A&P Ch. 3

Exocytosis is __________.

a process in which vesicles formed inside the cell fuse with the plasmalemma and discharge their contents outside the cell

Active transport is __________.

a process that requires ATP to pump molecules across a membrane against a concentration gradient

A sequence of three nitrogen bases can specify the identity of __________.

a single amino acid

A solution that is hypotonic to cytoplasm has __________.

a solute concentration lower than that of the cytoplasm

Which of the following is an example of the process of phagocytosis in the human body?

a white blood cell engulfing a bacterium

Most of the energy a cell needs to live is generated by the __________.

mitochondria

As the cell life cycle proceeds, cyclin levels climb, causing the maturation promoting factor (MPF) to appear in the cytoplasm, initiating the process of __________.

mitosis

The effect of diffusion in body fluids is that it tends to __________.

eliminate local concentration gradients

What is the continuous movement and exchange of membrane sections called?

membrane flow

In which phase of mitosis do the chromosomes align in the center of the cell?

metaphase

Hollow tubes in the cytoskeleton that give the cells strength and rigidity and anchor organelles are the __________.

microtubules

The cytoskeleton gives the cell strength and rigidity and anchors the position of major organelles. What are the primary components of the cytoskeleton?

microtubules

All of the following are membranous organelles EXCEPT __________. nucleus and endoplasmic reticulum mitochondria and lysosomes microvilli and centrioles Golgi apparatus and peroxisomes

microvilli and centrioles

Which of these statements is NOT correct? Control of metabolic processes by the information in DNA is indirect, because it is the enzymes, not the metabolic processes, that are controlled by the DNA. A polyribosome is the structure formed when ribosomes bind to endoplasmic reticulum. Protein synthesis is directly under the control of information from DNA nucleotide sequences, as transcribed into mRNA. Mutations are permanent alterations in a cell's DNA affecting the nucleotide sequence of one or more genes.

A polyribosome is the structure formed when ribosomes bind to endoplasmic reticulum.

If the DNA triplet is TAG, the corresponding codon on the mRNA strand will be __________.

AUC

Centrioles __________. have a 9 + 0 arrangement of microtubules are found in all animal cells capable of undergoing cell division are found in pairs, except during cell division All of the listed responses are correct.

All of the listed responses are correct.

The TCA cycle __________. is aerobic is important in ATP production occurs inside mitochondria All of the listed responses are correct.

All of the listed responses are correct.

Which of the following is true of transmembrane potential? Changes can trigger muscle contraction. It is measured in millivolts. Positive and negative charges are held apart. All of the listed responses are correct.

All of the listed responses are correct.

Protein channels within the plasma membrane __________.

permit water and ion movement at all times

Which organelle absorbs and breaks down fatty acids and other organic compounds?

peroxisome

How does facilitated diffusion differ from ordinary diffusion?

Carrier proteins are involved.

Which of these statements about cancer is FALSE? Cancer is a disease characterized by malignant cells, which often change shape and size. Cells in a malignant tumor maintain normal controls over their activities and locations. Secondary tumors are metabolically active and can stimulate the growth of blood vessels into the area. Malignant cells contain oncogenes that affect cell growth, differentiation, or division.

Cells in a malignant tumor maintain normal controls over their activities and locations.

The cell membrane isolates the cytoplasm from the surrounding fluid environment. Why is this important?

Cytoplasm has a composition different from that of the extracellular fluid, and the differences must be maintained.

Which of the following is NOT a function of microtubules? Serve as a monorail system to move vesicles or organelles. Form the mitotic spindle. Change the shape of the cell. Form microvilli.

Form microvilli.

In which phase does a cell make enough organelles for two functional cells?

G1

In which phase does centriole replication complete?

G2

What does M-phase promoting factor do?

It triggers the start of mitosis.

Which of these statements about the cytoplasm and cytosol is FALSE? Cytosol has a relatively high concentration of potassium ions. Cytosol has a relatively high concentration of soluble and insoluble carbohydrates. Masses of insoluble materials in the cytosol, or inclusions, include glycogen and lipids. Cytosol is a colloid with a consistency between that of maple syrup and almost-set gelatin.

Microfilaments are the largest components of the cytoskeleton.

What does the formation of a malignant tumor indicate?

Mitotic rates of cells are no longer responding to normal control mechanisms.

Which of these statements about chromosome structure is FALSE? The nucleoli contain genetic information for building the ribosomal RNA. DNA strands wound around histone proteins form structures called nucleosomes. Each chromosome contains DNA strands bound to histone proteins, which help package the DNA. Most of the DNA of a nucleus is concentrated in nucleoli when it is uncoiled.

Most of the DNA of a nucleus is concentrated in nucleoli when it is uncoiled.

In which phase of interphase does DNA replication take place?

S

The replication of DNA occurs primarily during which phase?

S phase

Why are lysosomes sometimes called "cellular suicide packets"?

The breakdown of lysosomal membranes can destroy a cell.

What is the most notable characteristic of the G0 phase of an interphase cell?

The cell is not preparing for mitosis.

Which of the following is an important characteristic of the transmembrane potential?

The ions held on either side of the plasma membrane have potential energy.

Which of the following statements about membrane permeability is FALSE? Cell membranes are described as selectively permeable because they permit passage of some materials and restrict passage of other materials. Carrier-mediated transport may use either passive or active processes. Active processes require the use of energy from the cell, usually in the form of ATP. The only basis on which membrane permeability to a substance is regulated is the electrical charge of the substance.

The only basis on which membrane permeability to a substance is regulated is the electrical charge of the substance.

Which of these statements about osmosis is FALSE? The osmotic pressure of a solution increases as the amount of water in it increases. Hydrostatic pressure is a force generated by pushing against a fluid, and it can be used to oppose osmotic pressure and measure it. Osmosis is important in the body for fluid shifts that counter severe alterations in water content. Water flows by osmosis across a membrane toward the solution with the higher solute concentration.

The osmotic pressure of a solution increases as the amount of water in it increases.

Which of the following is one of the great advantages of moving materials by active transport?

The process is not dependent on a concentration gradient.

Which of these statements about transmembrane potential is FALSE? The transmembrane potential of a cell is the result of equal distribution of ions and charges on both sides of the cell membrane. The average transmembrane potential of a neuron is about −70 mV. Transmembrane potentials in neurons average about 0.070 volts more negative inside the cell membrane than outside it. A transmembrane potential contains potential energy that can be changed or used to do work in a cell.

The transmembrane potential of a cell is the result of equal distribution of ions and charges on both sides of the cell membrane.

Why is the plasmalemma said to be selectively permeable?

They allow the free passage of some materials and restrict the passage of others.

Facilitated diffusion is __________.

a process in which a molecule is carried across a membrane with the help of membrane-bound carriers

Which of the following is true regarding the Na+/K+ exchange pump? This is a passive process. It exchanges intracellular K+ for extracellular Na+. The rate of ion transport is dependent only on the concentration of sodium ions. Three Na+ ions are exchanged for every two K+ ions.

Three Na+ ions are exchanged for every two K+ ions.

Ions and other small, water-soluble materials cross the plasma membrane only by passing through __________.

a channel

The difference between an area of high concentration of solute and an area of low concentration of solute is known as __________.

a concentration gradient

Hemolysis occurs when a red blood cell is placed in __________.

a hypotonic solution

Red blood cells are hemolyzed when the cells are placed in contact with __________.

a hypotonic solution

All transport through the plasma membrane can be classified as either __________.

active or passive

The genetically controlled death of cells is called __________.

apoptosis

What are the building blocks of all plants and animals?

cells

What are the two main lipids found in the structure of the plasmalemma?

cholesterol and phospholipids

A sequence of three nucleotide bases in the mRNA is called a(n) __________.

codon

Lysosomes __________. are the sites of protein synthesis are important sources of ATP production are the sites of lipid synthesis contain digestive enzymes

contain digestive enzymes

An injection of a concentrated salt solution into the circulatory system would result in __________.

crenation of the red blood cells

The movement of solutes from an area of high concentration to an area of lower concentration is an example of __________.

diffusion

Which of the following factors influence(s) diffusion rates?

distance, temperature, and molecular size

If a large, lipid-insoluble solute wanted to move passively through the plasmalemma, which transport mechanism would it need to use?

facilitated diffusion

What type of ribosome can be found attached to the rough endoplasmic reticulum?

fixed ribosomes

What is the functional unit of heredity?

gene

The process of differentiation resulting in the appearance of characteristic cell specializations involves __________.

gene repression (switching off)

A solution that contains a solute concentration greater than that in a cell is said to be __________.

hypertonic

The spreading process of a primary tumor is called __________, and the dispersion of malignant cells to establish a secondary tumor is called __________.

invasion; metastasis

The smooth endoplasmic reticulum (SER) has a variety of functions that center around the synthesis of __________.

lipids and carbohydrates

Cilia function to __________.

move fluids or secretions across the cell surface

Along the length of the DNA strand, information is stored in the sequence of __________.

nitrogenous bases

Ribosomal proteins and RNA are produced primarily in the __________.

nucleolus

The movement of water molecules from an area of high concentration to an area of lower concentration is an example of __________.

osmosis

The energy-producing process in the mitochondria involves a series of reactions in which __________ is consumed and __________ is generated.

oxygen; carbon dioxide

Which type of vesicular transport uses pseudopodia to surround a solid object?

phagocytosis

Because of its chemical-structural composition, the plasma membrane is called a __________.

phospholipid bilayer

Structurally, the plasma membrane is best described as a __________.

phospholipid bilayer interspersed with proteins

Most of the surface area of the plasma membrane consists of __________.

phospholipids

Which of the following membrane transport mechanisms requires ATP? facilitated diffusion simple diffusion osmosis pinocytosis

pinocytosis

The four stages of mitosis in correct sequence are __________.

prophase, metaphase, anaphase, telophase

What are the two classes of cells found in the human body?

sex cells and somatic cells

Membranous organelles differ from nonmembranous organelles in that membranous organelles are __________.

surrounded by lipid membranes that isolate them from the cytosol

During osmosis, water will always flow across a membrane toward the solution that has __________.

the higher concentration of solutes

The process of cytokinesis refers to __________.

the physical separation of the daughter cells

Water-soluble ions and molecules CANNOT enter certain regions of the cell membrane because of __________.

the presence of hydrophobic tails on the interior of the membrane

The smooth endoplasmic reticulum is __________.

the site of lipid synthesis

The process resulting in the assembly of a functional protein from messenger RNA is called __________.

translation

Which of the following terms refers to the effects of various osmotic solutions on cells? hydrostatic pressure tonicity osmosis osmolarity

tonicity

The process by which messenger RNA is formed from DNA is called __________.

transcription

What is the process in which RNA polymerase uses the genetic information to assemble a strand of mRNA?

transcription