Khan Academy Biology Questions Chapter 1

Which of the following is a potential exception to cell theory? A. Mitochondria B. Amoebas C. Fungal spores D. Asexual reproduction

A. Mitochondria

Cell theory states: I. All living cells must have a cell wall. II. All living cells require glucose for survival. III. The basic unit of life is a cell.

III only

Tay Sachs is a congenital disorder in which molecules called gangliosides are not properly digested and instead accumulate in cells, causing toxicity. Misfunction in which organelle can lead to Tay Sachs? A. Lysosome B. Golgi Apparatus C. Rough Endoplasmic Reticulum D. Nucleus

A. Lysosome

Porphyromonas gingivalis is a Gram-negative bacterium, found in the oral cavity, is negatively affected by the presence of oxygen. What term best describes this bacteria? A. Obligate anaerobe B. Obligate aerobe C. Facultative anaerobe D. Aerotolerant anaerobe

A. Obligate anaerobe

Which of the following is NOT found in both prokaryotes and eukaryotes? A. Ribosomes B. Nucleolus C. Double-stranded DNA D. Cytoskeleton

B. Nucleolus

Where does energy production take place in bacteria that can perform aerobic metabolism? A. Mitochondria B. Plasma membrane C. Nucleus D. Inclusion Bodies

B. Plasma membrane

What cellular process would you expect to immediately disrupt if you added a protein that depolymerized microtubules? A. Fatty acid catabolism B. Protein production C. Transcription D. Mitosis

D. Mitosis

What is the name of the phenomenon in which a white blood cell engulfs a pathogen? Which cytoskeletal structures are involved in this process? A. Phagocytosis and microtubules. B. Pinocytosis and microtubules. C. Exocytosis and microfilaments. D. Phagocytosis and microfilaments.

D. Phagocytosis and microfilaments.

Which of the following is NOT a premise of cell theory? I. All cells arise from other cells. II. All living cells require water for survival. III. All living things are only composed of cells.

II and III

Methanopyrus kandleri is an organism which lives in a hydrogen-carbon dioxide environment, and was first discovered in a hydrothermal vent where temperatures reached 230°F. What sort of organism is this? A. Archaea B. Cyanobacteria C. Protist D. Bacteria

A. Archaea

Which of the following is NOT a method bacteria use for genetic recombination? A. Binary Fission B. Conjugation C. Transduction D. Transformation

A. Binary Fission

The function of which cellular structure would be least affected by a malfunctioning Golgi apparatus? A. Endoplasmic reticulum B. Secretory vesicles C. Lysosome D. Plasma membrane

A. Endoplasmic reticulum

Inclusion cell disease is a congenital condition that comes from the lack of a single protein. On an intracellular level, proteins meant for the lysosome are sent to the extracellular space. Considering this phenotype, which organelle is most directly affected by the missing protein? A. Golgi Apparatus B. Rough endoplasmic reticulum C. Lysosomes D. Ribosomes

A. Golgi Apparatus

Which of the following statements about the systemic effect of bacterial cells are true? A. Gram-negative bacteria are more likely to cause systemic effects because their outer membrane protects them from several antibiotics, making treatment more difficult. B. Gram-positive bacteria are more likely to cause systemic effects because the lipopolysaccharide (LPS) in their membranes can act as a toxin to the circulatory system. C. Gram-negative bacteria are more likely to cause systemic effects because their lack of an outer membrane means they can more quickly infect host cells. D. Gram-positive bacteria are more likely to cause system effects because the peptidoglycan in their cell walls is tough and hard for medicine to penetrate.

A. Gram-negative bacteria are more likely to cause systemic effects because their outer membrane protects them from several antibiotics, making treatment more difficult.

Which of the following transcriptional control features are found in both prokaryotes and eukaryotes? A. Promoter repressors B. Introns c. Differential splicing D. 5' methyl-G capping

A. Promoter repressors

Your trachea have short hair-like cell process that move the mucus. What is the name of these hair like structures and which cytoskeletal elements form them? A. Villi, intermediate filaments B. Cilia, microtubules C. Microvilli, microtubules D. Flagella, microfilaments

B. Cilia, microtubules

Which central dogma of genetics had to be revisited after the discovery of a retrovirus? A. Transcriptase assists in the formation of proteins B. DNA makes RNA that makes protein C. RNA replication cannot occur prior to translation D. Messenger RNA does not always code for proteins

B. DNA makes RNA that makes protein

What is a hallmark characteristic of reverse transcriptase? A. It is encoded in the host cell's genome B. It challenges the central dogma of biology (DNA → RNA → Protein) C.It reads the genetic material backwards (3' → 5') D. It allows the virus to infect bacteria through endocytosis

B. It challenges the central dogma of biology (DNA → RNA → Protein)

Oncoviruses are a type of animal virus that can cause a neoplasm - an abnormal, often excessive, growth of tissue. Which type of virus is likely to be an oncovirus? A. Lytic viruses B. Lysogenic viruses C. Enveloped viruses D. Bacteriophage viruses

B. Lysogenic viruses

Which cytoskeletal structure is linked with the movements of a macrophage? A. Glycocalyx B. Microfilaments C. Microtubules D. Cilia and flagella

B. Microfilaments

The ciliary action of the cells lining the lumen of fallopian tube are responsible for transporting an egg from the ovaries to the uterus. Which cytoskeleton structures are linked to this movement? A. Microfilaments B. Microtubules C. Flagella D. Intermediate filaments

B. Microtubules

Viruses infect cells and replicate themselves by utilizing various enzymes and cellular components of their host cell. Could you apply the same tenets of cell theory to viral replication? A. Yes, viruses strictly adhere to cell theory because from one virus directly arises another virus. B. No, viruses do not strictly adhere to cell theory because viruses do not directly come from other viruses; they require an intermediate cell to replicate. C. No, viruses do not strictly adhere to cell theory because they are not living organisms. D. Yes, viruses strictly adhere to cell theory because an individual virus is a singular cellular unit.

B. No, viruses do not strictly adhere to cell theory because viruses do not directly come from other viruses; they require an intermediate cell to replicate.

Methicillin-resistant Staphylococcus aureus (MRSA) is an antibiotic-resistant "superbug" that can cause deadly infections in humans. What would these Gram-positive bacteria look like under a microscope? A. Pink rods B. Purple spheres C. Clear rods D. Purple spirals

B. Purple spheres

A 19th century scientist investigates cell growth by placing boiled broth in one Erlenmeyer flask and non-boiled broth in another flask. The scientist covered both flasks so that air could not enter the flasks and observed the flasks for two weeks. Neither flask grew any biological matter. From this the scientist concluded that abiogenesis or spontaneous generation was an invalid theory. A. The conclusion is an invalid conclusion because the scientist did not wait long enough for anaerobic cells to grow in the broth. B. The conclusion is an invalid conclusion because living objects often require air to grow regardless if their origin was spontaneous or not. C. Since no colonies of cells grew in either flask, the conclusion is a valid conclusion because spontaneous generation predicts that cells should grow spontaneously. D. Since no colonies of cells grew in either flask, the conclusion is a valid conclusion because cells can only grow from other cells.

B. The conclusion is an invalid conclusion because living objects often require air to grow regardless if their origin was spontaneous or not.

Rapid growth of cells is observed in tumors. One hypothesis of rapid tumor growth is that the creation of new cells uses old cells only as a scaffold to promote rapid growth similar to how crystal solids form. In this hypothesis, new cellular material is not created from preexisting cells. First a new nucleus of a cell attaches to the preexisting cells followed by the formation of the cytoplasm and lastly a cellular membrane forms around the cytoplasm-nucleus complex. This process can only happen if there is a pre-existing lattice network of cells that can function as a site of nucleation. A. This rapid growth hypothesis is supported by cell theory because all living things are made of cells. B. This hypothesis is not supported by cell theory because new cells are not created from older, preexisting cells. C.This rapid growth hypothesis is supported by cell theory because the basic unit of life is the cell. D. This hypothesis is not supported by cell theory because cell walls are required to grow new cells.

B. This hypothesis is not supported by cell theory because new cells are not created from older, preexisting cells.

A hybridization probe is a fragment of genetic material that is used to to detect the presence of nucleotide sequences that are complementary to the sequence of the probe. Which infectious agent could not be detected with a probe? A. A retrovirus B. A virus with single-stranded DNA material C. A prion D. A virus with double-stranded RNA material

C. A prion

Which of the following is most responsible for bacterial cell motility? A. Pseudopodia B. Pili C. Flagella D. Cilia

C. Flagella

Which of the following is an advantage eukaryotes have over prokaryotes? A. Streamlined transcription / translation process due to clear step-wise mechanism B. Improved cell motility due to protein-based flagella C. Increased compartmentalization allowing for specialization D. Increased stability of genetic information due to double-stranded DNA

C. Increased compartmentalization allowing for specialization

Mutations can change the overall structure of proteins. Predict the outcome of a harmful mutation that modifies the microfilaments of the cytoskeleton of a white blood cell. A. It would result in decreased levels of centriole activity. B. It would impair the spindle formation during mitosis. C. It would decrease its ability to phagocytose other cells. D. It would ameliorate the structural support of the cell.

C. It would decrease its ability to phagocytose other cells.

A couple is told by their doctor that the reason why they cannot have children is that the sperm of the male lack motility because it does not have the structures responsible for propulsion. Which cellular structures are likely to be the underlying cause of this lack of motility? A. Endoplasmatic reticulum B. Golgi apparatus C. Microtubules D. Vacuoles

C. Microtubules

Aneuploidogens are chemicals that may disrupt gamete formation by interfering with spindle formation and the last phase of cell division. As a result the embryo may have abnormal ploidy. Based on this information, which cytoskeletal structures and which cell division process are affected by aneuploidogens? A. Microfilaments and spermatogenesis, respectively. B. Macrofilaments and telophase, respectively. C. Microtubules and cytokinesis, respectively. D. Intermediate filaments and mitosis, respectively.

C. Microtubules and cytokinesis, respectively.

Which factor may help determine the antigenicity of a virus? A. The internal proteins B. The whole capsid C. Some of the capsomers D. The size of the virus

C. Some of the capsomers

What did Louis Pasteur's crooked neck flask experiment disprove? A. Most cells require oxygen in order to survive. B. The cell is the basic unit of life. C. Spontaneous generation is a method for the creation of new cells. D. All living organism are composed of cells.

C. Spontaneous generation is a method for the creation of new cells.

Certain types of arthritis, or inflammation of the joints, could be caused by viruses. In some cases, infected individuals experience an acute, rapid degradation of the chondrocytes that make up the articular capsule upon infection. Which type of virus is likely to cause such acute symptoms? A. A lytic virus, because it has a brief latent phase and immediately attacks the joints B. A lysogenic virus, because it would specifically target and quickly destroy the chondrocytes C. A lysogenic virus, because its virulence tends to be expressed immediately D. A lytic virus, because it would cause a rapid destruction of the articular capsule

D. A lytic virus, because it would cause a rapid destruction of the articular capsule

What distinguishes prions from viruses? A. Ability to cause infection B. Type of protein arrangement C. Presence of an envelope D. Absence of genetic material

D. Absence of genetic material

What did Schleiden and Schwann both discover individually? A. All cells have organelles. B. Spontaneous generation of cells is an incorrect theory. C. All livings things engage in metabolic functions. D. All living things are composed of one or more cells.

D. All living things are composed of one or more cells.

Which of the following is not involved in cell motility? A. Microtubules B. Flagella C. Microfilaments D. Intermediate filaments

D. Intermediate filaments

Reverse transcriptase is known for having poor proofreading activity. What would be a consequence of this? A. It could cause the host cell to incorrectly proofread as well B. It makes each new viral generation more viable C. It establishes lifelong infection in the host D. It could add to the virulence and transmission of the virus

D. It could add to the virulence and transmission of the virus

An antiviral drug specifically modifies viral receptors on a eukaryotic host cell. How might this affect the viral reproductive cycle? A. It would result in the degeneration of the viral capsid B. It would facilitate the process of viral endocytosis C. It would enhance the process of viral apoptosis D. It would prevent the virus from attaching to the host cell

D. It would prevent the virus from attaching to the host cell

Malformation of which cytoskeletal structures may be linked to an inability to contract muscle? A. Microtubules B. Intermediate filaments C. Centrioles D. Microfilaments

D. Microfilaments

The cytoskeleton of a cell can generate movements such as in cytokinesis, or propulsive forces outside the cell like flagella. Which structures are linked with these two movements? A. Microtubules and intermediate filaments, respectively. B. Microfilaments and intermediate filaments, respectively. C. Intermediate filaments and microtubules, respectively. D. Microfilaments and microtubules respectively.

D. Microfilaments and microtubules respectively.

Which of the following statements regarding DNA replication is true? A. Both prokaryotic and eukaryotic DNA has multiple origins of replication B. The timing of replication is tightly regulated in both eukaryotes and prokaryotes C. Eukaryotes use DNA gyrase, while prokaryotic DNA is small enough to not need it D. Prokaryotic polymerases work at a faster rate than eukaryotic ones

D. Prokaryotic polymerases work at a faster rate than eukaryotic ones

Which cellular function may be disrupted because of a malformation of the intermediate filaments? A. Transport of chemicals B. Ability to divide C. Formation of spindle D. Resilience to compression forces

D. Resilience to compression forces

Muscle cells will have increased amounts of which organelles? A. Rough endoplasmic reticulum and smooth endoplasmic reticulum B. Mitochondria and chloroplasts C. Rough endoplasmic reticulum and ribosomes D. Smooth endoplasmic reticulum and mitochondria

D. Smooth endoplasmic reticulum and mitochondria

A scientist is investigating a specimen in a laboratory. She is attempting to determine whether it is a virus or not. Which of the following would allow her to conclude that it is not a virus? A. The specimen is extremely small B. The specimen has no organelles C. The specimen has a protein coat D. The specimen contains DNA and RNA

D. The specimen contains DNA and RNA

The following is a graph of growth from a newly discovered species. What can be concluded from the graph? A. All living organisms including this new species are composed of cells. B. The new species grows in colonies that promote rapid expansion in cellular populations. C. In this species, cells must come from other cells: omni cellula e cellula. D. This species quintuples (x5) the number of cells every hour.

D. This species quintuples (x5) the number of cells every hour.

Kearns-Sayre syndrome is a disease caused by deletions in circular DNA that codes for proteins of the electron transport chain. What is its inheritance pattern? A. Through the paternal line B. Autosomal recessive C. X-linked D. Through the maternal line

D. Through the maternal line Mitochondria are inherited through the maternal line, the ETC takes place inside the mitochondria.

What type(s) of cells do you obtain after a F+ bacterium conjugates with a F- bacterium? A. Two F+ bacteria with identical plasmid and chromosomal DNA B. Two bacteria with identical plasmid and chromosomal DNA, but one is F+, and the other F- C. One new F- bacterium which transferred the plasmid to the other cell, which is now F+ D. Two F+ bacteria with identical plasmid but not chromosomal DNA

D. Two F+ bacteria with identical plasmid but not chromosomal DNA

In a histology lab a scientist observes the following features under the microscope. Which of these observations supports cell theory? I. Cardiac cells are joined by gap junctions and contain three nuclei. II. Mature platelet cells do not contain a nucleus, but do contain mitochondria. III. Spermatogonia undergoing mitosis. IV. The bulk of tissue samples from endocrine glands contain cells as their main building blocks.

III and IV