Bio Test 2
How many fatty acids are connected to a glycerol in a phospholipid? A. 0. B. 1. C. 2. D. 3. E. 4.
C. 2
The cell theory includes all of the following EXCEPT. A. All the life processes of metabolism occur in cells. B. All living things are composed of one or more cells. C. All cells are about the same size and contain organelles. D. Cells arise only by division of previously existing cells. E. The cell is the basic unit of organization of organisms.
C. All cells are about the same size and contain organelles.
1. _______________ is a form of genetic exchange in bacteria that involves contact between two cells. A. Transformation B. Transduction C. Conjugation D. Binary fission E. Budding
C. Conjugation
1. The _________ can be considered a sorting, processing and packaging center. A. centriole B. centrosome C. Golgi complex D. vacuole E. cytoskeleton
C. Golgi complex
The smooth endoplasmic reticulum: A. is absent in most plant cells. B. synthesizes proteins. C. provides structural support. D. synthesizes lipids. E. is required for ribosome synthesis.
D. synthesizes lipids.
If a cell is placed in a hypertonic solution one event that is sure to occur is that A. sugars and amino acids will move out of the cells. B. the cell wall will collapse inward. C. the cell will die of lack oxygen. D. the cell will of shrink as water moves out. the cell will swell as water moves in.
D. the cell will of shrink as water moves out.
1. Pili are involved in adhesion of bacterial cells to a substrate or host, or in transmission of __________ between bacteria. A. ribosomes B. cytoplasm C. vectors D. RNA E. DNA
E. DNA
1. Which of the following organelles contain small amounts of DNA and convert energy? A. Microfilaments and microtubules B. Lysozomes and peroxisomes C. ER and ribosomes D. Nucleus and ribosomes E. Mitochondria and chloroplasts
E. Mitochondria and chloroplasts
Which scientist first viewed living cells? a. Robert Hooke b. Matthias Schleiden c. Theodor Schwann d. Anton van Leeuwenhoek e. August Weismann
d. Anton van Leeuwenhoek
You want to determine the location of a specific protein in a cell using a colored stain. Which of the following is the best technique for this purpose? a. electron microscopy b. phase contrast microscopy c. bright-field microscopy d. fluorescence microscopy e. dark-field microscopy
d. fluorescence microscopy
The mean diameter of a bacterium is a. 10-3 m. b. 10-4 m. c. 10-5 m. d. 10-6 m. e. 10-7 m.
d. 10-6 m.
Differential centrifugation is a process that: a. separates different components of the cell that function differently. b. separates components of the cell that have a different chemical makeup. c. analyzes the chemical components of the cell. d. separates components of the cell that have different densities. e. allows researchers to view the contents of the cells.
d. separates components of the cell that have different densities.
Evidence that all living cells have a common origin is provided by: a.the cell theory, which states that the cell is the basic unit of life. b.the fact that all new cells come from previously existing cells. c.the fact that cells are the building blocks of the most complex plants. d.basic similarities in cell structure and chemistry. e.the fact that cells are the smallest units that can carry out all life activities.
d.basic similarities in cell structure and chemistry.
Which of the following descriptions or structures does NOT match the cell type? a. Sperm cells have flagella. b. Nerve cells have long, thin extensions. c. Epithelial cells are rectangular. d. White blood cells can change shape. e. Smallest cell are egg cells.
e. Smallest cell are egg cells.
What cell organelles are not surrounded by membranes? A. centrioles. B. nucleus. C. Golgi complex. D. lysosomes. E. mitochondria.
A. centrioles.
82. A cellular structure found in plant but not animal cells is the: A. chloroplast. B. ribosome. C. endoplasmic reticulum. D. microtubule. E. microfilament.
A. chloroplast.
1. The theory that chloroplasts and mitochondria had their evolutionary beginnings in eukaryotic cells as endosymbionts is supported by all of the following EXCEPT: A. chloroplasts and mitochondria are completely autonomous within eukaryotic cells. B. chloroplasts and mitochondria have DNA. C. chloroplasts and mitochondria have small ribosomes for protein synthesis. D. chloroplasts and mitochondria are approximately the same size as prokaryotic cells. E. chloroplasts and mitochondria have the same shape as prokaryotic cells.
A. chloroplasts and mitochondria are completely autonomous within eukaryotic cells.
1. glycoprotein destined for secretion from the cell would move through the Golgi complex in this sequence: A. cis face to medial region to trans face B. trans face to cis face to medial region C. trans face to medial region to cis face D. cis face to trans face to medial region E. medial face to trans face to cis face
A. cis face to medial region to trans face
The action of sodium-potassium pumps is an example of A. direct active transport B. pinocytosis C. aquaporin transport D. exocytosis E. facilitated diffusion
A. direct active transport
The bacterial flagellum contains A. flagellin. B. tubulin. C. cytoplasm. D. microtubules. E. actin.
A. flagellin.
In the coupled transport of glucose and sodium ions: A. glucose molecules are transported down their concentration gradient. B. sodium ions are transported down their concentration gradient. C. the transport of glucose powers the transport of sodium. D. ATP causes a conformational change in the carrier protein. E. an antiport carrier protein is involved.
A. glucose molecules are transported down their concentration gradient.
The distinctive feature of the chloroplasts is that they are A. green. B. invisible. C. larger than the nucleus. D. outside of the plasma membrane. E. contain enzymes.
A. green.
If the concentration of solutes in a cell is less than the concentration of solutes in the surrounding fluid, then the extracellular fluid is said to be: A. hypertonic. B. hypotonic. C. isotonic. D. stable. E. amphipathic.
A. hypertonic.
Cut flowers will stand erect in A. hypotonic medium. B. atonic medium. C. isotonic medium. D. hypertonic medium.
A. hypotonic medium.
Which of the following requires a transport protein? A. simple diffusion B. facilitated diffusion C. establishment of turgor pressure D. osmosis E. osmosis when a cell is in a hypertonic solution
B. facilitated diffusion
When plant cells are in a hypotonic environment, they A. undergo plasmolysis B. build up turgor pressure C. wilt D. decrease pinocytosis E. lose water to the environment
B. build up turgor pressure
Cytoskeletal filaments that are responsible for movement of the cells depend on the protein A. actin. B. flagellin. C. intermediate filament protein. D. keratin. E. vimentin.
B. flagellin.
The cytoskeletal subunit protein of the undulipodium is A. vimentin. B. flagellin. C. tubuJ.in. D. actin. E. cholesterol.
B. flagellin.
Because phopholipid molecules are free to move laterally, the membrane is said to be A. filmy. B. fluid. C. loose. D. permeable. E. soft.
B. fluid.
Mitochondria are intimately involved in the cells reactions with A. water. B. glucose. C. ammonia. D. oxygen. E. cations.
B. glucose.
Consider a U-tube that initially contains pure water on one side of a selectively permeable membrane and water plus solute on the other side. Which of the following best describes what will happen next? A. Solute molecules diffuse across the membrane faster than water molecules. B. The fluid level rises on the side containing the pure water. C. The diffusion of water molecules causes an osmotic pressure to build up in the tube. D. Solute molecules are transported across the membrane by facilitated diffusion. E. Some water molecules become "bound up" with solute molecules and do not diffuse freely.
C. The diffusion of water molecules causes an osmotic pressure to build up in the tube.
In the experiment in which Frye and Edidin fused the plasma membranes of a mouse and a human cell, what happened to the membrane proteins? A. They formed a spherical structure. B. They formed a bilayer. C. They moved laterally across the cell surface. D. They flip-flopped from one layer to the other. E. They reacted with cholesterol molecules on the membrane surface.
C. They moved laterally across the cell surface.
According to the fluid mosaic model, membranes consist of A. a lipid-protein sandwich B. mainly phospholipids with scattered nucleic acids C. a fluid phospholipid bilayer in which proteins are embedded D. a fluid phospholipid bilayer in which carbohydrates are embedded E. a protein bilayer that behaves as a liquid crystal
C. a fluid phospholipid bilayer in which proteins are embedded
1. 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. a structural MAP. B. a microfilament. C. a microtubule. D. an actin filament. E. a myosin filament.
C. a microtubule.
1. A bacterium that gains nourishment from dead organisms is referred to as: A. an autotroph. B. a parasite. C. a saprotroph. D. a chemoautotroph. E. a pathogen.
C. a saprotroph.
1. Most bacteria are: A. photoheterotrophs. B. chemoheterotrophs. C. autotrophs. D. heterotrophs. E. chemoautotrophs.
C. autotrophs.
Plant cells usually contain large membrane—bound sacs containing a highly concentrated solution. These organelles are called A. chloroplasts. B. central vacuole. C. Golgi complex. D. centrioles. E. nuclei.
B. central vacuole.
What cell structure is a center of energy metabolism? A. Golgi complex. B. chloroplast. C. rough endoplasmic reticulum. D. microtubule. E. smooth endoplasmic reticulum.
B. chloroplast.
Small molecules sometimes pass from one cell to another through A. adhering junctions. B. communicating junctions. C. ordinary junctions. D. organizing junctions. E. matrimonial junctions.
B. communicating junctions.
The movement of a material from a region of high concentration toward a region of low concentration by the random movement of molecules is called A. active transport. B. diffusion. C. osmosis. D. migration. E. Brownian movement.
B. diffusion.
What is the function of the nucleolus? a. import of cytoplasmic proteins. b. regulation of nuclear pores. c. site of ribosome assembly. d. storage of inactive DNA. e. synthesis of nuclear proteins.
c. site of ribosome assembly.
What kind of molecules are found in microtubules? A. carbohydrate called cellulose. B. protein called flagellin. C. protein called actin. D. protein called tubulin. E. protein called vimentin.
C. protein called actin.
What type of macromolecules form transmembrane molecules? A. lipids. B. polysaccharides. C. proteins. D. nucleic acids. E. prostaglandins.
C. proteins.
Cells such as plasma cells that secrete large quantities of antibodies (=proteins) have well-developed A. mitochondria. B. smooth endoplasmic reticulum C. rough endoplasmic reticulum. D. cytoskeleton. E. lysosomes.
C. rough endoplasmic reticulum.
Microfilaments are found in A. bacteria. B. animal cells. C. plant cells. D. animal and plant cells. E. bacteria and plant and animal cells.
D. animal and plant cells.
Plasmids of bacteria often have genes involved in: A. reproduction. B. motility. C. viral resistance. D. antibiotic resistance. E. photosynthesis.
D. antibiotic resistance.
What macromolecule is typical for bacteria? A. a closed, circular DNA molecule. B. membrane phospholipids. C. 1 ipopolysaccharide. D. peptidoglycan. E. NAD.
D. peptidoglycan.
Which of the following structures or activities is NOT directly part of the endomembrane system? A. budding B. lysosomes C. ribosomes D. peroxisomes E. Golgi complex
D. peroxisomes
The membrane that surrounds a phagocytized particle is derived from the A. Golgi complex. B. lysosomes. C. endoplasmic reticulum. D. plasma membrane. E. nuclear envelope.
D. plasma membrane.
. Which of the following molecules is least likely to cross a cellular membrane by simple diffusion? A. carbon dioxide B. nitrogen C. oxygen D. potassium ion E. water
D. potassium ion
Nuclear pores apparently permit the passage of only A. chromosomes. B. glucose. C. ribose, nitrogen bases and phosphate. D. proteins and RNA. E. sodium ions.
D. proteins and RNA.
Membrane-bounded organelles facilitate faster chemical reactions because: A. reactants are within close proximity to each other. B. membranes lower the activation energy of biochemical reactions. C. membrane-bounded organelles act as catalysts for biochemical reactions. D. reactants move faster within membrane-bounded organelles. E. reactants are less likely to encounter each other within membrane-bounded organelles.
D. reactants move faster within membrane-bounded organelles.
What is the role of MHC molecules? A. transport of glucose by facilitated diffusion. B. recognition of the hormone insulin. C. recognition of self. D. recognition of a particle to be phagocytized. E. transport of glycine through a coupled channel.
D. recognition of a particle to be phagocytized.
What organelle would be best described by the metaphor assembly plant? A. nucleus. B. cytoskeleton. C. lysosomes. D. ribosomes. E. mitochondria.
D. ribosomes.
Biological membranes are normally permeable to: A. large, hydrophilic molecules. B. small, hydrophilic molecules. C. large, hydrophobic molecules. D. small, hydrophobic molecules. E. None of these.
D. small, hydrophobic molecules.
A chain of round bacteria would be called: A. spirilla. B. diplococci. C. bacilli. D. streptococci. E. streptobacilli.
D. streptococci.
Which of the following is/are most closely associated with the breakdown of ingested material? A. Ribosomes B. Smoot ER C. Mitochondria D. Microfilaments E. Lysozomes
Lysozomes
The ratio of the size of the image seen with the microscope to the actual size of the object is called: a. magnification. b. resolution. c. resolving power. d. centrifugation. e. fractionation.
a. magnification.
What for cell structure packages proteins the export? a. Golgi complex. b. chloroplast. c. rough endoplasmic reticulum. d. microtubule. e. smooth endoplasmic reticulum.
a. Golgi complex.
Electron microscopes have a much higher resolution than either the human eye or any light microscope because: a. of their higher magnification. b. the lenses used are of much higher quality. c. of the very short (nanometer) wavelengths of electrons. d. the images are viewed on screens, rather than directly using an eyepiece or ocular lens. e. it can be used to view stained or living cells.
c. of the very short (nanometer) wavelengths of electrons.
1. Peptidoglycan is a macromolecule of the cell wall of a. Viroids. b. Archaea c. Bacteria d. Eukarya e. Plants.
c. Bacteria
Which of the following functional classes of proteins would have segments rich in hydrophobic amino acids? a.signal receptors. b. transport proteins. c. channel proteins. d. membrane pore proteins. e. all of the above.
c. channel proteins.
What bond(s) is(are) most important for membrane structure? a. ionic bonds. b. covalent bonds. c. hydrophobic bonds. d. hydrogen bonds. e. many weak bonds.
c. hydrophobic bonds.
What cell organelle is NOT part of GERL? a. endoplasmic reticulum. b. lysosomes. c. nucleus. d. plasma membrane. e. ribosomes.
c. nucleus.
Which solution has the highest osmotic pressure? A. 1 M glucose. B. 0.1 M glucose. C. 0.1 M sucrose. D. 0.05 M glucose. E. 0.05 M NaC1.
A. 1 M glucose.
94. Use the numbered choices to select the sequence that most accurately describes information flow in the eukaryotic cell. 1. DNA in nucleus 2. RNA 3. Mitochondria 4. Protein Synthesis 5. Ribosomes A. 1, 2, 5, 4 B. 3, 2, 5, 1 C. 5, 2, 3, 1 D. 4, 3, 2, 1 E. 1, 2, 3, 4
A. 1, 2, 5, 4
What is a typical molecule that would bind to a cell receptor? A. ATP. B. DNA. C. glycolipids. D. hormones. E. surface markers.
A. ATP.
. A 9 + 2 arrangement of microtubules best describes A. Cilia B. Centrosomes C. Basal Bodies D. Microfilaments E. Microvilli
A. Cilia
1. Bacteria that are C-autotrophs A. Do not require atmospheric oxygen for cellular respiration B. Manufacture their own organic materials from simple raw materials C. Must obtain organic compounds from other organisms D. Get their nourishment from dead organisms E. Produce endospores when oxygen levels are too low for active growth
A. Do not require atmospheric oxygen for cellular respiration
What cell structure is the site of synthesis and export of proteins to the plasma membrane? A. Golgi complex. B. chloroplast. C. rough endoplasmic reticulum. D. microtubule. E. smooth endoplasmic reticulum.
A. Golgi complex.
1. Which of the following statements concerning an F factor is FALSE? A. It is found in recipient cells, not donor cells. B. It is a DNA sequence. C. It is found in F+ cells. D. The F stands for fertility. E. It is involved with forming sex pili.
A. It is found in recipient cells, not donor cells.
1. Which of the following function(s) in cell movement? A. Microtubules B. Nucleolus C. Grana D. Smooth ER E. Rough ER
A. Microtubules
What is the most significant property of a phospholipid in terms of its participation in membrane structure? A. One end is nonpolar; the other is extremely polar. B. The entire molecule is very hydrophobic. C. The entire molecule is extremely polar. D. The entire molecule is extremely nonpolar. E. The entire molecule is very hydrophilic.
A. One end is nonpolar; the other is extremely polar.
Which of the following is/are most closely associated with protein synthesis? A. Ribosomes B. Smoot ER C. Mitochondria D. Microfilaments Lysozomes
A. Ribosomes
In the sodium-potassium pump A. cellular potassium is exchanged for extracellular sodium. B. potassium enters the cell by facilitated diffusion. C. potassium enters the cells by a coupled channel. D. sodium and potassium are both moved against a concentration gradient. E. cellular sodium levels are kept high.
A. cellular potassium is exchanged for extracellular sodium.
A cell takes in dissolved material by forming tiny vesicles around fluid droplets tapped by folds of the plasma membrane. This process is called A. indirect active transport B pinocytosis C. receptor-mediated endocytosis D. exocytosis E. facilitated diffusion.
B pinocytosis
Use the numbered choices to select the sequence that most accurately describes glycoprotein processing in the eukaryotic cell. 1. ER 2. Ribosomes 3. Cis face of Golgi 4. Trans face of Golgi 5. Transport vesicle 6. Grana 7. Plasma Membrane A. 1, 6, 2, 3, 4, 7 B. 2, 1, 3, 4, 5, 7 C. 7, 1, 2, 4, 3, 5 D. 2, 1, 4, 3, 5, 7 E. 2, 1, 7, 4, 5, 1
B. 2, 1, 3, 4, 5, 7
1. Endospores A. Are formed by some viruses B. Are extremely durable cells C. Are comparable to the reproductive spores of fungi and plants D. Cause fever and other symptoms of the host E. Are extremely vulnerable to infection by phages
B. Are extremely durable cells
_____________ are dormant structures formed by bacteria in response to adverse environmental conditions. A. Capsids B. Endospores C. Exotoxins D. Endotoxins E. Heterocysts
B. Endospores
1. Bacterial flagella A. Are homologous with eukaryotic flagella B. Exhibit a rotary motion C. Consist of a basal body and nine pairs of microtubules D. Are important in transduction E. Are characteristics of gram-positive bacteria
B. Exhibit a rotary motion
Flattened stacks of membranes apparently involved in the packaging, glycosylation, and export of materials from cells are known as A. lysosomes. B. Golgi complex. C. phagosomes. D. central vacuole. E. centriole.
B. Golgi complex.
What is meant by the term "fluid mosaic model"? A. It is the diffusion of lipid-soluble substances through the lipid bilayer. B. It is the movement of lipids and integral proteins within the lipid bilayer. C. It is the solubility of water in the membrane. D. It is the method of substance transport across the membrane. E. It is the movement of surface proteins through the membrane.
B. It is the movement of lipids and integral proteins within the lipid bilayer.
Which of the following statements about the sodium-potassium pump is true? A. It transports hydrogen ions out of the cell. B. It transports 3 sodium ions out of the cell in exchange for 2 potassium ions. C. It transports 2 sodium ions out of the cell in exchange for 2 potassium ions. D. It transports 2 sodium ions out of the cell in exchange for 3 potassium ions. E. It transports water directly out of the cell.
B. It transports 3 sodium ions out of the cell in exchange for 2 potassium ions.
Select the receptor mediated endocytosis events that are in the correct (before, after) order: A. Endosome fuses with lysosome; receptors are transported to plasma membrane and recycled. B. Ligand binds to receptors; coated vesicle forms by endocytosis. C. Contents are digested and released in the cytoplasm; ligand separates from its receptor. D. Endosome fuses with lysosome; receptors are transported to plasma membrane and recycled. E. None of the events are listed in the correct order.
B. Ligand binds to receptors; coated vesicle forms by endocytosis.
Nucleoli contain chromosomal regions that specialize in making: A. proteins. B. RNA. C. ribosomes. D. lipids. E. hormones.
B. RNA.
Which of the following statements about lipid bilayers is FALSE? A. They are self-sealing. B. They are inflexible. C. They spontaneously form closed vesicles. D. They can fuse with other bilayers. E. They resist forming free ends.
B. They are inflexible.
Penicillin is toxic to certain dividing bacterial cells because it prevents cell wall formation, causing the cells to burst. This indicates that the bacteria live in: A. a hypotonic medium. B. a hypertonic medium. C. an isotonic medium. D. a medium with a higher osmotic pressure than the cell. E. Both a hypertonic medium and a medium with a higher osmotic pressure than the cell.
B. a hypertonic medium.
1. Prokaryotes have their genetic information stored in: A. several small, circular pieces of DNA. B. a single, small, circular piece of DNA. C. a large, linear piece of DNA. D. several small, linear pieces of DNA. E. a large, circular piece of DNA.
B. a single, small, circular piece of DNA.
1. The cis face of the Golgi complex is most directly involved in which of the following? A. packaging molecules in vesicles B. accepting vesicles from the ER C. synthesizing proteins D. transporting molecules out of the Golgi E. catalyzing the efficient folding of proteins
B. accepting vesicles from the ER
According to the cell theory A. cells arise spontaneously from nonliving substances. B. all living things are composed of cells. C. all cells have the same number and kind of organelles. D. cells are identical in shape and size. E. all cells are surrounded by a cell wall.
B. all living things are composed of cells.
Rod-shaped bacteria are called: A. streptococci. B. bacilli. C. diplococci. D. vibrio. E. spirochete.
B. bacilli.
The most common mode of reproduction in bacteria is: A. binary fission. B. transformation. C. transduction. D. conjugation. E. mitosis.
A. binary fission.
Which of the following statements explaining the differences in number and types of peripheral proteins found on the inner and outer surfaces of cell membranes is correct? A. The functions of the membrane differ on the inside and outside of the cell. B. Not all proteins can pass through the membrane and, thus, more accumulate on the inside. C. Proteins on the outside of the membrane are synthesized at a slower rate than proteins on the inside of the membrane. D. Proteins on the outside of membrane are made extracellularly and are unable to penetrate the phospholipid bilayer and enter the cell.
A. The functions of the membrane differ on the inside and outside of the cell.
In the classic experiments by Bracht and Hammerling, the nucleus of Acetabularia was removed, the cap was cut off, a nucleus of a different species was inserted, and the cap was allowed to regenerate. The new cap was then removed. After the second regeneration, the cap was observed, and the following conclusion was made: A. The shape of the cap was controlled by the nucleus, thus, the nucleus was the control center of the cell. B. The shape of the cap was under the control of the stalk, which produced a control substance. C. The shape of the cap was independent of both the stalk and the holdfast. D. The "cren" caps were defective due to some mutation in the cap. Thus, "cren" caps are independent of control from both the base and the holdfast. E. At the time no conclusion could be made because in the early 20th century, biologists did not know about the composition of DNA
A. The shape of the cap was controlled by the nucleus, thus, the nucleus was the control center of the cell.
Which of the following functions best explains the reason for the asymmetrically oriented structure of the proteins in the cell membrane? A. These proteins are manufactured by free ribosomes. B. Each type of protein has its own function. C. These proteins pass through the ER membrane into the ER lumen. D. Enzymes are needed to modify the carbohydrate chains on these proteins. E. These proteins are initially formed by ribosomes on the rough ER.
A. These proteins are manufactured by free ribosomes.
Which of the following statements concerning biofilms is FALSE? A. They are formed by bacteria living in a watery environment. B. They enable bacteria to attach to solid surfaces. C. They are usually less than 2 μm thick. D. An example is dental plaque. E. They may develop on surgical implants.
A. They are formed by bacteria living in a watery environment.
1. Which of the following statements concerning centrioles is FALSE? A. They are present in most animal cells but not most plant cells. B. They are duplicated before cell division. C. They have a 9 + 2 arrangement of microtubules. D. They are found in the centrosome. E. They are thought to play a role in microtubule assembly.
A. They are present in most animal cells but not most plant cells.
1. In conjugation A. Two bacterial cells of different mating types come together, and genetic material is transferred from one to another B. A bacterial cell develops a bulge that enlarges and eventually separates from the mother cell C. Fragments of DNA released by a broken cell are taken in by another bacterial cell D. A phage carries bacterial genes from one bacterial cell to another E. Walls develop in the cell, which then divide into six new cells
A. Two bacterial cells of different mating types come together, and genetic material is transferred from one to another
What metaphor describes best the arrangement of proteins and lipids in the cell membrane? A. a chocolate layer cake with sugar frosting. B. an apple pie. C. a cheese cake with graham cracker crust. D. jello with fruit. E. an Oreo cooky
A. a chocolate layer cake with sugar frosting.
Which of the following processes requires the cell to expend metabolic energy directly (for example, from ATP)? A. active transport B. facilitated diffusion C. all forms of carrier-mediated transport D. osmosis E. simple diffusion
A. active transport
A bacterium containing sodium ions at a concentration of 0.1 mM lives in a pond that contains sodium ions at 0.005 mM. Evidently, sodium ions are entering the cell by: A. active transport. B. endocytosis. C. diffusion. D. facilitated diffusion. E. osmosis.
A. active transport.
A cell takes up or eliminates many kinds of molecules against a concentration gradient by means of A. active transport. B. diffusion. C. facilitated diffusion. D. pinocytosis. E. expenditure of ATP.
A. active transport.
The anion channel of an animal cell passes chloride by A. active transport. B. diffusion. C. facilitated diffusion. D. pinocytosis. E. expenditure of ATP.
A. active transport.
The polar character of the eptithelial cells of the gut are maintained because of the presence of A. adhering junctions. B. communicating junctions. C. ordinary junctions. D. organizing junctions. E. matrimonial junctions.
A. adhering junctions
Desmosomes that hold cells tight together under stress are A. adhering junctions. B. communicating junctions. C. ordinary junctions. D. organizing junctions. E. matrimonial junctions.
A. adhering junctions.
A plasma membrane is characteristic of A. all cells. B. prokaryotic cells only. C. Eukaryotic cells only. D. animal cells only. E. eukaryotic cells except plant cells.
A. all cells.
Peptidoglycan of the bacterial cell wall is made up of a polysaccharide backbone and side chains of A. amino acids. B. sugars. C. phospholipids. D. lipid polysaccharide. E. nucleotides.
A. amino acids.
The cells of which organisms are NOT surrounded by a cell wall? A. animals. B. fungi. C. plants. D. bacteria. E. algae.
A. animals.
One difference between tight junctions and dermatomes is that tight junctions: A. are regions where the plasma membrane from two neighboring cells are in actual contact. B. occur only in plants. C. involve connective microfilaments that traverse the space between adjacent cells. D. are anchored by microfilaments on the insides of the cell membranes of adjacent cells. E. contain a 24 nm space between two adjacent membranes.
A. are regions where the plasma membrane from two neighboring cells are in actual contact.
Osmotrophs are cells that A. are sensitive to osmosis. B. acquire some of their nutrients by facilitated diffusion. C. do not phagocytize. D. are always surrounded by a cell wall. E. feed on osmium.
A. are sensitive to osmosis.
Peptidoglycan is present in A. bacteria. B. animal cells. C. plant cells. D. animal and plant cells. E. bacteria and plant and animal cells.
A. bacteria.
Resolving power A. is greater with the light microscope than with the electron microscope. B. measures how easily solutes dissolve in water. C. measures the shortest distance two small objects can be placed together and still be seen as two objects after magnification. D. is the ration of the size of the image produced by a lens system to the actual size of the object. E. is the average diameter of an eukaryotic cell.
A. is greater with the light microscope than with the electron microscope.
Surface marker proteins can move A. laterally in the plane of the membrane. B. flip-flop between the two leaflets of the membrane. C. hardly within the of the solid lipid boundary. D. across tight junctions. E. in and out of the membrane.
A. laterally in the plane of the membrane.
Organelles surrounded by a double membrane and functioning in energy metabolism are A. mitochondria and chloroplasts. B. nucleus and mitochondria. C. nucleus and lysosomes. D. lysosomes, Golgi complex and endoplasmic reticulum. E. nucleus and chloroplasts.
A. mitochondria and chloroplasts.
Cells that produce energy in the absence of oxygen are devoid of A. mitochondria. B. ribosomes. C. nucleus. D. rough endoplasmic reticulum. E. cytoskeleton.
A. mitochondria.
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: A. nucleus. B. nucleolus. C. microtubule. D. mitochondria. E. lysosome.
A. nucleus.
Receptor molecules bind their specific 1igands A. on the exterior of the membrane. B. in the midst of fatty acid tails. C. at the cytoplasmic side of the membrane. D. in a hydrophobic environment. E. surrounded by a meshwork of scaffolding proteins
A. on the exterior of the membrane.
Which carrier protein is a symporter? A. one that co-transports glucose and sodium B. one that carries on facilitated diffusion C. one that moves two substances in opposite directions D. an ion channel E. the sodium-potassium pump
A. one that co-transports glucose and sodium
If a toxin, such as a bacterial toxin, destroys ribosomes, what cellular activity will be affected first? A. protein synthesis B. DNA synthesis C. movement D. energy storage E. active transport
A. protein synthesis
Facilitated diffusion: A. requires a transmembrane protein. B. requires ATP. C. can move molecules against a concentration gradient. D. is typically used to transport small nonpolar molecules. E. All of these.
A. requires a transmembrane protein.
What component is NOT a part of the plasma membrane? A. ribosomes. B. exterior glycoproteins and glycolipids. C. supporting cytoplasmic fibers. D. a lipid bilayer foundation. E. transmembrane proteins.
A. ribosomes.
Simple diffusion may involve the movement of ______________________ through the plasma membrane down a concentration gradient. A. small polar molecules B. small nonpolar molecules C. large polar molecules D. large nonpolar molecules E. water
A. small polar molecules
The medium surrounding a cell is called hypertonic when A. the concentration of solutes of the cytoplasm is lower than that of the medium. B. the concentration of solutes of the cytoplasm is higher than that of the medium. C. equal amounts of solutes are dissolved in the cytoplasm and surrounding medium. D. there is a lower concentration of dissolved molecules in the medium than in the cytoplasm. E. the cytoplasm is surrounded by a semi-permeable membrane.
A. the concentration of solutes of the cytoplasm is lower than that of the medium.
Although glucose molecules constantly diffuse into a cell along their concentration gradient, equilibrium is never reached and glucose continues to enter the cell. This is a direct result of: A. the very fast turnover rate of glucose metabolism. B. the continuous excretion of glucose from other parts of the cell. C. the rapid and continuous intracellular formation of glucose phosphates. D. the active transport of glucose. E. the ability of the cell to engulf glucose by pinocytosis.
A. the very fast turnover rate of glucose metabolism.
Junctions that help form the blood-brain barrier are A. tight junctions B. adhering junctions C. desmosomes D. gap junctions E. plasmodesmata
A. tight junctions
Solutions that are isotonic: A. are not in dynamic equilibrium. B. have equal concentrations of solute and water. C. have equal concentrations of solute but not water. D. have equal concentrations of water but not solute. E. will exhibit no net movement of water from one solution to the other.
B. have equal concentrations of solute and water.
If the concentration of solutes in the fluid surrounding a cell is higher than that inside the cell, the fluid surrounding the cell is A. atonic. B. hypertonic. C. hypotonic. D. hypnotic.
B. hypertonic.
The structural basis of the mitochondrial inner membrane is a bilayer of A. cytochromes and other pigments. B. lipids. C. protein. D. nucleic acid. E. carbohydrates.
B. lipids.
Membrane—bound vesicles rich in hydrolytic and digestive enzymes are called A. chloroplasts. B. lysosomes. C. mitochondria. D. nucleoli. E. endosomes.
B. lysosomes.
1. Which of the following is a key component of the cytoskeleton? A. centrosome B. microtubules C. DNA D. ribosomes E. endoplasmic reticulum
B. microtubules
82. Which of the following organelles plays an important role in apoptosis, or programmed cell death? A. ribosomes B. mitochondria C. chloroplasts D. vacuoles E. peroxisomes
B. mitochondria
chromosomes are composed of A. phospholipid and protein. B. nucleic acid and protein. C. DNA. D. nucleic acid and polysaccharides. E. protein and poJ.ysaccharides.
B. nucleic acid and protein.
Which of the following membrane activities does NOT require the expenditure of energy by the cell? A. active transport B. osmosis C. endocytosis D. exocytosis E. synthesis of more membrane
B. osmosis
1. Small hairlike structures on the surface of bacteria are called: A. capsids. B. pili. C. chromatids. D. plasmids. E. virons.
B. pili.
Chloroplasts are present in the cells of A. animals. B. plants. C. fungi. D. bacteria. E. protozoa.
B. plants.
1. Small circles of DNA called ______________ exist in addition to the bacterial chromosome. A. capsids B. plasmids C. chromatids D. pili E. centromeres
B. plasmids
1. Gram-positive bacteria would stain __________ in a gram stain because of a thick layer of __________ in their cell walls. A. green; peptidoglycan B. purple; peptidoglycan C. green; cellulose D. purple; polysaccharides E. red; polysaccharides
B. purple; peptidoglycan
The ability of a microscope to reveal fine detail is known as A. magnification. B. resolving power. C. cell fractionation. D. transmission microscopy. E. phase contrast microscopy.
B. resolving power.
What cell organelles are present in both the eukaryotic and prokaryotic cell? A. nucleus. B. ribosomes. C. undulipodia. D. mitochondria. E. Golgi complex.
B. ribosomes.
Cells such as the testosterone— producing cell of the testes have a well-developed A. mitochondria. B. smooth endoplasmic reticulum C. rough endoplasmic reticulum. D. cytoskej.eton. E. lysosomes.
B. smooth endoplasmic reticulum
1. The walls of bacteria contain peptidoglycan, which is: A. lipids crosslinked with sugars. B. sugars crosslinked with proteins. C. a protein. D. a lipid. E. a polysaccharide.
B. sugars crosslinked with proteins.
Studies of glucose transport in liposomes have revealed that: A. glucose is transported against a concentration gradient. B. the binding of glucose triggers a conformational change in the carrier protein. C. the transport of solutes via carrier proteins is faster than via channel proteins. D. glucose phosphates move readily across the membrane by simple diffusion. E. glucose moves readily across the membrane by simple diffusion.
B. the binding of glucose triggers a conformational change in the carrier protein.
Chromosomes are condensed in compact structures that are visible with the light microscope while A. the cell is dying. B. the cell is dividing. C. the cell is alive. D. proteins are synthesized. E. the nuclear pores are open.
B. the cell is dividing.
Plant cells are placed in a 4% salt solution. Which of the following statements is true? A. the salt solution is hypotonic. B. the cell undergoes plasmolysis. C. the cell will burst. D. the turgor pressure in the cell will burst. E. the osmotic pressure of the central vacuole is less than that of the cytoplasm.
B. the cell undergoes plasmolysis.
Penicillin works most effectively against gram-positive bacteria because: A. penicillin affects cell membranes. B. they have a thick peptidoglycan cell wall, and penicillin affects the synthesis of peptidoglycans. C. they have special protein channels that allow penicillin to enter the cell and halt the cell cycle. D. they are smaller than gram-negative bacteria and, thus, easily take up penicillin by diffusion. E. they contain prophages that negatively interact with penicillin.
B. they have a thick peptidoglycan cell wall, and penicillin affects the synthesis of peptidoglycans.
In order to pass through a cell membrane a hydrophilic molecule binds to a membrane protein which subsequently A. rotates through the membrane and releases the molecule in the cytoplasm. B. undergoes a conformational change forcing the molecule through a channel into the cytoplasm. C. diffuses laterally in the membrane. D. dissolves in the hydrophobic interior of the lipid bilayer. E. changes the polar character of the molecule.
B. undergoes a conformational change forcing the molecule through a channel into the cytoplasm.
An ABC transporter: A. is a type of water channel. B. uses the energy of ATP to transport solutes. C. uses gated channels to transport ADP. D. is present in kidney tubules and prevents dehydration. E. is a type of porin.
B. uses the energy of ATP to transport solutes.
All of the following are functions of the cell membrane EXCEPT: A. transmitting signals. B. participating in energy transfer. C. being freely permeable to all substances. D. regulating the passage of materials. E. participating in chemical reactions.
C. being freely permeable to all substances.
Receptor-mediated endocytosis: A. is a passive process. B. involves only membrane transport proteins. C. brings about the selective uptake of materials by enclosing them in membranous vesicles. D. does not require energy. E. is most likely to be found in cells that release large amounts of hormones.
C. brings about the selective uptake of materials by enclosing them in membranous vesicles.
1. Which of the following pairs is correctly matched? A. chloroplast—storage of enzymes B. lysosome—powerhouse of the cell C. centrosome—cell division D. plastids—structural support of the cell E. Golgi complex—production of energy
C. centrosome—cell division
Three distinctive features of plant cells are A. central vacuole, mitochondria, chloroplasts. B. centriolea, chloroplasts, cell wall. C. chloroplasts, cell wall, central vacuole. D. chloroplasts, cell wall, cilia. E. mitochondria, cell wall, centrio lea.
C. chloroplasts, cell wall, central vacuole.
What molecules in addition to proteins can function as surface markers of cells? A. ATP. B. linear or branching oligosaccharide groups. C. cholesterol. D. sodium ion. water.
C. cholesterol.
Anchoring junctions that hold cells together at one point as a spot weld does are A. tight junctions B. adhering junctions C. desmosomes D. gap junctions E. plasmodesmata
C. desmosomes
The passive movement of a substance along its concentration gradient is termed: A. active transport. B. dialysis. C. diffusion. D. exocytosis. E. osmosis.
C. diffusion.
What organelle forms a three-dimensional meshwork of membranes through the cell? A. chloroplast. B. chromosome. C. endoplasmic reticulum. D. mitochondria. E. ribosomes.
C. endoplasmic reticulum.
Transmembrane proteins A. are peripheral proteins B. are receptor proteins C. extend completely through the membrane D. extend along the surface of the membrane E. are secreted from the cell
C. extend completely through the membrane
Long, fine, threadlike organellea of motility that protrude from the surfaces of cells, are A. actin filaments. B. basal bodies. C. flagella. D. hairs. E. microtubules.
C. flagella.
Chloroplasts function in A. protein synthesis. B. production of energy by breakdown of glucose. C. harvesting of light energy. D. cell motility. E. phagocytosis.
C. harvesting of light energy.
The interior of the transmembrane, anion channel is lined by amino acids that are NOT A. highly polar. B. negatively charged. C. hydrophobic. D. positively charged. water soluble.
C. hydrophobic.
The part of the protein that extends in the lipid bilayer is composed of amino acids that are A. highly polar. B. negatively charged. C. hydrophobic. D. positively charged. E. water soluble.
C. hydrophobic.
The turgor pressure of a plant cell is positive in A. hypertonic medium. B. isotonic medium. C. hypotonic medium. D. hypnotic medium. E. atonic medium.
C. hypotonic medium.
If the concentration of solutes in the fluid surrounding a cell is lower than that inside the cell, the fluid surrounding the cell is A. atonic. B. hypertonic. C. hypotonic. D. hypnotic. E. isotonic.
C. hypotonic.
What structure is NOT a fiber of the cytoskeleton? A. actin filaments. B. intermediate filaments. C. long range filaments. D. microfilaments. E. microtubules.
C. long range filaments.
Proteins that are destined to become associated with the inner surface of the plasma membrane are: A. manufactured in the same way as protein hormones. B. manufactured in the same way as proteins destined to become external peripheral proteins. C. made on free ribosomes in the cytoplasm. D. made on ribosomes located on the rough endoplasmic reticulum. E. transported to the plasma membrane within a secretory vesicle.
C. made on free ribosomes in the cytoplasm.
Which of the following is not a function of the plasma membrane? A. transports materials B. helps structurally link cells C. manufactures proteins D. anchors the cell to the extracellular matrix E. has receptors that relay signals
C. manufactures proteins
Muscle cells actively engaged in energy production would have A. extensive rough endoplasmic reticulum. B. extensive smooth endoplasmic reticulum. C. many mitochondria. D. many lysosomes. E. many centrioles.
C. many mitochondria.
What cell structure is the repository of the genetic information that directs all of the activities of the living cell? A. endoplasmic reticulum. B. enzymes. C. nucleus. D. plasma membrane. E. ribosome.
C. nucleus.
What statement describes the permeability of a lipid bilayer INCORRECTLY? A lipid bilayer is A. completely impermeable to large water-soluble molecules. B. permeable to glucose and uncharged amino acids. C. permeable to lipids. D. permeable to small, uncharged, polar molecules such as water, carbon dioxide, ammonium and oxygen. E. impermeable to ions.
C. permeable to lipids.
Where do the mitochondria in a living cell come from? A. division of preexisting mitochondria. B. elaboration from vesicles produced by the endoplasmic reticulum. C. phagocytosis of aerobic bacteria from the environment. D. chloroplasts. E. ribosomes.
C. phagocytosis of aerobic bacteria from the environment.
A human white blood cell engulfs a bacterial cell by: A. carrier-mediated facilitated diffusion. B. exocytosis. C. phagocytosis. D. pinocytosis. E. the sodium-potassium pump.
C. phagocytosis.
The ability of a cell to engulf particles such as bacteria is called A. exocytosis. B. endocytosis. C. phagocytosis. D. pinocytosis. E. vesiculation.
C. phagocytosis.
Chloroplasts are part of A. bacteria. B. animal cells. C. plant cells. D. animal and plant cells. E. bacteria and plant and animal cells.
C. plant cells.
In indirect transport A. a uniporter moves a solute across a membrane against its concentration gradient B. a channel protein moves ions by facilitated diffusion C. the movement of one solute down its concentration gradient provides energy for transport of some other solute up its concentration gradient D. osmosis powers the movement of ions against their concentration gradient E. sodium is directly transported in one direction, and potassium is indirectly transported in the same direction
C. the movement of one solute down its concentration gradient provides energy for transport of some other solute
Even though bacteria lack membrane-bound organelles, such as chloroplasts and mitochondria, they can still perform the functions of these organelles by localizing certain metabolic enzymes on: A. the nuclear membranes. B. the endoplasmic reticulum. C. the plasma membrane. D. ribosomes. E. the cell wall.
C. the plasma membrane.
Some bacteria avoid being phagocytized by a host's immune system by means of: A. efficient use of their flagella. B. ameboid motion. C. their capsule. D. changing their cell wall structure. E. eliminating the use of a membrane.
C. their capsule.
A plant cell placed in a hypertonic solution will: A. remain unchanged. B. undergo lysis. C. undergo plasmolysis. D. swell slightly. E. become crenated.
C. undergo plasmolysis.
he size of eukaryotic cells is measured in A. 103 m B. 10-3 m C. 10-6 m D. 10-9 m E. 10-12 m
D. 10-9 m
The fluid mosaic model of membranes dates from A. 1830 (independence of Belgium). B. 1925. C. 1935. D. 1972. 1990.
D. 1972.
94. In eukaryotic cells, DNA is found in A. Chromosomes B. Chromatin C. Mitochondria D. A, B, and C E. A and B
D. A, B, and C
Which of the following describes how facilitated diffusion is powered? A. Facilitated diffusion is "free of cost." B. Facilitated diffusion is powered by the potential energy of the concentration gradient. C. ATP is required directly. D. Both A and B. E. A, B, and C.
D. Both A and B.
Which of the following are forms of carrier-mediated transport? A. Facilitated diffusion only B. Carrier-mediated active transport only C. Osmosis only D. Both facilitated diffusion and carrier-mediated active transport E. Facilitated diffusion, carrier-mediated active transport, and osmosis
D. Both facilitated diffusion and carrier-mediated active transport
What is the major evidence that mitochondria and chloroplasts are derived from bacterial endosymbionts? A. Both mitochondria and chloroplasts contain energy. B. Both organelles can be propagated separately in culture. C. Mitochondria consume oxygen and chloroplasts produce oxygen. D. Both organelles are surrounded by two membranes. E. Both organelles contain a circular DNA molecule.
D. Both organelles are surrounded by two membranes.
1. The extracellular matrix A. Consists mainly of myosin and RNA B. Projects to form microvilli C. Houses the centrioles D. Contains fibronectins that bind integrins E. Has an elaborate system of cristae
D. Contains fibronectins that bind integrins
71. Proteins made on ribosomes may be further modified within the: A. lysosomes. B. nucleus. C. mitochondria. D. Golgi complex. E. peroxisomes.
D. Golgi complex.
94. Which of the following structures would not be found in prokaryotic cells? A. Cell Wall B. Ribosomes C. Nuclear Area D. Nucleus E. Propeller-like Flagellum
D. Nucleus
Who proposed the fluid mosaic model of cell membrane structure in 1972? A. Davson and Singer B. Frye and Edidin C. Brown and Goldstein D. Singer and Nicholson
D. Singer and Nicholson
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? A. Lysosomes would not be formed. B. Facilitated diffusion would not occur. C. Lysosomes would be formed lacking hydrolytic enzymes. D. The phagocytic vacuole would not fuse with the lysosome. E. Endocytosis would not occur.
D. The phagocytic vacuole would not fuse with the lysosome.
If phospholipids form a spherical structure when placed in water, then which of the following is the most logical conclusion about those phosopholipid molecules? A. They are not amphipathic. B. They contain two fatty acid chains. C. They are cone-shaped. D. They form a bilayer. E. Both their ends are hydrophilic.
D. They form a bilayer.
Which of the following are most closely associated with photosynthesis? A. Basal Bodies B. Smooth ER C. Cristae D. Thylakoids E. MTOCs
D. Thylakoids
The fist microscope was developed by A. Darwin. B. Hooke. C. Johnson. D. Van Leeuwenhoek. E. Margulis.
D. Van Leeuwenhoek.
1. Most bacterial cells keep from bursting in a hypotonic environment by: A. an efficient water pump. B. a tough cell membrane. C. pumping large quantities of salts into the cell. D. a rigid cell wall. E. a stiff capsule.
D. a rigid cell wall.
What is the principal objection against the Danielli-Dawson model of a membrane? It does not A. describe a fluid structure. B. account for the bilayer of lipids that surrounds the cells as was shown earlier (1925 Gortel and Grendel). C. explain the trilayered structure seen electron microscopically. D. allow entrance of sugars, amino acids or nitrogen bases in the cell. explain the important role of phospholipids in the membrane.
D. allow entrance of sugars, amino acids or nitrogen bases in the cell.
Integral proteins: A. are weakly bound to the surface of the membrane. B. are strongly bound to the cytosolic surface of the membrane. C. have no hydrophobic portions. D. are completely embedded within the lipid bilayer. E. are amphipathic.
D. are completely embedded within the lipid bilayer.
Which of the following statements is not true? Biological membranes A. are composed partly of amphipathic lipids. B. have hydrophobic and hydrophilic regions. C. are typically in a fluid state. D. are made mainly of lipids and of proteins that lie in thin sheets on the membrane surface. E. function in signal transduction.
D. are made mainly of lipids and of proteins that lie in thin sheets on the membrane surface.
What function does NOT match the cellular structure? A. energy production -- mitochodria. B. protein synthesis -- ribosomes. C. intracellular digestion -- lysosomes. D. cell movement -- endoplasmic reticulum. E. assembly of ribosomes -- nucleolus.
D. cell movement -- endoplasmic reticulum.
Atoms are to chemicals what A. the Golgi complex is to GERL B. the nucleus is to living material. C. plasma membrane is to the cell. D. cells are to the living material. E. the brain is to humans.
D. cells are to the living material.
The hereditary material of the eukaryotic cell is contained in A. a single bare molecule of DNA. B. a single bare molecule of RNA. C. chromosomes in nucleus and cytoplasm. D. chromosomes in the nucleus. E. protein molecules of the chromosomes.
D. chromosomes in the nucleus.
A transmembrane protein differs from other membrane proteins because it: A. is covalently linked to the outer surface of the plasma membrane. B. is a glycoprotein with carbohydrates attached. C. is attached to the inside of the membrane by an ionic bond. D. completely extends through the membrane. E. is completely embedded within the membrane.
D. completely extends through the membrane.
1. The force necessary to cause microtubules of cilia and flagella to slide alongside one another is provided through the action of _________ proteins, which derive the energy to perform their work directly from ______ molecules. A. kinesin; ADP B. kinesin; glucose C. tubulin; ATP D. dynein; ATP E. dynein; ADP
D. dynein; ATP
What type of movement across the plasma membrane is(are) considered (an) example(s) of passive transport? A. the sodium-potassium pump. B. endocytosis. C. coupled channels. D. facilitated diffusion. E. cell identification.
D. facilitated diffusion.
A patient who has had a severe hemorrhage accidentally receives a large transfusion of distilled water directly into a major blood vessel. You would expect this mistake to: A. have no unfavorable effect as long as the water is free of bacteria. B. have serious, perhaps fatal consequences because there would be too much fluid to pump. C. have serious, perhaps fatal consequences because the red blood cells could shrink. D. have serious, perhaps fatal consequences because the red blood cells could swell and burst. E. have no serious effect because the kidney could quickly eliminate excess water.
D. have serious, perhaps fatal consequences because the red blood cells could swell and burst.
The higher the concentration of solute in a solution, the _________ the effective water concentration and the ________ the osmotic pressure. A. lower; lower B. lower; higher C. higher; higher D. higher; lower E. Answer cannot be determined from the information provided.
D. higher; lower
What is a typical molecule that would bind to a cell receptor? A. ATP. B. DNA. C. glycolipids. D. hormones. E. surface markers.
D. hormones.
A wilted flower placed in a vase of water for several hours became stiff and stood erect. When it was placed in a salt solution, it wilted. From this information we can say that the cells of the flower are: A. hypotonic to both fresh water and the salt solution. B. hypertonic to both the fresh water and the salt solution. C. hypertonic to fresh water but hypotonic to the salt solution. D. hypotonic to fresh water but hypertonic to the salt solution. E. isotonic to fresh water but hypotonic to the salt solution.
D. hypotonic to fresh water but hypertonic to the salt solution.
What description does NOT apply to the cell membrane? A. protects the cytoplasm. B. regulates the passage of materials into and out of the cell. C. allows communication with other cells. D. is a rigid, static structure. E. is unresponsive to changes in its outside environment.
D. is a rigid, static structure.
Pinocytosis: A. is engulfment of large particles by the cell. B. occurs in protozoans and algae but not in more complex organisms. C. involves the specific binding of molecules to receptors on the cell surface. D. is the nonspecific uptake of fluids by pinching inward of the plasma membrane. E. is movement of molecules against the concentration gradient through a permeable membrane.
D. is the nonspecific uptake of fluids by pinching inward of the plasma membrane.
Regions of the endoplasmic reticulum devoid of ribosomes are likely involved in A. energy capture. B. energy release. C. export of enzyme. D. lipid synthesis and detoxification. E. protein synthesis.
D. lipid synthesis and detoxification.
A key discovery that weakened the Davson-Danielli "sandwich" model of cell membranes was that: A. membrane proteins form a solid sheet on either side of the phospholipid bilayer. B. membrane proteins form a solid sheet separating the phospholipid layer. C. the phospholipids do not associate with each other in the hydrophobic region of membranes. D. membrane proteins were not uniform and did not form flattened sheets. E. membrane proteins occurred in regular organized patterns on the surface of membranes.
D. membrane proteins were not uniform and did not form flattened sheets.
What cell structure is a component of cilia and flagella? A. Golgi complex. B. chloroplast. C. rough endoplasmic reticulum. D. microtubule. E. smooth endoplasmic reticulum.
D. microtubule.
1. Bacteria: A. are incapable of locomotion. B. move by means of pili C. move by means of cilia. D. move by means of a rotating flagella. E. move by means of a whiplike flagella.
D. move by means of a rotating flagella.
The size of typical eukaryotic cells is measured in A. km B. mm C. m D. nm E. pm
D. nm
1. Which of the following structures would not be found in cells of a plant's roots? A. mitochondria B. chloroplasts C. endoplasmic reticulum D. nucleus E. Golgi complex
D. nucleus
The medium surrounding a cell is called hypotonic when A. the concentration of solutes of the cytoplasm is lower than that of the medium. B. there is a higher concentration of dissoved molecules in the medium than in the cytoplasm. C. equal amounts of solutes are dissolved in the cytoplasm and surrounding medium. D. there is a lower concentration of dissolved molecules in the medium than in the cytoplasm. E. the cytoplasm is surrounded by a semi—permeable membrane.
D. there is a lower concentration of dissolved molecules in the medium than in the cytoplasm.
What description does NOT characterize a cell membrane? A. fluid. B. unable to repair itself. C. asymmetrical regarding molecular composition. D. thin. E. flexible.
D. thin.
1. 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 reason for this is: A. to introduce antibodies to the phagocytic vesicles. B. to wrap the pathogen in additional membrane, rendering them harmless. C. to coat the bacteria in lipids derived from the Golgi complex, which cover and smother them. D. to mix the pathogens with strong hydrolytic enzymes and destroy them. E. to prepare the bacteria for export from the body.
D. to mix the pathogens with strong hydrolytic enzymes and destroy them.
Molecules that penetrate through the membrane are called A. doughnut molecules. B. penetration molecules. C. pore molecules. D. transmembrane molecules. E. thoroughfare molecules.
D. transmembrane molecules.
1. Bacteria that thrive in puncture wounds are likely to be A. Chemoautotrophs B. Photoautotrophs C. Chemoautotrophs D. Endospores E. Obligate anaerobes
E. Obligate anaerobes
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? A. The ratio of cell surface would decrease, compared to cell volume. B. The cell surface would shrivel. C. The surface area would remain constant. D. The number of membrane receptor proteins would decrease. E. The cell surface will keep expanding.
E. The cell surface will keep expanding.
Which of the following is not a characteristic of aquaporins? A. They are transmembrane proteins. B. They facilitate the rapid transport of water through the plasma membrane. C. They are located in mammalian kidney tubules. D. They respond to specific hormones. E. They cause dehydration.
E. They cause dehydration.
Which of the following statements concerning phospholipids is FALSE? A. They have two distinct regions, one strongly hydrophobic and the other strongly hydrophilic. B. They are amphipathic molecules. C. They have cylindrical shapes that allow them to associate with water most easily as a bilayer structure. D. They contain a polar organic group attached to a phosphate group. E. They contain three fatty acids chains.
E. They contain three fatty acids chains.
Which of the following is/are not associated with mitochondria? A. Cristae B. Aerobic Respiration C. Apoptosis D. Free Radicals E. Thylakoids
E. Thylakoids
What are the components of a glycolipid? A. a protein with attached carbohydrate moiety. B. a chain of amino acids with a fatty acid chain attached. C. a chain of amino acids with a polysaccharide attached. D. lipids connected to a repeating ribose-phosphate backbone. E. a lipid to which an oligosaccharide is linked.
E. a lipid to which an oligosaccharide is linked.
Cloroplasts are present in the cells of plants and A. animals. B. fungi. C. protozoa. D. bacteria. E. algae.
E. algae.
Which of the following properties of the lipid bilayer make the membrane more fluid at colder temperatures? A. short—chained fatty acid tails. B. polyunsaturated fatty acid chain. C. kinks in the fatty acid tails. D. presence of complex lipids such as cholesterol. E. all of the above.
E. all of the above.
Electrochemical gradients A. power simple diffusion B. are established by pinocytosis C. are necessary for transport by aquaporins D. are established by concentration gradients E. are a result of both an electric charge difference and a concentration difference between the two sides of the membrane
E. are a result of both an electric charge difference and a concentration difference between the two sides of the membrane
A plasma membrane is part of A. bacteria. B. animal cells. C. plant cells. D. animal and plant cells. E. bacteria and plant and animal cells.
E. bacteria and plant and animal cells.
Glycogen granules are present in A. bacteria. B. animal cells. C. plant cells. D. animal and plant cells. E. bacteria and plant and animal cells.
E. bacteria and plant and animal cells.
Vegetable oil is different from animal fat in that the phospholipids in vegetable oil have fatty acid tails that: A. solidify at room temperature. B. lack double bonds. C. are saturated. D. interact via van der Waals forces. E. bend.
E. bend.
Peripheral proteins are linked to either surface of the plasma membrane by: A. covalent disulfide bonds. B. associating with fatty acids through hydrophobic interactions. C. embedding in one side of the membrane and, thus, not extending through to the other side. D. associating with glycoproteins on the inner membrane surface. E. bonding to integral proteins through noncovalent interactions.
E. bonding to integral proteins through noncovalent interactions.
Which of the following processes is most adversely affected when a cell is poisoned by a toxin that inhibits ATP synthesis? Transmembrane movement of A. sodium. B. water. C. sugar. D. oxygen. E. chloride anion.
E. chloride anion.
DNA is associated with proteins, forming a complex called: A. chromosomes. B. nucleoli. C. nucleus. D. genes. E. chromatin.
E. chromatin.
One function of peroxisomes involves the process of: A. cell death. B. water storage. C. protein synthesis. D. DNA replication. E. detoxification.
E. detoxification.
A cell takes up or eliminates many kinds of molecules against a concentration gradient by means of A. coupled channels. B. diffusion. C. facilitated diffusion. D. pinocytosis. E. expenditure of ATP.
E. expenditure of ATP.
The locomotive structure of bacteria is called A. pillus. B. cillium. C. undulipodium. D. fimbria. E. flagellum.
E. flagellum.
Cholesterol within membranes functions as a(n) ____________ through its interactions with both hydrophobic and hydrophilic parts of phospholipids. A. water blocker B. pH buffer C. energy source D. temperature controller E. fluidity buffer
E. fluidity buffer
What metaphor best describes the function of the mitochondria? A. information center. B. internal scaffolding. C. stomach. D. packaging and shipping. E. furnace.
E. furnace.
Cells that have a wall composed of many layers of highly cross-linked peptidoglycan are A. gram—negative bacteria. B. animal cells. C. plant cells. D. yeasts. E. gram—positive bacteria.
E. gram—positive bacteria.
A eukaryotic cell: A. is usually smaller than a prokaryotic cell. B. has its DNA concentrated in one area of the cell without a nuclear membrane. C. typically has a cell wall, in addition to a plasma membrane. D. is exemplified by bacteria. E. has a variety of membranous organelles
E. has a variety of membranous organelles
In a lipid bilayer, ___________ fatty acid tails face each other within the bilayer and form a region that excludes water. A. hypertonic B. hyperosmotic C. hypotonic D. hydrophilic E. hydrophobic
E. hydrophobic
If equal amounts of water enter the cell as leave the cells than the medium surrounding the cell is A. atonic. B. hypertonic. C. hypotonic. D. hypnotic. E. isotonic.
E. isotonic.
If the concentration of solutes in the fluid surrounding a cell is equal to that inside the cell, the fluid surrounding the cell is A. atonic. B. hypertonic. C. hypotonic. D. hypnotic. E. isotonic.
E. isotonic.
Unlike plant cells, animal cells in hypotonic medium A. gain water. B. lose water. C. do not gain or lose water. D. lose valuable solutes. E. lyse (burst).
E. lyse (burst).
Phagocytic cells would have many A. chloroplasts. B. nucleoli. C. mitochondria. D. ribosomes. E. lysosomes.
E. lysosomes.
Which sets of two organelles are matched regarding function? A. lysosomes — centriole. B. nucleus — Golgi complex. C. endoplasmic reticulum —cytoskeleton. D. chromosomes — ribosomes. E. mitochondria — chloroplasts.
E. mitochondria — chloroplasts.
1. A(n) ___________________ bacterium would not be able to survive in the presence of oxygen. A. facultative aerobic B. facultative anaerobic C. facultative autotrophic D. obligate aerobic E. obligate anaerobic
E. obligate anaerobic
ABC transporters A. use the energy of ATP hydrolysis to transport certain ions and sugars B. are important in facilitated diffusion of certain ions C. are a small group of channel proteins D. are found mainly in plant cell membranes E. permit passive diffusion through their channels
E. permit passive diffusion through their channels
Rank the chemical composition of a typical membrane in order of abundance? A. polysaccharide > nucleic acid > phospholipid > protein. B. protein > polysaccharide > phospholipid > nucleic acid. C. phospholipid > nucleic acid > protein > polysaccharide. D. phospholipid > polysaccharide > nucleic acid > protein. E. phospholipid > protein > polysaccharide.
E. phospholipid > protein > polysaccharide.
Junctions that permit the transfer of water, ions, and molecules between adjacent plants cells are A. tight junctions B. adhering junctions C. desmosomes D. gap junctions E. plasmodesmata
E. plasmodesmata
Plant cells communicate with each other by cytoplasmic strands that extend through pores of the cell wall. The cytoplasmic extensions are called A. adhering junctions. B. communicating junctions. C. ordinary junctions. D. organizing junctions. E. plasmodesmata..
E. plasmodesmata..
What is the likely function of a transmembrane protein that is neither a channel component or a carrier molecule? Its function is to A. anchor glycolipids. B. participate in active transport. C. drive cell motility. D. transduce signals. E. provide surface identification.
E. provide surface identification.
Part of the endoplasmic reticulum is labeled 'rough' because it is studded by A. ch].oroplasts. B. chromosomes. C. surface markers. D. lysosomes. E. ribosomes.
E. ribosomes.
What sequence represents the pathway of a transmembrane glycoprotein of the plasma membrane? A. smooth ER lysosome Golgi. B. smooth ER plasma membrane. C. nucleus ribosome mitochondria. D. centrioe actin filaments coated pits. E. rough endoplasmic reticulum Golgi plasma membrane.
E. rough endoplasmic reticulum Golgi plasma membrane.
A cell contains a nuclear envelope, glycogen granules and mitochondria. What other structure will you find in this cell? A. cell wall. B. chloroplasts. C. peptidoglycan. D. central vacuole. E. rough endoplasmic reticulum.
E. rough endoplasmic reticulum.
A bottle of perfume is opened on the opposite side of the room and within minutes you begin to smell the perfume. This phenomenon is a classic example of: A. dialysis. B. osmosis. C. active transport. D. facilitated diffusion. E. simple diffusion.
E. simple diffusion.
What cell structure produces steroids in certain cells? A. Golgi complex. B. chloroplast. C. rough endoplasmic reticulum. D. microtubule. E. smooth endoplasmic reticulum.
E. smooth endoplasmic reticulum.
The principle active transport channel of the animal cell is the A. ATP pump. B. coupled channel. C. glucose pump. D. proton pump. E. sodium-potassium pump.
E. sodium-potassium pump.
1. All of the following functions are performed by plant vacuoles EXCEPT: A. maintaining hydrostatic (turgor) pressure. B. waste storage and recycling. C. storage of proteins. D. breakdown of unneeded cellular materials. E. storage of nucleic acids.
E. storage of nucleic acids.
How do phospholipid molecules line up in the two leaflets of the bilayer that forms spontaneously when the lipids are mixed with water? A. head-to-head. B. head-to-tail. C. polar end to polar end. D. alternating phosphate and fatty acid groups. E. tail-to-tail.
E. tail-to-tail
A laboratory technician accidently places red blood cells in a hypertonic solution. What happens? A. they undergo plasmolysis B. they build up turgor pressure C. they swell D. they pump solutes out E. they become dehydrated and shrunken
E. they become dehydrated and shrunken
In the mechanism of action of a proton pump, the role of ATP is to: A. cause a proton to bind to a carbohydrate. B. cause a cell to take up protons by endocytosis. C. cause a cell to release protons by exocytosis. D. transfer protons to the inside of a cell. E. transfer protons to the outside of a cell.
E. transfer protons to the outside of a cell.
Examples of molecules to which cell surface receptors respond include all of the following EXCEPT A. adrenalin. B. thyroxine. C. insulin. D. acetylcholine. E. water.
E. water.
When leaf cells lose so much water that turgor pressure falls, the plant A. closes up the water channels of the membranes. B. blooms. C. takes in water from the atmosphere. D. uses contractile vacuoles to increase water content. E. wilts.
E. wilts.
It is advantageous for cells to be small because: a.a small cell size prevents a cell from weighing too much. b.a small cell size occupies less space in nature where space is limited. c.a small cell has a small volume relative to surface area, thereby increasing efficient transport. d.a small cell has a small surface area relative to volume, thereby facilitating ion balance. e.a small cell is better able to conserve energy than a larger cell.
c.a small cell has a small volume relative to surface area, thereby increasing efficient transport.
One strategy that allows larger cells to have an effective surface area to volume ratio is: a. having a completely spherical shape. b. being short and fat. c. having thin, finger-like projections. d. having a thinner plasma membrane. e. locomotion.
c.having thin, finger-like projections.
The scanning electron microscope differs from the transmission electron microscope in that the scanning electron microscope: a. can view a live specimen. b. relies on the detection of electrons from the beam after contact with the specimens. c. can view the internal structure of a cell. d. utilizes a beam of light that passes through the specimen. e. gives a three dimensional image of the object being studied.
e. gives a three dimensional image of the object being studied.