Molecular and Cellular Biology Midterm 1 Study Guide Part 1

Chapter 2 Online Homework: Which part of an amino acid is always acidic? - Carboxyl functional group - Side chain ("R group") - None of the above - Amino functional group

- Carboxyl functional group

Chapter 1 Online Homework: Which type of microscopy has the greatest resolving power? - phase-contrast microscopy - fluorescence microscopy - digital video microscopy - electron microscopy - confocal scanning microscopy

- electron microscopy

Chapter 3 Online Homework: Which of the following three-letter symbols represents an amino acid that is polar and uncharged? - his - pro - ala - gln - asp

- gln

Chapter 1 Online Homework: Which of the following is closest to a micrometer in size? - a typical bacterial cell - the size of a ribosome - the length of a plant cell - the length of a chicken egg - the width of a strand of DNA

- a typical bacterial cell

Chapter 1 Online Homework: Which of the following is closest to a micrometer in size? - the width of a strand of DNA - the length of a plant cell - a typical prokaryotic cell - the size of a ribosome - the length of a chicken egg

- a typical prokaryotic cell

Chapter 1 Online Homework: Gregor Mendel was most influential in which field of biology? - chromatography - biochemistry - genetics - cytology - prokaryotic transformation

- genetics

Chapter 1 Online Homework: Gregor Mendel was most influential in which field of biology? - cytology - bacterial transformation - biochemistry - genetics - chromatography

- genetics

Chapter 3 Online Homework: Tertiary structure is NOT directly dependent on _____. - hydrogen bonds - peptide bonds - hydrophobic interactions - ionic bonds - bonds between sulfur atoms

- peptide bonds

Chapter 1 Online Homework: A microtome is used to - manipulate tiny objects. - focus short wavelengths of light. - view microscopic organisms. - slice thin sections of specimens. - dissect cellular organelles.

- slice thin sections of specimens.

Chapter 3 Online Homework: Match the choice on the left with the choice on the right. Haworth Projection:

- spatial structure

Chapter 2 Online Homework: Which of the following is not soluble in water? - sugars - amino acids - nucleic acids - lipids - disaccharides

- lipids

Chapter 2 Online Homework: Which of the following macromolecules is insoluble in water? - nucleic acids - amino acids - lipids - sugars - disaccharides

- lipids

Chapter 1 Online Homework: What was the limit of resolution Leeuwenhoek's microscope? - 0.83 μm - 8.3 μm - 83 μm - 830 μm

- 0.83 μm

Chapter 1 Online Homework: 1 mm = ________ nm - 1000 - 1,000,000 - 1/1000 - 10 - 1/1,000,000

- 1,000,000

Chapter 3 Exercise: Protein Folding: List the forces involved in stabilizing a folding protein, in order of relative strength (as discussed in class).

1) Disulfide (covalent) bonds 2) Ionic interactions 3) H-bonds - also, hydrophobic interactions (they have a range of strengths 4) Dipole-dipole 5) London dispersion (induced dipole)

Chapter 1 Exercise: What was the primary limitation of Hooke's microscope, and how was that overcome?

Limited by magnification power of only 30X.

Chapter 1 Exercise: For each of the following types of light microscopy list an application and an advantage/disadvantage of that method: Fluorescence:

The technique can allow visualization of locations within the cell, either by inherent fluorescence or by fluorescence tagged molecules. Limited by only seeing a single plane of the specimen at one time.

Chapter 3 Online Homework: Which of the following is found exclusively in RNA? - adenine - uracil - guanine - cytosine - thymine

- uracil

Chapter 1 Online Homework: Which of the following is an important characteristic for a model organism? - marginally characterized - widely studied - prone to random changes that alter primary characteristics - difficult to manipulate in the laboratory - all of the above

- widely studied

Chapter 3 Online Homework: In a nucleotide, the nitrogenous base is attached to the sugar's _____ carbon and the phosphate group is attached to the sugar's _____ carbon. - 1' ... 3' - 1' ... 2' - 2' ... 3' - 1' ... 5' - 2' ... 1'

- 1' ... 5'

Chapter 1 Online Homework: What are the approximate dimensions of the smallest structure that a contemporary cell biologist should be able to observe with a modern light microscope? - 400-500 nm - 200-350 nm - 100-200 nm - 50-100 nm

- 200-350 nm

Chapter 3 Online Homework: If a strand of DNA has the nitrogen base sequence 5'-ATTTGC-3', what will be the sequence of the matching strand? - 3'-TUUUCG-5' - 3'-ATTTGC-5' - 3'-GCAAAT-5' - 3'-UAAACG-5' - 3'-TAAACG-5'

- 3'-TAAACG-5'

Chapter 2 Online Homework: This atom can form up to _____ single covalent bond(s). - 1 - 0 - 2 - 4 - 3

- 4

Chapter 3 Online Homework: Nucleic acids are assembled in the _____ direction. - 2' to 3' - 1' to 5' - 5' to 1' - 5' to 3' - 4' to 5'

- 5' to 3'

Chapter 3 Online Homework: What is the complementary DNA sequence to 5′ ATGCTTGACTG 3′? - 5′ ATGCTTGACTG 3′ - 5′ CAGTCAAGCAT 3′ - 5′ ACTCTACGTAG 3′ - 5′ TACGAACTGAC 3′

- 5′ CAGTCAAGCAT 3′

Chapter 3 Online Homework: If a DNA double helix is 100 nucleotide pairs long and contains 25 adenine bases, how many guanine bases does it contain? - 25 - 150 - 50 - 75 - 200

- 75

Chapter 1 Online Homework: What was the limit of resolution of Hooke's microscope? - 0.83 μm - 8.3 μm - 83 μm - 830 μm

- 8.3 μm

Chapter 3 Exercise: In the Polymerase Chain Reaction technique the DNA helix must first be dissociated using heat to break the H-bonds. If a target DNA sequence is found to have a higher melting temperature (requires more heat to dissociate) what would that tell you about the nucleotide content of that region?

- A G-C rich region, due to the triple H-bonds between G-C versus the two in A-T requires more heat energy to get them to dissociate.

Chapter 2 Online Homework: Which of the following statements about the formation of polypeptides from amino acids is true? - A bond forms between the carboxyl functional group of one amino acid and the amino functional group of the other amino acid. - A bond can form between any carbon and nitrogen atom in the two amino acids being joined. - Polypeptides form by condensation or hydrolysis reactions. - The reaction occurs through the addition of a water molecule to the amino acids.

- A bond forms between the carboxyl functional group of one amino acid and the amino functional group of the other amino acid.

Chapter 3 Exercise: Describe a glycosidic bond. What type of bond is found in the structural polysaccharides? What type is found in energy storage polysaccharide?

- A glycosidic bond is a covalent bond connecting sugar monomers (often glucose). (See examples pages 63-66). A beta 1,4 glycosidic bond will be found connecting the glucose molecules in a structural polysaccharides, whereas is energy storage polysaccharides such as starch and glycogen we find the alpha 1,4 linkage.

Chapter 1 Online Homework: Which of the following is true of a nanometer? - A nanometer is equivalent to 10 Angstroms (Å). - A nanometer is one millionth of a meter. - The nanometer is the most common measurement used in measuring whole cells. - A nanometer is about the size of a common bacterial cell. - none of the above

- A nanometer is equivalent to 10 Angstroms (Å).

Chapter 2 Online Homework: Imagine this futuristic scenario: Life has been discovered on Mars and shown to contain a new type of macromolecule, named marsalive. You have been hired to study this new compound and want to determine whether marsalive is a structural or an informational macromolecule. What conclusions can be made based on the features? - A random pattern consisting of several different monomers would suggest an informational macromolecule. - A random pattern consisting of one or two different monomers would suggest an informational macromolecule. - A repetitive pattern consisting of one or two different monomers would suggest an informational macromolecule. - A random pattern consisting of several different monomers would suggest a structural macromolecule. - A repetitive pattern consisting of one or two different monomers would suggest a structural macromolecule. - A repetitive pattern consisting of several different monomers would suggest an informational macromolecule. - A repetitive pattern consisting of several different monomers would suggest a structural macromolecule.

- A random pattern consisting of several different monomers would suggest an informational macromolecule. - A repetitive pattern consisting of one or two different monomers would suggest a structural macromolecule.

Chapter 3 Online Homework: Match the choice on the left with the choice on the right. Nucleotide:

- AMP

Chapter 3 Online Homework: Which of the following statements is not true of the amino acids? - There are more than 60 different kinds of amino acids present in cells. - Amino acids have an N-terminus, C-terminus, and R groups. - Only around 20 amino acids are used in protein synthesis. - The R group of amino acids differs from one amino acid to another. - All amino acids exist in two stereoisomeric forms.

- All amino acids exist in two stereoisomeric forms.

Chapter 1 Online Homework: The Latin phrase omnis cellula e cellula refers to a cellular principle. Which of the following statements is the best interpretation of this phrase? - All cells arise only from preexisting cells. - The cell is the basic unit of structure. - Cells generally are found in clusters. - Tissues are composed of similar cells. - Organs are composed of tissues and cells.

- All cells arise only from preexisting cells.

Chapter 1 Online Homework: The Latin phrase omnis cellula e cellula refers to a cellular principle. Which of the following statements is the best translation of this phrase? - Organs are composed of tissues and cells. - All cells arise only from preexisting cells. - Cells generally are found in clusters. - The cell is the basic unit of structure. - Tissues are composed of similar cells.

- All cells arise only from preexisting cells.

Chapter 1 Online Homework: Which of the following is not a tenet of the cell theory? - All cells have a membrane-bound nucleus. - All cells arise from preexisting cells. - All organisms consist of one or more cells. - The cell is the basic unit of structure for all organisms. - none of the above

- All cells have a membrane-bound nucleus.

Chapter 2 Online Homework: Which of the following is NOT a consequence of the polar nature of water? - Water has a high surface tension. - Water has a high heat of vaporization. - Water has a high specific heat. - All of the other answer choices are consequences of the polar nature of water.

- All of the other answer choices are consequences of the polar nature of water.

Chapter 1 Online Homework: Which of the following statements does NOT correctly validate the three strands that compose modern cell biology? - Cellular structure arises from the combined structures of the macromolecules that compose cells. - Cellular DNA contains information about the structure and function of cellular proteins. - Mutations in the cellular DNA can compromise cellular and macromolecular structure and function. - All of the other available answer choices validate the relationships between the three strands that compose modern cell biology.

- All of the other available answer choices validate the relationships between the three strands that compose modern cell biology.

Chapter 3 Online Homework: The primary structure of a protein - is simply the order of amino acids from one end of the protein to another. - is important both genetically and structurally. - is the linear sequence of amino acids that are linked together by peptide bonds. - is important for determining the secondary and tertiary structure of a protein. - All of these statements are true.

- All of these statements are true.

Chapter 2 Online Homework: Which of the following is not attached to the central carbon atom in an amino acid? - A side chain ("R group") - An oxygen - A carboxyl functional group - An amino functional group

- An oxygen

Chapter 1 Online Homework: Which of the following accurately details the relationship between wavelength of illumination, lens quality, magnification, and the limit of resolution for light microscopy? - As shorter wavelength illumination and better quality lenses are used, magnification will decrease and the limit of resolution will decrease. - As shorter wavelength illumination and better quality lenses are used, magnification will increase and the limit of resolution will increase. - Magnification and limit of resolution are independent of wavelength of illumination and lens quality for light microscopy. - As shorter wavelength illumination and better quality lenses are used, magnification will increase and the limit of resolution will decrease.

- As shorter wavelength illumination and better quality lenses are used, magnification will increase and the limit of resolution will decrease.

Chapter 2 Online Homework: Which of the following is true of an asymmetric carbon atom? - A carbon with hydrogens attached at two locations is usually asymmetric. - Molecules may have only one asymmetric carbon atom. - A carbon with hydrogens attached at three locations is usually asymmetric. - Only amino acids have asymmetric carbon atoms. - Asymmetric carbon atoms create stereoisomers.

- Asymmetric carbon atoms create stereoisomers.

Chapter 2 Online Homework: Which of the following is true of an asymmetric carbon atom? - Molecules may have only one asymmetric carbon atom. - A carbon with hydrogens attached at two locations is usually asymmetric. - Only amino acids have asymmetric carbon atoms. - Methane has an asymmetric carbon. - Asymmetric carbon atoms create stereoisomers.

- Asymmetric carbon atoms create stereoisomers.

Chapter 1 Online Homework: The scientific work that established DNA, rather than protein, as the molecule of heredity is credited to - Avery, MacLeod, and McCarty. - Beadle and Tatum. - Watson and Crick. - Correns, von Tschermak, and de Vries. - Monod and Jacob.

- Avery, MacLeod, and McCarty.

Chapter 3 Online Homework: Which of the following is most similar to the Watson-Crick helix? - C-DNA - A-DNA - Z-DNA - B-DNA - mRNA

- B-DNA

Chapter 2 Online Homework: In the lab, you choose to design a simple experiment to distinguish between hydrophilic and hydrophobic substances. You start by adding equal amounts of vinegar and oil to a container. After shaking, the vinegar and oil levels separate, based upon polarity and density. To this you add glucose and sodium citrate and shake again. Where do you expect to find the glucose and sodium citrate in greatest quantities? - Both will be uniform throughout both layers. - Sodium citrate will concentrate in the vinegar, glucose in the oil. - Both will concentrate in the vinegar layer. - Both will concentrate in the oil layer. - The glucose will concentrate in the vinegar, sodium citrate in the oil.

- Both will concentrate in the vinegar layer.

Chapter 1 Online Homework: Which of the following is mismatched? - Drosophila melanogaster - embryogenesis - Mus musculus - immunology - Arabidopsis thaliana - plant gene function - Caenorhabditis elegans - photosynthesis - Escherichia coli - genetics

- Caenorhabditis elegans - photosynthesis

Chapter 2 Online Homework: Which of the following is not a fundamental property of carbon? - Carbon-containing molecules are diverse. - Carbon atoms are most likely to form ionic bonds with one another. - Carbon-containing molecules are stable. - Carbon has a valence of 4. - Carbon-containing molecules form stereoisomers.

- Carbon atoms are most likely to form ionic bonds with one another.

Chapter 2 Online Homework: Which of the following is not a fundamental property of carbon? - Carbon-containing molecules are diverse. - Carbon atoms are most likely to form ionic bonds with one another. - Carbon-containing molecules may form stereoisomers. - Carbon-containing molecules are stable. - Carbon has a valence of 4.

- Carbon atoms are most likely to form ionic bonds with one another.

Chapter 1 Online Homework: Which of the following is mismatched? - Chlamydomonas - cell differentiation - Escherichia coli - genetics - Arabidopsis - plant gene function - Mouse - immunology - Drosophila - embryogenesis

- Chlamydomonas - cell differentiation

Chapter 1 Online Homework: Which of the following can only be viewed by electron microscopy? - prokaryotes - frog eggs - nuclei - DNA - mitochondria

- DNA

Chapter 2 Online Homework: Which of the following is an informational macromolecule? - starch - polypeptide - glycogen - DNA - ATP

- DNA

Chapter 3 Online Homework: Which of these is a difference between a DNA and an RNA molecule? - DNA contains nitrogenous bases, whereas RNA contains phosphate groups. - DNA is double-stranded, whereas RNA is single-stranded. - DNA contains five-carbon sugars, whereas RNA contains six-carbon sugars. - DNA is a polymer composed of nucleotides, whereas RNA is a polymer composed of nucleic acids. - DNA contains uracil, whereas RNA contains thymine.

- DNA is double-stranded, whereas RNA is single-stranded.

Chapter 1 Online Homework: Suggest one advantage that DNA sequencing has over nucleic acid hybridization. - DNA sequencing can assess whether there is enough sequence complementarity to allow two strands to adhere to one another under specified conditions. - DNA sequencing makes it possible to identify species present in a sample of water, sewage, dirt, debris filtered from the air, or swab samples of organisms. - DNA sequencing makes it possible to determine the order of individual nucleotides along a DNA strand. - DNA sequencing makes it possible to determine the tertiary and quaternary structure of a DNA strand.

- DNA sequencing makes it possible to determine the order of individual nucleotides along a DNA strand.

Chapter 1 Online Homework: Suggest one advantage that the electron microscopy has over the light microscopy. - Electron microscopy uses video cameras to collect digital images for computer storage. - Electron microscopy is capable of much greater limit of resolution and hence much less resolving power. - Electron microscopy is capable of much greater resolution and hence much higher useful magnification. - Electron microscopy uses complex mathematical algorithms to increase the contrast and resolution of digital images.

- Electron microscopy is capable of much greater resolution and hence much higher useful magnification.

Chapter 1 Online Homework: Suggest one advantage that electrophoresis has over chromatography. - Electrophoresis separates molecules based on differences in chemical properties, thereby making it possible to separate molecules that undergo similar chemical reactions. - Electrophoresis separates molecules based on mass differences, thereby making it possible to separate molecules that are similar in molar mass. - Electrophoresis separates molecules based on differences in solubility, thereby making it possible to separate molecules that are similar in mass and size. - Electrophoresis separates molecules based on charge differences, thereby making it possible to separate molecules that are similar in size, shape, and density.

- Electrophoresis separates molecules based on charge differences, thereby making it possible to separate molecules that are similar in size, shape, and density.

Chapter 3 Online Homework: Which of the following accurately describes the structure of fibrous proteins? - Fibrous proteins usually contain a number of different domains with different structural motifs. - Fibrous proteins are usually composed of either α helices or β sheets throughout the molecule, giving them a highly ordered, repetitive structure. - Fibrous proteins are composed of an equal mixture of α helices and β sheets with interconnecting looped segments. - Fibrous proteins have a simple primary structure and very little secondary structure, resulting in long, thin fibers. - Fibrous proteins have an extensive tertiary and quaternary structure that affects the strength and elasticity of each fiber.

- Fibrous proteins are usually composed of either α helices or β sheets throughout the molecule, giving them a highly ordered, repetitive structure.

Chapter 1 Online Homework: Which of the following is true of fluorescence microscopy? - Fluorescent light is emitted throughout the specimen being viewed. - Fluorescence microscopy is used to view dead specimens only. - Fluorescence microscopy is best at viewing rounded, thicker specimens. - Fluorescence microscopy is able to overcome problems encountered with using confocal scanning microscopy. - Fluorescence microscopy presents images in three dimensions.

- Fluorescent light is emitted throughout the specimen being viewed.

Chapter 3 Exercise: What is the most common monosaccharide found in our biosphere?

- Glucose

Chapter 2 Exercise: Why are amphipathic molecules necessary in biological systems?

- High hydrophobic molecules like fatty acids also have a polar head group that interacts with the aqueous environment of our bodies.

Chapter 1 Online Homework: All of the following are model organisms, except - Homo sapiens. - Arabidopsis thialana. - Caenorhabditis elegans. - Saccharomyces cerevisiae. - Drosophila melanogaster.

- Homo sapiens.

Chapter 2 Online Homework: Which of the following statements concerning hydrocarbons is false? - Only hydrogen atoms are used to complete the valence requirements of carbon in hydrocarbons. - Hydrocarbons are the most abundant organic molecules in cells. - Octane is a hydrocarbon. - Phospholipids have hydrocarbon tails. - Hydrocarbons are insoluble in water.

- Hydrocarbons are the most abundant organic molecules in cells.

Chapter 1 Online Homework: Which of the following is an application of immunofluorescence microscopy? - Identifying which organelle or cellular compartment contains a particular protein. - Identification of specific components of the immune system. - Visualization of the natural fluorescence of a specimen under UV light. - Visualization of the surface structures of a specimen. - Construction of three-dimensional images of structures smaller than 10 nm.

- Identifying which organelle or cellular compartment contains a particular protein.

Chapter 3 Exercise: Where in a folded protein would you find? Why? a. A hydrophobic AA (list a few)

- Interior of protein due to hydrophobic collapse Val, Ala, Leu

Chapter 3 Online Homework: Which of the following is true of transfer RNA? - It functions in replication only. - It serves as the site of protein synthesis. - It is an important component of ribosomes. - It is responsible for the correct positioning of amino acids in a nascent polypeptide.

- It is responsible for the correct positioning of amino acids in a nascent polypeptide.

Chapter 2 Online Homework: Why is a selectively permeable membrane so important to living things? - It provides a good barrier between the inside and outside of the cell. - It allows cells to attach to adjacent tissues. - Proteins will avoid a selectively permeable membrane. - The membrane may absorb several times its weight in cholesterol. - all of the above

- It provides a good barrier between the inside and outside of the cell.

Chapter 2 Online Homework: How do large polar and charged molecules cross biological membranes? - Large polar and charged molecules can't cross biological membranes. - Large polar and charged molecules must be hydrolyzed before they can cross a biological membrane. - Large polar and charged molecules cross biological membranes via diffusion through the hydrophilic core of the membrane. - Large polar and charged molecules cross biological membranes via transport proteins that form hydrophilic channels through the membrane. - Large polar and charged molecules can't cross biological membranes, because they must be hydrolyzed before they can.

- Large polar and charged molecules cross biological membranes via transport proteins that form hydrophilic channels through the membrane.

Chapter 2 Online Homework: Because membranes usually are not permeable to polysaccharides, nucleic acids, and proteins, how are cells able to incorporate these molecules? - These macromolecules are only incorporated into structures outside the membrane. - Macromolecules are broken down extracellularly, and their subunits diffuse through the membrane. - Macromolecules are digested extracellularly, and their subunits move through transport proteins. - Macromolecules are transported via endocytosis and are digested within the cell. - Macromolecules are digested extracellularly, and their subunits move through transport proteins. Macromolecules are transported via endocytosis and are digested within the cell.

- Macromolecules are digested extracellularly, and their subunits move through transport proteins. Macromolecules are transported via endocytosis and are digested within the cell.

Chapter 2 Online Homework: Which of the following is not true of hydrocarbons? - Octane is a hydrocarbon. - Phospholipids have hydrocarbon tails. - Only hydrogen atoms are used to complete the valence requirements of carbon. - Hydrocarbons are insoluble in water. - Many hydrocarbons are used in living systems.

- Many hydrocarbons are used in living systems.

Chapter 3 Exercise: A certain protein is found to contain about 90% hydrophobic amino acids, where in the cell is it likely to be found?

- Most likely within the lipid bilayer of a membrane.

Chapter 1 Online Homework: In studying osteoporosis in humans, you wish to test a newly designed treatment for efficacy. Your best choice for a model organism would be - Arabidopsis thaliana. - Escherichia coli. - Mus musculus. - Pisum sativum. - Caenorhabditis elegans.

- Mus musculus.

Chapter 2 Online Homework: Which monomers make up RNA? - Nucleotides - Simple sugars - Amino acids - Polymers

- Nucleotides

Chapter 3 Exercise: Where in a folded protein would you find? Why? b. A polar AA (list a few)

- On the exterior surface of the protein due to interaction with aqueous surroundings. Ser, Met, Cys

Chapter 2 Exercise: Why do macromolecules need to be synthesized in the compartment where they are needed?

- Only small molecules or monomers may pass into the cell. Once synthesized macromolecules are too large to traverse out of the membranes and therefore remain inside.

Chapter 3 Online Homework: Complete the following vocabulary exercise relating to the level of structure in proteins. _______ structure is the sequence of amino acids in a protein.

- Primary

Chapter 3 Online Homework: Two proteins associated with a rare neurodegenerative disorder have been sequenced. Protein A contains many polar amino acids with small regions containing nonpolar, hydrophobic amino acids. Protein B is rich in nonpolar, hydrophobic amino acids with only two small regions containing polar amino acids. What might this suggest about the two proteins? - Protein A is fibrous and Protein B is globular. - Protein A is most likely and enzyme and Protein B is most likely a storage protein. - Protein A may be a cytoplasmic protein and Protein B may be a membrane associate protein. - The two proteins may have different secondary structures. - Protein A and Protein B are complementary parts of a supramolecular structure.

- Protein A may be a cytoplasmic protein and Protein B may be a membrane associate protein.

Chapter 2 Online Homework: Which polymers are composed of amino acids? - Nucleic acids - Monomers - Proteins - Carbohydrates

- Proteins

Chapter 3 Online Homework: Which of the following is true of purines? - Purines bind readily to deoxyribose but not to ribose. - Purines have a double-ringed structure. - Cytosine is a purine. - Adenine's bonding to thymine is stronger than is guanine's to cytosine. - Both adenine and thymine are purines.

- Purines have a double-ringed structure.

Chapter 3 Online Homework: Complete the following vocabulary exercise relating to the level of structure in proteins. _______ structure is the result of two or more protein subunits assembling to form a larger, biologically active protein complex.

- Quaternary

Chapter 3 Online Homework: The chemical nature of each amino acid is determined by which of the following groups? - hydrogen - R - carboxyl - amino - hydroxyl

- R

Chapter 3 Online Homework: The chemical nature of each amino acid is determined by which of the following groups? - hydroxil - carboxyl - amino - R - hydrogen

- R

Chapter 1 Online Homework: Which scientist is credited with coining the term cell from the Latin cellulae? - Robert Brown - Theodor Schwann - Matthias Schleiden - Robert Hooke - Antonie van Leeuwenhoek

- Robert Hooke

Chapter 1 Online Homework: In 1665, ________ used a microscope that he had built to examine thin slices of ________. While examining this material, he observed tiny compartments that he called cellulae. - Rudolf Virchow; collagen - Antonie van Leeuwenhoek; sperm cells - Robert Brown; plant material - Theodor Schwann; animal tissue - Robert Hooke; cork

- Robert Hooke; cork

Chapter 1 Online Homework: Suggest one advantage that scanning electron microscopy has over transmission electron microscopy. - Scanning electron microscopy makes it possible to only visualize cells and tissues as if in two dimensions. - Scanning electron microscopy makes it possible to visualize subcellular structures and macromolecules as if in two dimensions. - Scanning electron microscopy makes it possible to visualize subcellular structures and macromolecules as if in three dimensions. - Scanning electron microscopy makes it possible to only visualize cells and tissues as if in three dimensions.

- Scanning electron microscopy makes it possible to visualize subcellular structures and macromolecules as if in three dimensions.

Chapter 3 Online Homework: Complete the following vocabulary exercise relating to the level of structure in proteins. _______ structure describes the alpha-helices and beta-sheets that are formed by hydrogen bonding between backbone atoms located near each other in the polypeptide chain.

- Secondary

Chapter 3 Exercise: Describe the structure of the DNA double helix.

- See features of DNA double helix on pages 58-59. Include in description: complementary anti-parallel strands connected via the sugar phosphate backbone which runs in a 5' to 3' orientation. The bases H- bind between the strands to hold them together, the base pairs will always be either A-T (2 H-bonds) or G-C (3 H-bonds).

Chapter 2 Online Homework: Which of the following statements about self-assembly is false? - Molecular chaperones are sometimes required for the proper folding and assembly of complex proteins. - The noncovalent interactions that drive supramolecular assembly processes are similar to those that dictate the folding of individual protein molecules. - Self-assembly requires specific chemical conditions. - Self-assembly only occurs in structures composed of protein. - All of the above.

- Self-assembly only occurs in structures composed of protein.

Chapter 1 Online Homework: Suggest one advantage that bioinformatics has over sequencing of a genome. - Sequencing of a genome uses computer analysis to aid in understanding and interpreting those data in terms of gene numbers and expression, whereas bioinformatics simply provides a large amount of data about the DNA present in the genome. - Sequencing of a genome simply provides a large amount of data about the DNA present in the genome, whereas bioinformatics uses computer analysis to aid in understanding and interpreting those data in terms of gene numbers and expression. - Sequencing of a genome simply provides a large amount of data about the DNA present in the genome, whereas bioinformatics techniques such as image and signal processing allow extraction of useful results from small amounts of raw data. - Sequencing of a genome simply provides a large amount of data about the DNA present on a chromome, whereas bioinformatics provides a large amount of data about the DNA present in the entire genome.

- Sequencing of a genome simply provides a large amount of data about the DNA present in the genome, whereas bioinformatics uses computer analysis to aid in understanding and interpreting those data in terms of gene numbers and expression.

Chapter 1 Online Homework: Which of the following is false of brightfield microscopy? - Specimens are always viewed without being stained. - White light is utilized. - Phase-contrast microscopy is a variant of brightfield microscopy. - Light passes through the object being examined. - Specimens usually must be fixed.

- Specimens are always viewed without being stained.

Chapter 2 Online Homework: Why do polar substances such as NaCl dissolve so readily in water? - The sodium ions repel the negative end of the water molecule. - NaCl is a very dry powder, and the water is able to soak into the salt. - Spheres of hydration form between the water and the ions. - The charged ends of the water molecules are able to surround the oppositely charged salt ion. - Spheres of hydration form between the water and the ions. The charged ends of the water molecules are able to surround the oppositely charged salt ion.

- Spheres of hydration form between the water and the ions. The charged ends of the water molecules are able to surround the oppositely charged salt ion.

Chapter 2 Online Homework: Why isn't this insect drowning? - It is difficult to change the temperature of water. - Surface tension. - The insect is very light. - The insect is swimming. - The insect is flying just above the water surface.

- Surface tension.

Chapter 3 Online Homework: Complete the following vocabulary exercise relating to the level of structure in proteins. ______ structure is achieved when a protein folds into a compact, three-dimensional shape stabilized by interactions between side-chain R groups of amino acids

- Tertiary

Chapter 3 Online Homework: Which of the following statements is the most accurate reflection of native protein tertiary structure? - Tertiary structure is the overall three-dimensional shape of a protein. It is determined by hydrogen bonds, interactions between hydrophobic R groups, ionic bonds between R groups, van der Waals interactions, and disulfide bridges. - The protein tertiary structure results from all amino acids in a protein adopting secondary structure. - Protein tertiary structure is present only to allow for the formation of protein quaternary structure. - Protein tertiary structure is present only to allow for the formation of multiple functional domains

- Tertiary structure is the overall three-dimensional shape of a protein. It is determined by hydrogen bonds, interactions between hydrophobic R groups, ionic bonds between R groups, van der Waals interactions, and disulfide bridges.

Chapter 3 Online Homework: Cellulose, chitin, and the polysaccharide that makes up the cell walls of many bacteria are the structural polysaccharides, whereas starch and glycogen are the main storage polysaccharides. What must be true about these two classes of polysaccharides? - The alpha-glycosidic bonds of storage polysaccharides are less stable than the beta-glycosidic bonds of structural polysaccharides. - The beta-glycosidic bonds of storage polysaccharides are less stable than the alpha-glycosidic bonds of structural polysaccharides. - The beta-glycosidic bonds of storage polysaccharides are more stable than the alpha-glycosidic bonds of structural polysaccharides. In addition, chemical stability correlates with permanence or nonreactivity. Which of the two types of polysaccharides would be expected to remain the same for longer? - The alpha-glycosidic bonds of storage polysaccharides are more stable than the beta-glycosidic bonds of structural polysaccharides.

- The alpha-glycosidic bonds of storage polysaccharides are less stable than the beta-glycosidic bonds of structural polysaccharides.

Chapter 3 Online Homework: Explain why the chosen amino acids are likely to be found in the interior of a protein molecule. - The chosen amino acids are the most polar members of each pair. - The chosen amino acids are the most compact members of each pair. - The chosen amino acids are the least compact members of each pair. - The chosen amino acids are the least polar members of each pair.

- The chosen amino acids are the least polar members of each pair.

Chapter 3 Online Homework: Explain why cysteine residues with free sulfhydryl groups tend to be localized on the exterior of a protein molecule, whereas those involved in disulfide bonds are more likely to be buried in the interior of the molecule. - The free sulfhydryl group is much larger than the disulfide bond. - The free sulfhydryl group is polar; the disulfide bond is much less polar. - The disulfide bond is polar; the free sulfhydryl group is much less polar. - The disulfide bond is much larger than the free sulfhydryl group.

- The free sulfhydryl group is polar; the disulfide bond is much less polar.

Chapter 2 Online Homework: The addition of some amphipathic molecules (such as detergents) to water decreases the surface tension of water. Which of the following must be true? - The specific heat of water is increasing. - The intermolecular hydrogen bonding of water is being weakened by the detergent. - Water is becoming more polar. - The boiling point of water is increasing.

- The intermolecular hydrogen bonding of water is being weakened by the detergent.

Chapter 1 Online Homework: Define limit of resolution. - The limit of resolution of a microscope is the shortest distance between four separate points in a microscopes field of view that can still be distinguished as distinct entities. - The limit of resolution of a microscope is a measure of how close together two points can be and still be distinguished from one another when viewed through the microscope. - The limit of resolution of a microscope is the minimum distance or angular separation between two point objects which allows them to be resolved according to the Rayleigh criterion. - The limit of resolution of a microscope is the clearance distance between the closest surface of the cover glass and the objective front lens.

- The limit of resolution of a microscope is a measure of how close together two points can be and still be distinguished from one another when viewed through the microscope.

Chapter 3 Online Homework: Which of the following statements about DNA structure is true? - The pentose sugar in DNA is ribose. - The nucleic acid strands in a DNA molecule are oriented antiparallel to each other, meaning they run in opposite directions. - Hydrogen bonds formed between the sugar‑phosphate backbones of the two DNA chains help to stabilize DNA structure. - Nucleic acids are formed through phosphodiester bonds that link nucleosides together.

- The nucleic acid strands in a DNA molecule are oriented antiparallel to each other, meaning they run in opposite directions.

Chapter 2 Exercise: Nucleic acids and proteins are considered "informational" molecules versus polysaccharides. Why?

- The order of the monomers contains the information needed for protein synthesis, in the case of the nucleic acids, and the information needed to fold/assemble in the case of the proteins. - On the back the functional groups from left to right are: amine, amide (or carbonyl), hydroxyl, amide (or carbonyl), carboxyl

Chapter 2 Online Homework: While synthesizing a new blue pigment, a chemist notices that the new compound accumulates between an aqueous (water) environment and a hydrophobic environment. When added to a mixture of oil and water, the pigment creates a blue ring around the droplets of oil. Which of the following statements best describes this new pigment? - The pigment is a polar molecule and is forming hydrogen bonds with both the water and oil molecules. - The pigment is neither polar nor nonpolar; it is apolar. - The pigment is hydrophilic and will not form hydrophobic bonds with the oil. - The pigment is probably hydrophobic and is attempting to bond with the oil. - The pigment is amphipathic, having polar and nonpolar regions.

- The pigment is amphipathic, having polar and nonpolar regions.

Chapter 2 Exercise: Membranes: Describe what is meant by selective barriers.

- The protein channels are very specific for what goes in/out of the cells.

Chapter 2 Online Homework: Which of the following is false regarding water's specific heat? - The specific heat of water is similar to most liquids. - Water's high specific heat has a temperature-buffering effect. - Water gains and loses heat more slowly than most other solvents do. - Heat applied to water must initially break a number of hydrogen bonds. - The specific heat of water is 1.0 calorie per gram.

- The specific heat of water is similar to most liquids.

Chapter 2 Online Homework: Which of the following is false regarding water's specific heat? - The specific heat of water is 1.0 calorie per gram. - The specific heat of water is similar to that of most liquids. - Water's high specific heat has a temperature-buffering effect. - Heat applied to water must initially break a number of hydrogen bonds. - Water gains and loses heat more slowly than most other liquids do.

- The specific heat of water is similar to that of most liquids.

Chapter 2 Online Homework: An enzyme synthesized in the laboratory is found to have little activity when compared to the enzyme extracted from cell culture. Both enzymes were examined and have identical amino acid composition. What is the best explanation for the lack of activity of the synthesized enzyme? - The synthetic enzyme was not made of amino acids. - Denaturation of the synthesized enzyme was not complete. - The ATP required for self-assembly was present in the cell extract but not in the laboratory synthesis. - The van der Waals radius was altered during laboratory synthesis. - The synthesized enzyme was not folded correctly because molecular chaperones were not present.

- The synthesized enzyme was not folded correctly because molecular chaperones were not present.

Chapter 3 Exercise: What is the difference between glycogen and cellulose, both structurally and what functions they have?

- This question follows from the question above. The type of glycosidic linkage is the biggest difference, also the frequency of the alpha 1,6 branches. And the overall structure, as seen as discussed on pages 64-65. Also glycogen is the human form of glucose storage, and cellulose is the primary plant cell wall material and the bonds in cellulose cannot be digested by humans.

Chapter 2 Online Homework: __________ serve as hydrophilic channels through hydrophobic membranes, or they act as carriers of specific solutes. - Cytoskeletal proteins - Transport proteins - Soluble enzymes - Polysaccharides

- Transport proteins

Chapter 2 Online Homework: True or false? Enzymes in the digestive tract catalyze hydrolysis reactions. - True - False

- True

Chapter 3 Online Homework: Guanine and adenine are purines found in DNA. - True - False

- True

Chapter 2 Exercise: Membranes: Describe the lipid bilayer. What is needed to allow passage of material in/out of cells?

- Two layers of phospholipids, an inner and outer layer, with the hydrophobic tails on the inside of the bilayer and the polar headgroups in contact with the exterior and interior aqueous environments. Proteins in the bilayer provide channels.

Chapter 1 Online Homework: Suggest one advantage that ultracentrifugation has over centrifugation. - Ultracentrifugation allows to separate biomolecules with different physical properties, whereas conventional centrifugation precipitates all the biomolecules. - Ultracentrifugation is capable of much higher speeds and hence much greater centrifugal force than conventional centrifugation. - Ultracentrifugation allows to separate biomolecules based on their size, shape, and/or density, whereas separation in a conventional centrifugation is based on molecular mass only. - Ultracentrifugation allows to separate mixtures containing charged molecules, whereas conventional centrifugation separates neutral biomolecules only.

- Ultracentrifugation is capable of much higher speeds and hence much greater centrifugal force than conventional centrifugation.

Chapter 1 Online Homework: Which of the following is INCONSISTENT with the cellular basis of life? - All anatomical structures and physiological processes of an organism are consequences of emergent properties of cellular structures and cellular processes. - Cellular function is intimately linked to cellular structure. - Viruses are living, acellular parasites. - The nuclear and mitochondrial DNA of a cell contains all of the information necessary for cellular reproduction.

- Viruses are living, acellular parasites.

Chapter 2 Online Homework: Which of the following statements about the polymerization of macromolecules is false? - Often the energy needed for polymerization is supplied by ATP. - Macromolecules are synthesized by the stepwise addition of monomers. - Water is added to join the monomers of the macromolecules. - A monomer is usually activated by the coupling of the monomer to a carrier. - The polymer chain usually has two different ends.

- Water is added to join the monomers of the macromolecules.

Chapter 2 Online Homework: Which of the following statements about the polymerization of macromolecules is false? - The polymer chain usually has two different ends. - Water is added to join the monomers of the macromolecules. - Macromolecules are synthesized by the stepwise addition of monomers. - Often the energy needed for polymerization is supplied by ATP. - A monomer is usually activated by the coupling of the monomer to a carrier.

- Water is added to join the monomers of the macromolecules.

Chapter 2 Online Homework: While fishing, you make the following observations: a. Water spiders appear to be able to walk on the surface of the water. b. Flat rocks may be made to skip across the water.Which of the following properties of water can explain these observations? - Water is an excellent solvent. - Water molecules are heavy. - Water molecules are cohesive. - Water molecules are polar. - Water molecules are heavy and cohesive.

- Water molecules are cohesive.

Chapter 2 Online Homework: While fishing, a biology student makes the following observations: 1) Water spiders appear to be able walk on the surface of the water. 2) Flat rocks may be made to skip across the water.Which of the following properties of water can explain these observations? - Water is an excellent solvent. - Water molecules create spheres of hydration around solute molecules. - Water molecules are cohesive. - Water molecules are often associated via hydrogen bonds. - Water molecules are often associated via hydrogen bonds and cohesive.

- Water molecules are often associated via hydrogen bonds and cohesive.

Chapter 2 Online Homework: Why do ionic substances such as NaCl dissolve so readily in water? - NaCl is a very dry powder, and the water is able to soak into the salt. - The sodium ions repel the negative end of the water molecule. - Water molecules form spheres of hydration around the sodium and chloride ions. - The charged ends of the water molecules are able to surround the oppositely charged salt ion. - Water molecules form spheres of hydration around the sodium and chloride ions. Also the charged ends of the water molecules are able to surround the oppositely charged salt ion.

- Water molecules form spheres of hydration around the sodium and chloride ions. Also the charged ends of the water molecules are able to surround the oppositely charged salt ion.

Chapter 2 Online Homework: Biologically, which of the following is the least important characteristic of water? - Water is a good solvent. - Water typically contains isotopes of hydrogen. - Water has a temperature-stabilizing capacity. - Water molecules are polar. - Water molecules form numerous hydrogen bonds.

- Water typically contains isotopes of hydrogen.

Chapter 2 Online Homework: Biologically, which of the following is the least important characteristic of water? - Water molecules are polar. - Water is a good solvent. - Water typically contains isotopes of hydrogen. - Water molecules have numerous hydrogen bonds. - Water has a temperature-stabilizing capacity.

- Water typically contains isotopes of hydrogen.

Chapter 2 Online Homework: The moon lacks life and varies dramatically in temperature. If we could keep a layer of water spread on the surface of the moon, what effect would it have? - Because water has a high heat of vaporization, the temperatures would rise to the upper extremes. - Physical conditions would remain the same. - The temperatures would drop to the lower extremes. - Life would be possible, but it would have to withstand these extremes in temperature. - Water would absorb and hold heat and moderate the temperature extremes.

- Water would absorb and hold heat and moderate the temperature extremes.

Chapter 1 Online Homework: Which of the following scientists revolutionized biology by demonstrating that living organisms were also governed by the laws of physics and chemistry by synthesizing urea in the laboratory from ammonium cyanate? - Wöhler - Rohrer - Mendel - Schwann - van Leeuwenhook

- Wöhler

Chapter 1 Online Homework: Which of the following model organisms contributed the most to connecting the genetic strand and the biochemical strand of modern cell biology through the use of genetic techniques and biochemical techniques to show molecules interacting in vivo? - Pea plants illustrated the behavior of trait inheritance between generations. - Mutants of Drosophila melanogaster allowed for the mapping of genetic traits to particular chromosomes. - Yeast mutants and yeast two-hybrid systems allow for the characterization of genetic mutants and determination of how specific proteins interact within a living cell. - Yeast was used to isolate enzymes into a cell-free extract that could carry out fermentation.

- Yeast mutants and yeast two-hybrid systems allow for the characterization of genetic mutants and determination of how specific proteins interact within a living cell.

Chapter 1 Online Homework: Would he have been able to see any of the structures shown in the figure below? - Yes, he would. - No, he wouldn't.

- Yes, he would.

Chapter 3 Online Homework: A discrete, locally folded unit of protein tertiary structure usually having a specific function best describes __________. - quaternary structure - a domain - a complex - a motif

- a domain

Chapter 3 Online Homework: The components of a nucleotide are - a six-carbon sugar, an ester linkage, and a four-ringed hydrocarbon. - a three-carbon alcohol with a hydroxyl group on each carbon and three fatty acids. - two six-carbon sugars attached with an α(1→4)α(1→4) glycosidic bond. - a five-carbon sugar, a phosphate group, and a nitrogen-containing aromatic base. - a carboxyl group, an amine group, and a variable R group.

- a five-carbon sugar, a phosphate group, and a nitrogen-containing aromatic base.

Chapter 2 Online Homework: Which of the following molecules is most likely to cross the cell membrane directly by passive diffusion? - fructose and insulin - a steroid hormone (a hydrocarbon) - fructose (a sugar) - Na+ - insulin (a polypeptide)

- a steroid hormone (a hydrocarbon)

Chapter 1 Online Homework: A scientific hypothesis is __________. - a test in which only specific conditions are allowed to vary - a testable explanation of a natural phenomenon - the same as a theory - a theory that has been confirmed

- a testable explanation of a natural phenomenon

Chapter 3 Online Homework: For the following pairs of amino acids, choose the one that is more likely to be found in the interior of a protein molecule. - glycine - alanine

- alanine

Chapter 1 Online Homework: Cell biology emerged from which of the following fields of biology? - cytology - biochemistry - genetics - all of the above - none of the above

- all of the above

Chapter 1 Online Homework: Of the following specialized procedures, which may be used with the electron microscope? - freeze fracturing - negative staining - shadowing with gold - scanning electron microscopy - all of the above

- all of the above

Chapter 3 Online Homework: The primary structure of a protein - is simply the order of amino acids from one end of the protein to another. - is important both genetically and structurally. - is important for determining the secondary and tertiary structure of a protein. - is the linear sequence of amino acids that are linked together by peptide bonds. - all of the above

- all of the above

Chapter 3 Online Homework: Complementary relationships between purines and pyrimidines - allow adenine to form two hydrogen bonds with thymine (or uracil) and guanine to form three hydrogen bonds with cytosine to form double-stranded nucleic acids. - allow the interaction of the oppositely charged amino acids to form the tertiary structure of proteins. - allow adjacent bases in a nucleotide chain to stack tightly, stabilizing the DNA double helix. - provide highly ordered, repetitive bonding to form α helices and β sheets within proteins. - allow adenine to form two hydrogen bonds with thymine (or uracil) and guanine to form three hydrogen bonds with cytosine to form double-stranded nucleic acids, and also allow adjacent bases in a nucleotide chain to stack tightly, stabilizing the DNA double helix.

- allow adenine to form two hydrogen bonds with thymine (or uracil) and guanine to form three hydrogen bonds with cytosine to form double-stranded nucleic acids.

Chapter 1 Online Homework: Radioisotopes have been important in the study of biochemical pathways because they __________. - allow scientists to view individual molecules - provide an important energy source for all organisms - are major natural components of all cells - allow scientists to trace the fate of specific molecules

- allow scientists to trace the fate of specific molecules

Chapter 2 Online Homework: Which of the following functional groups and compounds is polar, contains one or more electronegative atoms in a bond, and can reversibly ionize within the physiological pH range? - alcohol (--OH) - hydrocarbon - amine - carbonyl/ketone

- amine

Chapter 2 Online Homework: Which of the following is not an activated monomer? - glucose-6-phosphate - uracil triphosphate - amino acid - adenosine triphosphate - aminoacyl tRNA

- amino acid

Chapter 3 Online Homework: Match the choice on the left with the choice on the right. Monomer of Protein:

- amino acid

Chapter 3 Online Homework: Proteins are polymers of _____. - nucleotides - hydrocarbons - glycerol - amino acids - CH2O units

- amino acids

Chapter 1 Online Homework: Phase-constrast:

- amplifies variations in density

Chapter 3 Online Homework: Which of the following has the greatest number of glycosidic bonds? - glucose - amylose - DNA - triacylglycerol - vitamin A

- amylose

Chapter 1 Online Homework: Initially thought to be true because ______ cells do not have _______, which made it hard to distinguish individual cells using the crude microscopes available to early investigators; shown by Schwann (1839) to be incorrect for _______ cells, which have well-defined boundaries of _______ fibers, and later extended to all ______ cells.

- animal - cell walls - cartilage - collagen - animal

Chapter 1 Online Homework: Which ones? Select all that apply. - animal cells - bacteria cells - plant cells

- animal cells - plant cells

Chapter 1 Online Homework: Which ones? Select all that apply. - animal cells - plant cells - bacteria cells

- animal cells - plant cells - bacteria cells

Chapter 3 Online Homework: Which of the following is an example of a defensive protein? - cell surface receptor - myosin - antibody - hormone - keratin

- antibody

Chapter 2 Online Homework: Choose the item in the right column that best matches each item in the left column. Molecular Chaperone:

- assists in protein assembly

Chapter 2 Online Homework: Match the interaction or bond with the phrase that best describes it. Hydrophobic Interaction:

- association of nonpolar groups

Chapter 1 Online Homework: Consider the structures shown in the figure below. Which of these structures would both Hooke and van Leeuwenhoek have been able to see with their respective microscopes? Which, if any, would van Leeuwenhoek have been able to see that Hooke could not? Which, if any, would a contemporary cell biologist be able to see that neither Hooke nor van Leeuwenhoek could see? van Leeuwenhoek but not Hooke:

- bacterium - chloroplast - mitochondrion

Chapter 1 Online Homework: Cell biology emerged from which of the following fields of biology? - cytology and biochemistry - cytology - genetics - biochemistry - biochemistry, cytology, and genetics

- biochemistry, cytology, and genetics

Chapter 3 Online Homework: The term amphipathic describes the characteristic of some molecules that have ________. - only a single polar region - no polar regions - two nonpolar regions - both a polar and a nonpolar region - two polar regions

- both a polar and a nonpolar region

Chapter 2 Online Homework: Which of the following is a unit of energy? - joule - calorie - watt - mole - both calorie and joule

- both calorie and joule

Chapter 1 Online Homework: Which type of microscopy enhances and amplifies slight changes in the phase of transmitted light? - fluorescence microscopy - phase-contrast microscopy - both differential interference contrast microscopy and phase-contrast microscopy - differential interference contrast microscopy - digital video microscopy

- both differential interference contrast microscopy and phase-contrast microscopy

Chapter 2 Online Homework: All of the following are common functional groups found in biological molecules except - sulfhydryl groups. - butyl groups. - amino groups. - phosphate groups. - carbonyl groups.

- butyl groups.

Chapter 2 Online Homework: Which of the following is a unit of energy? - calorie - bond - mole - watt - calorie and bond

- calorie

Chapter 3 Online Homework: Cellulose belongs to which of the following groups of macromolecules? - lipids - proteins - carbohydrates - nucleic acids - none of the above

- carbohydrates

Chapter 3 Online Homework: Cellulose belongs to which of the following groups of macromolecules? - nucleic acids - lipids - carbohydrates - proteins - none of these

- carbohydrates

Chapter 2 Online Homework: What atom forms the backbone of almost all biological molecules? - carbon - hydrogen - sulfur - nitrogen - phosphorus

- carbon

Chapter 2 Online Homework: What inorganic precursors are needed to synthesize proteins? - carbon, water, oxygen, and phosphate - carbon, water, oxygen, nitrogen, and phosphate - carbon, water, oxygen, sodium, and phosphate - carbon, water, oxygen, nitrogen, and sulfurcarbon, water, and oxygen

- carbon, water, oxygen, sodium, and phosphate

Chapter 2 Online Homework: Choose the item in the right column that best matches each item in the left column. Structural Polysaccharide:

- cellulose

Chapter 2 Online Homework: Which of the following is a structural polysaccharide? - glycogen - fructose - cellulose - starch - All of the above are structural polysaccharides.

- cellulose

Chapter 2 Online Homework: Which one of the following biological polymers is mismatched with its monomer? - enzyme - amino acid - protein - amino acid - chitin - monosaccharide - DNA - nucleotide - cellulose - amino acid

- cellulose - amino acid

Chapter 1 Online Homework: You wish to obtain a pure mitochondria sample from lysed cells. The best way to obtain this sample would be - agarose gel electrophoresis - .chromatography. - centrifugation. - polyacrylamide gel electrophoresis. - chromatography and polyacrylamide gel electrophoresis.

- centrifugation.

Chapter 1 Online Homework: You wish to obtain a purified sample of mitochondria from lysed cells. The best way to obtain this sample would be - both centrifugation and polyacrylamide gel electrophoresis. - chromatography. - agarose gel electrophoresis. - centrifugation. - polyacrylamide gel electrophoresis.

- centrifugation.

Chapter 2 Online Homework: The term amphipathic refers to those molecules that are - hydrophobic. - nonpolar at both ends. - charged at both ends but with opposite charges. - hydrophilic. - charged at one end and nonpolar at the other.

- charged at one end and nonpolar at the other.

Chapter 1 Online Homework: Which of the following types of light microscopy improves the resolution of thick specimens by illuminating one plane of the specimen at a time? - differential interference contrast microscopy - confocal microscopy - fluorescence microscopy - brightfield microscopy - phase-contrast microscopy

- confocal microscopy

Chapter 3 Online Homework: Which of the following is not a characteristic of DNA? - composed of nucleotides - antiparallel strands - double-stranded - contains ribose - complementarity

- contains ribose

Chapter 2 Online Homework: What type of bond is joining the two hydrogen atoms? - covalent - hydrogen - ionic - hydrophobic - hydrophilic

- covalent

Chapter 1 Online Homework: Scanning electron microscopy (SEM) is especially suited to - examine internal cellular structure. - create a sense of depth. - observe living specimens. - create a sense of depth and observe living specimens. - create a sense of depth, examine internal cellular structure and observe living specimens.

- create a sense of depth.

Chapter 1 Online Homework: Scanning electron microscopy (SEM) is especially suited to - both observing living specimens and creating a sense of depth. - examining internal cellular structure. - creating a sense of depth. - simultaneously observing living specimens, examining internal cellular structure, and creating a sense of depth. - observing living specimens.

- creating a sense of depth.

Chapter 3 Online Homework: Match the choice on the left with the choice on the right. Pyrimidine:

- cytosine

Chapter 3 Online Homework: Identify three possible components of a DNA nucleotide. - cytosine, phosphate group, ribose - cytidine, phosphate group, ribose - guanine, phosphate group, ribose - adenine, phosphate group, ribose - deoxyribose, phosphate group, uracil - deoxyribose, phosphate group, thymine

- deoxyribose, phosphate group, thymine

Chapter 1 Online Homework: SEM:

- detects electrons deflected from the surface of the specimen

Chapter 1 Online Homework: TEM:

- detects electrons passing through a specimen

Chapter 2 Online Homework: A(n) _____ bond joins these two oxygen atoms. - hydrogen - quadruple covalent - double covalent - single covalent - ionic

- double covalent

Chapter 3 Online Homework: In eukaryotic cells DNA has the appearance of a _____. - single strand - letter U - double helix - triple helix - circle

- double helix

Chapter 1 Online Homework: Which type of microscopy has the greatest resolving power? - phase-contrast - digital video - confocal scanning - fluorescence - electron

- electron

Chapter 1 Online Homework: A scientist is examining motile protist. He wishes to determine their direction of movement. Which of the following microscopic techniques is least likely to be used to view these cells? - fluorescence microscopy - differential interference contrast microscopy - light microscopy - electron microscopy - phase-contrast microscopy

- electron microscopy

Chapter 1 Online Homework: A scientist is examining motile protozoa. He wishes to determine their direction of movement. Which of the following microscopic techniques is least likely to be used to view these cells? - electron microscopy - phase-contrast microscopy - differential interference contrast microscopy - fluorescence microscopy - light microscopy

- electron microscopy

Chapter 2 Online Homework: The tendency of an atom to pull electrons toward itself is referred to as its _____. - ionic potential - electronegativity - covalency - polarity - tonicity

- electronegativity

Chapter 1 Online Homework: Which of the following biochemical techniques uses an electrical field to separate macromolecules based on their mobility through a semisolid gel? - electrophoresis. - chromatography. - light microscopy. - mass spectrometry. - ultracentrifugation.

- electrophoresis.

Chapter 2 Online Homework: Match the interaction or bond with the phrase that best describes it. Ionic Bond:

- electrostatic interactions

Chapter 3 Online Homework: Which of the following is not a polysaccharide? - glycogen - extensin - starch - cellulose - chitin

- extensin

Chapter 2 Online Homework: Each water molecule is joined to _____ other water molecules by ____ bonds. - four ... hydrogen - four ... polar covalent - three ... ionic - two ... polar covalent - two ... hydrogen

- four ... hydrogen

Chapter 3 Online Homework: For the following pairs of amino acids, choose the one that is more likely to be found in the interior of a protein molecule. - aspartate - glutamate

- glutamate

Chapter 2 Online Homework: Which of the following is not a structural polysaccharide? - peptidoglycan - cellulose - chitin - glycogen - All of the above are structural polysaccharides.

- glycogen

Chapter 3 Online Homework: Which of the following is a purine? - cysteine - thymine - cytosine - uracil - guanine

- guanine

Chapter 1 Online Homework: Which laws were formulated by Mendel? - thermodynamics - heredity - diffusion - ideal gas laws - gravity

- heredity

Chapter 2 Online Homework: What name is given to the bond between water molecules? - polar covalent - single (nonpolar) covalent - hydrogen - hydrophobic - ionic

- hydrogen

Chapter 2 Online Homework: Which of the following is important in protein folding after the formation of a polypeptide? - hydrophobic interactions - van der Waals interactions - ionic bonding - hydrogen bonding - hydrogen bonding, ionic bonding, van de Waals interactions, and hydrophobic interactions.

- hydrogen bonding, ionic bonding, van de Waals interactions, and hydrophobic interactions.

Chapter 3 Online Homework: The secondary structure of a protein results from _____. - hydrogen bonds - peptide bonds - hydrophobic interactions - bonds between sulfur atoms - ionic bonds

- hydrogen bonds

Chapter 3 Online Homework: The two strands of a DNA double helix are held together by _____ that form between pairs of nitrogenous bases. - hydrophilic interactions - ionic bonds - hydrogen bonds - covalent bonds - S—S bonds

- hydrogen bonds

Chapter 3 Online Homework: The two strands of DNA are held together by ________; thus ________. - antiparallel bonds; double-stranded DNA is amphipathic - ionic bonds; double-stranded DNA separates into two separate strands in water - hydrophobic interactions; double-stranded DNA separates into two separate strands when dissolved in a hydrocarbon (hydrophobic) solvent - covalent bonds; double-stranded DNA is very stable at a range of temperatures - hydrogen bonds; double-stranded DNA separates into two separate strands at high temperatures

- hydrogen bonds; double-stranded DNA separates into two separate strands at high temperatures

Chapter 2 Online Homework: Monomers are removed from polymers by ________ reactions. - condensation - neutralization - redox - hydrolysis - substitution

- hydrolysis

Chapter 3 Online Homework: Which of the following contributes to the stability of the DNA double helix? - covalent bonding between complementary purine and pyrimidine bases. - ionic bonds between the negatively charged phosphate groups and the positively charged pyrimidine bases. - hydrophobic interactions between aromatic bases at the center of the double helix and ionic bonds between the negatively charged phosphate groups and the positively charged pyrimidine bases - hydrophobic interactions between aromatic bases at the center of the double helix - hydrogen bonding between the phosphate and sugar groups in the backbone of the double helix

- hydrophobic interactions between aromatic bases at the center of the double helix

Chapter 3 Online Homework: What are the three general types of amino acids? - hydrophobic, polar (noncharged), polar (charged) - acidic, basic, and neutral - α helices, β sheets, and looped segments - positive, negative, and noncharged - covalent, noncovalent, and van der Waals forces

- hydrophobic, polar (noncharged), polar (charged)

Chapter 2 Online Homework: Choose the item in the right column that best matches each item in the left column. Important in Hydrogen Bonding:

- hydroxyl group

Chapter 1 Online Homework: Scientists use various terms to describe conclusions reached through the scientific method. Which of the following terms conveys the least degree of certainty? - hypothesis - theory - law - both hypothesis and theory - both theory and law

- hypothesis

Chapter 1 Online Homework: When scientists use the scientific method, they use terms to indicate their degree of certainty. Which of the following terms conveys the least degree of certainty? - hypothesis - theory - law - both hypothesis and theory - both theory and law

- hypothesis

Chapter 1 Online Homework: The outcome of the joining of cytology and biochemistry yielded a better understanding of the cell by - identification of biochemical pathways and creating bioinformatics. - identification of cellular structures. - creating bioinformatics. - identification of cellular structures and biochemical pathways. - identification of cellular biochemical pathways.

- identification of cellular structures and biochemical pathways.

Chapter 1 Online Homework: The outcome of the joining of cytology and biochemistry yielded a better understanding of the cell by - identification of cellular structures. - identification of cellular biochemical pathways. - demonstration of bioinformatics. - identification of cellular structures and cellular biochemical pathways. - identification of cellular biochemical pathways and demonstration of bioinformatics

- identification of cellular structures and cellular biochemical pathways.

Chapter 3 Online Homework: RNA and DNA differ - in that RNA contains uracil and DNA contains thymine. - in that RNA contains nucleosides and DNA contains nucleotides. - in that RNA contains ribose and DNA contains deoxyribose. - in that RNA contains ribose and uracil, and DNA contains deoxyribose and thymine. - All of these are correct.

- in that RNA contains ribose and uracil, and DNA contains deoxyribose and thymine.

Chapter 1 Online Homework: Initially thought to be true because living organisms seem to ______ in complexity ______, unlike other systems known to early chemists or physicists; misconception laid to rest by Wohler demonstration (1828) that ______, a compound made by living organisms, could be synthesized in the laboratory from an ______ starting compound.

- increase - spontaneously - urea - inorganic

Chapter 2 Online Homework: Self-assembly of some structures may depend on - the presence of lipids in the cytosol. - the size of the monomers. - information supplied by preexisting structures. - the time associated with forming noncovalent interactions. - all of the above.

- information supplied by preexisting structures.

Chapter 3 Online Homework: A peptide bond - is a covalent bond between the carboxyl carbon of one amino acid and the amino nitrogen of a second amino acid. - is a covalent bond between the functional R groups of adjacent amino acids. - is a noncovalent bond that dictates the tertiary structure of a protein. - is a covalent bond between the NH group of one polypeptide and the CO group of an adjacent polypeptide that holds together multimeric proteins. - is a covalent bond between adjacent glucose molecules in a peptide.

- is a covalent bond between the carboxyl carbon of one amino acid and the amino nitrogen of a second amino acid.

Chapter 1 Online Homework: Once a scientific theory becomes a law, it - becomes static. - cannot be changed. - is irrefutable. - cannot be challenged. - is subject to modification.

- is subject to modification.

Chapter 3 Online Homework: Proline is referred to as the "helix breaker" because - its only found in the L form, which is incompatible with helical protein structure. - it lacks a charged functional groups for ionic bonding. - it is hydrophobic. - it has a polar functional group. - it lacks the hydrogen atom needed for hydrogen bonding.

- it lacks the hydrogen atom needed for hydrogen bonding.

Chapter 3 Online Homework: Which of the following is a disaccharide? - glucose - amylose - fructose - galactose - lactose

- lactose

Chapter 1 Online Homework: All of the following biochemical techniques have allowed us to understand cell structure and function except - light microscopy. - electrophoresis. - mass spectrometry. - chromatography. - ultracentrifugation.

- light microscopy.

Chapter 1 Online Homework: Brightfield:

- light passes directly through specimen

Chapter 2 Online Homework: Choose the item in the right column that best matches each item in the left column. Membrane Structure:

- lipid bilayer

Chapter 1 Online Homework: Consider the structures shown in the figure below. Which of these structures would both Hooke and van Leeuwenhoek have been able to see with their respective microscopes? Which, if any, would van Leeuwenhoek have been able to see that Hooke could not? Which, if any, would a contemporary cell biologist be able to see that neither Hooke nor van Leeuwenhoek could see? Hooke and van Leeuwenhoek:

- liver cell

Chapter 2 Online Homework: Phosphatidyl ethanolamine is a major class of membrane phospholipid. Therefore, it is __________. - very soluble in water - completely hydrophobic - made up of a nonpolar head and two polar tails - made up of a polar head and two nonpolar tails

- made up of a polar head and two nonpolar tails

Chapter 1 Online Homework: The steps of the scientific method, in the correct order, are: - collect data, interpret results, test the hypothesis, make observations, and design experiments. - design experiments, draw conclusions, collect data, interpret results, make observations, and test the hypothesis. - make observations, formulate the hypothesis, design experiments, collect data, interpret results, and draw conclusions. - collect data, interpret results, test the hypothesis, design experiments, make observations, and draw conclusions. - none of the above

- make observations, formulate the hypothesis, design experiments, collect data, interpret results, and draw conclusions.

Chapter 1 Online Homework: Which technique discussed in the textbook would allow a cell biologist to determine the size and composition of an individual protein? - electrophoresis - centrifugation - bioinformatics - mass spectrometry

- mass spectrometry

Chapter 3 Online Homework: For the following pairs of amino acids, choose the one that is more likely to be found in the interior of a protein molecule. - methionine - cysteine

- methionine

Chapter 2 Online Homework: Which of the following molecules is involved with assisted assembly? - molecular chaperones - helper proteins - tobacco mosaic viruses - water molecules - none of the above

- molecular chaperones

Chapter 1 Online Homework: Jacques Monod and Francois Jacob deduced the mechanism responsible for the regulation of prokaryotic gene expression. They are, therefore, responsible for launching the era of - molecular genetics. - light microscopy. - radioisotopes. - biochemistry. - the scientific method.

- molecular genetics.

Chapter 1 Online Homework: Jacques Monod and François Jacob deduced the mechanism responsible for the regulation of bacterial gene expression. They are, therefore, responsible for launching the era of - radioisotopes. - light microscopy. - molecular genetics. - biochemistry. - the scientific method.

- molecular genetics.

Chapter 2 Online Homework: A(n) _____ refers to two or more atoms held together by covalent bonds. - molecule - ion - isotope - shell - community

- molecule

Chapter 1 Online Homework: Originally thought to be true because the order of nucleotide ______ in DNA was erroneously considered to be an invariant ______ repeating sequence; disproved by Avery et al. for ______ (1944) and by Hershey and Chase for ______ ______ (1952).

- monomers - tetranucleotide - bacteria - bacterial viruses

Chapter 2 Online Homework: Match the interaction or bond with the phrase that best describes it. Hydrogen Bond:

- noncovalent attraction among water molecules

Chapter 2 Online Homework: Choose the item in the right column that best matches each item in the left column. Informational Macromolecule:

- nucleic acid

Chapter 3 Online Homework: DNA is composed of building blocks called _____. - nucleic acids - Gs - nucleotides - adenines - amino acids

- nucleotides

Chapter 2 Online Homework: The hierarchical nature of cellular structure is accurately illustrated in which of the following lists of substances (from smallest to largest)? - nucleotides, DNA, chromosome, nucleus, cell - cellulose, glucose, cell wall, cell - protein, membrane, amino acids, chloroplast, cell - nucleotides, chromosome, DNA, nucleus, cell - nucleotides, nucleus, DNA, chromosome, cell

- nucleotides, DNA, chromosome, nucleus, cell

Chapter 3 Online Homework: Which of the following pairs correctly matches the monomer with its polymer? - peptides; proteins - terpenes; nucleic acids - nucleotides; nucleic acids - amino acids; polysaccharides - glucose; proteins

- nucleotides; nucleic acids

Chapter 1 Online Homework: Which organelle is round and derives its name from the Latin word for "kernel"? - Golgi complex - mitochondrion - chloroplast - nucleus - lysosome

- nucleus

Chapter 2 Online Homework: Imagine this futuristic scenario: Life has been discovered on Mars and shown to contain a new type of macromolecule, named marsalive. You have been hired to study this new compound and want to determine whether marsalive is a structural or an informational macromolecule. What features would you look for? - the physical properties of monomers - number of different kinds of monomers - the energy of bonding between monomers - the frequency of occurrence of the most stable form - the arrangement of monomers - the elemental composition of monomers

- number of different kinds of monomers - the arrangement of monomers

Chapter 3 Online Homework: What type of bond joins the monomers in a protein's primary structure? - hydrogen - hydrophobic - S - S - ionic - peptide

- peptide

Chapter 2 Online Homework: The cell membrane can be described most accurately as - impermeable to all polar molecules. - permeable to all small molecules and ions. - impermeable to larger molecules independent of their chemical characteristics. - permeable to some molecules and impermeable to others. - permeable to all molecules except water.

- permeable to some molecules and impermeable to others.

Chapter 2 Online Homework: The cell membrane can be described most accurately as - permeable to most small molecules but impermeable to larger ones. - permeable to only larger molecules. - permeable to all molecules. - permeable to some molecules and impermeable to others. - impermeable to all polar molecules.

- permeable to some molecules and impermeable to others.

Chapter 1 Online Homework: Which type of microscope can detect density differences and thereby see organelles in living cells? - fluorescence - SEM - TEM - phase contrast

- phase contrast

Chapter 3 Online Homework: For the following pairs of amino acids, choose the one that is more likely to be found in the interior of a protein molecule. - tyrosine - phenylalanine

- phenylalanine

Chapter 3 Online Homework: A nucleotide is composed of a(n) _____. - phosphate group, a nitrogen-containing base, and a hydrocarbon - phosphate group, a nitrogen-containing base, and a five-carbon sugar - sulfhydryl group, a nitrogen-containing base, and a five-carbon sugar - amino group, a nitrogen-containing base, and a five-carbon sugar - glycerol, a nitrogen-containing base, and a five-carbon sugar

- phosphate group, a nitrogen-containing base, and a five-carbon sugar

Chapter 3 Online Homework: The nucleoside triphosphate molecules in DNA are linked together in the 5'→3' by a(n) ________ bridge. - phosphate - phosphodiester - covalent - phosphatidyl - peptide

- phosphodiester

Chapter 2 Online Homework: The unequal sharing of electrons within a water molecule makes the water molecule _____. - hydrophobic - change easily from a liquid to gaseous form - polar - have a low surface tension - ionic

- polar

Chapter 2 Online Homework: In this molecule, what type of bond is found between the oxygen and hydrogens? - nonpolar covalent - polar covalent - ionic - hydrophobic - hydrophilic

- polar covalent

Chapter 2 Online Homework: Which of the following is not a possible noncovalent interaction? - polar covalent bonding - van der Waals interactions - hydrophobic interactions - ionic bonding - hydrogen bonding

- polar covalent bonding

Chapter 2 Online Homework: Which of the following biomolecules are long polymers of repeating monomers? - lipids - proteins - nucleic acids - polysaccharides - polysaccharides, nucleic acids, and proteins

- polysaccharides, nucleic acids, and proteins

Chapter 1 Online Homework: The classic work of Friedrich Wöhler (1828) that united the fields of biology and chemistry was based on the - analysis of gene segregation. - discovery of ATP. - discovery of yeast ferments. - production of urea in the laboratory. - identification of nucleotide bases.

- production of urea in the laboratory.

Chapter 3 Online Homework: The amino acid referred to as the "helix breaker" (because it lacks the hydrogen atom needed for hydrogen bonding) is - phenylalanine. - proline. - valine. - methionine. - leucine.

- proline.

Chapter 1 Online Homework: Which of the following is smallest? - bacterium - mitochondrion - virus - ribosome - protein

- protein

Chapter 3 Online Homework: Match the choice on the left with the choice on the right. Multimeric Complex:

- quaternary structure

Chapter 1 Online Homework: Melvin Calvin and his colleagues used which of the following to deduce the steps in the Calvin cycle? - ultracentrifugation - negative staining - electron microscopy - Drosophila melanogaster - radioisotopes

- radioisotopes

Chapter 1 Online Homework: Melvin Calvin and his colleagues used which of the following to deduce the steps in the Calvin-Benson cycle? - radioisotopes - ultracentrifugation - negative staining - Drosophila melanogaster - electron microscopy

- radioisotopes

Chapter 3 Online Homework: Based on the following amino acid sequence, which region(s) is/are hydrophobic?1[K-K-N-Q] - 2[A-G-G-V] - 3[Y-C-S-R] - 4[H-E-C-Y] - region 4 - region 3 - region 2 - region 1 - both regions 1 and 3

- region 2

Chapter 1 Online Homework: Early microscopes did not allow clear visualization of cells because they were limited by - magnification. - number of kernels. - refraction. - resolution. - resolution and magnification.

- resolution.

Chapter 1 Online Homework: Consider the structures shown in the figure below. Which of these structures would both Hooke and van Leeuwenhoek have been able to see with their respective microscopes? Which, if any, would van Leeuwenhoek have been able to see that Hooke could not? Which, if any, would a contemporary cell biologist be able to see that neither Hooke nor van Leeuwenhoek could see? None of the biologists:

- ribosomes - DNA Helix - microfilaments

Chapter 1 Online Homework: You are working on a project that involves the direct three-dimensional observation of DNA molecules. The microscope that would give you the best information at this time would be the - transmission electron microscope. - scanning tunneling microscope. - light microscope. - phase-contrast microscope. - none of the above

- scanning tunneling microscope.

Chapter 3 Online Homework: Fibrous proteins have extensive ________ structure, which allows them to be highly ordered and repetitive. - primary - multiprotein complex - secondary - quaternary - tertiary

- secondary

Chapter 3 Online Homework: Hydrogen bonding is most important in stabilizing the ________ structure of many proteins. - quaternary - secondary - primary - tertiary - all of the above

- secondary

Chapter 2 Online Homework: Match the interaction or bond with the phrase that best describes it. Covalent Bonding:

- sharing of electrons

Chapter 1 Online Homework: Fluorescence:

- shows specific molecules

Chapter 2 Online Homework: Carbon can form ________ covalent bonds. - single - double - triple - single and double - single, double, and triple

- single, double, and triple

Chapter 3 Online Homework: Match the choice on the left with the choice on the right. Polymer of Glucose:

- starch

Chapter 3 Online Homework: You can tell that this is an image of a DNA nucleotide and not an RNA nucleotide because you see a _____. - double-stranded molecule, not a single-stranded molecule - uracil nitrogenous base, not a thymine nitrogenous base - sugar with two, and not three, oxygen atoms - phosphate group, not a uracil - thymine nitrogenous base, not a uracil nitrogenous base

- sugar with two, and not three, oxygen atoms

Chapter 3 Online Homework: Disulfide bonds are often found to stabilize which of the following levels of protein structure? - secondary - primary, secondary, and tertiary - primary - tertiary - None of these structures involve disulfide bonds.

- tertiary

Chapter 3 Online Homework: Disulfide bonds are often found to stabilize which of the following levels of protein structure? - secondary - tertiary - primary - all of the above - none of the above

- tertiary

Chapter 3 Online Homework: A general trend in the structure of many biomolecules is - that four different monomers form the basis for the functional and structural properties of each polymer. - that each class of biomolecule forms one type of secondary structure independent of the order of the monomers in the polymer. - that each class of biomolecule can form either fibrous or globular conformations depending on the chemical conditions inside the cell. - that they are all soluble in water independent of the size of the polymer. - that the order and bonding of monomers form the basis for the secondary and tertiary structure of the polymer.

- that the order and bonding of monomers form the basis for the secondary and tertiary structure of the polymer.

Chapter 2 Online Homework: Detergents are best able to dissolve oil from fabric or dishes during washing because - because detergents are nonpolar, they increase the size of the oil droplet, allowing the water to be more effective at removing the oil. - the negatively charged end is associated with a sphere of hydration, while the positively charged end interacts with the oil droplet. - the positively charged end is associated with a sphere of hydration, while the negatively charged end interacts with the oil droplet. - the nonpolar end is associated with a sphere of hydration, while the charged end interacts with the oil droplet. - the charged end is associated with a sphere of hydration, while the nonpolar end interacts with the oil droplet.

- the charged end is associated with a sphere of hydration, while the nonpolar end interacts with the oil droplet.

Chapter 2 Online Homework: Detergents are best able to dissolve oil from fabric or dishes during washing because - the negatively charged end is associated with water molecules, while the positively charged end interacts with the oil droplet. - the nonpolar end is associated with water molecules, while the charged end interacts with the oil droplet. - detergents are nonpolar, they increase the size of the oil droplet, allowing the water to be more effective at removing the oil. - the charged end is associated with water molecules, while the nonpolar end interacts with the oil droplet. - the positively charged end is associated with water molecules, while the negatively charged end interacts with the oil droplet.

- the charged end is associated with water molecules, while the nonpolar end interacts with the oil droplet.

Chapter 1 Online Homework: The limit of resolution can best be defined as - the distance that an object must be moved to be distinguished from its background. - the solvent that must be available to remix a solution. - the magnification power of a microscope. - the inverse of the wavelength of light; it is greatest for black light. - the distance that two objects must be apart to be distinguished as separate objects.

- the distance that two objects must be apart to be distinguished as separate objects.

Chapter 1 Online Homework: The scientific work that established DNA, rather than protein, as the molecule of heredity was performed prior to - the description of the enzymatic steps of glycolysis. - the elucidation of the double helix structure of DNA. - Antonie van Leeuwenhoek's observation of internal cell structures. - the formation of the chromosome theory of heredity. - Mendel's work on heredity.

- the elucidation of the double helix structure of DNA.

Chapter 3 Online Homework: Which of these nitrogenous bases is found in DNA but not in RNA? - thymine - uracil - cytosine - adenine - guanine

- thymine

Chapter 3 Online Homework: In a DNA double helix an adenine of one strand always pairs with a(n) _____ of the complementary strand, and a guanine of one strand always pairs with a(n) _____ of the complementary strand. - thymine ... cytosine - cytosine ... thymine - guanine ... adenine - cytosine ... uracil - uracil ... cytosine

- thymine ... cytosine

Chapter 1 Online Homework: You are studying the response of macrophages infected with the intracellular bacterium Brucella, specifically by examining which gene products are being expressed. You would be studying the macrophage ________ to obtain this information. - metabolome - genome - transciptome - amplicon - proteome

- transciptome

Chapter 2 Online Homework: Match the interaction or bond with the phrase that best describes it. van der Waals Interactions:

- transient interactions at very close range

Chapter 3 Online Homework: Which of the following is not a major functional class of proteins? - structural proteins - regulatory proteins - motility proteins - enzymes - trifunctional proteins

- trifunctional proteins

Chapter 2 Online Homework: Ionic bonds are important in biological structures. Which of the following pairs of molecules would form an ionic bond? - two water molecules - two phospholipids - two amino acids with oppositely charged functional groups - a water molecule and a lipid - two different stereoisomers of the same sugar

- two amino acids with oppositely charged functional groups

Chapter 3 Online Homework: Which of the following is not a base used in DNA replication? - cytosine - thymine - adenine - guanine - uracil

- uracil

Chapter 1 Online Homework: Confocal:

- uses a laser to view a single plane of a specimen

Chapter 3 Online Homework: Which of the following is a nonpolar (hydrophobic) amino acid? - tyrosine - aspartate - serine - lysine - valine

- valine

Chapter 1 Online Homework: Which of the following can only be viewed by electron microscopy? - nuclei - frog eggs - mitochondria - bacteria - viruses

- viruses

Chapter 1 Online Homework: Initially thought to be true because of the demonstration by Pasteur that ______ cells were needed for _______ fermentation; Buchner and Buchner showed later (1897) that extracts from yeast cells could substitute for _______ cells, an effect we now know to be due to the presence in the extracts of the _______ that catalyze the various reactions in the fermentation process.

- yeast - alcoholic - intact - enzymes

Chapter 1 Exercise: Describe why microscopy was the primary tool that opened up the field of cell theory:

It allowed scientist to visualize what was inside the cell. The tool of magnification allowed observation of structure and function within the cell.

Chapter 1 Exercise: Consider the Scientific Method, although it may seem rather formal and methodical you probably use this sort of analysis in your daily life. Reflect on a recent encounter you've had in which you have posited a hypothesis and from it developed a theory. State your hypothesis and how it became a theory. [This can be very simple, an example: recently while visiting a friend I noticed a pattern of designs on her bathroom wall and hypothesized that there must be a piece of the design obscured by the towels hanging from a rack, so I moved the towels and proved my hypothesis by finding a piece of the design that fit into the pattern].

Make your own example

Chapter 1 Exercise: For each of the following types of light microscopy list an application and an advantage/disadvantage of that method: Phase contrast:

Useful in observing living cells.

Chapter 1 Exercise: For each of the following types of light microscopy list an application and an advantage/disadvantage of that method: Brightfield (stained):

Uses light to observe cell. Dyes enhance contrast, but still the sample must be fixed.

Chapter 1 Exercise: For each of the following types of light microscopy list an application and an advantage/disadvantage of that method: Brightfield (unstained):

Uses light to observe sample, has little contrast and sample must be fixed.

Chapter 3 Online Homework: To which of the following classes of sugars does glucose belong? - tetrose - heptose - hexose - pentose - triose

hexose

Chapter 1 Exercise: In terms of cellular observation what is the difference(s) between Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM)? SEM -

scans the surface and gives an image of the outside of a specimen.

Chapter 1 Exercise: In terms of cellular observation what is the difference(s) between Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM)? TEM -

transmits through a sample therefore allows visualizing inside the cell