Chapter 4 & 5

The diameter of a typical eukaryotic cell is approximately ten times the diameter of a typical prokaryote. What is the ratio of the volume of typical eukaryotic:prokaryotic cells? 100:1 1000:1 10:1

1000:1

Prokaryotes are classified as belonging to two different domains. What are the domains? Bacteria and Archaea Bacteria and Eukarya Bacteria and Protista Archaea and Protista Bacteria and Fungi

Bacteria and Archaea

Which of the following are common traits of chloroplasts and mitochondria? Both are found in plant and animal cells. Both reproduce by meiosis. Both have their own DNA. Both are surrounded by a single membrane. Proteins for both are synthesized on ribosomes in the rough ER.

Both have their own DNA.

What role does a transcription factor play in a signal transduction pathway? By binding to a plasma membrane receptor it initiates a cascade. It relays a signal from the cytoplasm to the plasma membrane. It activates relay proteins. By binding to DNA it triggers the transcription of a specific gene. It is a plasma membrane protein that binds signal molecules.

By binding to DNA it triggers the transcription of a specific gene.

Which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly? CO2 glucose starch K+ an amino acid

CO2

Which of the following statements concerning cells of bacteria and archaea is correct? DNA is present in both archaea and bacteria. Archaea contain small membrane-enclosed organelles; bacteria do not. Archaea contain a membrane-bound nucleus; bacteria do not. DNA is present in the mitochondria of both bacteria and archaea.

DNA is present in both archaea and bacteria.

A cell has formed a food vacuole as it ingested a food particle. Which of the following events is associated with the breakdown of that food particle? Proteins for digestion of the food particle were initially processed in mitochondria. Proteins for digestion of the food are made by ribosomes in the Golgi apparatus. The membrane of the food vacuole is derived from the cell wall. Enzymes for the breakdown of the food are delivered to the food vacuole from the cytosol. Digestion of the food particle occurs in a vesicle enclosed by a membrane that separates the digestion from the cytoplasm.

Digestion of the food particle occurs in a vesicle enclosed by a membrane that separates the digestion from the cytoplasm.

What is the most likely pathway taken by a newly synthesized protein that will be secreted by a cell? Golgi → ER → lysosomes nucleus → ER → Golgi ER → Golgi → nucleus ER → lysosomes → vesicles that fuse with plasma membrane ER → Golgi → vesicles that fuse with plasma membrane

ER → Golgi → vesicles that fuse with plasma membrane

Why are there often so many steps between the original signal event and the cell's response? Long, highly specific pathways minimize the possibility that a relay molecule accidentally could activate a pathway leading to a secondary response. The accumulation of genetic mutations over time has added redundant steps to the pathway. Lengthy pathways provide the opportunity for the initial pathway molecules to recycle back to inactive forms should additional signaling molecules be present. Each transduction is a checkpoint. Each step in a cascade produces a large number of activated products, causing signal amplification as the cascade progresses.

Each step in a cascade produces a large number of activated products, causing signal amplification as the cascade progresses.

At puberty, an adolescent female body changes in both structure and function of several organ systems, primarily under the influence of changing concentrations of estrogens and other steroid hormones. How can one hormone, such as estrogen, mediate so many effects? Estrogen is produced in very large concentration and therefore diffuses widely. Estrogen binds to specific receptors inside many kinds of cells, each of which have different responses to its binding. Estrogen has specific receptors inside several cell types, but each cell responds in the same way to its binding. Estrogen is kept away from the surface of any cells not able to bind it at the surface. The subcomponents of estrogen, when metabolized, can influence cell response.

Estrogen binds to specific receptors inside many kinds of cells, each of which have different responses to its binding.

_____ aid in the coordination of the activities of adjacent animal cells. Plasmodesmata Keratin fibers Desmosomes Tight junctions Gap (communicating) junctions

Gap (communicating) junctions

Which of the following produces and modifies polysaccharides that will be secreted? lysosome mitochondrion vacuole Golgi apparatus peroxisome

Golgi apparatus

Why isn't the mitochondrion classified as part of the endomembrane system? It is not involved in protein synthesis. It is not attached to the outer nuclear envelope. It is a static structure. It has too many vesicles. Its structure is not derived from the ER or Golgi.

Its structure is not derived from the ER or Golgi.

Which of the following functions is NOT associated with the cytoskeleton in eukaryotic cells? determining the shape of animal cells the contraction of muscle cells in animals the beating of cilia or flagella maintaining the position of the nucleus in the cell Movement of RNA molecules from the nucleus to the cytoplasm

Movement of RNA molecules from the nucleus to the cytoplasm

_____ catalyzes the production of _____, which then opens an ion channel that releases _____ into the cell's cytoplasm. Phospholipase C ... IP3 .... Ca2+ Adenylyl cyclase ... cyclic AMP ... Ca2+ Phospholipase C ... cyclic AMP ... Ca2+ Protein kinase ... PIP2 ... Na+ Adenylyl cyclase ... IP3 .... Ca2+

Phospholipase C ... IP3 .... Ca2+

Which of the following statements correctly describes some aspect of protein secretion from prokaryotic cells? The mechanism of protein secretion in prokaryotes is probably the same as that in eukaryotes. Proteins that are secreted by prokaryotes are synthesized on ribosomes that are bound to the cytoplasmic surface of the plasma membrane. In prokaryotes, the ribosomes that are used for the synthesis of secreted proteins are located outside of the cell. Prokaryotes contain large pores in their plasma membrane that permit the movement of proteins out of the cell. Prokaryotes are unlikely to be able to secrete proteins because they lack an endomembrane system.

Proteins that are secreted by prokaryotes are synthesized on ribosomes that are bound to the cytoplasmic surface of the plasma membrane.

Which one of the following statements about the endomembrane system is correct? Most of the phospholipids of the endomembrane system are synthesized in the mitochondria. The endoplasmic reticulum is continuous with the plasma membrane. Mitochondria function in the modification and sorting of lipids and proteins. Proteins that will be secreted from the cell are likely to be found in closed spaces bounded by membranes of the endomembrane system. Ribosomes move lipids and proteins among the different organelles of the endomembrane system.

Proteins that will be secreted from the cell are likely to be found in closed spaces bounded by membranes of the endomembrane system.

Proton pumps are used in various ways by members of every domain of organisms: Bacteria, Archaea, and Eukarya. What does this most probably mean? Proton pumps must have evolved before any living organisms were present on Earth. Cells of each domain evolved proton pumps independently when oceans became more acidic. Proton gradients across a membrane were used by cells that were the common ancestor of all three domains of life. Proton pumps are necessary to all cell membranes. The high concentration of protons in the ancient atmosphere must have necessitated a pump mechanism.

Proton gradients across a membrane were used by cells that were the common ancestor of all three domains of life.

What are the functions of signal transduction pathways? Select all that apply. Signal transduction pathways amplify the effect of a signal molecule. Signal transduction pathways convert a signal on a cell's surface to a specific cellular response. Signal transduction pathways allow different types of cells to respond differently to the same signal molecule.

Signal transduction pathways amplify the effect of a signal molecule. Signal transduction pathways convert a signal on a cell's surface to a specific cellular response. Signal transduction pathways allow different types of cells to respond differently to the same signal molecule.

A semipermeable membrane is placed between the following solutions. Which solution will decrease in volume? Solution A: 1.4% (m/v) starch Solution B: 7.62% (m/v) starch

Solution A: 1.4% (m/v) starch

Which of the following statements correctly describes the normal tonicity conditions for typical plant and animal cells? The animal cell is in an isotonic solution, and the plant cell is in a hypertonic solution. The animal cell is in a hypotonic solution, and the plant cell is in an isotonic solution. The animal cell is in a hypertonic solution, and the plant cell is in an isotonic solution. The animal cell is in an isotonic solution, and the plant cell is in a hypotonic solution. The animal cell is in a hypertonic solution, and the plant cell is in a hypotonic solution.

The animal cell is in an isotonic solution, and the plant cell is in a hypotonic solution.

Choose the best description of the cell cytoskeleton. The cell cytoskeleton is a dynamic network of fibers that can be quickly dismantled and reassembled to change cell shape and the position of cell components. The cell cytoskeleton is similar to an animal skeleton in providing rigid internal support and structure to the cell. The cell cytoskeleton serves as permanent scaffolding to anchor cell components into position within the cell cytoplasm.

The cell cytoskeleton is a dynamic network of fibers that can be quickly dismantled and reassembled to change cell shape and the position of cell components.

When a plant cell, such as one from a peony stem, is submerged in a very hypotonic solution, what is likely to occur? The cell will become turgid. Plasmolysis will shrink the interior. The cell membrane will lyse. The cell will burst. The cell will become flaccid.

The cell will become turgid.

Which statement correctly describes the nuclear envelope of a eukaryotic cell? The nuclear envelope is a single membrane, consisting of a phospholipid bilayer. Plasmadesmosomes in the nuclear envelope permit the exchange of macromolecules between the nucleus and the cytoplasm. All of the proteins of the cell are synthesized on ribosomes bound on the nuclear envelope. The nuclear envelope is continuous with the endoplasmic reticulum. The outer layer of the nuclear envelope is coated with laminin.

The nuclear envelope is continuous with the endoplasmic reticulum.

Identify the correct statement about differences between rough and smooth endoplasmic reticulum (ER). Rough ER consists of a network of membranous tubules and sacs called cisternae, whereas smooth ER is less complex. The outer surface of smooth ER lacks ribosomes, whereas the outer surface of rough ER has ribosomes. Smooth ER is part of the endomembrane system of the eukaryotic cell, and rough ER is not. SubmitMy AnswersGive Up

The outer surface of smooth ER lacks ribosomes, whereas the outer surface of rough ER has ribosomes.

Which of the following statements about osmosis is correct? The presence of aquaporins (proteins that form water channels in the membrane) should speed up the process of osmosis. Osmosis is the diffusion of water from a region of lower water concentration to a region of higher water concentration. Osmotic movement of water into a cell would likely occur if the cell accumulates water from its environment. If a solution outside the cell is hypertonic compared to the cytoplasm, water will move into the cell by osmosis. If a cell is placed in an isotonic solution, more water will enter the cell than leaves the cell.

The presence of aquaporins (proteins that form water channels in the membrane) should speed up the process of osmosis.

When protein membrane receptors are activated, what usually happens? The receptors open and close in response to protein signals. A change occurs on only one membrane surface: exterior or interior. A change occurs in intracellular ion concentration. The receptor preferentially binds with lipid or glycolipid signal molecules. The receptor changes conformation after binding with signal polypeptides.

The receptor changes conformation after binding with signal polypeptides.

The cell walls of bacteria, fungi, and plant cells and the extracellular matrix of animal cells are all external to the plasma membrane. Which of the following is a characteristic common to all of these extracellular structures? They are constructed of polymers that are synthesized in the cytoplasm and then transported out of the cell. They must block water and small molecules in order to regulate the exchange of matter and energy with their environment. They must provide a rigid structure that maintains an appropriate ratio of cell surface area to volume. They must permit information transfer between the cell's cytoplasm and the nucleus. They are composed of a mixture of lipids and carbohydrates.

They are constructed of polymers that are synthesized in the cytoplasm and then transported out of the cell.

Which of the following is true of transcription factors? They regulate the synthesis of DNA in response to a signal. They transcribe ATP into cAMP. They initiate the epinephrine response in animal cells. They control gene expression. They regulate the synthesis of lipids in the cytoplasm.

They control gene expression.

In facilitated diffusion, what is the role of the transport protein? Transport proteins provide a protein site for ATP hydrolysis, which facilitates the movement of a solute across a membrane. Transport proteins provide a hydrophilic route for the solute to cross the membrane. Transport proteins organize the phospholipids to allow the solute to cross the membrane. Transport proteins provide the energy for diffusion of the solute. Transport proteins provide a low-resistance channel for water molecules to cross the membrane.

Transport proteins provide a hydrophilic route for the solute to cross the membrane.

What happens when two solutions separated by a selectively permeable membrane reach osmotic equilibrium? Water molecules no longer move between the solutions. Water molecules continue to move from the hypotonic solution to the hypertonic solution. Water molecules move between the two solutions, but there is no net movement of water across the membrane.

Water molecules move between the two solutions, but there is no net movement of water across the membrane.

Mammalian blood contains the equivalent of 0.15 M NaCl. Seawater contains the equivalent of 0.45 M NaCl. What will happen if red blood cells are transferred to seawater? The blood cells will expend ATP for active transport of NaCl into the cytoplasm. Water will leave the cells, causing them to shrivel and collapse. NaCl will be exported from the red blood cells by facilitated diffusion. The blood cells will take up water, swell, and eventually burst. NaCl will passively diffuse into the red blood cells.

Water will leave the cells, causing them to shrivel and collapse.

Which of the following molecular movements is due to diffusion or osmosis? When a plant cell is placed in concentrated salt water, water moves out of the cell. Cells of the pancreas secrete insulin into the bloodstream. The sodium-potassium pump pumps three sodium ions out of a neuron for every two potassium ions it pumps in.

When a plant cell is placed in concentrated salt water, water moves out of the cell.

The smallest cell structure that would most likely be visible with a standard (not super-resolution) research-grade light microscope is a microtubule. a microfilament. a nuclear pore. a mitochondrion. a ribosome.

a mitochondrion.

If the concentration of phosphate in the cytosol is 2.0 mM and the concentration of phosphate in the surrounding fluid is 0.1 mM, how could the cell increase the concentration of phosphate in the cytosol? passive transport diffusion active transport osmosis facilitated diffusion

active transport

A protein kinase activating many other protein kinases is an example of _____. amplification sensitization a cellular response deactivation mutualism

amplification

All of the following are part of a prokaryotic cell except a cell wall. ribosomes. a plasma membrane. DNA. an endoplasmic reticulum.

an endoplasmic reticulum

The movement of potassium into an animal cell requires high cellular concentrations of potassium. an energy source such as ATP. a potassium channel protein. a cotransport protein. low cellular concentrations of sodium.

an energy source such as ATP.

Which of the following are among the most common second messengers? kinase and phosphate groups calcium ion and cAMP GTP and GDP G proteins and GTP kinase and phosphatase

calcium ion and cAMP

Which of the following correctly matches an organelle with its function? lysosome ... movement mitochondrion ... photosynthesis nucleus ... cellular respiration central vacuole ... storage ribosome ... manufacture of lipids

central vacuole ... storage

Which structure is NOT part of the endomembrane system? chloroplast Golgi apparatus nuclear envelope ER plasma membrane

chloroplast

Thylakoids, DNA, and ribosomes are all components found in nuclei. vacuoles. lysosomes. chloroplasts. mitochondria.

chloroplasts.

Singer and Nicolson's fluid mosaic model of the membrane proposed that membranes are a phospholipid bilayer. consist of protein molecules embedded in a fluid bilayer of phospholipids. consist of a mosaic of polysaccharides and proteins. are a phospholipid bilayer between two layers of hydrophilic proteins. are a single layer of phospholipids and proteins.

consist of protein molecules embedded in a fluid bilayer of phospholipids.

Which of these acts as a second messenger? adenylyl kinase G protein protein kinase G-protein-linked receptor cyclic AMP

cyclic AMP

The primary role of _____ is to bind animal cells together. tight junctions plasmodesmata gap (communicating) junctions the cytoskeleton desmosomes

desmosomes

The movement of the hydrophobic gas nitrous oxide (N2O) (laughing gas) into a cell is an example of cotransport. diffusion across the lipid bilayer. osmosis. facilitated diffusion. active transport.

diffusion across the lipid bilayer.

The presence of cholesterol in the plasma membranes of some animals makes the animal more susceptible to circulatory disorders. enables the membrane to stay fluid more easily when cell temperature drops. makes the membrane less flexible, allowing it to sustain greater pressure from within the cell. enables the animal to remove hydrogen atoms from saturated phospholipids. enables the animal to add hydrogen atoms to unsaturated phospholipids.

enables the membrane to stay fluid more easily when cell temperature drops.

Calcium ions that act as second messengers are stored in _____. chloroplasts peroxisomes endoplasmic reticula mitochondria lysosomes

endoplasmic reticula

The evolution of eukaryotic cells most likely involved endosymbiosis of an aerobic bacterium in a larger host cell-the endosymbiont evolved into mitochondria. acquisition of an endomembrane system, and subsequent evolution of mitochondria from a portion of the Golgi. anaerobic archaea taking up residence inside a larger bacterial host cell to escape toxic oxygen-the anaerobic bacterium evolved into chloroplasts. an endosymbiotic fungal cell that evolved into the nucleus.

endosymbiosis of an aerobic bacterium in a larger host cell-the endosymbiont evolved into mitochondria.

Which of these extracellular signal molecules could diffuse through a plasma membrane and bind to an intracellular receptor? glycerol estrogen starch cellulose glucose

estrogen

Plasmodesmata in plant cells are most similar in function to which of the following structures in animal cells? peroxisomes gap junctions extracellular matrix desmosomes tight junctions

gap junctions

Ions can travel directly from the cytoplasm of one animal cell to the cytoplasm of an adjacent cell through gap junctions. desmosomes. tight junctions. intermediate filaments. plasmodesmata.

gap junctions.

In a plant cell, DNA may be found in the nucleus, mitochondria, and chloroplasts. only in the nucleus. in the nucleus, mitochondria, chloroplasts, and peroxisomes. only in the nucleus and mitochondria. only in the nucleus and chloroplasts.

in the nucleus, mitochondria, and chloroplasts.

The extracellular matrix is thought to participate in the regulation of animal cell behavior by communicating information from the outside to the inside of the cell via which of the following? DNA and RNA integrins the nucleus gap junctions plasmodesmata

integrins

Endocytosis moves materials _____ a cell via _____. out of ... membranous vesicles into ... facilitated diffusion into ... a transport protein into ... membranous vesicles out of ... diffusion

into ... membranous vesicles

Thyroid hormones bind to _____ receptors. tyrosine-kinase steroid intracellular plasma membrane ion-channel G-protein-linked

intracellular

A signal molecule is also known as a(n) _____. receptor initiator ligand protein key

ligand

The advantage of light microscopy over electron microscopy is that light microscopy provides for higher magnification than electron microscopy. light microscopy provides higher contrast than electron microscopy. light microscopy provides for higher resolving power than electron microscopy. specimen preparation for light microcopy does not produce artifacts. light microscopy allows one to view dynamic processes in living cells.

light microscopy allows one to view dynamic processes in living cells.

Hydrolytic enzymes must be segregated and packaged to prevent general destruction of cellular components. In animal cells, which of the following organelles contains these hydrolytic enzymes? glyoxysome central vacuole lysosome chloroplast peroxisome

lysosome

Which of the following contains hydrolytic enzymes? Golgi apparatus vacuole lysosome mitochondrion peroxisome

lysosome

Which organelle plays a role in intracellular digestion? lysosome ribosome plasmodesma chloroplast Golgi apparatus

lysosome

A bacterium engulfed by a white blood cell through phagocytosis will be digested by enzymes contained in secretory vesicles. vacuoles. Golgi vesicles. lysosomes. peroxisomes.

lysosomes

The cilia and flagella of eukaryotic cells are composed of _____. microtubules microfilaments tonofilaments pili intermediate filaments

microtubules

Movement of vesicles within the cell depends on what cellular structures? actin filaments and ribosomes microtubules and motor proteins actin filaments and microtubules centrioles and motor proteins actin filaments and motor proteins

microtubules and motor proteins

What types of proteins are not synthesized in the rough ER? plasma membrane proteins secreted proteins endoplasmic reticulum proteins mitochondrial proteins extracellular matrix proteins

mitochondrial proteins

Which organelle is the primary site of ATP synthesis in eukaryotic cells? peroxisome lysosome vacuole mitochondrion Golgi apparatus

mitochondrion

Which plant cell organelle contains its own DNA and ribosomes? glyoxysome Golgi apparatus peroxisome vacuole mitochondrion

mitochondrion

Which structure is common to plant and animal cells? wall made of cellulose centriole central vacuole mitochondrion chloroplast

mitochondrion

Which of the following membrane activities requires energy from ATP hydrolysis? movement of glucose molecules into a bacterial cell from a medium containing a higher concentration of glucose than inside the cell movement of Na+ ions from a lower concentration in a mammalian cell to a higher concentration in the extracellular fluid movement of water into a cell facilitated diffusion of chloride ions across the membrane through a chloride channel movement of carbon dioxide out of a paramecium

movement of Na+ ions from a lower concentration in a mammalian cell to a higher concentration in the extracellular fluid

A cell has the following molecules and structures: enzymes, DNA, ribosomes, plasma membrane, and mitochondria. It could be a cell from a bacterium. any kind of organism. nearly any eukaryotic organism. any multicellular organism, such as a plant or an animal. an animal, but not a plant.

nearly any eukaryotic organism.

The chemical reactions involved in respiration are virtually identical between prokaryotic and eukaryotic cells. In eukaryotic cells, ATP is synthesized primarily on the inner membrane of the mitochondria. In light of the endosymbiont theory for the evolutionary origin of mitochondria, where is most ATP synthesis likely to occur in prokaryotic cells? on the endoplasmic reticulum on the plasma membrane in the cytoplasm on the inner nuclear envelope on the inner mitochondrial membrane

on the plasma membrane

What name is given to the process by which water crosses a selectively permeable membrane? diffusion passive transport pinocytosis osmosis phagocytosis

osmosis

Which of the following is characterized by a cell releasing a signal molecule into the environment, followed by a number of cells in the immediate vicinity responding? paracrine signaling hormonal signaling autocrine signaling synaptic signaling endocrine signaling

paracrine signaling

Which animal cell organelle contains enzymes that transfer hydrogen from various substrates to oxygen? Golgi apparatus lysosome vacuole mitochondrion peroxisome

peroxisome

A white blood cell engulfing a bacterium is an example of _____. facilitated diffusion receptor-mediated endocytosis exocytosis pinocytosis phagocytosis

phagocytosis

Which of the following types of molecules are the major structural components of the cell membrane? nucleic acids and proteins phospholipids and cellulose proteins and cellulose phospholipids and proteins glycoproteins and cholesterol

phospholipids and proteins

The difference between pinocytosis and receptor-mediated endocytosis is that pinocytosis requires cellular energy, but receptor-mediated endocytosis does not. pinocytosis can concentrate substances from the extracellular fluid, but receptor-mediated endocytosis cannot. pinocytosis is nonselective in the molecules it brings into the cell, whereas receptor-mediated endocytosis offers more selectivity. pinocytosis brings only water molecules into the cell, but receptor-mediated endocytosis brings in other molecules as well. pinocytosis increases the surface area of the plasma membrane, whereas receptor-mediated endocytosis decreases the plasma membrane surface area.

pinocytosis is nonselective in the molecules it brings into the cell, whereas receptor-mediated endocytosis offers more selectivity.

Mitochondria are found in _____. animal cells only all cells plant cells only animal cells and prokaryotic cells, but not plant cells plant and animal cells

plant and animal cells

All of the following serve an important role in determining or maintaining the structure of plant cells. Which of the following are distinct from the others in their composition? microfilaments plant cell walls microtubules nuclear lamina intermediate filaments

plant cell walls

The volume enclosed by the plasma membrane of plant cells is often much larger than the corresponding volume in animal cells. The most reasonable explanation for this observation is that plant cells have a much more highly convoluted (folded) plasma membrane than animal cells. plant cells are capable of having a much higher surface-to-volume ratio than animal cells. plant cells can have lower surface-to-volume ratios than animal cells because plant cells synthesize their own nutrients. plant cells contain a large vacuole that reduces the volume of the cytoplasm. animal cells are more spherical, whereas plant cells are elongated.

plant cells contain a large vacuole that reduces the volume of the cytoplasm.

Which type of organelle is found in plant cells but not in animal cells? mitochondria ribosomes nuclei plastids none of these

plastids

When a potassium ion (K+) moves from the soil into the vacuole of a cell on the surface of a root, it must pass through several cellular structures. Which of the following correctly describes the order in which these structures will be encountered by the ion? plasma membrane → primary cell wall → cytoplasm vacuole secondary cell wall → plasma membrane → primary cell wall cytoplasm → vacuole primary cell wall → plasma membrane → cytoplasm vacuole primary cell wall → plasma membrane → cytoplasm secondary cell wall → vacuole primary cell wall → plasma membrane → lysosome cytoplasm → vacuole

primary cell wall → plasma membrane → cytoplasm vacuole

A cell with a predominance of free ribosomes is most likely constructing an extensive cell wall or extracellular matrix. producing primarily proteins for secretion. enlarging its vacuole. digesting large food particles. producing primarily cytoplasmic proteins.

producing primarily cytoplasmic proteins.

Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules? glycogen proteins cellulose lipids nucleic acids

proteins

Which of the following is present in a prokaryotic cell? ER ribosome mitochondrion nuclear envelope chloroplast

ribosome

ECM proteins are made by ribosomes in which part of a eukaryotic cell? rough ER nuclear envelope Golgi apparatus mitochondria cytoplasm

rough ER

Which structure is the site of the synthesis of proteins that may be exported from the cell? free cytoplasmic ribosomes rough ER lysosomes plasmodesmata Golgi vesicles

rough ER

A signal transduction pathway is initiated when a _____ binds to a receptor. G protein tyrosine kinase calmodulin signal molecule cyclic AMP

signal molecule

A signal transduction pathway is initiated when a _____ binds to a receptor. signal molecule tyrosine kinase G protein calmodulin cyclic AMP

signal molecule

When a neuron responds to a particular neurotransmitter by opening gated ion channels, the neurotransmitter is serving as which part of the signal pathway? relay molecule signal molecule transducer endocrine molecule receptor

signal molecule

What kinds of molecules pass through a cell membrane most easily? large polar small and hydrophobic ionic large and hydrophobic monosaccharides such as glucose

small and hydrophobic

The liver is involved in detoxification of many poisons and drugs. Which of the following structures is primarily involved in this process and therefore abundant in liver cells? Golgi apparatus smooth ER nuclear envelope transport vesicles rough ER

smooth ER

Which type of organelle or structure is primarily involved in the synthesis of oils, phospholipids, and steroids? lysosome ribosome mitochondrion contractile vacuole smooth endoplasmic reticulum

smooth endoplasmic reticulum

A(n) _____ is an example of a signal molecule that can bind to an intracellular receptor and thereby cause a gene to be turned on or off. nucleic acid ion protein steroid carbohydrate

steroid

Celery stalks that are immersed in fresh water for several hours become stiff and hard. Similar stalks left in a 0.15 M salt solution become limp and soft. From this we can deduce that the fresh water is isotonic and the salt solution is hypertonic to the cells of the celery stalks. the fresh water is hypertonic and the salt solution is hypotonic to the cells of the celery stalks. the fresh water and the salt solution are both hypertonic to the cells of the celery stalks. the fresh water is hypotonic and the salt solution is hypertonic to the cells of the celery stalks. the fresh water and the salt solution are both hypotonic to the cells of the celery stalks.

the fresh water is hypotonic and the salt solution is hypertonic to the cells of the celery stalks

Tay-Sachs disease is a human genetic abnormality that results in cells accumulating and becoming clogged with very large, complex, undigested lipids. Which cellular organelle must be involved in this condition? the lysosome mitochondrion the endoplasmic reticulum the Golgi apparatus membrane-bound ribosomes

the lysosome

Which of the following is a major cause of the size limits for certain types of cells? the need for sufficient surface area to support the cell's metabolic needs the difference in plasma membranes between prokaryotes and eukaryotes limitation on the strength and integrity of the plasma membrane as cell size increases evolutionary progression in cell size; more primitive cells have smaller sizes rigid cell walls that limit cell size expansion

the need for sufficient surface area to support the cell's metabolic needs

The permeability of a biological membrane to a specific polar solute may depend on which of the following? the amount of cholesterol in the membrane the types of transport proteins in the membrane the phospholipid composition of the membrane the presence of unsaturated fatty acids in the membrane the types of polysaccharides present in the membrane

the types of transport proteins in the membrane

Which of these cell junctions form a barrier to the passage of materials? keratin fibers plasmodesmata tight junctions gap (communicating) junctions desmosomes (anchoring junctions)

tight junctions

Which of these is the second of the three stages of cell signaling? gene activation reception binding of a neurotransmitter to a plasma membrane receptor transduction cell response

transduction

In a liver cell detoxifying alcohol and some other poisons, the enzymes of the peroxisome remove hydrogen from these molecules and use the hydrogen to break down hydrogen peroxide. transfer the hydrogen to oxygen molecules to generate hydrogen peroxide. combine the hydrogen with water molecules to generate hydrogen peroxide. transfer the hydrogen to the mitochondria.

transfer the hydrogen to oxygen molecules to generate hydrogen peroxide.

Beginning within the nucleus, the first step leading to the synthesis of a polypeptide is _____. transferring of information from DNA to messenger RNA translation of a DNA nucleotide sequence into a sequence of amino acids removal of introns from RNA and the stitching together of exons linking of nucleotides to form a polypeptide translation of an RNA nucleotide sequence into a sequence of amino acids

transferring of information from DNA to messenger RNA

When biologists wish to study the internal ultrastructure of cells, they can achieve the finest resolution by using a super-resolution fluorescence microscope. transmission electronic microscope. phase-contrast light microscope. confocal fluorescence microscope. scanning electron microscope.

transmission electronic microscope.

Which of the following best describes the structure of a biological membrane? two layers of phospholipids with proteins embedded between the two layers a fluid structure in which phospholipids and proteins move freely between sides of the membrane two layers of phospholipids (with opposite orientations of the phospholipids in each layer) with each layer covered on the outside with proteins a mixture of covalently linked phospholipids and proteins that determines which solutes can cross the membrane and which cannot two layers of phospholipids with proteins either crossing the layers or on the surface of the layers

two layers of phospholipids with proteins either crossing the layers or on the surface of the layers

Which organelle often takes up much of the volume of a plant cell? Golgi apparatus vacuole peroxisome mitochondrion lysosome

vacuole

Which of the following clues would tell you if a cell is prokaryotic or eukaryotic? whether or not the cell carries out cellular metabolism the presence or absence of a rigid cell wall the presence or absence of ribosomes whether or not the cell contains DNA whether or not the cell is partitioned by internal membranes

whether or not the cell is partitioned by internal membranes