Biology: The Cell

The ability of a cell to detect chemical stimuli and move toward or away from them is called what? A. Chemotaxis B. Chemosynthesis C. Chemosynthetic D. Chemical sense

A. Chemotaxis

Where does DNA transcription to mRNA occur? A. Nucleus B. Cytoplasm C. Ribosome D. Nucleoid

A. Nucleus

What is the main function of the nucleolus? A. Ribosomal RNA synthesis B. DNA replication C. Cell devision D. Chromosome assembly

A. Ribosomal RNA synthesis

Which cell type is long and thin? A. Cuboidal Cells B. Columnar Cells C. Squamous Cells D. Scalene Cells

B. Columnar Cells

Where does prokaryotic DNA replication occur? A. Nucleus B. Cytoplasm C. Ribosome D. Nucleoid

B. Cytoplasm Prokaryotes DO NOT have a nucleus.

Where does mRNA get translated to proteins in a cell? A. Nucleus B. Cytoplasm C. Ribosome D. Nucleoid

B. Cytoplasm mRNA translation to proteins occurs in the cytoplasm by the ribosomes.

Which eukaryotic membrane-bound organelle is described as the power plants of the cell, in reference to their important metabolic functions? A. Endoplasmic Reticulum B. Golgi Apparatus C. Mitochondria D. Ribosomes

C. Mitochondria

Which cell type is flat and scalelike? A. Cuboidal Cells B. Columnar Cells C. Squamous Cells D. Scalene Cells

C. Squamous Cells

What are genetic elements capable of inserting and removing themselves from the genome called? A. Histones B. Transcription Factors C. Transposons D. Transcriptase

C. Transposons Transposons are genetic elements capable of inserting and removing themselves from the genome. This phenomenon is not limited to prokaryotes; it has been seen in eukaryotes as well. If a transposon is inserted within a coding region of a gene, that gene may be disrupted.

Cytoskeleton

Cytoskeleton

True or False: Prokaryotes do not contain any membrane-bound organelles, and their genetic material is organized into a double stranded linear molecule of DNA concentrated in an area of the cell called the nucleoid region.

False. Prokaryotes do not contain any membrane-bound organelles, and their genetic material is organized into a single circular molecule of DNA concentrated in an area of the cell called the nucleoid region.

True or False: Prokaryotic cells contain a true nucleus encoded in a membrane.

False. Prokaryotic cells do not contain a nucleus.

True or False: Prokaryotes lack a nucleus and membrane-bound organelles.

True. Prokaryotes lack a nucleus and membrane-bound organelles.

True or False: Unlike eukaryotic cells, viruses lack organelles and a nucleus.

True. Unlike eukaryotic cells, viruses lack organelles and a nucleus.

Put the following bacterial growth phases in order: -Stationary Phase -Exponential Phase/Log Phase - Lag Phase - Death Phase

1. Lag Phase 2. Exponential Phase/Log Phase 3. Stationary Phase 4. Death Phase In a new environment, the bacteria first adapt to the new local conditions during the lag phase. As the bacteria adapt, growth increases, causing an exponential increase in the number of bacteria in the colony during the exponential phase (aka log phase). As the number of bacteria in the colony grows, resources are often reduced. The reduction of resources slows reproduction, and the stationary phase results. After the bacteria have exceeded the ability of the environment to support the number of bacteria, a death phase occurs as resources in the environment have been depleted.

What is the term for bacteria that are unable to use oxygen for metabolism, but are not harmed by its presence in the environment? A. Aerotolerant Anaerobes B. Facultative Anaerobes C Obligate Anaerobes D. Obligate Aerobes

A. Aerotolerant Anaerobes

Which cell type is cube-shaped? A. Cuboidal Cells B. Columnar Cells C. Squamous Cells D. Scalene Cells

A. Cuboidal Cells

What allows for the diffusion of molecules throughout the cell? A. Cytosol B. Phospholipid Bilayer C. Nuclear Membrane or Envelope D. Nuclear Pores

A. Cytosol The cytosol allows for the diffusion of molecules throughout the cell.

What does collagen and elastin form? A. Extracellular Matrix B. Connective Tissue C. Epithelia D. Cytoskeleton

A. Extracellular Matrix Most cells in connective tissues produce and secrete materials such as collagen and elastin to form the extracellular matrix. Osteoblasts which produce osteoid (the material that hardens into bone) and chondroblasts which produce cartilage are both considered to be connective tissue.

To form the pilus during conjugation, bacteria must contain a plasmid known as sex factor that contain the necessary gene. Which is an example of a sex factor? A. F (fertility) Factor B. Episomes C. Vector D. Transposons

A. F (fertility) Factor Bacteria possessing this plasmid are termed F+ cells; those without are called F- cells.

Which of the following organelles is surrounded by a single membrane? A. Lysosomes B. Mitochondria C. Nuclei D. Ribosomes

A. Lysosomes Lysosomes are vesicular organelles that digest material using hydrolytic enzymes. They are surrounded by a single membrane. Both mitochondria and nuclei are surrounded by double membranes. Ribosomes must not be surrounded by membranes because they are not only found in eukaryotes, but also in prokaryotes, which lack any membrane-bound organelles.

Which cytoskeleton component is involved in cytokinesis during mitosis? A. Microfilaments B. Microtubules C. Intermediate Filaments D. Myosin

A. Microfilaments During mitosis cytokinesis, the cleavage furrow is formed from microfilaments.

Which component of the cytoskeleton is made up of solid polymerized rods of actin? A. Microfilaments B. Intermediate Filaments C. Microtubules D. A and B

A. Microfilaments Microfilaments also play a role in cytokinesis in mitosis.

Which component of the mitochondria serves as a barrier between the cytosol and the inner environment of the mitochondrion? A. Mitochondria outer membrane B. Mitochondria inner membrane C. Mitochondrial matrix D. Mitochondrial intermembrane space

A. Mitochondria outer membrane The outer membrane serves as a barrier between the cytosol and the inner environment of the mitochondrion.

Where does eukaryotic DNA replication occur? A. Nucleus B. Cytoplasm C. Ribosome D. Nucleoid

A. Nucleus

Match the following to its appropriate location - Hydrophilic - Hydrophobic A. Outer portion of phospholipid bilayer B. Inner portion of phospholipid bilayer

A. Outer portion of phospholipid bilayer - Hydrophophilic B. Inner portion of phospholipid bilayer- Hydrophobic

What cycle is a virus in if it leaves the cell by fusing with its plasma membrane in a process known as extrusion? A. Productive Cycle B. Lysogenic Cycle C. Lytic Cycle D. Dormant

A. Productive Cycle The process of extrusion allows for survival of the host cell, and continued use of the host cell by the virus. A virus in this states is said to be in a productive cycle.

Match the terms to its correct definition: - Cocci - Spirilli - Bacilli A. Rod-Shaped Bacteria B. Spherical-Shaped Bacteria C. Spiral-Shaped Bacteria

A. Rod-Shaped Bacteria - Bacilli B. Spherical-Shaped Bacteria - Cocci C. Spiral-Shaped Bacteria - Spirilli

What do bacteriophages use to inject their genetic material into the bacteria? A. Tail Sheath B. Tail Fibers C. Capsid D. None of the above

A. Tail Sheath Bacteriophages do not actually enter bacteria. They inject their genetic material, leaving the remaining structures outside the infected cell. The tail sheath can act like a syringe, injecting genetic material into a bacterium.

Which genetic recombination process requires a vector? A. Transduction B. Transformation C. Transposon D. Conjugation

A. Transduction Transduction is the only genetic recombination process that requires a vector- a virus that carries genetic material from one bacterium to another. Viruses are obligate intracellular pathogens, which means that they cannot reproduce outside of a host cell. Because of this, bacteriophages (viruses that infect bacteria) can accidentally trap a segment of host DNA during assembly. When the bacteriophage infects another bacterium, it can release this trapped DNA into the new host cell. This transferred DNA can then integrate into the genome, giving the new host additional genes.

What surrounds the nucleus? A. Cell Membrane B. Nuclear Membrane/Envelope C. Cytoplasm D. Endoplasmic Reticulum

B Nuclear Membrane/Envelope The nucleus is surrounded by the nuclear membrane or envelope, a double membrane that maintains a nuclear environment separate and distinct from the cytoplasm.

What are viruses that specifically targets bacteria called? A. Virions B. Bacteriophages C. Prions D. Viroids

B. Bacteriophages - Bacteriophages are viruses that specifically targets bacteria. - Virions is the term for the viral progeny produced when a virus replicates - Prions are infectious proteins - Viroids are small pathogens consisting of a very short circular single-stranded RNA that infect plants.

Bone, cartilage, tendons, ligaments, adipose tissue, and blood are all examples of what? A. Extracellular Matrix B. Connective Tissue C. Epithelia D. Cytoskeleton

B. Connective Tissue

What is a subset of plasmids (extrachromosomal/extragenomic material that many bacteria contain) that are capable of integrating into the genome of the bacterium called? A. F (fertility) Factor B. Episomes C. Vector D. Transposons

B. Episomes Plasmids often carry genes that impart some benefit to the bacterium, such as antibiotic resistance. Plasmids may also carry additional virulence factors, or traits that increase how pathogenic a bacterium is. A subset of plasmids called episomes are capable of integrating into the genome of the bacterium.

What is the term for bacteria that can use oxygen for aerobic metabolism and switch to anaerobic metabolism if oxygen is not present? A. Aerotolerant Anaerobes B. Facultative Anaerobes C Obligate Anaerobes D. Obligate Aerobes

B. Facultative Anaerobes

What are the functions of smooth ER? I. Lipid synthesis II. Detoxification of certain drugs and poisons III. Transport of proteins from the RER to the golgi apparatus IV. Modification to materials from the ER. A. I only B. I, II and III C. I and II D. I, II, III, and IV

B. I, II, and III I. Lipid synthesis II. Detoxification of certain drugs and poisons III. Transport of proteins from the RER to the golgi apparatus IV. Modification to material from the ER is the function of golgi apparatus.

What are the functions of the cytoskeleton? I. Provide structure to the cell II. Help the cell maintain its shape III. Provides a conduit for transport of materials around the cell IV. Provide the cell with water resistance A. I and II only B. I, II, and III only C. I, II, and IV only D. I, II, III, and IV

B. I, II, and III only The cytoskeleton functions to: I. Provide structure to the cell II. Help the cell maintain its shape III. Provides a conduit for transport of materials around the cell

Which component of the cytoskeleton includes keratin, desmin, vimentin, and lamins, and is involved in cell-cell adhesion? A. Microfilaments B. Intermediate Filaments C. Microtubules D. All of the above

B. Intermediate Filaments Intermediate filaments are able to withstand a tremendous amount of tension, making the cell structure more rigid. They also help anchor other organelles, including the nucleus.

What cycle is a virus in if it does not lyse the bacterium, and instead integrates into the host genome as a provirus or prophage? A. Productive Cycle B. Lysogenic Cycle C. Lytic Cycle D. Dormant

B. Lysogenic Cycle In this case, the virus will be replicated as the bacterium reproduces because it is now a part of the host's genome. Although the virus may remain integrated into the host genome indefinitely, environmental factors (radiation, light, or chemicals) will cause the provirus to leave the genome and revert to a lytic cycle (making the host virulent).

What are membrane-bound structures containing hydrolytic enzymes that are capable of breaking down many different substrates, including substrates ingested by endocytosis and cellular waste products? A. Mitochondria B. Lysosomes C. Ribosomes D. Peroxisomes

B. Lysosomes Lysosomes are membrane-bound structures containing hydrolytic enzymes that are capable of breaking down many different substrates, including substrates ingested by endocytosis and cellular waste products. The lysosomal membrane sequesters these enzymes to prevent damage to the cell. However, release of these enzymes can occur in a process known as autolysis. Like mitochondria, when lysosomes release their hydrolytic enzymes, it results in apoptosis. In this case, the released enzymes directly lead to the degradation of cellular components.

Which cytoskeleton component is involved in anaphase during mitosis and emanate from the centrioles? A. Microfilaments B. Microtubules C. Intermediate Filaments D. Actin

B. Microtubules

Which of the following is NOT found in prokaryotes? A. Ribosomes B. Mitochondria C. Cytoskeleton D. Cell Membrane

B. Mitochondria Prokaryotes lack mitochondria. Instead, the cell membrane is used for the electron transport chain and generation of ATP. Prokaryotes do contain a primitive cytoskeleton, but it is not nearly as complex as the one found in eukaryotes. Prokaryotes also contain ribosomes, but this ribosome is a different size from that found in eukaryotes: prokaryotic ribosomes contain 30S and 50S subunits, whereas eukaryotic ribosomes contain 40S and 60S subunits.

Where are the molecules and enzymes necessary for the electron transport chain housed? A. Mitochondria outer membrane B. Mitochondria inner membrane C. Mitochondrial matrix D. Mitochondrial intermembrane space

B. Mitochondria inner membrane The inner membrane contains the molecules and enzymes necessary for the electron transport chain.

Where is genetic material encoded in deoxyribonucleic acid (DNA) and is organized into chromosomes A. Nucleolus B. Nucleus C. Cytoplasm D. Nuclear Membrane

B. Nucleus Within the nucleus, genetic material is encoded in DNA, which is organized into chromosomes. The nucleus contains all of the genetic material necessary for replication of the cell.

Which type of virus carries reverse transcriptase? A. Bacteriophage B. Retrovirus C. Single-stranded RNA viruses D. B and C

B. Retrovirus Retroviruses are enveloped, single-stranded RNA viruses that carry an enzyme called reverse transcriptase, which synthesizes DNA from single-stranded RNA. The DNA then integrates into the host cell genome, where it is replicated and transcribed as if it were the host cell's own DNA. * HIV is an example of a retrovirus.

Which epithelia type consists of multiple cell layers? A. Simple Epithelia B. Stratified Epithelia C. Pseudostratified Epithelia D. B and C

B. Stratified Epithelia

What allows a bacteriophage to recognize and connect to the correct host cell? A. Tail Sheath B. Tail Fibers C. Capsid D. None of the above

B. Tail Fibers The tail fibers help the bacteriophage to recognize and connect to the correct host cell.

Which form of bacterial genetic recombination results from the integration of foreign genetic material into the host genome? A. Transduction B. Transformation C. Transposon D. Conjugation

B. Transformation Transformation results from the integration of foreign genetic material into the host genome. The foreign genetic material most frequently comes from other bacteria that, upon lysing, spill their contents in the vicinity of a bacterium capable of transformation. Many gram-negative rods are able to carry out this process.

After infection, what must occur to the viral genetic material in order for the virus to reproduce? A. Transduction B. Translation C. Conjugation D. Transformation

B. Translation After infection, translation must occur to the viral genetic material in order for the virus to reproduce. This requires translocation of the genetic material to the correct location in the cell.

Which organelle receives materials from the ER in vesicles and may also modify cellular products through the introduction of signal sequences, which direct the delivery of the product to a specific cellular location? A. Smooth ER B. Rough ER C. Golgi Apparatus D. Lysosome

C. Golgi Apparatus The Golgi apparatus consists of stacked membrane-bound sacs. Materials from the ER are transferred to the Golgi apparatus in vesicles. Once in the the Golgi apparatus, these cellular products may be modified by the addition of various groups, including carbohydrates, phosphates, and sulfates. The Golgi apparatus may also modify cellular products through the introduction of signal sequences, which direct the delivery of the product to a specific cellular location. If the product is destined for secretion, then the secretory vesicle merges with the cell membrane and its contents are released via exocytosis.

Mitochondrial DNA is: I. circular. II. self-replicating. III. single-stranded. A. I only B. II only C. I and II D. I, II, and III

C. I and II: circular and self-replicating Mitochondria are thought to have evolved from an anaerobic prokaryote engulfing an aerobic prokaryote and establishing a symbiotic relationship; therefore, mitochondrial DNA, or mDNA, is likely to be similar to bacterial DNA. Both mDNA and bacterial DNA are organized into a single circular chromosome of double-stranded DNA that can replicate during binary fission.

What are the functions of the cytoskeleton? I. Provide structure to the cell II. Help the cell maintain its shape III. Provide a conduit for the transport of materials around the cell IV. Protect the cell A. I and II only B. III only C. I, II, and III only D. I, II, III and IV

C. I, II, and III The cytoskeleton functions to: I. Provide structure to the cell II. Help the cell maintain its shape III. Provide a conduit for the transport of materials around the cell

What cycle is a bacteriophage in if it lyses the bacterium? A. Productive Cycle B. Lysogenic Cycle C. Lytic Cycle D. Dormant

C. Lytic Cycle

What cycle is a bacteriophage in if the bacteria infected is considered virulent? A. Productive Cycle B. Lysogenic Cycle C. Lytic Cycle D. Dormant

C. Lytic Cycle During the lytic cycle, the bacteriophage makes maximal use of the cell's machinery with little regard for the survival of the host cell. Once the host is swollen with new virions, the cell lyses, and other bacteria can be infected.

Which component of the cytoskeleton is made up of hollow polymers of tubulin proteins? A. Microfilaments B. Intermediate Filaments C. Microtubules D. All of the above

C. Microtubules Cilia and flagella are composed of microtubules and contain the 9 + 2 structure in eukaryotes. Microtubules also provide the primary pathway along which motor proteins like kinesin (moves things anterograde, from negative to positive) and dynein (moves things retrograde, from positive to negative) carry vesicles. Centrioles are found in a region of the cell called the centrosome. They are the organizing centers for microtubules and are structured as nine triplets of microtubules with a hollow center. Centrioles play a role in anaphase in mitosis: microtubules emanating from the centrioles attach to chromosomes via kinetochores and pull the sister chromatids apart.

What is the space inside the mitochondrial inner membrane called? A. Mitochondria outer membrane B. Mitochondria inner membrane C. Mitochondrial matrix D. Mitochondrial intermembrane space

C. Mitochondrial matrix The space inside the inner membrane is called the mitochondrial matrix. The pumping of protons from the mitochondrial matrix to the intermembrane space establishes the proton-motive force; ultimately, these protons flow through ATP synthase to generate ATP during oxidative phosphorylation.

What is the term for bacteria that cannot survive in an oxygen-containing environment? A. Aerotolerant Anaerobes B. Facultative Anaerobes C Obligate Anaerobes D. Obligate Aerobes

C. Obligate Anaerobes Anaerobes that cannot survive in an oxygen-containing environment are called obligate anaerobes; the presence of oxygen leads to the production of reactive oxygen-containing radicals in these species, which leads to cell death.

What is the term for the subviral particle that causes disease by triggering misfolding of other proteins, usually involving the conversion of a protein from an alpha-helical structure to a beta-pleated sheet? A. Virions B. Bacteriophages C. Prions D. Viroids

C. Prions Prions are infectious proteins and are, thus, also nonliving things. The conversion of a protein from an alpha-helical structure to a beta-pleated sheet reduces the solubility of the protein, as well as the ability of the cell to degrade the misfolded protein. Prions are known to cause mad cow disease and familial fatel insomnia in humans.

Which of the following is not a function of the smooth endoplasmic reticulum? A. Lipid synthesis B. Poison detoxification C. Protein synthesis D. Transport of proteins

C. Protein synthesis Protein synthesis takes place in ribosomes.

A bacterium with a conjugative plasmid integrated into its chromosomal DNA is referred to as what? A. Episome B. Hfr (high frequency of recombination) C. F (fertility) factor D. A and B

D. A and B Episome and Hfr (high frequency of recombination). A high-frequency recombination cell is a bacterium with a conjugative plasmid integrated into its chromosomal DNA. The integration of the plasmid into the cell's chromosome is through homologous recombination. A conjugative plasmid capable of chromosome integration is also called an episome. Hfr cells are created when the F factor, which exists as a plasmid within the cell, is integrated into a cell's chromosome

Which epithelia type consists of one layer of cells? A. Simple Epithelia B. Stratified Epithelia C. Pseudostratified Epithelia D. A and C

D. A and C Simple and pseudostratified epithelia have one layer of cells. Pseudostratified epithelia appear to have multiple layers due to differences in cell height, but are actually only one layer.

Prokaryotes reproduce asexually in the form of what? A. Transduction B. Transformation C. Conjugation D. Binary Fission

D. Binary Fission Binary Fission is a simple form of asexual reproduction seen in prokaryotes. The circular chromosome attaches to the cell wall and replicates while the cell continues to grow in size. Eventually, the plasma membrane and cell wall begin to grow inward along the midline of the cell to produce two identical daughter cells.

Which bacterial genetic recombination is the bacterial form of mating (sexual reproduction) and involves sex factors (F factor) and the formation of a conjugation bridge? A. Transduction B. Transformation C. Transposon D. Conjugation

D. Conjugation Conjugation is bacterial form of mating (sexual reproduction). It involves two cells forming a conjugation bridge between them that allows for the transfer of genetic material. The bridge is made up of appendages called sex pili that are found on the donor male. To form the pilus, bacteria must contain plasmids known as sex factors, such as F (fertility) factors. Bacteria possessing this plasmid are termed F+ cells; those without are called F- cells. During conjugation between an F+ and an F- cell, the F+ cell replicates its F factor and donates the copy to the recipient, converting it to an F+ cell. This enables the cell obtaining the new plasmid to then transfer copies to other cells.

What are the tenets of the cell theory? I. All living things are composed of cells. II. The cell is the basic functional unit of life. III. Cells arise only from preexisting cells. IV. Cells carry genetic information in the form of deoxyribonucleic acid (DNA). This genetic material is passed on from parent to daughter cell. A. I and II B. I, II, and III C. I only D. I, II, III, and IV

D. I, II, III, and IV I. All living things are composed of cells. II. The cell is the basic functional unit of life. III. Cells arise only from preexisting cells. IV. Cells carry genetic information in the form of deoxyribonucleic acid (DNA). This genetic material is passed on from parent to daughter cell.

Which of the following genetic information may a virus be composed of? I. Single-stranded linear or circular DNA II. Double-stranded linear or circular DNA III. Single-stranded linear or circular RNA IV. Double-stranded linear or circular RNA A. I and II only B. III and IV only C. I and III only D. I, II, III, and IV

D. I, II, III, and IV The genetic material that a virus is composed of may be circular or linear, single- or double-stranded, and composed of either DNA or RNA.

What is the space between the inner and outer membrane of the mitochondria called? A. Mitochondria outer membrane B. Mitochondria inner membrane C. Mitochondrial matrix D. Mitochondrial intermembrane space

D. Mitochondrial intermembrane space The space between the inner and outer membrane of the mitochondria is called the intermembrane space.

What is the term for bacteria that require oxygen for metabolism? A. Aerotolerant Anaerobes B. Facultative Anaerobes C Obligate Anaerobes D. Obligate Aerobes

D. Obligate Aerobes

What is the term for bacteria that require oxygen? A. Aerotolerant Anaerobes B. Facultative Anaerobes C Obligate Anaerobes D. Obligate Aerobes

D. Obligate Aerobes - require oxygen Aerotolerant Anaerobes - use fermentation to produce ATP. They do not utilize oxygen, but oxygen molecules do not harm them. Facultative Anaerobes - an organism that makes ATP by aerobic respiration if oxygen is present, but is capable of switching to fermentation or anaerobic respiration if oxygen is absent. Obligate Anaerobes - die in the presence of oxygen.

What are the membrane-bound organelles that contain hydrogen peroxide and has the primary function of breaking down very long chain fatty acids via beta-oxidation? A. Mitochondria B. Lysosomes C. Ribosomes D. Peroxisomes

D. Peroxisomes Peroxisomes contain hydrogen peroxide.

What is the term for the pathogens that can bind to a large number of RNA sequences and will silence genes in the plant genome? A. Virions B. Bacteriophages C. Prions D. Viroids

D. Viroids Viroids are small pathogens consisting of a very short circular single-stranded RNA that infect plants. Viroids are classically thought of as plant pathogens, but human viroids do exist, such as hepatitis D virus (HDV). Alone HDV is innocuous; however when coinfected with hepatitis B virus (HBV), HDV is able to exert its silencing function of human hepatocytes.

True or False: In prokaryotes, RNA is transcribed in the nucleolus and translation occurs in the cytoplasm.

False In prokaryotes, RNA is transcribed and translated in the cytoplasm.

True or False: Bacterial ribosome is significantly larger than eukaryotic ribosome.

False. Bacterial ribosome is significantly smaller than eukaryotic ribosome.

True or False: Mitosis is faster than binary fission.

False. Because binary fission requires fewer events than mitosis, it can proceed more rapidly. Some strains of E. coli can replicate every 20 minutes under ideal growth conditions.

True or False: Both flagella and centrioles contain nine doublets of microtubules on the outside and two microtubules on the inside.

False. Centrioles consist of 9 triplets of microtubules and a hollow center, while flagella consist of nine doublets on the outside and two microtubules on the inside.

True or False: Enveloped viruses are harder to kill.

False. Enveloped viruses are easier to kill. Viruses are composed of genetic material a protein coat, and sometimes an envelope containing lipids. The protein coat is known as a capsid. If an envelope is present, it will surround the capsid and is composed of phospholipids and virus-specific proteins. The envelope is very sensitive to heat, detergents, and desiccation: thus, enveloped viruses are easier to kill.

True or False: Gram-negative bacterial cell walls are very thin and appear pink-red after staining. They contain more peptidoglycan compared to gram-positive bacteria. They also contain outer membranes containing phospholipids and lipopolysaccharides.

False. Gram-negative bacterial cell walls are very thin and appear pink-red after staining. They contain less peptidoglycan compared to gram-positive bacteria. They also contain outer membranes containing phospholipids and lipopolysaccharides. Gram-negative bacterial envelops do not absorb the crystal violet stain, but absorbs the safranin counterstain, which makes the cell appear pink-red. Interestingly, lipopolysaccharides are the part of the gram-negative bacteria that triggers an immune response in human beings; the inflammatory response to lipopolysaccharides is much stronger than the response to lipoteichoic acid from gram-positive bacteria.

True or False: If a virus is a negative sense RNA then the genome may be directly translated to functional proteins by the ribosomes of the host cell, just like mRNA.

False. If a virus is a positive sense RNA then the genome may be directly translated to functional proteins by the ribosomes of the host cell, just like mRNA. Negative-sense RNA viruses require synthesis of an RNA strand complementary to the negative-sense RNA strand, which can then be used as a template for protein synthesis. Negative-sense RNA viruses must carry an RNA replicase in the virion to ensure that the complementary strand is synthesized. * Single-stranded RNA viruses may be positive or negative sense.

True or False: Mitochondria are thought to have evolved from an anaerobic prokaryote engulfing an aerobic eukaryote and establishing a symbiotic relationship.

False. Mitochondria are thought to have evolved from an anaerobic prokaryote engulfing an aerobic prokaryote and establishing a symbiotic relationship.

True or False: The parenchyma is the nonfunctional parts of the organ.

False. The parenchyma is the functional parts of the organ. Epithelial cells constitute the parenchyma, or the functional parts of the organ. For example, nephrons in the kidney, hepatocytes in the liver, and acid-producing cells of the stomach are all composed of epithelial cells.

True or False: Viruses are living organisms.

False. Viruses are not considered living organisms because they are unable to reproduce on their own and because they may contain ribonucleic acid (RNA) as their genetic information.

True or False: Whereas connective tissues contribute to the parenchyma of an organ, epithelial cells are the main contributors to the stroma or support structure.

False. Whereas epithelial cells contribute to the parenchyma (the functional tissue) of an organ, connective tissues are the main contributors to the stroma or support structure.

Prokaryotes are single-celled organisms, but do contain a cell wall and cell membrane which together are known as the envelope. Which is the outer barrier of the cell?

The cell wall forms the outer barrier of the cell. The next layer is the cell membrane (plasma membrane), which is composed of phospholipids, similar to that of a eukaryote.

Fill in the blanks: The genetic material (DNA) contains coding regions called __________. Linear DNA is wound around organizing proteins known as __________, and is then further wound into linear strands called __________. The location of DNA in the nucleus allows for the compartmentalization of DNA transcription separate from RNA translation. Finally, there is a subsection of nucleus known as the __________, where the ribosomal RNA (rRNA) is synthesized. This subsection actually takes up approximately 25% of the volume of the entire nucleus and can often be identified as a darker spot in the nucleus. - nucleolus - histones - genes - chromosomes

The genetic material (DNA) contains coding regions called genes. Linear DNA is wound around organizing proteins known as histones, and is then further wound into linear strands called chromosomes. The location of DNA in the nucleus allows for the compartmentalization of DNA transcription separate from RNA translation. Finally, there is a subsection of nucleus known as the nucleolus, where the ribosomal RNA (rRNA) is synthesized. The nucleolus actually takes up approximately 25% of the volume of the entire nucleus and can often be identified as a darker spot in the nucleus.

If you're facing the lumen, what are you facing?

The lumen refers to the hollow inside of an organ or tube, or the outside world, while the other side consists of the underlying blood vessels and structural cells.

True or False: Actin filaments are organized into bundles and networks and are resistant to both compression and fracture, providing protection for the cell.

True. Actin filaments are organized into bundles and networks and are resistant to both compression and fracture, providing protection for the cell.

True or False: All bacteria contain a cell membrane and cytoplasm, and some have flagella or fimbriae.

True. All bacteria contain a cell membrane and cytoplasm, and some have flagella or fimbriae.

True or False: Bacteria outnumber the eukaryotic cells in our bodies about ten to one.

True. Bacteria outnumber the eukaryotic cells in our bodies about ten to one

True or False: Because viruses cannot reproduce independently, they are considered obligate intra-cellular parasites.

True. Because viruses cannot reproduce independently, they are considered obligate intra-cellular parasites. Viruses must express and replicate genetic information within a host cell because they lack ribosomes to carry out protein synthesis.

True or False: Mitochondria contain some of their own genes and can replicate independently via binary fission.

True. Endosymbiosis theory - Mitochondria are thought to have evolved from an anaerobic prokaryote engulfing an aerobic prokaryote and establishing a symbiotic relationship.

True or False: Eukaryotic cells contain a true nucleus encoded in a membrane.

True. Eukaryotic cells contain a true nucleus encoded in a membrane.

True or False: Gram-positive bacterial cell walls appear deep purple after staining and consist of a thick layer of peptidoglycan and lipoteichoic acid.

True. Gram-positive bacterial cell walls appear deep purple after staining and consist of a thick layer of peptidoglycan and lipoteichoic acid. The bacterial envelop absorbs the crystal violet stain, which makes it appear purple.

True or False: The mitochondria can kick-start a process known as apoptosis, or programmed cell death.

True. In addition to keeping the cell alive by providing energy, the mitochondria are also capable of killing the cell by release of enzymes from the electron transport chain. This release kick-starts a process known as apoptosis, or programmed cell death.

True or False: In bacteria, there are two main types of cell walls.

True. In bacteria, there are two main types of cell walls: gram positive and gram negative.

True or False: In eukaryotes, RNA is transcribed in the nucleolus and translation occurs in the cytoplasm.

True. In eukaryotes, RNA is transcribed in the nucleolus and translation occurs in the cytoplasm.

True or False: Peroxisomes contain hydrogen peroxide and functions to breakdown very long chain fatty acids via beta-oxidation.

True. Peroxisomes also participate in the synthesis of phospholipids and contain enzymes involved in the pentose phosphate pathway.

True or False: The endoplasmic reticulum (ER) is contiguous with the nuclear membrane.

True. The ER is a series of interconnected membranes that are actually contiguous with the nuclear envelope.

True or False: The rough ER is studded with ribosomes, which permits the translation of proteins destined for secretion into its lumen.

True. The rough ER is studded with ribosomes, which permits the translation of proteins destined for secretion into its lumen.

True or False: Viruses can only infect a specific set of cells. In order to infect a cell, the virus has to bind to specific receptors on the host cell. Without the proper receptors, a cell is essentially invisible to the virus.

True. Viruses can only infect a specific set of cells. In order to infect a cell, the virus has to bind to specific receptors on the host cell. Without the proper receptors, a cell is essentially invisible to the virus.

True or False: During conjugation, the transfer of genetic material is unidirectional, from the donor male (+) to the recipient female (-).

True: During conjugation, the transfer of genetic material is unidirectional, from the donor male (+) to the recipient female (-).

True or False: Nuclear pores in the nuclear membrane allow for selective two-way exchange of material between the cytoplasm and the nucleus.

True: Nuclear pores in the nuclear membrane allow for selective two-way exchange of material between the cytoplasm and the nucleus.