Ch. 3 Cellular Level of Organization Flashcards
Because they are embedded within the membrane, ion channels are examples of (BLANK).
A. Receptor Proteins.
B. Integral Proteins.
C. Peripheral Proteins.
D. Glycoproteins.
B. Integral Proteins.
Explanation: Ion channels span the lipid bilayer and are permanently embedded, making them integral membrane proteins.
Incorrect Answers:
A. Receptor Proteins — These can transmit signals but are not necessarily ion channels.
C. Peripheral Proteins — These are attached to only one side of the membrane and do not form channels.
D. Glycoproteins — These play a role in cell recognition, not necessarily transport.
The diffusion of substances within a solution tends to move those substances (BLANK) their (BLANK) gradient.
A. Up; Electrical.
B. Up; Electrochemical.
C. Down; Pressure.
D. Down; Concentration.
Correct Answer: D. Down; Concentration.
Explanation: Substances move from an area of higher to lower concentration without energy input — that’s diffusion.
Incorrect Answers:
A. Up; Electrical — Diffusion does not move substances against their gradient.
B. Up; Electrochemical — Passive processes like diffusion do not work “up” a gradient.
C. Down; Pressure — Pressure gradients apply to filtration, not diffusion.
Ion pumps and phagocytosis are both examples of (BLANK).
A. Endocytosis.
B. Passive Transport.
C. Active Transport.
D. Facilitated Diffusion.
C. Active Transport.
Explanation: Both processes require energy — ion pumps use ATP to move ions, and phagocytosis requires energy to engulf particles.
Incorrect Answers:
A. Endocytosis — Applies to phagocytosis but not ion pumps.
B. Passive Transport — This does not require energy — unlike both examples here.
D. Facilitated Diffusion — Uses membrane proteins but doesn’t consume energy.
Choose the answer that best completes the following analogy: Diffusion is to (BLANK) as endocytosis is to (BLANK).
A. Filtration; Phagocytosis.
B. Osmosis; Pinocytosis.
C. Solutes; Fluid.
D. Gradient; Chemical Energy.
D. Gradient; Chemical Energy.
Explanation: Diffusion is passive and driven by a gradient, while endocytosis is active and powered by energy.
Incorrect Answers:
A. Filtration; Phagocytosis — Filtration is pressure-driven, not a passive chemical gradient.
B. Osmosis; Pinocytosis — Osmosis is a form of diffusion, but the analogy doesn’t match the mechanism-based structure.
C. Solutes; Fluid — Describes the materials involved, not the process driving them.
Choose the term that best completes the following analogy: Cytoplasm is to cytosol as a swimming pool containing chlorine and flotation toys is to (BLANK).
A. The Walls Of The Pool.
B. The Chlorine.
C. The Flotation Toys.
D. The Water.
D. The Water.
Explanation: Cytosol is the fluid component of cytoplasm, just like water is the fluid component in a swimming pool.
Incorrect Answers:
A. The Walls Of The Pool — These represent structure/boundary, more like the cell membrane.
B. The Chlorine — This represents dissolved substances, not the fluid medium itself.
C. The Flotation Toys — These are like organelles — parts of the cytoplasm, not the cytosol.
The rough ER has its name due to what associated structures?
A. Golgi Apparatus.
B. Ribosomes.
C. Lysosomes.
D. Proteins.
B. Ribosomes.
Explanation: The ‘rough’ appearance of the rough endoplasmic reticulum (ER) is due to ribosomes attached to its surface.
Incorrect Answers:
A. Golgi Apparatus — This is a separate organelle involved in protein packaging.
C. Lysosomes — These contain digestive enzymes and are not attached to the ER.
D. Proteins — While the ER helps produce proteins, they don’t create the ‘rough’ texture.
Which of the following is a function of the rough ER?
A. Production Of Proteins.
B. Detoxification Of Certain Substances.
C. Synthesis Of Steroid Hormones.
D. Regulation Of Intracellular Calcium Concentration.
A. Production Of Proteins.
Explanation: The rough ER synthesizes proteins, especially those destined for membranes or export.
Incorrect Answers:
B. Detoxification Of Certain Substances — This is a function of the smooth ER.
C. Synthesis Of Steroid Hormones — Also a function of the smooth ER.
D. Regulation Of Intracellular Calcium Concentration — Primarily managed by the smooth ER in muscle cells.
Which of the following is a feature common to all three components of the cytoskeleton?
A. They All Serve To Scaffold The Organelles Within The Cell.
B. They Are All Characterized By Roughly The Same Diameter.
C. They Are All Polymers Of Protein Subunits.
D. They All Help The Cell Resist Compression And Tension.
C. They Are All Polymers Of Protein Subunits.
Explanation: Microfilaments, intermediate filaments, and microtubules are all made of repeating protein subunits.
Incorrect Answers:
A. Scaffold The Organelles — Microfilaments play a lesser role in scaffolding compared to others.
B. Same Diameter — They vary significantly in diameter.
D. Resist Compression And Tension — Not all cytoskeletal elements do both.
Which of the following organelles produces large quantities of ATP when both glucose and oxygen are available to the cell?
A. Mitochondria.
B. Peroxisomes.
C. Lysosomes.
D. ER.
A. Mitochondria.
Explanation: Mitochondria are the site of aerobic respiration, generating large amounts of ATP.
Incorrect Answers:
B. Peroxisomes — Involved in fatty acid breakdown, not ATP production.
C. Lysosomes — Break down waste but don’t make ATP.
D. ER — Synthesizes proteins/lipids but doesn’t produce ATP.
The nucleus and mitochondria share which of the following features?
A. Protein-Lined Membrane Pores.
B. A Double Cell Membrane.
C. The Synthesis Of Ribosomes.
D. The Production Of Cellular Energy.
B. A Double Cell Membrane.
Explanation: Both the nucleus and mitochondria are enclosed by double membranes.
Incorrect Answers:
A. Protein-Lined Membrane Pores — Found in the nucleus but not mitochondria.
C. Synthesis Of Ribosomes — Occurs in the nucleolus, not mitochondria.
D. Production Of Cellular Energy — Only mitochondria perform this.
Which of the following structures could be found within the nucleolus?
A. Chromatin.
B. Histones.
C. Ribosomes.
D. Nucleosomes.
C. Ribosomes.
Explanation: The nucleolus is where rRNA is made and ribosome assembly begins.
Incorrect Answers:
A. Chromatin — Found in the nucleus but not the nucleolus specifically.
B. Histones — These bind DNA in chromatin, not part of nucleolar function.
D. Nucleosomes — Structural units of chromatin, not part of the nucleolus.
Which of the following sequences on a DNA molecule would be complementary to GCTTATAT?
A. TAGGCGCG.
B. ATCCGCGC.
C. CGAATATA.
D. TGCCTCTC.
C. CGAATATA.
Explanation: DNA base pairing: G–C and A–T. Complement of GCTTATAT is CGAATATA.
Incorrect Answers:
A. TAGGCGCG — Incorrect base pairing.
B. ATCCGCGC — Incorrect sequence and base pair mismatch.
D. TGCCTCTC — Does not correspond with correct pairing rules.
Place the following structures in order from least to most complex organization: chromatin, nucleosome, DNA, chromosome.
A. DNA, Nucleosome, Chromatin, Chromosome.
B. Nucleosome, DNA, Chromosome, Chromatin.
C. DNA, Chromatin, Nucleosome, Chromosome.
D. Nucleosome, Chromatin, DNA, Chromosome.
A. DNA, Nucleosome, Chromatin, Chromosome.
Explanation: DNA is the simplest. It wraps around histones to form nucleosomes → nucleosomes form chromatin → chromatin condenses into chromosomes.
Incorrect Answers:
B, C, D — All place the components in incorrect hierarchical or structural order.
Which of the following is part of the elongation step of DNA synthesis?
A. Pulling Apart The Two DNA Strands.
B. Attaching Complementary Nucleotides To The Template Strand.
C. Untwisting The DNA Helix.
D. None Of The Above.
B. Attaching Complementary Nucleotides To The Template Strand.
Explanation: Elongation is the stage where DNA polymerase adds nucleotides to form the new strand.
Incorrect Answers:
A. Pulling Apart Strands — Part of initiation.
C. Untwisting The Helix — Also initiation.
D. None Of The Above — Incorrect because B is correct.
Which of the following is not a difference between DNA and RNA?
A. DNA Contains Thymine Whereas RNA Contains Uracil.
B. DNA Contains Deoxyribose And RNA Contains Ribose.
C. DNA Contains Alternating Sugar-Phosphate Molecules Whereas RNA Does Not Contain Sugars.
D. RNA Is Single Stranded And DNA Is Double Stranded.
C. DNA Contains Alternating Sugar-Phosphate Molecules Whereas RNA Does Not Contain Sugars.
Explanation: Both DNA and RNA have sugar-phosphate backbones; RNA does contain sugars (ribose).
Incorrect Answers:
A. Thymine vs. Uracil — True difference.
B. Deoxyribose vs. Ribose — Accurate difference.
D. Single vs. Double Strand — Accurate structural difference.
Transcription and translation take place in the (BLANK) and (BLANK), respectively.
A. Nucleus; Cytoplasm.
B. Nucleolus; Nucleus.
C. Nucleolus; Cytoplasm.
D. Cytoplasm; Nucleus.
A. Nucleus; Cytoplasm.
Explanation: Transcription occurs in the nucleus where DNA is converted into mRNA. Translation occurs in the cytoplasm, where ribosomes use the mRNA to synthesize proteins.
Incorrect Answers:
B. Nucleolus; Nucleus — The nucleolus makes rRNA, not where transcription occurs.
C. Nucleolus; Cytoplasm — Transcription is in the nucleus, not the nucleolus.
D. Cytoplasm; Nucleus — This reverses the actual process order.
How many “letters” of an RNA molecule, in sequence, does it take to provide the code for a single amino acid?
A. 1.
B. 2.
C. 3.
D. 4.
C. 3.
Explanation: A sequence of three RNA bases (a codon) codes for one amino acid.
Incorrect Answers:
A. 1 — A single base cannot code for an amino acid.
B. 2 — Two bases are insufficient to encode all 20 amino acids.
D. 4 — Codons are three bases, not four.
Which of the following is not made out of RNA?
A. The Carriers That Shuffle Amino Acids To A Growing Polypeptide Strand.
B. The Ribosome.
C. The Messenger Molecule That Provides The Code For Protein Synthesis.
D. The Intron.
D. The Intron.
Explanation: Introns are non-coding segments of DNA. Though they are transcribed into RNA, they are removed and not part of the final functional RNA molecule.
Incorrect Answers:
A. The Carriers (tRNA) — These are RNA molecules.
B. The Ribosome — Ribosomes are partly made of rRNA.
C. The Messenger Molecule (mRNA) — This is RNA.
Which of the following phases is characterized by preparation for DNA synthesis?
A. G0.
B. G1.
C. G2.
D. S.
B. G1.
Explanation: G1 is the first ‘gap’ phase where the cell grows and prepares for DNA replication in the upcoming S phase.
Incorrect Answers:
A. G0 — A resting phase with no cell cycle activity.
C. G2 — Occurs after DNA synthesis and prepares for mitosis.
D. S — This is when DNA synthesis actually occurs, not preparation for it.
A mutation in the gene for a cyclin protein might result in which of the following?
A. A Cell With Additional Genetic Material Than Normal.
B. Cancer.
C. A Cell With Less Genetic Material Than Normal.
D. Any Of The Above.
D. Any Of The Above.
Explanation: Cyclins regulate cell cycle checkpoints. A mutation could lead to improper DNA replication, uncontrolled division (cancer), or incorrect segregation of chromosomes.
Incorrect Answers:
A. A Cell With Additional Genetic Material — Possible outcome of replication errors.
B. Cancer — Cyclin mutation can lead to loss of cell cycle control.
C. A Cell With Less Genetic Material — May result from improper chromosome segregation.
What is a primary function of tumor suppressor genes?
A. Stop All Cells From Dividing.
B. Stop Certain Cells From Dividing.
C. Help Oncogenes Produce Oncoproteins.
D. Allow The Cell To Skip Certain Phases Of The Cell Cycle.
B. Stop Certain Cells From Dividing.
Explanation: Tumor suppressor genes prevent the division of cells that may be damaged or mutated.
Incorrect Answers:
A. Stop All Cells From Dividing — That would halt growth and repair entirely.
C. Help Oncogenes Produce Oncoproteins — This is the opposite of their role.
D. Allow The Cell To Skip Certain Phases — That’s a harmful outcome of mutation, not a normal function.
Arrange the following terms in order of increasing specialization: oligopotency, pleuripotency, unipotency, multipotency.
A. Multipotency, Pleuripotency, Oligopotency, Unipotency.
B. Pleuripotency, Oligopotency, Multipotency, Unipotency.
C. Oligopotency, Pleuripotency, Unipotency, Multipotency.
D. Pleuripotency, Multipotency, Oligopotency, Unipotency.
D. Pleuripotency, Multipotency, Oligopotency, Unipotency.
Explanation: This sequence moves from least to most specialized: pluripotent cells can become almost any cell, while unipotent can only become one specific type.
Incorrect Answers:
A–C — These place one or more stages in the wrong order of specialization.
Which type of stem cell gives rise to red and white blood cells?
A. Endothelial.
B. Epithelial.
C. Hematopoietic.
D. Mesenchymal.
C. Hematopoietic.
Explanation: Hematopoietic stem cells are multipotent cells in bone marrow that give rise to all types of blood cells.
Incorrect Answers:
A. Endothelial — Form the lining of blood vessels.
B. Epithelial — Form skin and mucosal layers.
D. Mesenchymal — Can become bone, cartilage, or fat, but not blood cells.
What multipotent stem cells from children are sometimes banked by parents?
A. Fetal Stem Cells.
B. Embryonic Stem Cells.
C. Cells From The Umbilical Cord And From Baby Teeth.
D. Hematopoietic Stem Cells From Red And White Blood Cells.
C. Cells From The Umbilical Cord And From Baby Teeth.
Explanation: These are common sources of banked stem cells due to their accessibility and multipotency.
Incorrect Answers:
A. Fetal Stem Cells — Less commonly banked and more ethically complex.
B. Embryonic Stem Cells — Not typically stored privately due to legal and ethical reasons.
D. Hematopoietic Stem Cells — These are the type of stem cell often stored, but the source (C) is more precise.
Which of the following are not one of the main types of RNA involved in protein synthesis?
A) tRNA.
B) fRNA.
C) rRNA.
D) mRNA.
B) fRNA.
Explanation: fRNA is not one of the main types of RNA involved in protein synthesis. The primary types of RNA in this process are messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA), which play essential roles in transcription and translation.
What type of diffusion is of a substance with the aid of a membrane protein?
A) ATP diffusion.
B) Facilitated diffusion.
C) Enunciated diffusion.
D) Simple diffusion.
B) Facilitated diffusion.
Explanation: Facilitated diffusion is a type of passive transport in which a substance moves across a cell membrane with the help of a membrane protein. This process allows molecules that cannot directly pass through the lipid bilayer, such as ions or larger polar molecules, to enter or exit the cell without requiring energy.
What is the third stage of mitosis (and meiosis), during which sister chromatids separate into two new nuclear regions of a dividing cell?
A) Anaphase.
B) Prophase.
C) Metaphase.
D) Telophase.
A) Anaphase.
Explanation: Anaphase is the third stage of mitosis (and meiosis) in which sister chromatids are pulled apart by spindle fibers and move toward opposite poles of the cell. Mitosis begins with prophase, where chromatin condenses into chromosomes and the spindle apparatus forms. In metaphase, chromosomes align at the cell’s equatorial plate. Anaphase follows, separating sister chromatids, and finally, telophase restores two new nuclear regions as the cell prepares for cytokinesis.
What is the term used to describe the “skeleton” of a cell that is formed by rod-like proteins that support the cell’s shape and provide, among other functions, locomotive abilities?
A) Cytoplasm.
B) Cytosol.
C) Nuclear envelope.
D) Cytoskeleton.
D) Cytoskeleton.
Explanation: The cytoskeleton is a network of rod-like protein structures that provide structural support, maintain cell shape, and facilitate movement. It consists of microfilaments, intermediate filaments, and microtubules, which also aid in intracellular transport and cell division.
What term describes the condition of being committed to a single specialized cell type?
A) Pluripotent.
B) Multiplotent.
C) Unipotent.
D) Totipotent.
C) Unipotent
Explanation: Unipotent describes a cell that is committed to differentiating into only one specialized cell type. Unlike totipotent, pluripotent, or multipotent cells, which can develop into multiple cell types, unipotent cells have the most limited differentiation potential, typically maintaining and regenerating specific tissues.
Which cellular organelle functions in protein synthesis?
A) Nucleus.
B) Ribosome.
C) Golgi apparatus.
D) Smooth ER.
B) Ribosome
Explanation: Ribosomes are the cellular organelles responsible for protein synthesis. They translate messenger RNA (mRNA) into polypeptide chains by linking amino acids together, either freely in the cytoplasm or attached to the rough endoplasmic reticulum.
