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Questions and Answers
What is the primary function of the lysosomes?
What is the primary function of the lysosomes?
Which structure is primarily involved in the synthesis of ribosomal RNA?
Which structure is primarily involved in the synthesis of ribosomal RNA?
What is the role of microtubules in the cell?
What is the role of microtubules in the cell?
Which organelle is involved in ATP production?
Which organelle is involved in ATP production?
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What do kinesin motor proteins mediate?
What do kinesin motor proteins mediate?
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What is the main function of epithelial tissue?
What is the main function of epithelial tissue?
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Which of the following best describes the smooth endoplasmic reticulum (SER)?
Which of the following best describes the smooth endoplasmic reticulum (SER)?
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Which proteins are found in the intermediate filaments of the cytoskeleton?
Which proteins are found in the intermediate filaments of the cytoskeleton?
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What type of metabolism does an obligate anaerobe perform?
What type of metabolism does an obligate anaerobe perform?
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Which feature distinguishes Gram-positive bacteria from Gram-negative bacteria?
Which feature distinguishes Gram-positive bacteria from Gram-negative bacteria?
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What is the main function of plasmids in prokaryotes?
What is the main function of plasmids in prokaryotes?
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Which process describes the transfer of genetic material from one bacterium to another via a bacteriophage?
Which process describes the transfer of genetic material from one bacterium to another via a bacteriophage?
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Which characteristic is true for both Archaea and Eukaryotes?
Which characteristic is true for both Archaea and Eukaryotes?
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Which of the following distinguishes eukaryotic cells from prokaryotic cells?
Which of the following distinguishes eukaryotic cells from prokaryotic cells?
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During glycolysis, what is the primary end product generated?
During glycolysis, what is the primary end product generated?
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In the lysogenic cycle, what happens to the viral DNA in the host cell?
In the lysogenic cycle, what happens to the viral DNA in the host cell?
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What cellular structure is involved in chemical signaling and signal transduction?
What cellular structure is involved in chemical signaling and signal transduction?
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Which of the following is true regarding retroviruses?
Which of the following is true regarding retroviruses?
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Which statement best describes transposons?
Which statement best describes transposons?
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During which phase of the cell cycle does DNA replication occur?
During which phase of the cell cycle does DNA replication occur?
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What role do cyclins play in the cell cycle?
What role do cyclins play in the cell cycle?
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What is the primary function of the rough endoplasmic reticulum (ER)?
What is the primary function of the rough endoplasmic reticulum (ER)?
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Study Notes
Eukaryotic Organelles
- Nucleus: Organizes DNA into chromosomes, houses nuclear pores, site of transcription (DNA → RNA).
- Nucleolus: Subsection of the nucleus where ribosomal RNA (rRNA) is produced.
- Mitochondria: Site of metabolic processes and ATP production. Inner membrane folds (cristae) contain enzymes for the electron transport chain (ETC). Reproduce independently via binary fission. Can initiate apoptosis.
- Lysosomes: Contain hydrolytic enzymes for substrate breakdown. Enzyme release leads to autolysis (cell self-destruction).
- Endoplasmic Reticulum (ER): Series of interconnected membranes continuous with the nuclear envelope. Synthesizes lipids and modifies proteins.
- Rough ER (RER): Studded with ribosomes; site of protein translation for secretion.
- Smooth ER (SER): Synthesizes lipids, detoxifies, stores calcium ions.
- Golgi Apparatus: Stacked membrane-bound sacs; modifies, packages, and directs cellular products to specific locations.
- Peroxisomes: Contain hydrogen peroxide; break down long-chain fatty acids (beta-oxidation). Involved in phospholipid synthesis, and the pentose phosphate pathway.
Cytoskeleton Proteins
- Microfilaments: Composed of actin; provide structural support, cause muscle contractions via interactions with myosin, form the cleavage furrow during cytokinesis.
- Microtubules: Composed of tubulin; create pathways for motor proteins (kinesin and dynein). Form cilia and flagella, and are part of the mitotic spindle's structure; centrioles (in centrosomes) organize microtubules.
- Intermediate Filaments: Maintain and strengthen the cytoskeleton, anchor organelles, and facilitate cell-cell adhesion. Examples include keratin and desmin.
Microtubular Motor Proteins
- Kinesin: Facilitates anterograde transport (away from the nucleus).
- Dynein: Facilitates retrograde transport (toward the nucleus).
Epithelial and Connective Tissues
- Epithelial Tissue: Covers/lines the body; functions in absorption, secretion, sensation, immunity, desiccation prevention. Parenchyma refers to the epithelial component of an organ (the functional parts).
- Connective Tissue: Supports the body; provides a scaffold for epithelial cells. The stroma refers to the connective tissue component of an organ (the supportive structure). Examples: bone, cartilage, tendons, ligaments, adipose tissue, blood.
Prokaryotic Cells (Bacteria & Archaea)
- Prokaryotic Characteristics: Lacks membrane-bound organelles, single circular DNA, divides via binary fission. Electron transport chain (ETC) occurs on the cell membrane.
- Gram-Positive Bacteria: Thick peptidoglycan cell wall, lipoteichoic acid; stain purple in Gram staining.
- Gram-Negative Bacteria: Thin peptidoglycan layer, outer membrane with phospholipids and lipopolysaccharides; stain pink-red in Gram staining.
- Aerobes, Anaerobes, Facultative Anaerobes, Aerotolerant Anaerobes: Classification based on oxygen requirement for metabolism.
Prokaryotic Genetics
- Plasmids: Extrachromosomal DNA; may carry antibiotic resistance or virulence genes. Episomes can integrate into the bacterial chromosome.
- Transposons: Genetic elements that can move (insert or remove) themselves within the genome (found in both prokaryotes and eukaryotes).
- Bacterial Genetic Recombination Methods:
- Transformation: Uptake of environmental DNA.
- Conjugation: Transfer of DNA between bacteria via a conjugation bridge (sex pilus), often involving plasmids with sex factors in the donor.
- Transduction: Transfer of DNA using a bacteriophage as a vector.
Viruses and Subviral Particles
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Viral Genomes: Can be DNA or RNA, single-stranded or double-stranded.
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Single-Stranded RNA Viruses: Categories include positive-sense (directly translated) and negative-sense (requires complementary strand synthesis by RNA replicase before translation).
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Retroviruses: Single-stranded RNA genomes; use reverse transcriptase to synthesize DNA from RNA, which is then integrated into the host genome.
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RNA Polymerase: Enzyme that synthesizes RNA from DNA during transcription.
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Bacteriophage Life Cycles:
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Lytic Cycle: Virus produces new virions (viral particles), leading to cell lysis; virulent bacteria.
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Lysogenic Cycle: Virus integrates into host genome (provirus or prophage) and replicates with the host cell; provirus may leave the genome.
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Prions: Infectious proteins that cause misfolding of other proteins, impacting solubility and degradation.
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Viroids: Plant pathogens, small circular RNA molecules that can turn off genes and cause metabolic/structural changes.
Prokaryotes vs. Archaea vs. Eukaryotes vs. Viruses
- Archaea: Similar to Bacteria (prokaryotic features) but also similar to eukaryotes (starting translation with methionine, similar RNA polymerases).
- Bacteria, Archaea, Eukaryotes, Viruses: Comparison table provided distinguishing their key characteristics (cell type, nucleus, organelles, cell wall, cellular division, chromosome type, cell membrane, and ribosomes).
Other Cellular Processes
- Cell Membrane: Phospholipid bilayer, proteins, cholesterol, carbohydrates; passive and active transport mechanisms (diffusion, osmosis, facilitated diffusion, primary/secondary active transport). Endocytosis (phagocytosis, pinocytosis), exocytosis.
- Cell Cycle: Stages (G1, S, G2, M phase) including checkpoints, cyclins, and cyclin-dependent kinases (CDKs). Phases of mitosis and meiosis comparison.
- Signal Transduction: Ligand binding to receptors (e.g., G-protein coupled receptors, receptor tyrosine kinases), second messengers (e.g., cAMP, calcium ions, IP3), signal amplification, differing types of cellular signaling (autocrine, paracrine, endocrine, juxtacrine).
- Metabolism: Glycolysis, citric acid cycle (Krebs cycle), oxidative phosphorylation; role of electron transport chains and chemiosmosis in ATP production in mitochondria.
- Gene Expression: DNA transcription to RNA; RNA processing (splicing, capping, polyadenylation); mRNA translation to proteins (role of ribosomes, tRNAs, codons); post-translational modifications and regulation (epigenetics, enhancers, silencers).
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Description
This quiz covers the major organelles found in eukaryotic cells, including their functions and characteristics. You'll explore the roles of the nucleus, mitochondria, lysosomes, endoplasmic reticulum, and Golgi apparatus. Test your knowledge on how these organelles contribute to cellular processes and the overall function of the cell.
