Unit 1 Hw Study

Short, bristle-like structures that extrude from the surface of a prokaryotic cell are called.... fimbriae. flagella. pili. mating bridges. cilia

fimbriae.

A researcher discovers a chemical compound which prevents the incorporation of ergosterol in the plasma membrane We can predict that this compound would be toxic to which kinds of organisms? animals viruses bacteria fungi plants

fungi

Prokaryotic cells house a single circular chromosome in their __________. ribosomes nucleoid region periplasmic space nucleus

nucleoid region

You have isolated a new eukaryotic organism which is unicellular and performs photosynthesis. The organism is most likely classified as a(n) fungus. plant-like protista. fungi-like protista. animal.bacterium.

plant-like protista.

What structure acts as a selective barrier, regulating the traffic of materials into and out of the cell? nuclear envelope endomembrane system extracellular matrix cytoskeleton plasma membrane

plasma membrane

Which of the following can be determined using simple stains? size, shape and cellular arrangementsize and shape the presence of endospores the presence of capsules the number and position of flagella

size, shape and cellular arrangement

Where are lipids made in the cell? rough endoplasmic reticulum (ER) Golgi apparatus smooth endoplasmic reticulum (ER) ribosomes mitochondria

smooth endoplasmic reticulum

Minor mutations and/or gene transfers may lead to the development of a new______ and is a term that describes very closely related organisms that are slight genetic variants of one another. strand genus species strain

strain

Microbes and humans have evolved a variety of ________ relationships, including ________ where microbes help the host.

symbiotic; mutualism

An atom is best described as.... defined by its number of electrons. the smallest unit of an element. having a nucleus containing protons and electrons. always containing an equal number of protons and neutrons. defined by its atomic mass.

the smallest unit of an element.

Integral proteins are mostly involved in transport function. receptors. enzymatic function. recognition sites.

transport function.

A cation forms when an atom loses one or more negatively-charged electrons. True or False

true

Which of the following is part of the endomembrane system? flagellum ribosomes Golgi apparatus cytoskeleton mitochondria

Golgi apparatus

Why are chemical agents like lysozyme more likely to damage Gram-positive bacteria than Gram-negative bacteria? Gram-negative bacteria have porins. Gram-negative bacteria have a thicker peptidoglycan layer in their cell wall. Gram-negative bacteria have a thin peptidoglycan layer in their cell wall. Gram-negative bacteria lack a cell wall. Gram-negative bacteria have an outer membrane as part of their cell wall.

Gram-negative bacteria have an outer membrane as part of their cell wall.

Choose the mismatched pairing(s). Amphipathic molecules: Found in plasma membranes Hydrophobic molecules: Polar Hydrophilic: Oil Hydrophilic molecules: Interact with water

Hydrophobic molecules: Polar Hydrophilic: Oil

_____________ is a type of sexual reproduction that occurs in eukaryotes and results in four genetically unique haploid daughter cells. Binary fission Endosymbiosis Meiosis Mitosis

Meiosis

Choose the true statement(s) about mitochondria. Mitochondria do not have their own DNA. Photosynthetic cells lack mitochondria. Mitochondria make most of a cell's ATP. Mitochondria have 70S ribosomes.

Mitochondria make most of a cell's ATP. Mitochondria have 70S ribosomes.

How do normal prion proteins (PrP) differ from the infectious prion proteins? Normal PrP are found in all mammals; infectious PrP are found in only cows. Normal PrP are found on mammals; infectious PrP are found on reptiles. Normal PrP have alpha-helices; infectious PrP have beta-pleated sheets. Normal PrP lack nucleic acid; infectious PrP have nucleic acid.

Normal PrP have alpha-helices; infectious PrP have beta-pleated sheets.

Which of the following infectious agents usually requires an immune-compromised person to establish an infection? A normal virus Opportunistic pathogen True pathogen Re-emerging pathogens

Opportunistic pathogen

Choose the true statement(s) about normal microbiota. To be marked correct, you'll need to select all true statements, as there may be more than one correct answer. Our normal microbiota only include bacteria. Human normal microbiota are found in all body sites. Our normal microbiota do not include potential pathogens. Our normal microbiota help to train our immune system.

Our normal microbiota help to train our immune system

Choose the true statement(s) about prokaryotic external appendages. Pili allow for adhesion, movement, and aid in gene transfer through conjugation. Flagella allow for motility. Fimbriae aid in gene transfer through conjugation. The glycocalyx promotes adhesion and interferes with phagocytosis.

Pili allow for adhesion, movement, and aid in gene transfer through conjugation. Flagella allow for motility. The glycocalyx promotes adhesion and interferes with phagocytosis.

The normal function of the PrP protein in mammals is believed to be: assisting proteins in forming beta-pleated sheets. assisting in normal synaptic development and function. assisting in normal membrane development and function. assisting proteins in forming alpha-helices.

assisting in normal synaptic development and function.

How does water enter and exit a cell? By use of an integral transport protein By simple diffusion across the membrane By simple diffusion or by use of an integral transport protein By use of a peripheral transport protein

By simple diffusion or by use of an integral transport protein

Which of the following statements is false? Eukaryotic cells evolved from prokaryotic cells. Archaea and Bacteria are prokaryotic domains. Prokaryotes are unicellular and lack a membrane-bound nucleus .Eukaryotes have a much simpler genetic makeup than prokaryotic cells. Eukarya is a eukaryotic domain.

.Eukaryotes have a much simpler genetic makeup than prokaryotic cells.

...........................

:) God bless.

Consider the reaction AB → A + B. What is the product of this reaction? A B AB A and B A, B, and AB

A and B

Why is it so difficult to kill acid-fast bacteria? Acid-fast bacteria have mycolic acid in their cell walls, which limits drug entry. Acid-fast bacteria make acids that inactivate antibiotics. Acid-fast bacteria divide rapidly, making it hard to limit their population Acid-fast bacteria make endospores and can go dormant to avoid drug therapies. Acid-fast bacteria have a thick peptidoglycan layer that protects them.

Acid-fast bacteria have mycolic acid in their cell walls, which limits drug entry

Why do electron microscopes have a better resolution versus light microscopes? An electron beam has a wavelength of about 1 nm, and resolution improves with smaller wavelengths. The additional steps necessary to prepare the sample for viewing provide the improved resolution. An electron beam has a wavelength of about 800 nm, and resolution improves with larger wavelengths. The lenses used to focus the electron beam are more adjustable than the ones in a light microscope. The lenses, knobs, and strength of the electron beam can all be highly controlled, which also explains why electron microscopes are so expensive.

An electron beam has a wavelength of about 1 nm, and resolution improves with smaller wavelengths.

Select the true statement(s) about ionic bonds. Ionic bonds are required to form polar molecules. An ionic bond requires the transfer of electrons from one atom to another. The atoms of ionic compounds only exist as ions in a solution. An ionic bond is an electrostatic force that exists between cations and anions.

An ionic bond requires the transfer of electrons from one atom to another. An ionic bond is an electrostatic force that exists between cations and anions.

In the Spring of 2009, a novel H1N1 virus emerged that had a new combination of genes from pigs, humans, and birds. As a result, the virus spread quickly, resulting in a swine flu pandemic. Which of the following concepts explains why the outbreak occurred? Narrow tropism Attenuation Antigenic shift Antigenic drift

Antigenic shift

Why is a specimen smaller than 200 nm not visible with a light microscope? The lenses only go to 100 X magnification power. Anything smaller than 200 nm cannot interact with visible light. It is too easy to lose on the stage. Visible light is only good at wavelengths below 390 nm.

Anything smaller than 200 nm cannot interact with visible light.

Choose the true statement(s) about polar covalent bonds. Atoms within a molecule may take on a charge due to the unequal sharing of electrons. The presence of dipoles in polar molecules lay the foundation for ionic bonds. These types of bonds commonly involve highly electronegative atoms, like hydrogen. These types of bonds generate dipoles.

Atoms within a molecule may take on a charge due to the unequal sharing of electrons These types of bonds generate dipoles.

Choose the true statement about cilia and flagella. Both cilia and flagella use an oar-like motion for motility. Both cilia and flagella tend to be the same length. Cilia and flagella can be found in eukaryotes and prokaryotes. Cilia and flagella are surrounded by a membrane and sprout from centrioles.

Cilia and flagella are surrounded by a membrane and sprout from centrioles

______are molecules made up of more than one type of element. Isotopes Isomers Cations Compounds

Compounds

Choose the mismatched pairing(s). Decomposition reaction: AB → A + B Synthesis reaction: A + B → AB Hydrolysis reaction: AB + H2O → A + B Dehydration synthesis: A + BC → AC + B

Dehydration synthesis: A + BC → AC + B

Which of the following is NOT a step in bacterial cell division? Disappearance of nuclear envelope Cell elongation Splitting apart of two new daughter cells Replication of the genetic material

Disappearance of nuclear envelope

Which of the following is true about endospores? Endospores are only viable for a short time. Endospores are considered reproductive structures. Endospores are highly resistant to environmental stress. Endospores are metabolically active structures. Endospores are susceptible to various chemicals.

Endospores are highly resistant to environmental stress

Proper hand-washing technique can remove normal microbiota. True False

False

Unlike antibiotics which target the 70S bacterial ribosomes, there are no known chemical substances which can bind to 80S eukaryotic ribosomes. True or False

False

Twelve cells Nine cells Eighteen cells Twenty-four cells Forty-eight cells It is impossible to determine.

Forty-eight cells

You have isolated a new organism which has eukaryotic cells, is multicellular, grows as hyphae, does not perform photosynthesis, and has a cell wall. This organism most likely belongs to which kingdom? Bacteria Archaea Protista Fungi either Fungi or Protista

Fungi

_____________ bacteria lack an outer membrane, have a thick layer of peptidoglycan, contain teichoic acid, and lack mycolic acid. Gram-positive Gram-variable Gram-negative Acid-fast

G Positive

Select the incorrect pairing. Capsule: A carbohydrate layer that aids bacterial adhesion to host tissues Slime layer: a fairly disorganized sticky carbohydrate-enriched layer Pili: protein structures that may aid in cell movement Fimbriae: structures that are important to helping cells form biofilms Glycocalyx: a carbohydrate layer found within the cell wall

Glycocalyx: a carbohydrate layer found within the cell wall

Choose the false statement regarding prokaryotic plasma membranes. Ions and large polar substances can diffuse through the plasma membrane without assistance. Gases, water, and small non-charged substances can diffuse through the selectively permeable plasma membrane. The plasma membrane's phospholipid bilayer contains hydrophilic phosphates and hydrophobic fatty acids. The plasma membrane is a phospholipid bilayer that serves as barrier for a cell.

Ions and large polar substances can diffuse through the plasma membrane without assistance.

_____________ are atoms with the same number of protons but a different number of neutrons. Compounds Isotopes Ions Molecules

Isotopes

How does the Gram staining procedure differentiate between Gram-negative and Gram-positive bacteria? -It differentiates between Gram-positive versus Gram-negative bacteria by detecting the presence of mycolic acid in the cell wall of certain Gram-positive bacteria. - It differentiates between Gram-positive versus Gram-negative bacteria by bringing out differences in cellular proteins. - It differentiates between Gram-positive and Gram-negative bacteria based on cell wall composition. -It differentiates between Gram-positive versus Gram-negative bacteria based on differences in cell wall rigidity.

It differentiates between Gram-positive and Gram-negative bacteria based on cell wall composition.

Choose the false statement about the eukaryotic cytoskeleton. It is an extension of the glycocalyx. It assists with maintaining the cell's shape. It arises from the centrosome. It protects against external mechanical stress forces.

It is an extension of the glycocalyx.

What is meant by light rays being divergent? It is spreading out It is coming together to a focused beam It is heading upwards

It is spreading out

Choose the true statement(s) concerning the eukaryotic glycocalyx. It plays a role in cell communications. It is only in cells that have a cell wall. It promotes or prevents cell adhesion where appropriate. It is mainly made of lipids.

It plays a role in cell communications. It promotes or prevents cell adhesion where appropriate

hoose the true statement(s). To be marked correct, you'll need to select all true statements, as there may be more than one correct answer. Kingdom Fungi includes unicellular and multicellular organisms. Protists are strictly unicellular. The four kingdoms of eukaryotes each include members that may conduct sexual and/or asexual reproduction. The four kingdoms of eukaryotes include Animalia, Plantae, Fungi, and Protista.

Kingdom Fungi includes unicellular and multicellular organisms. The four kingdoms of eukaryotes each include members that may conduct sexual and/or asexual reproduction. The four kingdoms of eukaryotes include Animalia, Plantae, Fungi, and Protista.

Which of the following terms refers to a bacterium moving towards a light source? Negative chemotaxis Positive chemotaxis Positive phototaxis Negative phototaxis

Positive phototaxis

How does the number of infectious prions increase? Prions reproduce by binary fission. Prions transform normal proteins into the misfolded beta-pleated sheet configuration; therefore, prions multiply by conversion. Prions reproduce by mitosis. Prions form multimers which can then form more single copies of the prion protein.

Prions transform normal proteins into the misfolded beta-pleated sheet configuration; therefore, prions multiply by conversion.

Select the false statement about the differences between eukaryotes and prokaryotes. Prokaryotes only include unicellular archaea and bacteria. Prokaryotic cells can exhibit both asexual and sexual reproduction, whereas eukaryotes only carry out asexual reproduction. Most prokaryotes have a single circular chromosome, as compared to a eukaryote's larger genome spread across multiple linear chromosomes. Eukaryotes have a defined nucleus and other membrane bound organelles, while prokaryotes lack a nucleus.

Prokaryotic cells can exhibit both asexual and sexual reproduction, whereas eukaryotes only carry out asexual reproduction.

Select all of the true statements regarding biomolecules and their building block monomers. - Nucleotides are built from nucleic acids. - Proteins are built from amino acids. - Carbohydrates are built from monosaccharides. - Fatty acids are built from glycerol.

Proteins are built from amino acids. Carbohydrates are built from monosaccharides.

Choose the false statement(s) about acids and bases. - Pure water has more H+ ions than OH- ions. - Bases release OH- ions in an aqueous solution. - Acids contribute H+ ions to an aqueous solution. - If an acid is added to an acidic solution, the pH will increase.

Pure water has more H+ ions than OH- ions. If an acid is added to an acidic solution, the pH will increase.

_________ is the ability to distinguish two distinct points as separate. Refractive index Resolution Total magnification Micrograph

Resolution

Which of the following is mismatched? Mitochondria: site of ATP production in a cell Nucleus: houses the cell's DNA Cytoskeleton: maintains the cell's shape Ribosomes: central to RNA production in a cell

Ribosomes: central to RNA production in a cell

Which of the following is incorrectly matched? Base: Release hydroxide ions (OH-) in an aqueous solution Water: Is the solvent in aqueous solutions Salt: Formed by the combination of hydrogen ions (H+) and hydroxide ions (OH-) Acid: Release hydrogen ions (H+) in an aqueous solutionp H: Measure of the acidity or basicity of a solution

Salt: Formed by the combination of hydrogen ions (H+) and hydroxide ions (OH-)

Which of the following genome types has been observed in viruses? Single-stranded RNA Double-stranded RNA Protein-based Single-stranded DNA

Single-stranded RNA Double-stranded RNA Single-stranded DNA

Select the true statement(s) about microbes. To be marked correct, you'll need to select all true statements, as there may be more than one correct answer. The domain Archaea does not include microbes. Some microbes are visible to the naked eye. Viruses and prions are considered microbes. Most microbes are pathogens.

Some microbes are visible to the naked eye. Viruses and prions are considered microbes.

Which of the following is true regarding the bacterial plasma membrane only, and not the archaeal plasma membrane? The bacterial plasma membrane occurs as a monolayer or in a bilayer format. The bacterial plasma membrane only occurs as a bilayer. The plasma membrane is made up primarily of phospholipids. Tetraether lipids are adaptations, which allow bacteria to thrive in harsh, extreme environments.

The bacterial plasma membrane only occurs as a bilayer.

Choose the true statement about the Domain Bacteria. The Domain Bacteria is made up of prokaryotes and likely originated 3.8 billion years ago. The Domains Bacteria and Archaea are genetically identical. Bacteria inhabit extreme environments and are not linked to human diseases. The Domain Eukarya is more closely related to the Domain Bacteria than to the Domain Archaea.

The Domain Bacteria is made up of prokaryotes and likely originated 3.8 billion years ago

Why are the beta-pleated multimers of PrP potentially pathogenic? They are found on the surface of immune cells, resulting in damage to the immune system. They repress the immune system. The multimers are more stable and resistant to protease. They are not detected by other organisms.

The multimers are more stable and resistant to protease

A feature of many of the isotopes that are used in the field of medicine is that the isotopes are radioactive. What does this mean? The atoms with the greatest atomic mass are used. The nucleus of the isotope is unstable and breaks down over time. Cationic forms of the atom are used. The same number of atoms are arranged into different molecular structures. Anionic forms of the atoms are used.

The nucleus of the isotope is unstable and breaks down over time

In a typical brightfield microscope (seen in the animation), at which point does magnification begin? The objective lens The stage The ocular lens The condenser lens The lamp

The objective lens

Choose the true statement(s) about the prokaryotic cytoskeleton. The prokaryotic cytoskeleton directs construction of a rigid cell wall. The prokaryotic cytoskeleton contains standard actin and tubulin proteins. The prokaryotic cytoskeleton acts as a scaffolding to organize mitosis. The prokaryotic cytoskeleton provides general organization of the cytoplasm.

The prokaryotic cytoskeleton directs construction of a rigid cell wall. The prokaryotic cytoskeleton provides general organization of the cytoplasm.

Why are receptors on the cell surface necessary for bacterial movement? The receptors actually spin the flagella. The receptors sense the stimulus and send signals to the flagella. The bacterium contains receptors that are sensitive to light. The receptors physically alter shape to steer the bacterium.

The receptors sense the stimulus and send signals to the flagella.

You are studying an unknown virus that does not perform transcription to make viral proteins. The virus has a positive, sense-stranded RNA genome. The viral genome must encode reverse transcriptase. The viral genome must encode RNA-dependent RNA polymerases. The virus has a double-stranded RNA genome.

The virus has a positive, sense-stranded RNA genome.

You observe that a novel virus penetrates the host cell through membrane fusion. Which of the following statements must also be true regarding this virus and its replicative cycle? The virus does not undergo uncoating. The virus releases from host cells by budding. The virus undergoes lysogenic replication. Replication occurs in the nucleus of the host cell.

The virus releases from host cells by budding.

Which statement is true about carbohydrates? They consist of simple sugars which contain carbon, hydrogen, and oxygen in a 2: 1: 2 ratio. They maybe saturated or unsaturated. They are a component of the cell wall of different types of organisms. They have primary, secondary, tertiary, and quaternary structure. They are usually hydrophobic.

They are a component of the cell wall of different types of organisms.

What happens to the light rays when they hit the specimen? They are absorbed by the stage. They are focused into a small area towards the objective lens. They are diverted to the ocular lens. They are reflected, refracted, or absorbed by the specimen.

They are reflected, refracted, or absorbed by the specimen.

Which of the following statements describes eukaryotic cells? They may contain a cell wall made of peptidoglycan. They may contain 80S or 70S ribosomes in their cytoplasm. They contain membrane-bound organelles such as a nucleus. They may divide using binary fission, mitosis, or meiosis. They have a cell wall.

They contain membrane-bound organelles such as a nucleus.

What makes phospholipid membranes good at keeping some molecules out, and allowing others to freely pass? They have both hydrophilic and hydrophobic regions. They are positively charged. They are completely hydrophobic. They are completely hydrophilic.

They have both hydrophilic and hydrophobic regions. (Phospholipids have two distinct portions.)

How are prions different from other infectious agents? They lack protein. They cause cardiovascular disease. They lack nucleic acid. They cannot replicate.

They lack nucleic acid.

How are viruses different from eukaryotic cells? They do not contain protein. They do not contain genetic material. They require a host in order to reproduce. They do not contain enzymes.

They require a host in order to reproduce.

What is the function of the structural elements of a virus? To provide a source of energy for the virus To package and protect the viral genome To use all of the cell proteins

To package and protect the viral genome

What is the role of the ocular lens? To recreate the image in the viewer's eye To focus the light to a high intensity in a small area To do the bulk of the magnification To adjust the wavelength of light

To recreate the image in the viewer's eye

Only a small minority of microbes are human pathogens. T or F?

True

What results when a single bacterium reproduces? One parent cell and a genetically identical daughter cell One parent cell and a genetically different cell Two genetically identical daughter cells Two genetically unique daughter cells

Two genetically identical daughter cells

Which of the following are ways that viruses differ from prokaryotes and eukaryotes? Unlike prokaryotes and eukaryotes, viruses do not have genomes. Unlike prokaryotes and eukaryotes, viruses are classified as acellular particles. Unlike prokaryotes and eukaryotes, viruses are not considered alive. Unlike prokaryotes and eukaryotes, viruses are incapable of replicating independently from a host cell.

Unlike prokaryotes and eukaryotes, viruses are classified as acellular particles. Unlike prokaryotes and eukaryotes, viruses are not considered alive. Unlike prokaryotes and eukaryotes, viruses are incapable of replicating independently from a host cell.

___________ are usually found in an atom's outermost shell and tend to participate in chemical reactions. Shared electrons Valence electrons Neutral neutrons Reactive protons

Valence electrons

Which reaction has X and Y as reactants? X + YZ → Y + XZ XY + W → WY + X XY → X + Y XY + AB → XB + AY X + Y → XY

X + Y → XY

Most prokaryotic cells reproduce extremely quickly. by meiosis. by mitosis. by binary fission. sexually.

by binary fission.

Prokaryotic and eukaryotic ribosomes share which of the following features? composed of a large and a small subunit and composed of protein and rRNA contain a large and a small subunit composed of protein and rRNAfunction is making DNA composed of protein and rRNA, composed of a large and a small subunit, and function is making DNA

composed of a large and a small subunit and composed of protein and rRNA

The structural framework in a cell is the endoplasmic reticulum (ER). extracellular matrix. endomembrane system .plasma membrane. cytoskeleton.

cytoskeleton

Which of the following is not one of the four main groups of biomolecules? carbohydrates nucleic acids lipids electrolytes proteins

electrolytes

In a polar covalent bond, electrons are shared unequally between more than two atoms. electrons are shared unequally between two atoms. electrons are shared equally between two atoms. an acid and a base neutralize each other to form a salt. electrons are transferred from one atom to another.

electrons are shared unequally between two atoms.

All of the following are examples of inclusion bodies in prokaryotic cells except __________. carboxysomes magnetosomes glycogen granules endospores

endospores

Bacterial plasma membranes differ from eukaryotic plasma membranes in that bacterial membranes always contain cholesterol while eukaryotic membranes rarely do. True or False

false

The primary function of the nucleus is..... serving as the site of ribosome synthesis of protein. digestion and processing of nutrients. serving as the site of most of the cell's chemical reactions. production of the cell's energy molecule, ATP. housing the cell's DNA.

housing the cell's DNA

A glycoprotein...... can be used in enzymatic functions. can be used as a receptor. is a type of peripheral protein. is a type of peripheral protein above that can be used as a receptor or in enzymatic functions.

is a type of peripheral protein above that can be used as a receptor or in enzymatic functions.

Which of the following organelles breaks down worn-out organelles? rough endoplasmic reticulum (ER) lysosomes Golgi apparatus mitochondria smooth endoplasmic reticulum (ER)

lysosomes

What carries instructions for making proteins from the nucleus into the cytoplasm? mRNA DNA ribosomes ATP Rough ER

mRNA

Immersion oil is required to _________. magnify a sample so that it is easier to see when the high-powered objective lens is used. enhance the brightness of the light that illuminates the specimen enhance specimen contrast to make viewing easier when the high-powered lens is used minimize scattered light when the high-powered lens is used

minimize scattered light when the high-powered lens is used

Mitochondria do not participate in which function? regulation of cell division production of ATP motility programmed cell death production of amino acids and vitamins

motility

Taxis is..... caused by the undulating motion of a bacterium. another word for stimulus. another term for bacterial tumbling. movement towards or away from a stimulus.

movement towards or away from a stimulus.

The symbiotic relationship represented by the production of vitamin K in the human large intestine by Escherichia coli is best described as _________.

mutualism

Fungal infections are called coencytic .mycoses. dimorphic. basidium. sporgangia.

mycoses

Which of the following is (are) used to classify viruses? Capsid symmetry Viral genome size Type of nucleic acid present Viral particle size

type of nucleic acid present, capsid symmetry (You may recall that viruses are grouped according to the following properties: type of nucleic acid present, capsid symmetry, presence or absence of envelope, and genome architecture. Size of either viral particle or viral genome are not used for viral classification, but may aid in viral identification.)

When do opportunistic pathogens tend to cause disease? after the host is already infected with a different pathogen when the host is weakened when the host didn't wash with soap when the host is old when the host is young

when the host is weakened