocytosis

This is the name for the currently held theory describing the plasma membrane structure.

fluid mosaic model

Identify the two different types of membrane-associated molecules that comprise the glycocalyx.

glycolipids and glycoproteins

This is the diffusion of water molecules across a membrane.

osmosis

This is the outermost continuous boundary of a human cell.

plasma membrane (plasmalemma)

Cell aging may be related to production of what charged molecules produced by the mitochondria?

radicals (free radicals)

Which letter indicates the nucleolus? A) A B) B C) C D) D E) E

A) A

Membrane-bound organelles have the same type of membrane as the plasma membrane except A) for the absence of a glycocalyx. B) for the absence of cholesterol. C) the nonpolar tails face outward. D) they are all covered with ribosomes.

A) for the absence of a glycocalyx.

This membranous organelle is the site of protein synthesis for proteins that are secreted by the cell. A) Golgi apparatus B) lysosome C) rough endoplasmic reticulum D) mitochondria E) peroxisome

C) rough endoplasmic reticulum

Peroxisomes A) are the toxic waste removal system of the cell. B) are involved in the production of ATP. C) contain some of the code necessary for their own duplication. D) synthesize proteins for use outside the cell.

A) are the toxic waste removal system of the cell.

During mitosis, the kinetochore microtubules of the mitotic spindle A) attach to chromatids and align them at the metaphase plate. B) push on the chromatids. C) anchor the centriole to the cell membrane. D) push the two poles of the cell apart.

A) attach to chromatids and align them at the metaphase plate.

Which of the following does not pass through nuclear pores? A) chromatin B) messenger RNA C) proteins D) ribosomal RNA

A) chromatin

The ________ face of the Golgi apparatus is ________ to receive spherical vesicles from the rough endoplasmic reticulum. A) cis; convex B) trans; concave C) cis; flattened D) trans; convex

A) cis; convex

The stiffest elements of the cytoskeleton, analogous to the bones of the human body, are A) microtubules. B) microfilaments. C) intermediate filaments. D) the cytosol.

A) microtubules.

The longest arrays of microtubules that assemble from each centrosome during prophase form filaments called A) mitotic spindle fibers. B) kinetochores. C) asters. D) the nuclear envelope.

A) mitotic spindle fibers.

Embedded in the plasma membrane of cells, cholesterol molecules act to A) stabilize the membrane. B) make the membrane more resistant to freezing. C) destabilize the membrane, leading to heart attacks. D) participate in pinocytosis.

A) stabilize the membrane.

Peroxisomes function to A) synthesize and degrade hydrogen peroxide. B) store cellular free radicals. C) produce pigments. D) regulate membrane permeability.

A) synthesize and degrade hydrogen peroxide.

The theory proposing that aging results from the effects of free radicals is primarily a theory of A) wear and tear. B) genetically programmed aging. C) progressive disorder of immunity. D) cross-linking of glucose.

A) wear and tear.

The cytoskeletal elements that are analogous to the muscles of the body which generate pseudopodia and contractile forces in conjunction with myosin are A) microtubules. B) microfilaments. C) intermediate filaments. D) integral proteins.

B) microfilaments.

The cytoskeletal elements that form a ring to "squeeze" the two daughter cells apart during cytokinesis are A) microtubules. B) microfilaments. C) intermediate filaments. D) the microtrabecular lattice.

B) microfilaments.

Which of the following is associated with protein synthesis? A) mitochondria B) ribosomes C) chloroplasts D) smooth endoplasmic reticulum

B) ribosomes

Which membranous organelle stores calcium and is a primary site of lipid metabolism? A) Golgi apparatus B) smooth endoplasmic reticulum C) mitochondrion D) peroxisome

B) smooth endoplasmic reticulum

The plasma membrane is composed of all of the following except A) glycoproteins. B) tubulin protein. C) cholesterol. D) phospholipids.

B) tubulin protein.

Phospholipids of the plasma membrane are arranged A) around a central layer of cholesterol. B) in a single layer with polar heads facing outwards. C) as a bilayer with their nonpolar tails sandwiched between the polar heads. D) as a bilayer with their polar heads sandwiched between the nonpolar tails.

C) as a bilayer with their nonpolar tails sandwiched between the polar heads.

During what phase of the cell cycle is the DNA duplicated? A) metaphase B) anaphase C) interphase D) prophase

C) interphase

The double membrane structure is unique to the A) lysosome. B) peroxisome. C) mitochondrion. D) nucleolus.

C) mitochondrion.

Cisternae of this organelle are continuous with the nuclear envelope. A) Golgi apparatus B) lysosome C) rough endoplasmic reticulum D) mitochondria E) peroxisome

C) rough endoplasmic reticulum

The plasma membrane is A) a single-layered membrane that surrounds the nucleus of the cell. B) a single-layered membrane enclosing the plasma. C) the membrane surrounding the cell. D) a membrane composed of tiny shelves or cristae.

C) the membrane surrounding the cell.

Which is not part of interphase? A) G1 B) G2 C) M D) S

C) M

Describe how cellular differentiation results in structural variation among cells in the human body.

Cellular differentiation is the result of highly regulated gene activation/inactivation in the developing embryo. The products of gene activation are proteins. As the embryo develops, certain cells will begin to produce proteins that neighboring cells do not produce. As development progresses, these unique protein "signatures" lead to differences in cellular function. For example, in muscle cells actin and myosin proteins predominate which results in their unique contractile properties.

Which of the following is not a cytoskeleton element? A) microtubule B) microfilament C) intermediate filament D) centriole

D) centriole

This membranous organelle contains oxidase and catalase enzymes. A) Golgi apparatus B) lysosome C) rough endoplasmic reticulum D) mitochondria E) peroxisome

E) peroxisome

A mitotic spindle develops during early telophase of mitosis.

False

Chromatin is composed of DNA wound around proteins known as actin.

False

During anaphase, the chromosomes are moved to the center of the cell.

False

During the G1 phase, DNA is replicated in the cytoplasm.

False

During the S phase, cells are characterized by rapid growth.

False

Extended chromatin is tightly wound around histones.

False

Microtubules are composed of actin.

False

Ribosomes consist of two subunits, each surrounded by a membrane.

False

The smooth ER contains its own molecules of DNA.

False

Describe the two checkpoints that occur during interphase.

The G1 checkpoint ensures that the cell has reached a maximum size and has replicated the necessary organelles and enzymes to synthesize DNA. The G2 checkpoint, checks to see whether replication errors or DNA damage has occurred during DNA synthesis.

An example of a type of cell with high rates of mitosis is a cell of the skin.

True

Cytokinesis is the physical division of the cytoplasm between the two newly formed cells that result from mitosis.

True

Hypercholesterolemia is an inherited disease in which the body's cells lack the protein receptors that bind to cholesterol-delivering LDLs.

True

Peroxisomes are important in detoxification of a number of toxic substances, for instance, hydrogen peroxide.

True

Telomeres are structures that limit the maximum number of times cells can divide.

True

The nucleolus serves as the cell's ribosome-producing machine.

True

This phase is the physical division of the cytoplasm between the two newly formed cells that result from mitosis.

cytokinesis

This network of rods running throughout the cytosol acts as a cell's "bones," "muscles," and "ligaments."

cytoskeleton

This is the type of protein involved in transport mechanisms across the plasma membrane.

integral proteins (transmembrane proteins)

Which of the following cytoskeleton elements are the largest in diameter? A) microtubules B) microfilaments C) intermediate filaments D) centrioles

A) microtubules

Functions of the Golgi apparatus include all of the following except A) synthesis of lysosomes. B) DNA replication. C) plasma membrane formation. D) production of secretory granules.

B) DNA replication.

Cell division is analogous to A) two buildings duplicating their parts and fusing. B) a building duplicating its blueprint and then forming a new building by splitting in two. C) a building forming another building by random accumulation of materials. D) a building forming another building through a loss of some of its parts.

B) a building duplicating its blueprint and then forming a new building by splitting in two.

The process of cellular aging may involve all of the following except A) accumulated damage by free radicals. B) decreased production of lysosomes. C) excessive metabolic rate. D) progressive shortening of telomeres.

B) decreased production of lysosomes.

Transcription of DNA requires the presence of A) centrosomes. B) extended chromatin. C) histones. D) nucleosomes.

B) extended chromatin.

The nuclear envelope is continuous with the rough ER, but it differs from the rough ER in that it A) is not associated with ribosomes. B) has unique pores. C) consists of two membranes separated by a space. D) consists of tubes, like the smooth ER.

B) has unique pores.

In the cell life cycle, DNA is replicated during A) interphase G1. B) interphase S. C) prophase I. D) prophase II.

B) interphase S.

These organelles are often called the "demolition crew" of the cell. A) Golgi apparatus B) lysosome C) rough endoplasmic reticulum D) mitochondria E) peroxisome

B) lysosome

This organelle is defective in the inherited disorder Tay-Sachs disease. A) Golgi apparatus B) lysosome C) rough endoplasmic reticulum D) mitochondria E) peroxisome

B) lysosome

This organelle is primarily a sac of powerful digestive enzymes called acid hydrolases. A) Golgi apparatus B) lysosome C) rough endoplasmic reticulum D) mitochondria E) peroxisome

B) lysosome

When a phagocytic white blood cell ingests a foreign bacterial cell, the vesicle fuses with this organelle. A) Golgi apparatus B) lysosome C) rough endoplasmic reticulum D) mitochondria E) peroxisome

B) lysosome

During what phase of mitosis does the mitotic spindle break down and disappear? A) metaphase B) anaphase C) telophase D) late prophase

C) telophase

Which of the following statements about integral proteins in the plasma membrane is false? A) Most extend all the way through the membrane. B) Some attach to the glycocalyx. C) They determine which molecules are transported through the membrane. D) They are more abundant by volume than the membrane phospholipids.

D) They are more abundant by volume than the membrane phospholipids.

Which of the following is an inclusion, not an organelle? A) lysosome B) microtubule C) mitochondrion D) glycosome

D) glycosome

In chromatin, the DNA molecule wraps around proteins called A) nucleotides. B) codons. C) integral protein. D) histones.

D) histones.

The plasma membrane is important for all the following reasons except A) it determines what substances enter and exit the cell. B) it separates the ECF from the ICF. C) it acts as a site for cell-to-cell interaction and recognition. D) it is an important site for DNA transcription.

D) it is an important site for DNA transcription.

In the process of phagocytosis, the organelles whose enzymes break down ingested foreign cells are the A) nucleoli. B) smooth endoplasmic reticulum. C) peroxisomes. D) lysosomes.

D) lysosomes.

This organelle contains a single DNA molecule and is capable of self-replication. A) Golgi apparatus B) lysosome C) rough endoplasmic reticulum D) mitochondria E) peroxisome

D) mitochondria

This organelle is characterized by folded membranes called cristae. A) Golgi apparatus B) lysosome C) rough endoplasmic reticulum D) mitochondria E) peroxisome

D) mitochondria

This organelle is involved in production of cellular energy. A) Golgi apparatus B) lysosome C) rough endoplasmic reticulum D) mitochondria E) peroxisome

D) mitochondria

This organelle produces ATP molecules. A) Golgi apparatus B) lysosome C) rough endoplasmic reticulum D) mitochondria E) peroxisome

D) mitochondria

Differentiate phagocytosis from receptor-mediated endocytosis.

In phagocytosis, the cell extends pseudopods and engulfs the foreign protein/foreign cell, which is often degraded after the phagocytic vesicle fuses with a lysosome. In receptor-mediated endocytosis, specific membrane receptors bind specific extra-cellular molecules. Once bound, the membrane deforms inward, creating a vesicle with the receptors and molecules inside. The vesicle contents are released into the cytoplasm or fuse with a lysosome, with the receptors recycled back to the membrane.

Describe the mitochondria.

These are long, thin organelles, that have their own DNA molecule which allows for self-replication. They produce ATP molecules, which are the equivalent of cellular energy. They are bound by two membranes. The inner one is highly folded into cristae, where many of the critical molecules involved in ATP production are imbedded.