Biology Exam Chapters 5-7
A shortage of phosphorus in the soil would make it especially difficult for a plant to manufacture __________.
DNA-----The backbone of a nucleic acid consists of alternating sugar and phosphate groups
When a protein is denatured, why does it lose its functionality?
Denaturation breaks the intramolecular bonds, such as hydrogen bonds and van der Waals interactions, that hold the protein in its three-dimensional shape. Without the proper shape, the protein cannot function.
In terms of cellular function, what is the most important difference between prokaryotic and eukaryotic cells?
Eukaryotic cells are compartmentalized, which allows for specialization.
Which of the following sequences represents the order in which a protein made in the rough endoplasmic reticulum might move through the endomembrane system?
Golgi apparatus → lysosome-----right answer feedback: Correct. Proteins of the endomembrane system are synthesized in the rough ER, modified and sorted in the Golgi, and then transported to other organelles of the endomembrane system such as vacuoles.
Which of the following statements concerning carbohydrates associated with the plasma membrane is correct? Carbohydrates associated with the plasma membrane are located on both surfaces of the membrane. The carbohydrate composition of most eukaryotic plasma membranes is quite similar. Carbohydrates are found associated with the membranes of prokaryotic cells only. Membrane carbohydrates function primarily in cell-cell recognition. Carbohydrates on the plasma membrane are typically long, complex chains of several dozen monosaccharides.
Membrane carbohydrates function primarily in cell-cell recognition---Variations in carbohydrate structure distinguish one species from another, one individual from another, and even one cell type from another.
A single plant cell is placed in an isotonic solution. Salt is then added to the solution. Which of the following would occur as a result of the salt addition?
Water would leave the cell by osmosis, causing the volume of the cytoplasm to decrease.
The peptide bond is __________.
a covalent bond joining amino acids together to form a polypeptide
Which of the following would be LEAST likely to diffuse through a plasma membrane without the help of a transport protein?
a large, polar molecule
The subunits (monomers) in cellulose are linked together by __________.
glycosidic linkages
Cilia and flagella move due to the interaction of the cytoskeleton with which of the following? mitochondria tubulin motor proteins pseudopodia actin
motor proteins---right answer feedback: Correct. Motor proteins, such as dynein, use energy to move parts of the cytoskeleton.
Which of the following groups is primarily involved in synthesizing molecules needed by the cell?
ribosome, rough endoplasmic reticulum, smooth endoplasmic reticulum
A dish of animal cells was grown in the presence of radioactive phosphorous. The phosphorous largely ended up in nucleotides inside the actively growing animal cells. In which cellular structure or structures would you predict the majority of the radioactive phosphorous to accumulate?
the nucleus
A substance moving from outside the cell into the cytoplasm must pass through __________.
the plasma membrane
The "primary structure" of a protein refers to __________.
the sequence of amino acids along a polypeptide chain
One characteristic shared by sucrose, lactose, and maltose is that __________.
they are all disaccharides
Which of the following are pyrimidines found in the nucleic acid DNA?
thymine and cytosine
Which of the following lists ranks these molecules in the correct order by size from smallest to largest?
water, glucose, sucrose, protein
The internal solute concentration of a plant cell is about 0.8 M. To demonstrate plasmolysis, it would be necessary to suspend the cell in what solution? distilled water 1.0 M 0.4 M 0.8 M 150 mM.
1.0 M
Green olives may be preserved in brine, which is a 30% salt solution. How does this method of preservation prevent microorganisms from growing in the olives?
A 30% salt solution is hypertonic to the bacteria, so they lose too much water and undergo plasmolysis--- If a cell is placed in a hypertonic solution, it will lose water to its environment, shrivel, and probably die.
What do Alzheimer's, Parkinson's, and mad cow disease have in common?
All are associated with the buildup of misfolded proteins in cells.
Which statements about the sidedness of the plasma membrane is correct? Every integral membrane protein has a specific orientation in the plasma membrane. The asymmetrical distribution of membrane proteins, lipids, and carbohydrates across the plasma membrane is determined as the membrane is being constructed. Parts of proteins that are exposed on the cytoplasmic side of the endoplasmic reticulum are also exposed on the cytoplasmic side of the plasma membrane. The two lipid layers may differ in specific lipid composition. All of the listed responses are correct.
All of the listed responses are correct.
Which of the following is true regarding complementary base pairing in DNA and RNA molecules?
Although the base pairing between two strands of DNA in a DNA molecule can be thousands to millions of base pairs long, base pairing in an RNA molecule is limited to short stretches of nucleotides in the same molecule or between two RNA molecules.
Cells A and B are the same size, shape, and temperature, but cell A is metabolically less active than cell B. and cell B is actively converting oxygen to water in cellular respiration. Oxygen will diffuse more rapidly into cell __________ because __________.
B ... the diffusion gradient in cell B is steeper---As long as a metabolically active cell converts oxygen to water during cellular respiration shortly after it enters, diffusion into the cell will continue because the concentration gradient favors movement in that direction
Which of the following statements correctly describes a common characteristic of a plant cell wall and an animal cell extracellular matrix? Both are permeable to water and small solutes. Both contain large amounts of collagen. Both are composed primarily of carbohydrates. Both are permeable to water and small solutes, and both contain large amounts of collagen. Both are permeable to water and small solutes, both contain large amounts of collagen, and both are composed primarily of carbohydrates.
Both are permeable to water and small solutes.
Seawater is hypertonic to cytoplasm in vertebrate cells and in plant cells. If a red blood cell and a plant cell were placed in seawater, what would happen to the two types of cells?
Both cells would lose water; the red blood cell would shrivel, and the plant plasma membrane would pull away from the cell wall.
Which of the following molecules is a monosaccharide?
C6H12O6
Carbohydrates can function in which of the following ways?
Carbohydrates can function in which of the following ways?
Which of the following statements is true about cell fractionation?
Cell fractionation separates cells into their component parts.
Which of the following statements about chloroplasts and mitochondria is true?
Chloroplasts and mitochondria synthesize some of their own proteins.
High cholesterol levels are considered a major risk factor for heart disease. If it is so bad for humans, why does the body make cholesterol in the first place?
Cholesterol is the precursor for many important molecules such as sex hormones.
Which of the following is FALSE in respect to eukaryotic chromosomes?
Chromosomes appear only as a cell is about to divide.
Which statement about the cytoskeleton is true? Microtubules are chains of proteins that resist stretching. Plant cells lack a cytoskeleton because they have a rigid cell wall. Intermediate filaments are hollow tubes of protein that provide structural support. Microfilaments are more permanent structures in cells compared to intermediate filaments and microtubules. Components of the cytoskeleton often mediate the movement of organelles within the cytoplasm.
Components of the cytoskeleton often mediate the movement of organelles within the cytoplasm.-----right answer feedback: Correct. The interaction of motor proteins with the cytoskeleton is responsible for the movement of organelles in cells.
The type of bond that forms to join monomers (such as sugars and amino acids) into polymers (such as starch and proteins) is a(n) __________ bond.
Covalent
Which of these statements describes some aspect of facilitated diffusion? Facilitated diffusion of solutes may occur through channel or transport proteins in the membrane. Facilitated diffusion of solutes occurs through phospholipid pores in the membrane. Facilitated diffusion requires energy to drive a concentration gradient. Facilitated diffusion is another name for osmosis. There is only one kind of protein pore for facilitated diffusion.
Facilitated diffusion of solutes may occur through channel or transport proteins in the membrane.
Which of the following is FALSE in regard to facilitated diffusion? Facilitated diffusion can occur by means of transport proteins. Facilitated diffusion can occur through protein channels. Facilitated diffusion requires the hydrolysis of ATP. Facilitated diffusion requires a concentration gradient. Facilitated diffusion can move ions across membranes.
Facilitated diffusion requires the hydrolysis of ATP.
Nutritionally, saturated triacylglycerols are considered to be less healthful than unsaturated triacylglycerols. What is the difference between them?
For carbon skeletons of equal length, saturated triacylglycerols have more hydrogen atoms than unsaturated triacylglycerols do. (unsaturated has the "kink")
A researcher made an interesting observation about a protein made by the rough endoplasmic reticulum and eventually found in a cell's plasma membrane. The protein in the plasma membrane was actually slightly different from the protein made in the ER. The protein was probably altered in the __________.
Golgi apparatus
Microtubules and microfilaments commonly work with which of the following to perform many of their functions? ribosomes RNA lysosomes Golgi apparatus None of the listed responses is correct.
Golgi apparatus----right answer feedback: Correct. Microtubules guide vesicles from the ER to the Golgi and from the Golgi to the plasma membrane.
Which of the following statements about diffusion is true? It occurs when molecules move from a region of lower concentration to a region of higher concentration. It involves only the movement of water molecules. It always requires integral proteins of the cell membrane. It requires expenditure of energy by the cell. It is a passive process.
It is a passive process.
Which of the following functions of membrane proteins is important in tissue formation during embryonic development in animals? Membrane proteins possess enzymatic activity. Membrane proteins form channels, which move substances across the membrane. Membrane proteins attach the membrane to the cytoskeleton. Membrane proteins with short sugar chains form identification tags that are recognized by other cells. All of the listed responses are correct.
Membrane proteins with short sugar chains form identification tags that are recognized by other cells---Cell-cell recognition is an important function of membrane proteins, and this cell-cell recognition is important in tissue formation during embryogenesis.
Generally, animals cannot digest (hydrolyze) the glycosidic linkages between the glucose molecules in cellulose. How then do cows get enough nutrients from eating grass?
Microorganisms in their digestive tracts hydrolyze the cellulose to individual glucose units.
Which of the following is FALSE? Mitochondria have more than one membrane. The folds of the inner mitochondrial membrane are called cristae. Mitochondria are involved in energy metabolism. Mitochondria contain ribosomes in the intermembrane space. Mitochondria possess their own DNA.
Mitochondria contain ribosomes in the intermembrane space.-----right answer feedback: Correct. The ribosomes in the mitochondria are found in the matrix of the mitochondria, not in the intermembrane space.
A selectively permeable membrane separates two solutions. Water is able to pass through this membrane; however, sucrose (a disaccharide) and glucose (a monosaccharide) cannot pass. The membrane separates a 0.2-molar sucrose solution from a 0.2-molar glucose solution. With time, how will the solutions change?
Nothing will happen, because the two solutions are isotonic to one another---Osmotic pressure is produced by the concentration of dissolved substances and is not influenced by the relative sizes of the solutes.
Which of the following statements about passive transport is correct? Passive transport does not occur in the human body. Passive transport operates independently of the concentrations of the moving solute. Passive transport operates independently of diffusion. In passive transport, solute movement stops when the solute concentration is the same on both sides of the membrane. Passive transport permits the solute to move in either direction, but the net movement of solute molecules occurs down the concentration gradient of the molecule.
Passive transport permits the solute to move in either direction, but the net movement of solute molecules occurs down the concentration gradient of the molecule.
Which of the following is a true statement comparing phospholipids and triacylglycerols (fats and oils)?
Phospholipid molecules have a distinctly polar "head" and a distinctly nonpolar "tail," whereas triacylglycerols are predominantly nonpolar.
Which of the following statements about the role of phospholipids in the structure and function of biological membranes is correct? Phospholipids form a structure in which the hydrophobic portion faces outward. Phospholipids are completely unable to interact with water. Phospholipids form a single sheet in water. They are triacylglycerols, which are commonly available in foods. Phospholipids form a selectively permeable structure.
Phospholipids form a selectively permeable structure.
Which of the following describes a difference between DNA and RNA?
RNA molecules generally consist of a single polynucleotide chain, whereas DNA molecules generally consist of two polynucleotide chains organized into a double helix. Both molecules contain adenine, guanine and cytosine, but DNA also contains thymine and RNA also contains uracil. They contain different sugars.
What is the functional connection between the nucleolus, nuclear pores, and the nuclear membrane?
Subunits of ribosomes are assembled in the nucleolus and pass through the nuclear membrane via the nuclear pores.
The plasma membrane is referred to as a "fluid mosaic" structure. Which of the following statements about that model is true? The fluid aspect of the membrane is due to the lateral and rotational movement of phospholipids, and embedded proteins account for the mosaic aspect. The mosaic aspect of the membrane is due to the glycosylation of phospholipids on the cytoplasmic side of the membrane. The fluid aspect of the membrane is due to the behavior of phospholipids, and the mosaic aspect is due to the presence of carbohydrates. The fluid aspect of the membrane describes its structure at normal temperatures, and the mosaic aspect describes the behavior of the membrane as the temperature is lowered. Only phospholipids are capable of moving in the membrane.
The fluid aspect of the membrane is due to the lateral and rotational movement of phospholipids, and embedded proteins account for the mosaic aspect.
Your intestine is lined with individual cells. No fluids leak between these cells from the gut into your body. Why?
The intestinal cells are bound together by tight junctions.
Amylase is an enzyme that breaks down starch. Why cannot the same enzyme break down cellulose?
The monosaccharide monomers in cellulose are bonded together differently than those in starch.
If a small droplet of triacylglycerol molecules is suspended in water, the fat molecules form a "ball of spaghetti" with no particular orientation. But if a droplet of phospholipid molecules is put in water, all the molecules point outward, toward the water. Phospholipids are forced into this orientation because phospholipids have __________.
a charged or polar end and an uncharged or nonpolar end
The concentration of solutes in a red blood cell is about 2%, but red blood cells contain almost no sucrose or urea. Sucrose cannot pass through the membrane, but water and urea can. Osmosis would cause red blood cells to shrink the most when immersed in which of the following solutions?
a hypertonic sucrose solution---When a cell is placed in a hypertonic environment, water will leave the cell, causing it to shrink.
Which of the following lists represents the chemical components of a nucleotide?
a nitrogenous base, a phosphate group, and a pentose sugar
A glucose molecule is to starch as __________.
a nucleotide is to a nucleic acid
A particular cell has a nucleus and chloroplasts in addition to the fundamental structures required by all cells. Based on this information, this cell could be __________.
a photosynthetic protist cell or a plant cell
In a hydrolysis reaction, __________, and in this process water is __________.
a polymer is broken up into its constituent monomers ... consumed
Manufacturers make vegetable oils solid or semisolid at room temperature by __________.
adding hydrogen atoms to the fatty acid hydrocarbon chains, thereby converting carbon-carbon double bonds to single bonds
Based on complementary base pairing, you would expect the percentage of __________ to be equal to the percentage of __________.
adenine......thymine----Adenine and thymine form a complementary base pair
Protein molecules are polymers (chains) of __________.
amino acid molecules
Lipids differ from other large biological molecules in that they ______.
are not truly polymers
Consider two cells with the same volume but with very different surface areas due to differences in their shapes. The cell with the larger surface area is likely to __________.
be involved in the rapid uptake of compounds from the cell's environment----right answer feedback: Correct. The high surface area is likely to be associated with high transport rates of compounds across the plasma membrane. The greater the surface area, the greater the potential for transport.
Which of the following molecules is most likely to passively diffuse across the plasma membrane?
carbon dioxide
Which of the following is the simplest collection of matter that can live?
cell
Which of the following components of a tossed salad will pass through the human digestive tract and be digested the least?
cellulose (in the lettuce)
Which of the following structures is found in animal cells but NOT in plant cells? mitochondria plasma membrane Golgi apparatus rough endoplasmic reticulum centrioles
centrioles
Which type of protein shields a newly forming protein from cytoplasmic influences while it is folding into its functional form?
chaperonins-----right answer feedback: Correct. Chaperonins shield proteins from "bad influences" (interactions with other molecules in the cytoplasm) while they are folding into their functional forms.
At a conference, the speaker's grand finale was sautéing mealworms (insect larvae) in butter and serving them to the audience. They were crunchy (like popcorn hulls) because their exoskeletons contain the polysaccharide __________.
chitin
Basal bodies are most closely associated with which of the following cell components? the central vacuole nucleus cilia mitochondria Golgi apparatus
cilia---right answer feedback: Correct. The microtubule assembly of a cilium or flagellum is anchored in the cell by a basal body.
What is the process by which monomers are linked together to form polymers?
dehydration reaction
Consider a protein that is made in the rough endoplasmic reticulum. You observe that when the synthesis of the protein is completed, the protein is located in the ER membrane. Where else in the cell might this protein be found?
embedded in the plasma membrane, functioning in the transport of molecules into the cell
Carbohydrates are used in our bodies mainly for __________.
energy storage and release
Which of the following is NOT a function of membrane proteins? enzymatic activity transport intercellular joining cell-cell recognition energy, carbon, and nitrogen storage
energy, carbon, and nitrogen storage
Some lipids are formed when fatty acids are linked to glycerolThese subunits are linked together by __________.
ester linkages------right answer feedback: Correct. In making a fat, each of the three fatty acid molecules is bonded to a glycerol molecule by an ester linkage type of covalent bond.
Which of the following organelles is UNLIKELY to show enhanced abundance in pancreatic cells that secrete large amounts of digestive enzymes?
free cytoplasmic ribosomes----right answer feedback: Correct. Secreted proteins are not synthesized on free cytoplasmic ribosomes; therefore, these ribosomes would not show enhanced abundance.
A polysaccharide that is used for storing energy in human muscle and liver cells is __________.
glycogen
Bacterial cells are prokaryotic. Unlike a typical eukaryotic cell, they __________.
have no membrane-bounded organelles in their cytoplasm
Enzyme molecules require a specific shape to perform their catalytic function. Which of the following might alter the shape of an enzymatic protein?
heating the protein, a change in salt concentrations or pH, a change in salt concentrations or pH, denaturing the protein
Which of the following terms can be correctly used to describe compounds that do NOT mix with water?
hydrophobic
The fatty acid tails of a phospholipid are __________ because they __________.
hydrophobic ... have no charges to which water molecules can adhere
Chloroplasts and mitochondria are thought to be of prokaryotic origin. One piece of evidence that supports this hypothesis is that these organelles contain prokaryotic-like ribosomes. These ribosomes are probably most similar to ribosomes found __________.
in bacterial cells
Consider the currently accepted fluid mosaic model of the plasma membrane. Where in the plasma membrane would cholesterol most likely be found?
in the interior of the membrane---right answer feedback: Correct. The steroid cholesterol, wedged between phospholipid molecules in the plasma membranes of animals, helps stabilize the membrane.
A protein that ultimately functions in the plasma membrane of a cell is most likely to have been synthesized __________.
in the rough endoplasmic reticulum
A researcher wants to film the movement of chromosomes during cell division. Which type of microscope should she choose and why is it the best choice?
light microscope, because the specimen is alive
The sex hormones estradiol and testosterone belong to which class of molecules?
lipids---right answer feedback: Correct. Steroids, such as estradiol and testosterone, are lipids based on their insolubility in water. The molecules are characterized by a carbon skeleton consisting of four fused rings of carbon atoms.
Which of the following categories best describes the function of the rough endoplasmic reticulum?
manufacturing
Which of the following structures is found in eukaryotic but NOT prokaryotic cells?
mitochondria
Which of the following five membranes is most likely to have a lipid composition that is distinct from those of the other four?
mitochondrial outer membrane----right answer feedback: Correct. The mitochondria are not part of the endomembrane system and must synthesize their own lipids.
Which type of cell is most likely to have the largest number of mitochondria?
muscle cells in the legs of a marathon runner----right answer feedback: Correct. Cellular respiration releases energy that cells need in order to carry out their functions. Active muscle cells need large amounts of energy.
Consider the currently accepted fluid mosaic model of the plasma membrane. Where in the membrane would carbohydrates most likely be found?
on the outside (external) surface of the membrane---Membrane carbohydrates are covalently bonded to lipids or proteins and extend out from the external side of the plasma membrane as a means of cell identification
The lipids that form the main structural component of cell membranes are __________.
phospholipids
Dye injected into a plant cell might be able to enter an adjacent cell through __________.
plasmodesmata----right answer feedback: Correct. The cell walls of plant cells contain numerous channels, with strands of cytoplasm passing through them and connecting one cell's cytoplasm to that of an adjacent cell.
Which of the following features do prokaryotes and eukaryotes have in common?
ribosomes, plasma membrane, and cytoplasm
Which of the following organelles might be found inside other organelles? mitochondria the nucleolus transport vesicles ribosomes No organelles are found inside of other organelles.
ribosomes----right answer feedback: Correct. Ribosomes are nonmembranous organelles that are found in the cytoplasm but also in mitochondria and chloroplasts.
The α helix and β pleated sheet represent which level of protein structure?
secondary structure
You would expect a cell with an extensive Golgi apparatus to __________.
secrete large amounts of protein----Correct. The Golgi apparatus modifies and sorts the lipids and proteins produced in the ER. Cells that secrete large amounts of material require an extensive Golgi apparatus.
In what polysaccharide form do plants store glucose to be available later as an energy source?
starch
The polysaccharide that you are most likely to have eaten recently is __________.
starch
The overall three-dimensional shape of a single polypeptide is called its __________.
tertiary structure
Which of the following is/are likely to limit the maximum size of a cell?
the cell's surface-to-volume ratio, the shape of the cell, the time it takes a molecule to diffuse across a cell
