Biology Ch. 4 & 5
DAG
What activates protein kinase C? cAMP IP3 Calcium ions PIP2 DAG
black and white
What are the colors of an electron micrograph? -white and red -black and red -white and orange -black and white -black and orange
target cells
What type of cells must receive, relay, and respond to the information signaled? -Local regulators -Neurotransmitters -Target cells -GABA -Integrins
Endoplasmic reticulum
Where are calcium ions stored before a signaling pathway releases them into the cytosol? -Plasma membrane -Lysosome -Ribosome -Endoplasmic reticulum -Nucleus
exocytosis
Which cellular mechanism ejects products, such as hormones, by the fusion of a vesicle with the plasma membrane? -Pinocytosis -Exocytosis -Receptor-mediated endocytosis -Phagocytosis -Endocytosis
nucleus
A single cell in a smoker's lung has become cancerous. It doubles its DNA and divides much faster than a normal lung cell. The most likely change that would have caused this condition took place in the: -lysosome -nucleolus -nucleus -microtubule -mitochondria
hypertonic
Fluid that has a higher osmotic pressure than a cell is called ___________. -plasmolysis -hypertonic -hypotonic -turgor pressure -isotonic
false
G protein-linked receptors are transmembrane proteins with a binding site for a signaling molecule outside the cell and a neuron component inside the cell. -True -False
by the blood
How are hormones produced by endocrine glands typically transported to target cells? -Through interstitial fluid -By the blood -Through the air -Across a synapse -Via direct contact
false
Kinesin transports organelles toward the minus end of a microtubule. -true -false
True
LDL cholesterol is taken into the cell by receptor-mediated endocytosis. -True -False
false
Mitochondria play an important role in cell necrosis. -true -false
transcription factors
Most intracellular receptors are what type of protein? -Neurotransmitters -Enzymes -Steroids -DNA -Transcription factors
true
Most plasmodesmata contain a narrow cylindrical structure, called the desmotubule, which runs through the channel and connects the smooth ER of the two adjacent cells -true -false
false
Peroxisomes are found in large numbers in cells that synthesize, store, and degrade lipids, and one of their functions is to break down protein molecules. -true -false
false
Plasmolysis occurs in plant cells when the soil or water contains low concentrations of salts or fertilizers. -true -false
Golgi complex
Proteins that are synthesized by ribosomes may be further modified within which organelle? -Mitochondria. -Golgi complex. -Nucleus. -Lysosomes. -Peroxisomes.
false
The smooth ER is the primary site for the synthesis of proteins and cholesterol needed to make membranes. -true -false
-nucleolus -vacuoles -plastids -lyosome -rough endoplasmic reticulum -microfilaments
granular body within an organelle which consists of RNA and protein large membranous sacs of plants and fungi encloses an internal thylakoid membrane membranous sacs in animals ribosomes stud its outer surface rodlike structures consisting of actin choices: plastids vacuoles nucleolus microfilaments rough endoplasmic reticulum lysosome
false
Groups of eight connexin molecules cluster to form a cylinder that spans the plasma membrane. -True -False
a gap junction provides communication between cells
How do gap junctions differ from desmosomes? -A gap junction is a much larger space between cells. -A gap junction requires the use of ATP to open and close its channels. -A gap junction can control the passage of materials between cells. -A gap junction provides communication between cells. -A gap junction bridges the space between cells.
ligand
Typically, the gate of an ion channel remains closed until a(n) ____ binds to the receptor. -G protein -ligand -target cell -enzyme -first messenger
the concentration of a hormone is too high
Under which of the following situations would receptor downregulation most likely occur? -The concentration of a neurotransmitter is too low. -The concentration of a hormone is too high. -The number of G proteins is too high. -The cell is unable to manufacture cyclic AMP. -The number of receptors in the plasma membrane is too low.
Cyclic adenosine monophosphate
When food is scarce, the amoeba-like cellular slime mold, Dictyostelium, secretes which compound? Insulin Estrogen Glucocorticoid Glucagon Cyclic adenosine monophosphate
endoplasmic reticulum
Where are calcium ions stored before a signaling pathway releases them into the cytosol? -Lysosome -Nucleus -Plasma membrane -Ribosome -Endoplasmic reticulum
endocrine glands
Where are hormones produced in animals? -Blood cells -Neuron cells -Skin cells -Exocrine glands -Endocrine glands
endocrine glands
Where are hormones produced in animals? -Skin cells -Blood cells -Neuron cells -Endocrine glands -Exocrine glands
centrosome-cell division
Which cellular structure is correctly matched to the role it plays within the cell? -centrosome−cell division -chloroplast−storage of enzymes -Golgi complex−production of energy -plastids−structural support of the cell -lysosome−powerhouse of the cell
tyrosine kinases
Which is a major group of enzyme-linked receptors? -Ion channels -Phospholipases -Adenylyl cyclases -G proteins -Tyrosine kinases
rhodopsin
Which is a part of a signal transduction pathway that enables vision in dim light in vertebrates? -Rhodopsin -Histamine -Brassinosteroids -Phosphorylation -Acetylcholine
cyclic AMP
Which is an example of a second messenger? -An ion channel -Cyclic AMP -GABA -Protein kinase A -Insulin
cyclic AMP
Which is an example of a second messenger? -Protein kinase A -GABA -Cyclic AMP -An ion channel -Insulin
scanning electron microscope
The accompanying image is the product of which type of microscope? -phase-contrast light microscope -scanning electron microscope -normarski differential interference microscope -confocal fluorescence microscopre -transmission electron microscopie
false
The outer part of the enzyme-linked receptor has a binding site for a signaling molecule, and the part of the receptor that extends into the cytosol has a binding site for a specific G protein. __________________ -True -False
plasmolysis
The process by which the plasma membrane separates from the cell wall is called ______. -plasmolysis -isotonic -hypotonic -hypertonic -turgor pressure
electrochemical
The sodium-potassium pump is a carrier protein that maintains a(n) ____ gradient across the plasma membrane. -polar -nonpolar -electrochemical -concentration -phosphorous
hydrophobic
In a lipid bilayer, __________ fatty acid tails face each other within the bilayer and form a region that excludes water. -hyperosmtoic -hypertonic -hypotonic -hydrophilic -hydrophobic
true
In animal cells, the main microtubule organizing center (or centrosome) is important in cell division. -true -false
false
In cell membranes, cholesterol and glycoproteins are exposed to the extracellular surface for cell recognition and adhesion to other cells. -true -false
transporters
Carrier proteins are also called ______. -active transport -aquaporins -transporters -pores -passive transport
plasma membrane
A cell is surrounded by which distinctive surface membrane? -plasma membrane -trans membrane -biological membrane -peripheral membrane -integral membrane
Activation of adenylyl cyclase
During signal transduction of a G protein, the first messenger binds to the receptor, and the G protein is activated. What happens next? -Cellular response -Activation of adenylyl cyclase -Phosphorylation of the G protein -Formation of cAMP -Activation of protein kinase
true
Scaffold proteins organize groups of intracellular signaling kinases into signaling complexes true false
neurons
What transmits information electrically and chemically? -Neurons -Cell signaling -Receptors -Target cells -Hormones
Exocytosis
Which cellular mechanism ejects products, such as hormones, by the fusion of a vesicle with the plasma membrane? -Exocytosis -Phagocytosis -Receptor-mediated endocytosis -Endocytosis -Pinocytosis
true
The gas ethylene is a plant hormone that regulates a variety of processes, including seed germination and ripening of fruit -true -false
to transfer Na+ to the outside of a cell
The role of ATP in the sodium-potassium pump is -to assist a cell to release Na+ by exocytosis. -to assist a cell to take up Na+ by endocytosis. -to assist a Na+ to bind to a carbohydrate. -to transfer Na+ to the outside of a cell. -to transfer Na+ to the inside of a cell.
cell membranes
The smooth ER is the primary site for the synthesis of phospholipids and cholesterol needed to make ____. -ATP -hormones -cell membranes -ribosomes -DNA
microtubule
You isolate a cellular structure and determine that it is composed of α-tubulin and β-tubulin. Based on this evidence, you correctly identify this structure as a(n): -microfilament -microtubule -myosin filament -actin filament -structural MAP
The signaling molecules are diffused through interstitial fluid and act on nearby cells.
How is paracrine signaling different from other types of signaling? The signaling molecules are displayed on the cell surface and interact with nearby cells. The signaling molecules are diffused through interstitial fluid and act on nearby cells. The signaling molecules are hormones. The signaling molecules are transferred by electrical signals and act on nearby cells. The signaling molecules release neurotransmitters.
organelles
Specialized structures within a living cell are known as ___________. -unorganized structures. -prokaryotic structures. -organelles. -nuclei. -eukaryotic structures.
ATP
What does an ABC transporter use to move larger ions and molecules across the cell membrane? -Porins -Tunnels -Water -Signals -ATP
ribosomal RNA
What does the nucleolus, within the nucleus, synthesize? -ribosomal RNA -genes -DNA -hormones -messanger RNA
turgor pressure
What process halts the net movement of water from a hypotonic solution into a plant's cells and often provides the structural support to many plants? -Osmotic pressure -Turgor pressure -Facilitated diffusion -Plasmolysis -Dynamic equilibrium
neurons
What transmits information electrically and chemically? -Receptors -Neurons -Hormones -Target cells -Cell signaling
false
When a signaling molecule binds to a G protein-linked receptor, the ligand-receptor complex associates with GDP protein and causes GDP to be replaced by GTP -true -false
cell fractionation
Which technique is used to separate different part of cells so that they can be studied by both physical and chemical methods? -cell fractionation -object separation techniques -chemical separation techniques -physical separation techniques -biochemical techniques
simple diffusion
You light a scented candle in the guest bathroom. Within a few minutes, you can smell the candle's scent throughout the hallway. What process is occurring? -Osmosis -Dialysis -Active transport -Facilitated diffusion -Simple diffusion
chromatin
DNA is associated with certain proteins, forming a complex called: -chromatin -nucleoli -chromosomes -genes -nucleus
it will have serious, perhaps fatal consequences because the red blood cells could swell and burst
A patient who has had a severe hemorrhage accidentally receives a large transfusion of distilled water directly into a major blood vessel. What effect will this have on the patient? -It will have no serious effect because the kidney could quickly eliminate excess water. -It will have serious, perhaps fatal consequences because the red blood cells could swell and burst. -It will have serious, perhaps fatal consequences because there would be too much fluid to pump. -It will have serious, perhaps fatal consequences because the red blood cells could shrink. -It will have no unfavorable effect as long as the water is free from bacteria.
true
Almost every vertebrate cell has a primary cilium, a single cilium on the cell surface that serves as a cellular antenna. -true -false
The rapid addition of a phosphate to the glucose molecules
Although glucose molecules constantly diffuse into a red blood cell along their concentration gradient, equilibrium is never reached and a steep concentration gradient is continually maintained. What causes this? -The ability of the cell to engulf glucose by pinocytosis -The active transport of glucose -The rapid addition of a phosphate to the glucose molecules -The continuous excretion of glucose from other parts of the cell -The very fast turnover rate of glucose metabolism
The rapid addition of a phosphate to the glucose molecules
Although glucose molecules constantly diffuse into a red blood cell along their concentration gradient, equilibrium is never reached and a steep concentration gradient is continually maintained. What causes this? -The active transport of glucose -The ability of the cell to engulf glucose by pinocytosis -The continuous excretion of glucose from other parts of the cell -The rapid addition of a phosphate to the glucose molecules -The very fast turnover rate of glucose metabolism
true
Barbiturates and benzodiazepine drugs bind to GABA receptors to open chloride channels, inhibit neural impulse, and induce tranquility. __________________ -true -false
false
Biological membranes are one-dimensional fluids. -True -False
false
Biological membranes are one-dimensional fluids. -True -False
hormones
Consider the cellular process illustrated in the accompanying figure. What substance would most likely be transported in this manner? -Glucose -Carbon dioxide -Potassium ions -Bacteria -Hormones
false
Cotransport systems directly provide energy for active transport of solutes. -true -false
mRNA
DNA transcribes its information into what type of molecule? -myosin -chromosomes -mRNA -RNA -polypeptide
degrade the pathogens with hydrolytic enzymes for later export from the cell
During an infection, white blood cells travel to the infected site and phagocytize the pathogens. After phagocytosis, primary lysosomes fuse with the phagocytic vesicle to form a larger vesicle called a secondary lysosome. The purpose for this process is to: -coat the pathogens in lipids to tag it for neutralization -degrade the pathogens with hydrolytic enzymes for later export from the cell -isolate the pathogens in an additional membrane to render them harmless -degrade the pathogens into components, which the cell recycles or uses as an energy source -export the intact secondary lysosome containing the pathogens from the cell
dimer
During enzyme-linked reception, signal molecules bind to two tyrosine kinase receptors. The receptor proteins move closer together in the plasma membrane and pair, forming a(n) ____. -polypeptide chain -protein kinase cascade -gate -dimer -pathway
receptor
If the cells are physically close to one another, a signaling molecule on one cell may combine with a _________ on another cell. -receptor -peripheral membrane protein -ligand -vacuole -membrane
centrioles
In many cells, including almost all animal cells, the centrosome contains two structures called _________. -mitotic spindle -flagella -centrosome -centrioles -primary cilium
false
In scanning electron microscopy, an electron beam passes through a very thin slice of a specimen and then falls onto a photographic plate or a fluorescent screen -true -false
false
In scanning electron microscopy, an electron beam passes through a very thin slice of a specimen and then falls onto a photographic plate or a fluorescent screen. -true -false
binds calcium channel in the ER
In the IP3 pathway, what is the function of IP3? -Phosphorylates a protein -Activates adenylyl cyclase -Binds calcium channels in the ER -Activates protein kinase C -Activates phospholipase C
gap junctions
In the accompanying figure, what is the form of cellular junction? FIGURE 5-3 -Adhering junctions -Tight junctions -Desmosomes -Plasmodesmata -Gap junctions
They allow the transport of small molecules and ions between adjacent cells
In the accompanying figure, what is the role of the structures between the membranes? -They provide anchorage points between adjacent cells. -They provide structure to plant cells. -They allow the transport of small molecules and ions between adjacent cells. -They allow passage of materials through intercellular spaces. -They prevent the passage of materials through intercellular spaces.
true
Microfilaments are linked with one another and with other proteins by linker proteins. -true -false
true
Most plasmodesmata contain a narrow cylindrical structure, called the desmotubule, which runs through the channel and connects the smooth ER of the two adjacent cells. -True -False
coated vesicle forms by endocytosis
Once ligand molecules bind to receptors in coated pits of a plasma membrane, the next step of receptor-mediated endocytosis would be -coated vesicle forms by endocytosis. -ligands separate from receptors, which are recycled. -contents of secondary lysosome are digested and released into the cytosol. -endosome fuses with primary lysosome, forming secondary lysosome. -coating detaches from vesicle.
bonding to integral proteins through noncovalent interactions.
Peripheral proteins are linked to either surface of the plasma membrane by -associating with fatty acids through hydrophobic interactions. -covalent disulfide bonds. -associating with glycoproteins on the inner membrane surface. -bonding to integral proteins through noncovalent interactions. -embedding in only one side of the membrane.
membrane potential
Sodium-potassium pumps help to maintain a separation of charges across the plasma membrane, which is called the _________________. -membrane potential -symporter -macrophage -proton gradient -antiporter
a sodium gate opens
Suppose that acetylcholine binds its receptor on the surface of a muscle cell. What happens next? -Tyrosine kinase is activated. -A sodium gate opens. -A neurotransmitter crosses the synapse. -Tyrosine is phosphorylated. -G protein is activated.
cis face to medial region to trans face
A glycoprotein destined for secretion from the cell would move through the Golgi complex in which sequence? -medial face to trans face to cis face -trans face to medial region to cis face -trans face to cis face to medial region -cis face to medial region to trans face -cis face to trans face to medial region
The phagocytic vacuole would not fuse with the lysosome
A person has a genetic disease that prevents the phospholipids in the plasma membrane of the white blood cells from freely fusing with the other membranes within the cell. How would this disease affect phagocytosis? -Lysosomes would not be formed. -Lysosomes would be formed lacking hydrolytic enzymes. -The phagocytic vacuole would not fuse with the lysosome. -Endocytosis would not occur. -Facilitated diffusion would not occur.
It is the docking site for a signaling molecule.
A receptor on the cell surface usually has several domains. What is the function of the external domain? -It transmits the signal to the inside of the cell. -It is the docking site for a signaling molecule. -It holds the receptor within the membrane. -It functions as an enzyme. -It attaches the receptor to the DNA.
ATP is converted to cAMP
Adenylyl cyclase catalyzes the reaction in which -calcium ions bind calmodulin. -a protein is phosphorylated. -GTP is converted to GDP. -PIP2 is split. -ATP is converted to cAMP.
ATP is converted to cAMP
Adenylyl cyclase catalyzes the reaction in which calcium ions bind calmodulin. a protein is phosphorylated. ATP is converted to cAMP. GTP is converted to GDP. PIP2 is split.
False
Enzymes called proteases in the ER lumen catalyze folding of proteins into proper conformations. -true -false
The fatty acid tails solidify at room temperature.
How do the phospholipids in vegetable oil differ from those of animal fat? -The fatty acid tails bend. -The fatty acid tails solidify at room temperature. -The fatty acid tails interact via van der Waals forces. -The fatty acid tails lack double bonds. -The fatty acid tails are a chain of saturated fats.
The signaling molecules are diffused through interstitial fluid and act on nearby cells.
How is paracrine signaling different from other types of signaling? -The signaling molecules are hormones. -The signaling molecules are displayed on the cell surface and interact with nearby cells. -The signaling molecules are transferred by electrical signals and act on nearby cells. -The signaling molecules release neurotransmitters. -The signaling molecules are diffused through interstitial fluid and act on nearby cells.
The cell surface will keep expanding
In cells that are constantly involved in secretion, an equivalent amount of membrane must be returned to the interior of the cell for each vesicle that fuses with the plasma membrane; if this does not occur, then what would happen? -The cell surface will keep expanding. -The cell surface would shrivel. -The surface area would remain constant. -The ratio of cell surface would decrease, compared to cell volume. -The number of membrane receptor proteins would decrease.
the protein kinase activates a cellular response
In the cAMP signal transduction pathway, a protein kinase is activated. What happens next? -cAMP is converted to ATP. -GDP is replaced by GTP. -Adenylyl cyclase is activated. -G protein is activated. -The protein kinase activates a cellular response.
IP3 and DAG
In the phospholipase C signal transduction pathway, which pair of second messengers is produced? -PIP2 and IP3 -cAMP and IP3 -Phospholipase C and G protein -Phospholipase C and protein kinase A -IP3 and DAG
false
In the sodium-potassium pump, sodium ion release causes the carrier protein to return to its original shape and releases two K+ ions into the cell. -True -False
false
Insulin stimulates cells to take in glucose by facilitated diffusion, so the down regulation of insulin receptors increases the ability of cells to take in glucose. __________________ -true -false
keratins
Intermediate filaments are most closely associated with which of the following? -keratins -myosin -pseudopodia -microvilli -actin
plasma membrane
Mammalian red blood cells contain which type of membrane? -Peripheral membrane -Plasma membrane -Biological membrane -Trans membrane -Integral membrane
antiporters
Since sodium-potassium pumps transport sodium ions out of a cell and potassium ions into a cell, what type of carrier proteins are they? -Antiporters -ABC transporter -Uniporters -Symporters -Ion pumps
protein synthesis
The cellular structure indicated by the arrow in the accompanying figure is responsible for: FIGURE 4-2 -lipid and fatty acid metabolism -DNA replication -protein synthesis -digestion of unused organelles -cellular respiration
cyclic adenosine
The following are different types of neurotransmitters EXCEPT -norepinephrine. -cyclic adenosine. -dopamine. -serotonin. -acetylcholine.
G protein
The hydrolysis of GTP to GDP deactivates the ____. Ras protein protein kinase pathway G protein cAMP ligand-gated channel
MAP kinase
The main signaling cascade for cell division and differentiation is the ____ cascade. -calcium-calmodulin -cAMP -phospholipase C -MAP kinase -phosphoinositol
signaling molecule; G protein
The outer part of a G protein-linked receptor binds to a(n) ____, and its inner part binds to a(n) ____. -signaling molecule; tyrosine kinase -signaling molecule; G protein -G protein; tyrosine kinase -G protein; ion channel -ion channel; G protein
reception
The process of receiving an incoming signal is known as _______. -signal transduction -reception -response -receptor -signal transmission
the movement of lipids and integral proteins within the lipid bilayer
The term "fluid mosaic model" refers to -the movement of surface proteins through the membrane. -the diffusion of lipid-soluble substances across the lipid bilayer. -the movement of lipids and integral proteins within the lipid bilayer. -the method of substance transport across the membrane. -the solubility of water in the membrane.
neutral signaling is inbitied
What can happen when GABA binds to its receptor? -Enzyme-linked receptors are activated. -Neural signaling is inhibited. -New signals are transmitted. -Muscle contraction is stimulated. -Sodium ions enter the cell.
Exocytosis
What cellular process is represented in the accompanying figure? FIGURE 5-2 -Cotransport -Pinocytosis -Exocytosis -Lysis -Facilitated diffusion
molecular chaperones
What enzyme in the ER lumen catalyzes the efficient folding of proteins into proper conformations? -molecular chaperones -golgi complexes -proteasomes -digestive enzymes -calcium
aquaporins
What facilitates the rapid transport of water through the plasma membrane? -ABC transporters -Osmosis -Uniporters -Channel proteins -Aquaporins
Both D & E
What happens during the cotransport of glucose and sodium ions? -Sodium ions are transported down their concentration gradient. -Both D and E -Glucose molecules are transported against their concentration gradient. -The transport of glucose powers the transport of sodium. -ATP causes a conformational change in the carrier protein.
there is unregulated cell division
What happens when Ras proteins become stuck in their "on" state? -Cellular responses are slowed down. -There is an increase in protein synthesis. -Ligand-gated channels close off the membrane. -Additional ions are catalyzed. -There is unregulated cell division.
plasma membrane
What is a characteristic found in both prokaryotic and eukaryotic cells? -nucleoplasm -mitochondria -nucleus -chloroplast -plasma membrane
a calcium-binding protein
What is calmodulin? -A protein kinase -A calcium-binding protein -A phospholipase -A hormone -A phosphatase
plasmodesmata
What is found between adjacent plant cells that allows signal molecules to pass quickly from one cell to another? -Paracrine regulation -Prostaglandins -Endocrine glands -Neurotransmitters -Plasmodesmata
a transmembrane protein
What is required for facilitated diffusion to take place? -Energy from ATP -The transport of small nonpolar molecules -A transmembrane protein -Movement down a concentration gradient -The transport of large food particles
9+2 arrangement
What is the microtubule arrangement of a flagellum or cilium? -9+2 arrangement -9x1 array -9x3 structure -9+1 array -9+3 arrangement
Osmosis
What is the passive movement of water along a concentration gradient? -Facilitated diffusion -Simple diffusion -Osmosis -Cotransport -Plasmolysis
signal amplification
What is the process in which one activated receptor can give rise to thousands of final products? -Signal transduction -Signal termination -Signal amplification -Signal transmission -Signal transcription
to increase surface area
What is the purpose of the cristae of the inner membrane of mitochondria? -To store food -To increase surface area -To metabolize lipids -To break down nutrients -To transport waste
A hormone's signal is amplified.
What is typically the result of receptor upregulation? -The number of receptors decreases. -The sensitivity of a cell to a hormone decreases. -A hormone's signal is amplified. -The concentration of hormone molecules in the blood increases. -The number of genes that code for a receptor increases.
a hormones signal is amplified
What is typically the result of receptor upregulation? -A hormone's signal is amplified. -The sensitivity of a cell to a hormone decreases. -The number of genes that code for a receptor increases. -The concentration of hormone molecules in the blood increases. -The number of receptors decreases.
glycocalyx
What protects a cell and may help keep other cells at a distance? -extracellular matrix -microfilaments -cell wall -glycocalyx -middle lamella
adhering junctions
What type of cellular junction cements cells together that use cadherins as a belt around each cell? -Plasmodesmata -Desmosomes -Adhering junctions -Tight junctions -Gap junctions
fluorescence microscopy
What type of microscopy uses a laser to excite fluorophores in a thin "slice" through a cell? -fluorescence microscopy -normarski differential interference-contrast microscopy -confocal microscopy -scanning electron microscopy -phase contrast microscopy
false
When an enzyme-linked receptor is activated, a conformational change activates the extracellular kinases -true -false
false
When food is abundant, the cellular slime mold Dictyostelium secretes cAMP into the environment to signal the formation of a multicellular slug-shaped colony. -true -false
signal transmission, reception, signal transduction, response
Which list describes the correct sequence of events involved in cell signaling? -Signal transduction, reception, signal transmission, response -Response, signal transduction, signal transmission, reception -Signal transmission, signal transduction, reception, response -Reception, signal transmission, response, signal transduction -Signal transmission, reception, signal transduction, response
Histamine
Which local regulator is stored in cells of the immune system and released during an allergic reaction? -Nitric oxide -Histamine -A prostaglandin -A growth factor -A neurotransmitter
potassium ion
Which molecule is least likely to cross a cellular membrane by simple diffusion? -Potassium ion -Water -Nitrogen -Oxygen -Carbon dioxide
potassium ion
Which molecule is least likely to cross a cellular membrane by simple diffusion? -Nitrogen -Water -Oxygen -Carbon dioxide -Potassium ion
potassium ion
Which molecule is least likely to cross a cellular membrane by simple diffusion? -Oxygen -Water -Nitrogen -Potassium ion -Carbon dioxide
Mitochondria
Which of the following organelles plays an important role in apoptosis, or programmed cell death? -ribosomes -mitochondria -peroxisomes -vacuoles -chlorplasts
integrins-receptors
Which of the following pairs is correctly matched? -middle lamella−cellulose -fibronectins−wood -secondary cell wall−glycoproteins -integrins−receptors -primary cell wall−pectin
mitotic spindle
Which of the following serves as a framework for the orderly distribution of chromosomes during cell division? -centrosome -centrioles -mitotic spindle -flagella -primary cilium
they contain three fatty acids chains
Which of the following statements about phospholipids is false? -They are amphipathic molecules. -They have cylindrical shapes that allow them to associate with water most easily as a bilayer structure. -They contain three fatty acids chains. -They have two distinct regions, one strongly hydrophobic and the other strongly hydrophilic. -They contain a polar organic group attached to a phosphate group.
they contain three fatty acids
Which of the following statements about phospholipids is false? -They have two distinct regions, one strongly hydrophobic and the other strongly hydrophilic. -They are amphipathic molecules. -They contain three fatty acids chains. -They have cylindrical shapes that allow them to associate with water most easily as a bilayer structure. -They contain a polar organic group attached to a phosphate group.
micrometer
Which one of these are the most convenient unit for measuring cells? -micrometer -picometer -millimeter -centimeter -nanometer
one subunit binds ATP
Which statement about G protein is false? -One subunit is a GTPase. -One subunit binds GDP. -One subunit binds ATP. -One subunit binds GTP. -Its subunits can separate.
one subunit binds ATP
Which statement about G protein is false? -One subunit is a GTPase. -One subunit binds GTP. -Its subunits can separate. -One subunit binds ATP. -One subunit binds GDP.
They are inactivated when phosphorylated.
Which statement about Ras proteins is false? -They are G proteins. -They are active when bound to GTP. -They are inactivated when phosphorylated. -They are activated by tyrosine kinase receptors. -They include MAP kinases.
they have a 9+2 arrangement of microtubules
Which statement about centrioles is false? -They are found in the centrosome. -They are duplicated before cell division. -They are thought to play a role in microtubule assembly. -They are present in most animal cells but not most plant cells. -They have a 9 + 2 arrangement of microtubules.
they are also called ligands
Which statement about receptors is false? -They are found inside the cell and on the cell surface. -They are highly selective. -They are proteins or glycoproteins. -They are also called ligands. -They are activated by binding to a signaling molecule.
Figure B has a smaller surface area to volume ratio than Figure A.
Which statement about the accompanying figures is true? FIGURE 4-1 -Figure B has a smaller surface area to volume ratio than Figure A. -Figure B has a greater surface area to volume ratio than Figure A. -Figure B has a greater surface area than Figure A. -Figure B has a greater volume than Figure A. -Figure B has a smaller volume than Figure A.
having thin, finger-like projections
Which strategy is the most effective for larger cells to have an effective surface area to volume ratio? -having a thinner plasma membrane -having specialized structures that enable locomotion -having a completely spherical shape -being short and fat -having thin, finger-like projections
mitochondria and chloroplasts
Which two organelles are responsible for converting energy into forms that can be used by cells? -lysosomes and chloroplasts -mitochondria and chloroplasts -ribosomes and chloroplasts -mitochondria and peroxisomes -mitochondria and lysosomes
mitochondria and chloroplasts
Which two organelles are responsible for converting energy into forms that can be used by cells? -lysosomes and chloroplasts -ribosomes and chloroplasts -mitochondria and peroxisomes -mitochondria and lysosomes -mitochondria and chloroplasts
actin filaments
While testing an experimental drip on a vertebrate cell, you notice that the cell cortex becomes more fluid and the cell loses its ability to move. Despite this, you determine that cell strength is maintained. Based on these observations, you correctly conclude that the drug most directly affects: -α-tubulin -β-tubulin -actin filaments -myosin -intermediate filaments
it is slightly amphipathic because of the presence of one hydroxyl group
Why can cholesterol act as a "fluidity buffer" in cell membranes? -It is slightly hydrophobic because of the presence of one hydroxyl group. -It is slightly hydrophobic because of the presence of one carboxyl group. -It is slightly hydrophilic because of the presence of one hydrocarbon group. -It is slightly amphipathic because of the presence of one hydroxyl group. -It is slightly amphipathic because of the presence of one carboxyl group
a small cell has a small volume relative to surface area, which allows efficient transport through the plasma membrane
Why is it advantageous for cells to be small? -A small cell has a small surface area relative to volume, which allows efficient transport through the plasma membrane. -A small cell size occupies less space in nature where space is limited. -A small cell is better able to conserve energy than a larger cell. -A small cell size prevents a cell from weighing too much. -A small cell has a small volume relative to surface area, which allows efficient transport through the plasma membrane.
The fibroblasts no longer synthesize DNA in response to growth factors.
You conduct an experiment in which you inactivate Ras proteins in fibroblast cells. Which of the following is the most immediate consequence of this procedure? -The fibroblasts synthesize excess DAG. -The fibroblasts no longer synthesize DNA in response to growth factors. -The fibroblasts divide uncontrollably. -The fibroblasts no longer respond to calmodulin. -The fibroblasts synthesize excess G protein.
anchor cell to extracellular allow selective transport of ions or molecules use of ATP to transport solutes transmit information into cell catalyze reactions which take place within or along the membrane surface
integrins channels protein pumps signal transduction receptors membrane-bound enzymes choices: anchor cell to extracellular allow selective transport of ions or molecules use of ATP to transport solutes transmit information into cell catalyze reactions which take place within or along the membrane surface
1. enzyme linked receptor 2. enzyme linked receptor 3. ion channel linked receptor 4. G protein linked receptor 5. G protein linked receptor
phosphate comes from ATP---- protein kinase sites are active---- sodium ions enter the cell------ GDP is replaced the cell----- GDP is replaced with GTP------ DAG is the second messenger--- choices: -G protein linked receptor -enzyme linked receptor -ion channel linked receptor
