1. ^{The codons within the mRNA (B) are recognized by corresponding tRNA molecules within during protein translation.}
2. ^{equality/balance /space equal distance between molecules, equal no concentration gradient}

1. ^{cytoplasmic ribosomes}
2. ^Equilibrium

1. ^{organism a living thing; anything that can carry out life processes independently}
2. ^{Molecules move from higher concentration to lower concentration gradient, molecules "spread out" spontaneous happens automatically.}

1. ^organism
2. ^Diffusion

1. ^{the arrangement of parts in an organism}
2. ^{move easily through water, which is polar, but cannot pass directly through the lipid (nonpolar) part of the cell membrane.}
   
3. ^{All of the following are functions of membrane receptors, EXCEPT}

1. ^structure
2. ^Ions
3. ^{Membrane receptors do not play a role in cell adhesion.}

1. ^{Cells of the body mainly use ______ for the selective endocytosis of most macromolecules.}
2. ^{are whiplike, motile cellular extensions that occur, typically in large numbers, on the exposed surfaces of certain cells. Ciliary action moves substances in one direction across cell surfaces. Centrioles forming the bases of cilia and flagella are commonly referred to as basal bodies.}

1. ^{receptor-mediated endocytosis}
2. ^Cilia

1. ^{are able to detoxify substances by enzymatic action}
2. ^{move more quickly than larger ones, so they diffuse more rapidly.}
3. ^{Which of the following cell organelles is responsible for generating most of the energy the cell uses to perform work?}

1. ^Peroxisomes
2. ^{Smaller molecules}
3. ^{mitochondrion transfers the energy found in nutrient molecules to ATP, the molecule that cells use to supply power for chemical reactions.}

1. ^{transfer RNA, and ribosomal RNA play a role in protein synthesis.}
2. ^{Which of the following cell structures are involved in propelling substances across cell surfaces?}
3. ^{During transcription __________.}
4. ^{mRNA is read to produce DNA DNA is used as a template to make RNA t-RNA is used to build a protein mRNA is read to produce a protein}

1. ^{Messenger RNA}
2. ^{Cilia move in unison, creating a unidirectional current that propels substances across cell surfaces.}
3. ^{DNA is used as a template to make RNA}

1. ^{processes mediated by integral membrane proteins.}
2. ^{easily pass through the lipid (nonpolar) portion of the cell membrane.}
3. ^{Passive membrane transport processes include}

1. ^{passive and active transport}
2. ^Lipids
3. ^{movement of a substance down its concentration gradient}

1. ^{The energy from is used to transport sodium and potassium ions across the membrane and thereby establish for each of those ions.}
2. ^{Which of the following forms of vesicular transport processes are used by flu viruses, diphtheria, and cholera toxins to enter our cells?}

1. ^{ATP hydrolysis, concentration gradients}
2. ^{Flu viruses, diphtheria, and cholera toxins use receptor-mediated endocytosis to enter and attack our cells.}

1. ^{The DNA helix wraps around a group of histone proteins to form a structural unit called a}
2. ^{Which of the following processes allows cells to concentrate material that is present only in very small amounts in the extracellular fluid?}

1. ^nucleosome
2. ^{Receptor-mediated endocytosis is the main mechanism for the specific endocytosis and transcytosis of most macromolecules by body cells, and it is exquisitely selective. The mechanism also allows cells to concentrate material that is present only in very small amounts in the extracellular fluid.}

1. ^{help prevent molecules from passing through the extracellular space between adjacent cells; they are found in the digestive tract.}
2. ^{are anchoring junctions; they are found in areas subjected to pulling forces (i.e. cardiac muscle cells and skin).}
3. ^{are important for cell communication; they are found in electrically excitable tissue (i.e. heart and smooth muscle).}

1. ^{Tight junctions}
2. ^Desmosomes
3. ^{Gap junctions}

1. ^{Ribosomes are found .}
2. ^{of the plasma membrane ensures that the continual traffic across the membrane does not include undesirable substances. It also ensures that desirable cell contents are retained within the cell.}

1. ^{in the cytosol and on the rough endoplasmic reticulum}
2. ^{Selective permeability}

1. ^{allows molecules that cannot pass through the lipid component of the membrane to pass through via a more compatible protein channel or carrier. This includes ions and polar molecules.}

1. ^{Facilitated diffusion}

1. ^{The larger the , the faster the rate of diffusion. Higher concentration means there are more collisions, so the molecules bounce away from each other more rapidly.}

1. ^{Concentration gradient}

1. ^{is the second phase of mitosis. DNA has already replicated.}
2. ^{DNA replicates during . This process provides each new daughter cell with a full complement of genetic material.}
3. ^{begins when the chromosomes stop moving. Nuclear envelopes form, and the cell divides in two.}

1. ^Metaphase
2. ^interphase
3. ^Telophase

1. ^{During , the centromeres split and the spindle microtubules pull the sister chromatids to opposite poles of the cell. The single chromatids are now considered chromosomes.}
2. ^{is the first phase of mitosis. During this phase, the sister chromatids condense, the nuclear envelope and nucleoli disappear, and the spindle apparatus forms.}

1. ^anaphase
2. ^Prophase

1. ^{During , movement of the spindle microtubules force sister chromatids to the center of the cell.}
2. ^{begins when the chromosomes stop moving. Nuclear envelopes form, and nucleoli reappear. Ultimately, the cell divides in two by a process known as cytokinesis.}

1. ^metaphase
2. ^Telophase

1. ^{If cells are placed in a hypertonic solution containing a solute to which the membrane is impermeable, what could happen?}
2. ^{DNA is replicated during the ________ phase of the cell cycle}
3. ^{Cristae are found in which of the following cell organelles?}

1. ^{The cells will lose water and shrink}
2. ^{S Phase}
3. ^{mitochondria contain cristae produced by the inward folding of their inner membrane}.

1. ^{Which of the following statements is correct regarding net diffusion?}
2. ^{are the site of the majority of ATP production because of the specialized enzymes on their cristae.}

1. ^{The greater the concentration gradient, the faster the rate.}
2. ^Mitochondria

1. ^{The main component of the cytosol is}
2. ^{are the major structural protein associated with chromatin.}

1. ^WATER
2. ^{Histone proteins}

1. ^{Forms part of the protein synthesis site in the cytoplasm.}
   
2. ^{Act as ʺinterpreterʺ molecules that recognize specific amino acids and nucleotide base sequences.}
3. ^{Attaches the correct amino acid to its transfer RNA.}

1. ^{Ribosomal RNA}
2. ^{Transfer RNA}
3. ^{Synthetase enzymes}

1. ^{Provides the energy needed for synthesis reactions.}
2. ^{Found in the cytoplasm, this structure specifies the exact sequence of amino acids of the protein to be made.}
3. ^{May be attached to the ER or scattered in the cytoplasm.}

1. ^ATP
2. ^{Messenger RNA}
3. ^{Ribosomal RNA}

1. protein synthesis
2. RNA synthesis
3. protein folding, packaging, and modification
4. neutralize dangerous free radicals
5. support cellular structures
6. contain digestive enzymes

1. ribosome
2. nucleolus
3. endoplasmic reticulum
4. peroxisomes
5. cytoskeleton
6. lysosomes

1. ^{Which of the following does not serve as a signal for cell division?}
2. ^{which untwists the DNA helix and breaks bonds between the complementary nucleotides of the two parental ("old") DNA strands.}

1. ^{repressor genes}
2. ^{enzyme helicase}

1. ^{The resting membrane potential is mainly determined by}
2. ^{What is the primary function of the mitochondria?}

1. ^{resting membrane potential is mainly determined by the differential permeability of the plasma membrane to K+ and other ions.}
2. ^{Mitochondria are threadlike or lozenge-shaped membranous organelles. In living cells they squirm, elongate, and change shape almost continuously. They are the power plants of a cell, providing most of its ATP supply.}

1. ^{All cells that have a such that the inside (interior surface) of the cell membrane has a net negative charge while the outside (external surface) of the membrane has a net positive charge. Given the different (opposite) charges on either side of the cell membrane, the cell is considered to be polarized. This RMP, which results from separation of charged particles (ions) across the cell membrane, can be measured in millivolts (typically ranging from -50 to -100 mV depending on the cell type).}

1. ^{resting membrane potential (RMP)}

1. ^{Mitosis ________.}
2. ^{Which of the following builds new strands of DNA?}
3. following is NOT a function of lysosomes?

1. ^{is division of the nucleus}
2. ^{DNA polymerase is an enzyme that builds new strands of DNA. It does this by adding DNA nucleotides one at a time.}
3. ^{forming acid hydrolases which are necessary to help form cell membranes.}

1. ^{Your patient has the flu and reports 5 to 6 loose stools a day. He has experienced an isotonic fluid volume loss. What does "isotonic fluid loss" mean?}

1. ^{Water and electrolytes are lost in equal proportions.}

1. ^{Which statement best describes strand characteristics as it relates to DNA replication?}
2. ^{During DNA replication, which nucleotide will bind to an A nucleotide in the original or parental DNA strand?}

1. ^{The leading strand is built continuously, and the lagging strand is built in pieces.}
2. ^{T During DNA replication, A only binds with T and T only binds with A.}

1. ^{Which protein joins together the Okazaki fragments of DNA in the lagging strand?}
2. ^{The nucleolus}

1. ^{DNA ligase joins the Okazaki fragments in the lagging strand, turning it into a continuous strand.}
2. ^{is the site of ribosome assembly in a cell, are usually large in growing cells that are making large amounts of tissue proteins.}

1. ^{Which statement about DNA replication is FALSE?}
2. ^{Which of the following would not be a constituent of a plasma membrane?}
3. ^{are the dark-staining spherical bodies found within the nucleus}.

1. ^{DNA ligase adds nucleotides to the lagging strand.}
2. ^{messenger RNA}
3. ^{Nucleoli ("little nuclei")}

1. ^{Which statement about DNA replication is ?}

1. ^{DNA polymerase III builds a new strand by adding DNA nucleotides one at a time. The two strands of original or parental DNA are separated during DNA replication. 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.}

1. ^{Chromosomes uncoil to form chromatin.}
2. ^{Chromosomal centromeres split and chromosomes migrate to opposite ends of the cell.}
3. ^{Nuclear membrane and nucleolus disintegrate.}
4. ^{Chromosomes align on the spindle equator.}
5. ^{Centrioles move to opposite ends of the cell.}

1. ^Telophase
2. ^Anaphase
3. ^{Late prophase}
4. ^Metaphase
5. ^{Early prophase}

1. ^{is the diffusion of a solvent, such as water, across a selectively permeable membrane}
2. ^{are a major component of all cellular membranes, including the mitochondrial inner and outer membranes}

1. ^osmosis
2. ^{Phospholipids}

1. ^{which are lipids, pass through the plasma membrane via simple diffusion.}
2. ^{a gas, passes through the plasma membrane via simple diffusion.}
3. ^{Which structures are fingerlike projections that greatly increase the absorbing surface of cells?}

1. ^{Steroid hormones}
2. ^Oxygen
3. ^microvilli

1. ^{a small polar solute, uses a membrane transporter (a protein carrier) to cross the plasma membrane via facilitated diffusion. In simple diffusion, small nonpolar and lipid-soluble substances (including gases) diffuse directly through the lipid bilayer.}

1. ^Glucose

1. ^{Which of the following is a function of a plasma membrane protein?}
2. ^{What moves cell organelles from one location to another inside a cell?}
3. ^{Some hormones enter cells via}

1. ^{molecular transport through the membrane}
2. ^{Motor proteins}
3. ^{receptor-mediated endocytosis}

1. ^{Which statement is the most correct regarding transcription/translation?}

1. ^{The nucleotide sequence in a tRNA anticodon is an exact copy of the DNA triplet that coded for it except that uracil is substituted for thymine.}

^{All are regarding the membrane potential?}

_{^{The resting membrane potential occurs due to active transport of ions across the membrane due to the sodium-potassium pump.}}

_{^{In their resting state, all body cells exhibit a resting membrane potential.}}

_{^{The resting membrane potential is determined mainly by the concentration gradients and differential permeability of the plasma membrane to K+ and Na+ ions.}}

_{^{Both potassium and sodium ions can ʺleakʺ through the cell membrane due to diffusion.}}

^{1) Plays a role in the synthesis of steroid-based hormones and proteins.}

^{2) The actual site of protein synthesis.}

^{3) Hollow cytoskeletal elements that act as organizers for the cytoskeleton.}

^{4) Dense spherical bodies in the nucleus that are the synthesis site for ribosomal RNA.}

^{5) Houses DNA and RNA.}

1. ^{Endoplasmic reticulum}
2. ^Ribosomes
3. ^Microtubules
4. ^Nucleoli
5. ^Nucleus

1. ^{Which of the following names the 3 main parts of a human cell?}
2. ^{is the site of lipid production in a cell.}

1. ^{Human cells have 3 main parts: the plasma membrane, the cytoplasm, and the nucleus}
2. ^{Smooth endoplasmic reticulum}

1. ^{within the endomembrane system is consistent with its functions of sorting and modifying proteins being transported to various cellular locations.}

1. ^{Golgi apparatus}

1. ^{have a higher concentration of nonpenetrating solutes than seen in the cell (for example, a strong saline solution). Cells immersed in hypertonic solutions lose water and shrink, or crenate.}

1. ^{Hypertonic solutions}

1. ^{constituent of a plasma membrane?}
2. ^{Which transport process is the main mechanism for the movement of most macromolecules by body cells?}

1. ^{glycoproteins phospholipids glycolipids}
2. _{receptor-mediated endocytosis}

1. ^{Which of the following is not a factor that binds cells together?}

1. ^{glycolipids in the glycocalyx}

1. ^{Which of the following is a difference between primary and secondary active transport?}

1. ^{In primary active transport, the transport protein gets phosphorylated; in secondary active transport, the transport protein is not phosphorylated}

1. ^{Which type of cell junction acts as anchors and distributes tension through a cellular sheet and reduces the chance of tearing when it is subjected to great mechanical stress?}

1. ^desmosomes

1. ^{Apoptosis is programmed cell suicide; cancer cells do not undergo this process.}
2. _{The RNA responsible for bringing the amino acids to the ribosome for protein formation is}

1. ^TRUE
2. ^tRNA

1. ^{The functions of centrioles include}
2. ^{A gene can best be defined as}

1. ^{organizing the mitotic spindle in cell division}
2. ^{a segment of DNA that carries the instructions for one polypeptide chain}

1. ^{Which of the following is a principle of the fluid mosaic model of cell membrane structure?}

1. ^{Phospholipids form a bilayer that is largely impermeable to water-soluble molecules.}

1. ^{system refers to the movements of particles against the concentration gradient and uses more energy to move from lower to higher concentration gradients}
2. ^{system refers to movements of particles towards the concentration gradient and requires no energy to move from higher to lower concentration gradients.}

1. ^{Active transport}
2. ^{Passive transport}

1. ^{What is the difference between active and passive transport across the plasma membrane?}

1. ^{Active transport is ATP dependent, whereas passive transport uses only the kinetic energy of the particles for movement across the plasma membrane.}

1. ^{Which vesicular transport process occurs primarily in some white blood cells and macrophages?}

1. ^phagocytosis

1. ^{Which of these is not a function of the plasma membrane?}
2. ^{Cells may be said to be "sugar-coated" due to the presence of}

1. ^{It prevents potassium ions from leaking out and sodium ions from crossing into the cell.}
2. ^{glycocalyx is made up of glycoproteins, which are proteins with carbohydrate side chains located on the outside surface of the cell membrane, thus causing the cell to be sugar-coated.}

1. ^{are polar hydrophilic molecules that are not able to traverse the hydrophobic region of the phospholipid bilayer.}
2. ^{anchoring junctions found in areas subjected to pulling forces.}
3. ^{important for cell communication.}
4. ^{prevent molecules from passing through the extracellular space between adjacent cells.}

1. ^{Glucose and other monosaccharides}
2. ^desmosomes
3. ^{gap junctions}
4. ^{tight junctions}

Following function of lysosomes?

digesting particles taken in by endocytosis

breaking down bone to release calcium ions into the blood

degrading worn-out or nonfunctional organelles

1. ^{Mitochondria ________.}
2. ^{Definite changes in the _______of the cell membrane can be seen in a cell that is becoming cancerous.}

1. ^{contain some of the DNA and RNA code necessary for their own function}
2. ^{glycocalyx shows definite changes when the cell becomes cancerous and changes continuously to keep the immune system from recognizing it.}

1. _{is a special type of diffusion, which is always a passive process.}
2. ^{is a passive transport process during which molecules move down their concentration gradients through transport proteins.}

1. _Osmosis
2. ^{Facilitated diffusion}

1. ^{Hyper” means “high,” so a has a higher solute concentration than the solution to which it is being compared.}
2. ^{have less water to move than do hypotonic solutions.}

1. ^{hypertonic solution}
2. ^{Hypertonic solutions}

1. ^{The extracellular fluid will draw water out of the hypotonic intracellular fluid, so the cells will shrink. This is called crenulation.}
2. ^{In order to prevent the cells from either swelling or shrinking, the body fluids should be isotonic, meaning that they are at .}

1. ^hypertonic
2. ^equilibrium

1. ^{are found free in the cytoplasm or bound to the ER, not packaged within a vesicle.}
2. ^{are enzymes utilized for detoxification reactions that occur primarily within peroxisomes. Peroxisomes do not originate from the .}

1. ^Ribosomes
2. ^{Oxidases and catalases, Golgi apparatus}

1. ^{may be associated with either free ribosomes in the cytoplasm or bound ribosomes on the ER but would not be typically found within a vesicle.}

1. ^RNA

1. ^{which stores enzymes that catalyze the hydrolysis (digestion) of organic cellular materials}

1. ^lysosome

1. ^{which are associated with cholesterol, are more stable and less fluid than the rest of the membrane. They are assumed to be concentrating platforms for proteins, used for a variety of functions, but not to bind cells together. Also, glycolipids do not bind cells together.}

1. ^Lipid-rafts

1. ^{stabilizes the membrane, but does not act to bind cells together.}

1. ^Cholesterol

1. ^{three factors act to bind cells together:}

1. ^{(1) glycoproteins (and glycolipids) in forming the glycocalyx, which acts as an adhesive, (2) the wavy contours of the membranes of adjacent cells fitting together in a tongue-and-groove fashion, and (3) the formation of special membrane junctions.}

1. ^{cholesterol synthesis, and synthesis of the lipid components of lipoproteins are functions of the smooth endoplasmic reticulum.}
2. ^{Absorption, synthesis, and transport of fats are functions of the .}
3. ^{Storage of calcium ions is a function of the in muscle cells.}

1. ^{Lipid metabolism}
2. ^{smooth endoplasmic reticulum}
3. ^{smooth endoplasmic reticulum}

1. ^{The synthesizes all proteins secreted from the cell; it also functions as the cell's "membrane factory" because integral proteins and phospholipids that form part of all cellular membranes are manufactured there.}

1. ^{rough ER}

1. ^{is the synthesis of RNA using DNA.}
2. ^{The term literally means "out of the cell."}

1. ^{Transcription}
2. exocytosis

1. ^{Ribosomes, endoplasmic reticulum, and the Golgi apparatus functionally act in sequence to synthesize and modify proteins for secretory use (export) only, never for use by the cell. This statement is ________.}

1. ^{false; integral cell membrane proteins are also synthesized this way}

1. ^{A fuses with the plasma membrane and releases its contents to the extracellular fluid. This statement describes}

1. ^vesicle

1. ^{The uses ATP to move sodium and potassium ions across the plasma membrane. The sodium-potassium pump is activated by ATP. This activation allows the pump to transport sodium and potassium ions against their gradients.}

1. ^{sodium-potassium pump}

1. ^{The majority of water molecules moving across plasma membranes by osmosis do so via a process that is most similar to ____.}

1. ^{facilitated diffusion}

1. ^{A primary active transport process is one in which}

1. ^{molecules move through transport proteins that have been activated by ATP}

1. ^{Some transport processes use transport proteins in the plasma membrane, but do not require ATP. This type of transport is known as _____.}

1. ^{facilitated diffusion}

1. ^{such as the sodium-potassium ATPase (or pump), are activated when ATP is hydrolyzed. This activation allows for the transport of solutes across the plasma membrane against concentration gradients}

1. ^{Primary active transporters}

1. ^{have a polar head, the long fatty acid tails are nonpolar, making the membrane mostly nonpolar}
2. ^{Vesicular transport is involved in all of the following transport processes, EXCEPT}

1. ^{phospholipids}
2. ^{Solute pumps are considered active transporters and can move large or small molecules.}

1. ^{The is semipermeable, or selectively permeable, because some things can easily pass through it while others cannot.}
2. ^{Which of the following statements best describes the fluid mosaic model of the plasma membrane?}

1. ^{cell membrane}
2. ^{fluid mosaic model of the plasma membrane is composed of two layers of lipid molecules with protein molecules dispersed within.}

1. ^{is composed mostly of carbohydrates.}

1. ^glycocalyx

1. ^{What part of a cell membrane is usually in contact with the interstitial fluid?}
2. ^{are organelles and they are located within one of the major components of the cell.}

1. ^{The phosphate heads of the phospholipids are polar, so they are attracted to the polar water molecules.}
2. ^Ribosomes

1. ^{Organelles are the functional parts of cells—they are inside the cells, in the . Cells join to form tissues, and the tissues then join to form the organs that work together in organ systems.}

1. ^cytoplasm

1. ^{Where in a typical eukaryotic cell would you expect to find genes?}
2. ^{Pinocytosis is a type of}

1. ^{nucleus houses the DNA, which contains the genes. Genes determine what proteins the cell can make, which in turn determines what the cell can do.}
2. ^endocytosis

1. ^{Which of the following acts as the digestive system of the cell, breaking down materials?}

1. ^{Lysosomes use their enzymes to break down material, much as our digestive system breaks down the foods we consume. The root “lyse” means to loosen or separate, which is what the enzymes in lysosomes do to the chemical bonds in the items they digest.}

1. ^{Which of the following are considered anchoring junctions?}
2. ^{Lysosomes perform which of the following cellular functions?}

1. ^{Desmosomes are considered the anchoring junctions of adjacent cells.}
2. ^{intracellular digestion--Lysosomes are spherical membrane-bound sacs that contain many different digestive enzymes utilized within the cell.}

1. ^{Which of the following cell organelles possesses oxidase enzymes that function in neutralizing harmful free radicals?}

1. ^{Peroxisomes contain a wide variety of enzymes, including oxidases, which function in neutralizing harmful free radicals in the cells.}

1. ^{Which of the following cell organelles functions in supporting cellular structures and in generating cell movements?}
2. ^{Each corresponds to a codon of 3 nucleotides. Therefore, a coding region of 300 nucleotides contains 100 codons and will produce a polypeptide of 100 amino acids in length.}

1. ^{The cytoskeleton is an elaborate network of rods running throughout the cytosol, functioning in supporting cellular structures and in generating cell movements.}
2. ^{amino acid}

1. ^{Which of the following cell structures functions as the control center of the cell?}
2. ^{formation of bonds between sugar groups and phosphate groups that link the DNA nucleotides together.}

1. ^{The nucleus' genetic material, DNA, directs cellular activities by providing the instructions for protein synthesis.}
2. ^{DNA polymerase catalyzes}

1. _{^{a series of integral protein molecules (including occludins and claudins) in the plasma membranes of adjacent cells fuse together, forming an impermeable junction that encircles the cell. Tight junctions help prevent molecules from passing through the extracellular space between adjacent cells. For example, tight junctions between epithelial cells lining the digestive tract keep digestive enzymes and microorganisms in the intestine from seeping into the bloodstream.}}

1. ^{Tight junctions}

1. ^{The primary site of cellular ATP production in most cells is the}
2. ^{Which nucleic acid molecules are involved in transcription but not translation in the synthesis of a particular polypeptide?}

1. ^{mitochondrion nucleus ribosome lysosome}
2. ^{DNA is copied into mRNA in transcription within the nucleus in the synthesis of a particular polypeptide.}

1. ^{is a form of active transport.}
2. ^{Phagocytosis and pinocytosis}

1. ^Endocytosis
2. ^{are examples of different types of endocytosis.}

1. ^{Which type of membrane transport process uses ATP as a source of energy?}
2. ^{are not transferred between DNA strands during replication.}
3. ^{not the enzyme indicated by A, is the enzyme that joins the lagging strand fragments.}

1. ^{Active transport processes use ATP.}
2. ^Nucleotides
3. ^{DNA ligase}

1. ^{not the enzyme indicated by A, adds the first series of nucleotides that are composed of RNA nucleotides. This is the primer that is extended by DNA polymerase.}

1. ^Primase