Chapter 3
Which of the following events occurs during transcription? The message in mRNA is translated into a protein. mRNA binds to a ribosome in the cytoplasm. A molecule of RNA is formed based on the sequence of nucleotides in DNA. A cap is added to the RNA molecule. Those segments of the RNA strand that do not actually code for the protein are removed.
A molecule of RNA is formed based on the sequence of nucleotides in DNA.
The anticodon for the triplet UCA is TGT. AGC. TCA. AGU. AGT.
AGU.
Which of the following best describes the difference between active and passive transport mechanisms? Active mechanisms use energy to move solutes out of the cell. Passive mechanisms move solutes into the cell. Active mechanisms use energy to move solutes with their concentration gradients. Passive mechanisms move solutes against their concentration gradients. Active mechanisms use the energy stored in a solute's concentration gradient. Passive mechanisms do not use energy. Active mechanisms use energy to move solutes against their concentration gradients. Passive mechanism move solutes with their concentration gradients.
Active mechanisms use energy to move solutes against their concentration gradients. Passive mechanism move solutes with their concentration gradients.
During which phase of mitosis do the sister chromatids move apart? Metaphase Anaphase Prophase Telophase
Anaphase
The cessation of telomerase activity as we age limits the number of times a cell can replicate. Current research on telomerases is particularly useful in the fight against cancer. Why is this so? Cancer cells have telomerases that trigger the loss of stem cell populations. Telomerase activation may help reduce the amount of mechanical damage incurred by DNA in cancer cells. Cancer cells employ a mechanism that activates telomerases, which leads to uncontrolled cellular division. Cancer cells have telomerases that suppress the occurrence of cellular mutations.
Cancer cells employ a mechanism that activates telomerases, which leads to uncontrolled cellular division.
What is the name of the process by which the cytoplasm divides in two? Microtubule shortening Cytoplasmic streaming Cytokinesis Segregation
Cytokinesis
Which protein joins together the Okazaki fragments of DNA in the lagging strand? DNA polymerase the replication fork the leading strand RNA DNA ligase
DNA ligase
Which statement about DNA replication is FALSE? DNA ligase adds nucleotides to the lagging strand. DNA polymerase III builds a new strand by adding DNA nucleotides one at a time. Because the two strands of original or parental DNA run in opposite directions, the new strands must be made in different ways. The lagging strand is made of a series of fragments that must be joined together to make a continuous strand. The two strands of original or parental DNA are separated during DNA replication.
DNA ligase adds nucleotides to the lagging strand.
Which enzyme works simultaneously along both DNA strands to synthesize complementary strands of DNA? RNA polymerase DNA polymerase helicase ligase
DNA polymerase
Which of the following builds new strands of DNA? the replication fork DNA helicase the lagging strand of DNA DNA polymerase the leading strand of DNA
DNA polymerase
In general, the cell cycle lasts about 24 hours in a normal dividing cell. However, mitosis occurs over 1-3 hours, much less than the other stages. Which of the following choices best explains why? Mitosis is short to make sure no mistakes in DNA synthesis occur. The shorter mitosis stage is due to the need to synthesize critical proteins important for cell survival. During mitosis, cells are non-functional. The length of mitosis depends upon whether the cell was in G0 at the start of cell cycle.
During mitosis, cells are non-functional.
Which of the following lists, in correct order, the phases of interphase? S, cytokinesis, mitosis G1, prophase, and S G1, S, and G2 Prophase, metaphase, telophase
G1, S, and G2
Renewal or modification of the cell membrane is a function of the rough endoplasmic reticulum. ribosomes. microtubules. mitochondria. Golgi apparatus.
Golgi apparatus.
During which phase of the cell cycle does DNA duplication, or replication, take place? Interphase Prophase Anaphase Metaphase
Interphase
__________ function(s) as the template during translation. Messenger RNA Ribosomes DNA Transfer RNA
Messenger RNA
During which phase of mitosis do sister chromatids line up at the center of the cell? Anaphase Telophase Prophase Metaphase
Metaphase
During which phase of mitosis do the nuclear envelope and nucleoli disappear? Metaphase Anaphase Telophase Prophase
Prophase
________ are responsible for identifying and digesting damaged or denatured proteins. Lysosomes Peroxisomes Nucleosomes Proteasomes Endosomes
Proteasomes
The enzyme ________ is required for the synthesis of mRNA. RNA polymerase RNA synthetase deoxyribase phosphatase ribase
RNA polymerase
What is the link between Parkinson's disease and stem cell research? Parkinson's disease occurs because of lack of stem cells. Researchers have managed to generate induced pluripotent stem cells, which may differentiate into dopamine-producing neurons. Patients with Parkinson's disease produce a particularly promising type of neuronal stem cell that may be used to treat other neurodegenerative disorders. Studies with rats have shown how stem cells encourage the progressive loss of dopamine-producing cells associated with Parkinson's disease.
Researchers have managed to generate induced pluripotent stem cells, which may differentiate into dopamine-producing neurons.
A cell duplicates its chromosomes during the ________ phase. G1 S Go Gm G2
S
There is a lot of talk about stem cells in the media. What is unique about these cells? Stem cells are not affected by nutrient availability. Stem cells can provide a cure for all diseases. Stem cells can grow under any conditions. Stem cells are not fully differentiated.
Stem cells are not fully differentiated.
During which of the following phases does DNA replication occur? Synthesis prophase mitosis cytokinesis
Synthesis
During DNA replication, which nucleotide will bind to an A nucleotide in the original or parental DNA strand? G U A C T
T
Choose the correct statement about telomerases. Telomerases are enzymes that form telomeres. Telomerases are enzymes that are active throughout one's lifetime. Telomerases are functionally identical to DNA polymerases. Telomerases consist of specific groupings of nitrogenous bases that are repeated.
Telomerases are enzymes that form telomeres.
During which phase of mitosis do nuclear envelopes and the nucleoli reappear? Anaphase Metaphase Telophase Prophase
Telophase
The hormone epinephrine (adrenaline) increases the pumping rate of the sodium-potassium exchange pump in skeletal muscles. How would you expect this to affect the concentration of Na+ and K+ in the muscle cytoplasm? The Na+ and K+ concentrations would both increase. The Na+ and K+ concentrations would both decrease. The Na+ concentration would decrease and the K+ concentration would increase. The Na+ concentration would increase and the K+ concentration would decrease.
The Na+ concentration would decrease and the K+ concentration would increase.
The cell cycle is divided into two main parts: interphase and cell division. Interphase is the period in which the cell is performing normal functions and not actively engaged in cell division. Most of your body's cells spend a lot of their time in interphase. Before a cell can divide, what must occur during interphase? The chromosomes are duplicated in the nucleus. The DNA relaxes into chromosomes. The sister chromatids separate into chromosomes. The cell only performs its normal cell functions.
The chromosomes are duplicated in the nucleus.
Which statement best describes strand characteristics as it relates to DNA replication? The lagging strand is built continuously, and the leading strand is built in pieces. The leading and lagging strands are both built in fragments. The leading and lagging strands are both built continuously. The leading strand is built continuously, and the lagging strand is built in pieces.
The leading strand is built continuously, and the lagging strand is built in pieces.
Which of the following occurs during a single cycle of the sodium-potassium exchange pump? Two K+ ions are transported out of the cell. Three Na+ ions are transported into the cell. Three Na+ ions are transported out of the cell. Three K+ ions are transported into the cell.
Three Na+ ions are transported out of the cell.
During mitosis, chromatids separate into daughter chromosomes in anaphase. telophase. interphase. prophase. metaphase.
anaphase.
The genetically programmed death of cells is called replication. differentiation. mitosis. metastasis. apoptosis.
apoptosis.
A malignant neoplasm is often called a(n) cancer. swelling. infection. tumor. All of the answers are correct.
cancer.
As a red blood cell matures, it loses all of its DNA. As a result, it __________. can only divide once more cannot make new RNA becomes immortal is a mutant
cannot make new RNA
The potential difference across the cell membrane is due to the separation of cations and anions. phospholipids and proteins. water molecules. acids and bases. carbohydrate molecules.
cations and anions.
When a double helix of DNA is replicated, two complete helices are formed. Together, these helices are called sister __________. chromosomes chromatids centromeres telomeres
chromatids
The intake of materials from the extracellular fluid using vesicles is called endocytosis. exocytosis. osmosis. an ion exchange pump. facilitated transport.
endocytosis.
A vesicle fuses with the plasma membrane and releases its contents to the extracellular fluid. This statement describes _____. exocytosis active transport facilitated diffusion simple diffusion endocytosis
exocytosis
Which of these vesicular transport methods expels material from the cell? receptor-mediated endocytosis pinocytosis exocytosis phagocytosis
exocytosis
If a cell lacked the enzyme DNA polymerase, it could not form a new nuclear membrane during telophase. form complementary sequences of DNA. form spindle fibers. link segments of DNA together. maintain the integrity of the nuclear envelope.
form complementary sequences of DNA.
What concentration gradients are established and maintained by the sodium-potassium exchange pump? high Na+ concentration in the extracellular fluid; high K+ concentration in the cytoplasm high Na+ and K+ concentrations in the extracellular fluid high Na+ and K+ concentrations in the cytoplasm high Na+ concentration in the cytoplasm; high K+ concentration in the extracellular fluid
high Na+ concentration in the extracellular fluid; high K+ concentration in the cytoplasm
Differentiation requires __________ of particular genes to produce populations with __________ capabilities that form tissues. activation; unlimited inactivation; limited activation; limited inactivation; unlimited
inactivation; limited
In order for a cell to divide, all of its chromosomes must be duplicated in a process called DNA replication. During which phase of the cell cycle does DNA replication occur? mitosis interphase prophase cytokinesis
interphase
The stage in a cell's life cycle in which the cell performs its normal functions is called __________. interphase telophase prophase metaphase
interphase
When is DNA replicated? anaphase interphase interkinesis metaphase telophase
interphase
A molecule of ________ contains all the codons needed to produce a particular polypeptide. rRNA cRNA dRNA tRNA mRNA
mRNA
Which of following properties of the cytoskeleton is incorrect? provides cell strength controls cell shape supports organelles made of cytobones moves organelles
made of cytobones
Which phase of mitosis has chromosomes lining up in the center of the cell? cytokinesis prophase anaphase metaphase
metaphase
Nuclear division of somatic cells is known as meiosis. differentiation. mitosis. metamorphosis. cytokinesis.
mitosis.
A(n) ________ is a mutant of a regulatory gene that causes cancer. neogene oncogene monogene toxogene plasmogene
oncogene
Whenever positive and negative ions have been separated, a(n) ________ will be produced. resistance charged field potential difference flow of current energy cloud
potential difference
During which of the following phases does chromatin condense and become chromosomes? anaphase prophase interphase metaphase
prophase
Which of the following lists, in correct order, the phases of mitosis? prophase, metaphase, anaphase, cytokinesis interphase, prophase, metaphase, anaphase, telophase prophase, anaphase, metaphase, telophase prophase, metaphase, anaphase, telophase
prophase, metaphase, anaphase, telophase
Facilitated diffusion differs from simple diffusion in that facilitated diffusion __________. doesn't need a gradient is an ion pump needs ATP requires a protein carrier
requires a protein carrier
Which of the following is least likely to increase the rate of diffusion? small molecule size small concentration gradient higher concentration of molecules high temperature
small concentration gradient
Synthesis of lipids and glycogen takes place at the ribosomes. smooth ER. Golgi apparatus. rough ER. mitochondria.
smooth ER.
In order to maintain cellular homeostasis, an exchange pump ejects ________ ions from the cell and imports ________ ions. potassium; sodium sodium; calcium calcium; sodium sodium; potassium potassium; calcium
sodium; potassium
The principal cations in our body fluids are ________ and ________. calcium; magnesium chloride; bicarbonate sodium; chloride sodium; calcium sodium; potassium
sodium; potassium
The chromosomal structure that limits the number of cell divisions of a cell is the __________. histones kinetochore telomere centromere
telomere
The potential difference across the cell membrane is known as the cellular potential. the membrane potential. the membrane difference. the cellular difference. both membrane potential and cellular difference.
the membrane potential.
Facilitated diffusion differs from ordinary diffusion in that facilitated diffusion consumes ATP. the rate of molecular movement is not limited by the number of available carrier molecules. facilitated diffusion moves molecules from an area of lower concentration to an area of higher concentration. facilitated diffusion never eliminates the concentration gradient. the rate of molecular movement is limited by the number of available carrier molecules.
the rate of molecular movement is limited by the number of available carrier molecules.
Cells become more specialized by __________. converting to an immune cell replicating themselves over and over turning on specific genes turning off specific genes
turning off specific genes
All of the following membrane transport mechanisms are passive processes except vesicular transport. osmosis. facilitated diffusion. movement of water. diffusion.
vesicular transport.
The set of three nucleotides on the mRNA strand that are read by the ribosome is termed the __________. "tRNA" "triplet" "anti-codon" "codon"
"codon"
Which of the following conditions would cause (net) glucose to be transported into a cell via facilitated diffusion? Assume ATP is present inside the cell. 5.5 mM glucose in cytoplasm; 5.5 mM glucose in extracellular fluid 5 mM glucose in cytoplasm; 0.5 mM glucose in extracellular fluid 0.5 mM glucose in cytoplasm; 5 mM glucose in extracellular fluid 5 mM glucose in cytoplasm; 5 mM glucose in extracellular fluid
0.5 mM glucose in cytoplasm; 5 mM glucose in extracellular fluid
Microfilaments consist of the protein called actin. anchor the cytoskeleton to membrane proteins. with myosin, produce cell movement. control the consistency of cytoplasm. All of the answers are correct.
All of the answers are correct.
Microtubules have which of the following functions? They form structural components of organelles. They provide a mechanism for changing the cell shape. They move chromosomes during cell division. Molecular motors move along them. All of the answers are correct.
All of the answers are correct.
Peroxisomes are more abundant in cells with higher metabolic rates. absorb and break down fatty acids, generating hydrogen peroxide in the process. are produced from other peroxisomes. contain enzymes that break down hydrogen peroxide. All of the answers are correct.
All of the answers are correct.
What is a possible rationale for the difference between the DNA in chromatin and chromosome form? The condensed chromatin keeps the DNA organized through cell division. The loosely organized chromatin facilitates transcription. The structure of chromatin allows DNA-binding proteins to access the DNA. All of the listed answers are possible rationales for chromatin-chromosome DNA differences.
All of the listed answers are possible rationales for chromatin-chromosome DNA differences.
What is the best description of the cell's plasma membrane? It is its outermost boundary. It regulates exchange with the exterior. It has a phospholipid bilayer. All of these are true of a cell's plasma membrane.
All of these are true of a cell's plasma membrane.
Which of the following statements about cells is FALSE? Cells join together to form organelles, which then form our organs and organ systems. Cells are the most basic units of life. Although human cells are diverse in size, shape, and function, they have essentially the same organelles and general structure. The cells in our bodies collectively carry out all of the functions necessary for us to stay alive.
Cells join together to form organelles, which then form our organs and organ systems.
The odd position of Jackson's heart is related to a disorder with his cilia called Primary Ciliary Dyskinesia (PCD). What are cilia? Cilia are numerous motile extensions of the plasma membrane that have an internal arrangement of nine pairs of microtubules surrounding a central microtubule pair (9+2 array). Cilia are finger-shaped cytoplasmic projections of the plasma membrane that increase the surface area of the cell. Cilia are very long singular extensions of the cytoplasm. They have an internal arrangement of nine pairs of microtubules surrounding a central microtubule pair (9+2 array). Cilia exist in pairs and are structures composed of an internal arrangement of nine microtubule triplets arranged in a cylindrical structure.
Cilia are numerous motile extensions of the plasma membrane that have an internal arrangement of nine pairs of microtubules surrounding a central microtubule pair (9+2 array).
Chromosomes consist of histones bound to __________. ribosomes messenger RNA polysaccharides DNA
DNA
Which one of the following does not play a role in translation? tRNA Amino acids Anticodon Ribosomes DNA
DNA
Forensic scientists employed in crime fighting rely on DNA fingerprints. Which of the following statements does NOT verify the usability of DNA fingerprints in fighting crimes? DNA fingerprints can be obtained from tissues samples as varied as semen, blood, and hair. DNA fingerprints are unique to everyone, even identical twins. Perpetrators of violent crimes, such as rape and murder, have been convicted based on DNA fingerprinting. DNA fingerprints of convicted felons are collected in a database accessible to crime fighters.
DNA fingerprints are unique to everyone, even identical twins.
Chromosomes consist of ________ and ________. RNA; proteins DNA; proteins RNA; carbohydrates water; RNA DNA; lipids
DNA; proteins
The majority of individuals with PCD have defects associated with the ciliary protein dynein, which functions in the cilia's motility. Many of these affected individuals have mutations associated with two genes: DNAI1 and DNAH5. How do genes relate to proteins? Genes are a type of RNA molecule that brings the appropriate amino acids to the ribosome complex during protein synthesis. Genes are the molecules of RNA that translocate from the nucleus to associate with ribosomes during translation of protein synthesis. Genes are a set of nucleotides in a strand of DNA that specify the specific sequence of the amino acids that comprise a protein. Genes are the molecule that adds the nucleotides to the RNA strand during transcription. Mutations in these molecules cause the wrong nucleotides to be inserted, ultimately creating a fault protein during translation.
Genes are a set of nucleotides in a strand of DNA that specify the specific sequence of the amino acids that comprise a protein.
What is the basic difference between simple diffusion and facilitated diffusion across a cell membrane? In simple diffusion, molecules move down the concentration gradient but in facilitated diffusion molecules move up the concentration gradient. Simple diffusion requires molecules to move through special doorways in the cell membrane. Simple diffusion is passive but facilitated diffusion is an active process that uses energy. In facilitated diffusion, molecules only move with the aid of a protein in the membrane.
In facilitated diffusion, molecules only move with the aid of a protein in the membrane.
Cilia are composed of microtubules. How are microtubules different from the other cytoskeletal filaments? Microtubules are large bundles composed of the protein myosin. They are generally 15 nanometers in size. Microtubules are the smallest cytoskeletal element with a diameter of 5 nanometers and they are composed of the protein actin. Microtubules vary in size from 9-11 nanometers and have different protein compositions depending upon the type of cell. Microtubules are hollow tubes with a diameter of 25 nanometers and are composed of the protein tubulin.
Microtubules are hollow tubes with a diameter of 25 nanometers and are composed of the protein tubulin.
Which of the following is most likely to move through the cell membrane by facilitated diffusion? small lipids CO2 Na+ O2
Na+
The Na+-K+ ATPase pump is important for secondary active transport of other solutes. How does this pump work to bring in other solutes? K+ is pumped out of the cell, creating a lower K+ concentration inside the cell. Na+ is pumped out of the cell, creating a lower Na+ concentration inside the cell. Na+ is pumped into the cell, creating a lower concentration of Na+ outside the cell.
Na+ is pumped out of the cell, creating a lower Na+ concentration inside the cell.
It used to be believed that non-coding sequences of DNA were useless. What statement shows the erroneousness of this belief? Just like the coding sequences of DNA, non-coding sequences are also inherited from generation to generation. While non-coding sequences of DNA do not code for protein synthesis, they nonetheless hold the code for the manufacture of enzymes. Short tandem repeats, so useful in the establishment of DNA fingerprints, are found within non-coding sequences. A series of repeated amino acids imparts a unique function to the non-coding sequences of DNA.
Short tandem repeats, so useful in the establishment of DNA fingerprints, are found within non-coding sequences.
_______ cells are all of the cells of the body except the reproductive cells (sperm and oocytes). Main Somatic Corpus Primary Core
Somatic
If a person is severely dehydrated, their extracellular fluids will become hypertonic to the intracellular fluid. What do you predict will happen to the person's cells? The cells will swell. Extracellular fluids do not impact cell size, because cells contain intracellular fluid. The cells will lose water and shrink. The cells will rupture.
The cells will lose water and shrink.
The effectiveness of certain anesthetics depends in part on their lipid solubility. Why is this? Polar substances, such as lipid-soluble drugs, have high solubility. The hydrophobic core of the phospholipid bilayer enables lipid-soluble substances to readily pass through the plasma membrane. The hydrophilic nature of lipid-soluble drugs speeds up their passage through the plasma membrane. Lipid-soluble drugs trigger the opening of certain channels, which they can use to pass through the plasma membrane.
The hydrophobic core of the phospholipid bilayer enables lipid-soluble substances to readily pass through the plasma membrane.
What happens to a patient's red blood cells when a hypotonic solution is given? The red blood cells would expand and eventually hemolysis would result. The red blood cells will crenate. The red blood cells would stay the same size.
The red blood cells would expand and eventually hemolysis would result.
If more solute particles are added to the right side of a beaker with a selectively permeable membrane (thus the particles cannot move to the left side), which way will the water in the beaker move, and why will it move in that direction? Water will move to the left side of the beaker because the left side is hypotonic compared to the right side. Water will move to the right side of the beaker because the right side is hypertonic compared to the left side. Water will move to the right side of the beaker because it is hypotonic compared to the left side.
Water will move to the right side of the beaker because the right side is hypertonic compared to the left side.
The plasma membrane is composed of a bilayer of phospholipids. carbohydrates and proteins. carbohydrate molecules. a bilayer of proteins. carbohydrates and lipids.
a bilayer of phospholipids.
Identify the role of cholesterol in the plasma membrane. affects membrane permeability anchors the phospholipids enables ions to pass forms enzymes All of the answers are correct.
affects membrane permeability
Some cells contain large numbers of mitochondria while others have relatively few or none. This suggests that cells with large numbers of mitochondria have a high energy demand. cells with small numbers of mitochondria have a large ATP supply. cells with large numbers of mitochondria have a low energy demand. some cells are older than others. cells with large numbers of mitochondria are short-lived.
cells with large numbers of mitochondria have a high energy demand.
Carriers transport solutes across the plasma membrane by __________. making solutes more soluble in the plasma membrane forming a pore in the membrane, which allows solutes to pass through changing shape as the solutes bind, causing the solutes to move across the membrane opening channel gates that allow solutes to pass
changing shape as the solutes bind, causing the solutes to move across the membrane
The complex structures of DNA and protein found in the cell nucleus are chromatin and histones. nucleoplasm. nucleases. histones. mitochondria.
chromatin and histones.
The organelles and the watery component of the cell together is called protoplasm. cytoplasm. interstitial fluid. extracellular fluid. cytosol.
cytoplasm.
The watery component of the cytoplasm is called extracellular fluid. a colloidal gel. cytosol. interstitial fluid. protoplasm.
cytosol.
The movement of oxygen from an area of high concentration to an area of low concentration is an example of filtration. diffusion. osmosis. active transport. facilitated transport.
diffusion.
When activated, lysosomes function in cell division. formation of new cell membranes. digestion of materials. synthesis of lipids. synthesis of proteins.
digestion of materials.
Pinocytosis is a form of __________. osmosis diffusion endocytosis exocytosis
endocytosis
Which of the following is not required for osmosis to occur? energy concentration gradient selectively permeable membrane wate
energy
Which of the following descriptors regarding cytoplasm is false? variable consistency the material that fills a cell extracellular fluid contains more protein includes cytoskeleton includes cytosol
extracellular fluid contains more protein
Passive movement of a solute by a carrier protein is called __________. facilitated diffusion sodium-potassium exchange active transport simple diffusion
facilitated diffusion
Some transport processes use transport proteins in the plasma membrane, but do not require ATP. This type of transport is known as _____. active transport facilitated diffusion endocytosis exocytosis simple diffusion
facilitated diffusion
The majority of water molecules moving across plasma membranes by osmosis do so via a process that is most similar to ____. a process that requires energy from the cell simple diffusion facilitated diffusion active transport cotransport
facilitated diffusion
If an animal cell lacked centrioles, it would not be able to metabolize sugars. form the mitotic spindle. move. synthesize proteins. produce DNA.
form the mitotic spindle.
Which of the following is not a major function of proteins in the cell membrane? forming channels anchoring cells to other structures forming the entire glycocalyx acting as receptors
forming the entire glycocalyx
The functional units of DNA that contain the instructions for making one or more proteins are codons. ribosomes. RNA. genes. chromosomes.
genes.
Diffusion of a substance across the cell membrane is influenced by all of the following except hydrolysis of ATP. lipid solubility. the presence of the membrane channels. the charge on the ion. concentration gradient.
hydrolysis of ATP.
The tails of a phospholipid molecule are hydrophobic. hydrophilic. facing the cytosol. interlocked to provide membrane strength. composed of amino acids.
hydrophobic.
Which of the following solutions contains the most solute? hypotonic equilibrium isotonic hypertonic
hypertonic
A solution that contains a lower osmotic pressure than the cytoplasm of a cell is called hypertonic. isotonic. merotonic. hypotonic. homotonic.
hypotonic.
Where in a typical eukaryotic cell would you expect to find genes? in the chromatin within the cell's cytoplasm in the DNA within the cell's nucleus in the nucleolus within the nucleus in chromosomes within the cytosol
in the DNA within the cell's nucleus
A gene is a set of specific instructions that directs carbohydrate synthesis. produces amino acids for proteins. copies DNA strands for mitosis. controls the process of mitosis. indicates the sequence of amino acids in a protein molecule.
indicates the sequence of amino acids in a protein molecule.
Of the three major fluid compartments in the body, what is the fluid that surrounds the cells called? plasma intracellular fluid interstitial fluid
interstitial fluid
DNA __________. is processed to remove introns is transcribed into mRNA contains uracil is non-complementary
is transcribed into mRNA
In general, to maintain homeostasis the relationship between our intracellular and extracellular fluids should be which of the following? intracellular should be hypotonic to extracellular intracellular and extracellular should both be hypertonic isotonic to each other intracellular should be hypertonic to extracellular
isotonic to each other
Receptor molecules on the surface of cells bind specific molecules called, in general, recognizers. ligands. binders. reactants. bonders.
ligands.
Which of the following acts as the digestive system of the cell, breaking down materials? endoplasmic reticulum lysosome ribosome nucleus
lysosome
Which organelle is involved in the destruction of bacteria and old organelles and the liberation of enzymes? centrioles lysosomes endoplasmic reticulum (ER) peroxisomes
lysosomes
Which of the following does not occur during RNA processing? mRNA attaches to the small subunit of a ribosome. Segments of RNA that do code for the protein are reconnected. Segments of the RNA strand that do not actually code for the protein are removed. Adenine nucleotides are added to the end of the RNA strand, forming a tail. A modified guanine nucleotide is added to the beginning of the RNA strand as a cap.
mRNA attaches to the small subunit of a ribosome
Which of the following is a correct statement about mRNA? mRNA moves from the nucleus to the cytoplasm following RNA processing. mRNA binds directly to amino acids during translation. Segments of mRNA that code for protein are removed before translation. mRNA is transcribed from DNA in the cytoplasm. mRNA includes a cap that consists of extra adenine nucleotides.
mRNA moves from the nucleus to the cytoplasm following RNA processing.
The endoplasmic reticulum is an example of a(n) ________ organelle. extracellular filamentous interstitial bound membranous
membranous
Actin is the subunit of __________. thick filaments ribosomes microtubules microfilaments
microfilaments
Components of the cytoskeleton may include all of the following except thick filaments. microsomes. microfilaments. intermediate filaments. microtubules.
microsomes.
Each of the following is a function of smooth endoplasmic reticulum except synthesis of steroid hormones. storage and release of calcium ions. modification of protein. detoxification of drugs. synthesis of triglycerides.
modification of protein.
A primary active transport process is one in which __________. an intracellular vesicle fuses with the plasma membrane and releases its contents to the extracellular fluid molecules pass directly through the phospholipid bilayer of the plasma membrane the plasma membrane folds inward to form a vesicle containing extracellular material molecules move across the plasma membrane without an input of energy molecules move through transport proteins that have been activated by ATP
molecules move through transport proteins that have been activated by ATP
Which of the following best explains diffusion? exchange of nonpolar molecules for polar molecules movement of molecules farther away from equilibrium movement of molecules from where there are fewer of them to where there are more movement of molecules from an area of high concentration to an area of low concentration
movement of molecules from an area of high concentration to an area of low concentration
One of the characteristics of cancer cells is an increased need for protein production. Of the following choices, which organelle would be most closely associated with meeting this need? nucleoli mitochondria proteosomes Golgi apparatus
nucleoli
Most of a cell's DNA is located in its nucleus. nucleolus. ribosomes. Golgi apparatus. lysosomes.
nucleus.
The control center for cellular operations is the endoplasmic reticulum. mitochondria. ribosome. nucleus. Golgi apparatus.
nucleus.
What is the normal direction of calcium transport via the calcium pump? out of the cell, against its concentration gradient into the cell, with the calcium concentration gradient into the cell, against the calcium concentration gradient out of the cell, with the calcium concentration gradient
out of the cell, against its concentration gradient
Organelles that break down fatty acids and hydrogen peroxide are peroxisomes. lysosomes. nuclei. toxisomes. endocytic vesicles.
peroxisomes.
What part of a cell membrane is usually in contact with the interstitial fluid? phosphate heads of phospholipids hydrophobic molecules cholesterol fatty acid tails
phosphate heads of phospholipid
The backbone of the plasma membrane is a __________ bilayer. diglyceride glycolipid protein phospholipid
phospholipid
Which of the following is the main component of the cell membrane? phospholipids cholesterol carbohydrates water
phospholipids
The sodium-potassium pump uses ATP to move sodium and potassium ions across the plasma membrane. This statement describes _____. facilitated diffusion secondary active transport simple diffusion exocytosis primary active transport
primary active transport
Tubulin is a protein that forms the tubular portion of the cytosol. lipid that assembles into microtubules. lipid that forms the ER. carbohydrate that assembles into microtubules. protein that assembles into microtubules.
protein that assembles into microtubules.
Phosphates are abundant in the intracellular fluid. What is the other major intracellular anion? chloride potassium proteins bicarbonate
proteins
Ribosomes are composed of protein and glycogen. rRNA ATP. DNA steroids.
rRNA.
Which of the following is NOT one of the three major components of a typical eukaryotic cell? ribosome nucleus plasma membrane cytoplasm
ribosome
The site of translation is ribosomes in the cell nucleus. ribosomes in the cell cytoplasm. the cell nucleus. the Golgi apparatus. the plasma membrane.
ribosomes in the cell cytoplasm.
Which of the following is a characteristic of the cell membrane? fully permeable not permeable impermeable semipermeable
semipermeable
Water crosses the plasma membrane primarily by means of __________. active transport facilitated diffusion simple diffusion phagocytosis
simple diffusion
Which of the following is the major extracellular cation? calcium magnesium sodium potassium
sodium
One function of the cytoskeleton is to provide __________. energy production strength and integrity to the cell sensitivity the division of the cell
strength and integrity to the cell
Amino acids are transferred to the ribosome to be incorporated into a growing polypeptide chain by rRNA. aRNA. pRNA. tRNA. mRNA.
tRNA.
As each codon arrives at the active site of a ribosome, it attracts another molecule containing the anticodon. This molecule is called rRNA. RER. mRNA. DNA. tRNA.
tRNA.
The smallest living unit within the human body is an organ. a protein. a tissue. the cell. an organ system.
the cell.
What is the energy source used by the calcium pump during its normal operation? the calcium concentration gradient the hydrolysis of ATP the ATP concentration gradient the calcium pump
the hydrolysis of ATP
Inheritable mitochondrial disorders negatively affect which essential function directly? the formation of the spindle apparatus essential for the process of cellular division the production of ATP the synthesis of fatty acids the breakdown of fatty acids
the production of ATP
The process of protein formation directed by mRNA is called auscultation. transcription. mitosis. replication. translation.
translation.
Channel proteins, as indicated by the arrow, are involved in __________. anchoring immune recognition chemicals transport
transport
Thymine is replaced by which nitrogen base in RNA? thymine is not replaced in RNA cytosine ribose uracil guanine
uracil
