Cell Ultrastructure Overview
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Questions and Answers

What is the primary function of the centrosome?

  • Organizes microtubules (correct)
  • Contains digestive enzymes
  • Synthesizes lipids
  • Forms complex oligosaccharides

    • Lysosomes are primarily responsible for lipid synthesis.

    False

    What is the role of proteases in the Trans-Golgi?

    Proteolysis of peptides into active forms

    The ____________ junctions seal neighboring cells together to prevent leakage.

    <p>tight</p> Signup and view all the answers

    Match the following cell structures with their functions:

    <p>Centrosome = Organizes microtubules Rough ER = Synthesizes proteins Smooth ER = Site of lipid synthesis Lysosomes = Waste disposal system</p> Signup and view all the answers

    What is the primary characteristic of peptide hormones?

    <p>Stored in cells and released when needed</p> Signup and view all the answers

    Osmosis is the movement of solutes from areas of high concentration to areas of low concentration.

    <p>False</p> Signup and view all the answers

    What hormone is primarily associated with regulating water balance in the body?

    <p>ADH</p> Signup and view all the answers

    Steroid hormones require __________ proteins to travel in the bloodstream.

    <p>transport</p> Signup and view all the answers

    Match the term with its correct definition:

    <p>Osmolality = Concentration of solutes in plasma per kg of solvent Hypernatremia = Low sodium concentration in the blood Oncotic pressure = Pressure exerted by proteins that pulls fluid into a solution Hypoalbuminemia = Lower oncotic pressure due to decreased albumin levels</p> Signup and view all the answers

    Which of the following hormones is not classified as a peptide hormone?

    <p>Testosterone</p> Signup and view all the answers

    Hyponatremia refers to an excess of sodium in the blood.

    <p>False</p> Signup and view all the answers

    Which of the following is considered the most potent Reactive Oxygen Species (ROS)?

    <p>Hydroxyl Radical</p> Signup and view all the answers

    Neutrophils and monocytes use myeloperoxidase to convert hydrogen peroxide into superoxide.

    <p>False</p> Signup and view all the answers

    What role does the hydroxyl radical play in free radical reactions?

    <p>Initiator of chain reactions that form lipid peroxides and organic radicals</p> Signup and view all the answers

    Reactive Oxygen Species are linked to __________, homeostasis, and some cancers.

    <p>ageing</p> Signup and view all the answers

    Match the following Reactive Oxygen Species with their characteristics:

    <p>Superoxide = A precursor to hydrogen peroxide Hydrogen Peroxide = Can be converted into hypochlorite Hydroxyl Radical = Most potent of ROS Hypochlorite = Produced by combining H2O2 and Cl-</p> Signup and view all the answers

    What is primarily produced during increased beta oxidation?

    <p>Acetyl CoA</p> Signup and view all the answers

    Which Reactive Oxygen Species can be lipid soluble and cause damage away from the site of formation?

    <p>Hydroxyl Radical</p> Signup and view all the answers

    Ketone bodies can only be utilized by liver tissues.

    <p>False</p> Signup and view all the answers

    The absence or impairment of NADPH oxidase can lead to chronic granulomatous disease.

    <p>True</p> Signup and view all the answers

    What happens to the production of β-hydroxybutyrate when there is untreated insulin-dependent diabetes mellitus?

    <p>It increases.</p> Signup and view all the answers

    What external factors can contribute to the generation of Reactive Oxygen Species?

    <p>UV radiation, tobacco, and drugs</p> Signup and view all the answers

    Superoxide is often reduced to __________, which can subsequently lead to other reactive oxygen species.

    <p>hydrogen peroxide</p> Signup and view all the answers

    The process that describes the sudden release of reactive oxygen species by immune cells is called __________.

    <p>Respiratory Burst</p> Signup and view all the answers

    Match the following ketone bodies with their chemical forms:

    <p>Acetoacetate = C4H6O3 β-hydroxybutyrate = C4H8O3 Acetone = C3H6O Acetoacetyl CoA = C4H6O-CoA</p> Signup and view all the answers

    Which of the following ketone bodies cannot be used as a fuel by most tissues?

    <p>Acetone</p> Signup and view all the answers

    The Haber-Weiss Cycle contributes to the formation of superoxide in the immune response.

    <p>True</p> Signup and view all the answers

    Name two ketone bodies that can enter the bloodstream.

    <p>Acetoacetate and β-hydroxybutyrate.</p> Signup and view all the answers

    Oxygen is highly reactive and forms free radicals through __________ respiration.

    <p>cellular</p> Signup and view all the answers

    Study Notes

    IMMS

    • IMMS is an abbreviation, likely referring to a subject or program. Insufficient context provided.

    Cell Ultrastructure 1

    • Cells are highly structured.
    • A diagram shows various organelles and components within a typical eukaryotic cell.
    • Organelles include (but are not limited to) nucleus, nucleolus, ribosomes, rough and smooth endoplasmic reticulum, Golgi apparatus, Golgi vesicles, cytoplasm, vacuoles, mitochondria, plasma membrane, centrosome, microfilaments, microtubules, lysosomes and peroxisomes.

    Cell Ultrastructure 2

    • Nucleus: Largest membrane-bound organelle; stores and transmits genetic information; synthesizes proteins determining cell structure and function.
    • Nuclear Envelope: Double membrane with nuclear pores allowing RNA movement.
    • Chromatin: DNA and proteins; condenses into chromosomes during cell division.
    • Golgi Apparatus: Modifies and processes macromolecules synthesized in the ER.
    • Rough ER: Site of protein synthesis; studded with ribosomes.
    • Ribosomes: Two subunits; involved in protein synthesis.
    • Mitochondria: Produce ATP; consist of outer and inner membranes, matrix (Krebs cycle) and intermembrane space (nucleotide synthesis).
    • Vesicles: Small membrane-bound organelles, various types (cellular surface derived, Golgi-derived, ER-derived). Transport and store materials.
    • Vacuole: Membrane-enclosed chamber; stores and excretes materials.
    • Cytoplasm: Site of glycolysis; comprises cytosol, organelles, and inclusions.
    • Nucleolus: Located within the nucleus; produces ribosomal RNA; no membrane.
    • Cell Junctions: Connect cells, including tight junctions, adherens, desmosomes, gap junctions, and hemi-desmosomes.
    • Plasma Membrane: Double layer of phospholipids; controls passage of molecules (endo/exocytosis), acts as a selective barrier.

    Molecular Building Blocks

    • Atoms: Basic building blocks of macromolecules; include carbon, hydrogen, oxygen, nitrogen, sulfur, and phosphorus.
    • Macromolecules: Larger, complex molecules; formed from simple molecules (sugars, lipids, amino acids). Include haemoglobin, DNA, glycogen, rhodopsin, and collagen.
    • Carbohydrates: Monosaccharides, disaccharides, oligosaccharides, and polysaccharides; composed of sugars joined by glycosidic bonds. Examples include glycogen, formed of glucose residues.
    • Nucleotides: Composed of nitrogenous base, sugar, and phosphate; building blocks of nucleic acids; source of energy (phosphate bonds).
    • Lipids: Triglycerides are three fatty acids bound to glycerol. Fatty acid chains are typically hydrophobic; unsaturated fatty acids have double bonds (commonly cis).
    • Proteins: Amino acids linked by peptide bonds; polypeptide chains fold into 3D structures (primary, secondary, tertiary, and quaternary); structure defines function.
    • Amino Acids: Building blocks of proteins; contain amino group, carboxyl group, and specific side chain; usually L-form.
    • Peptide Bonds: Formed by condensation reactions (water released); highly stable; partial double bonds.
    • Enzymes: Catalysts; provide alternative reaction pathways with lower activation energy; speed up reactions.

    Communication and Homeostasis

    • Communication Types: Autocrine (self-signaling), paracrine (local signaling), endocrine (hormonal), exocrine (external secretions).
    • Body Fluid Compartments: Total volume (approximately 42L ECF, 28L ICF)
    • Water Balance: Intake (drinking, diet, IV); Loss (kidneys, insensible losses, faeces); Regulation (ADH, aldosterone, ANP).
    • Dehydration: Causes (deprivation, vomiting, diarrhoea); Consequences (thirst, inelastic skin, sunken eyes, raised haematocrit, weight loss, hypotension).
    • Water Excess: Causes (excessive intake, decreased water loss); Consequences (hyponatremia, cerebral overperfusion).
    • Hormones: Chemical messengers; three types: peptide, steroid, and amino-acid derivative.
    • Solution/Water Definitions
    • Osmosis: Movement of solvent through a semi-permeable membrane.
    • Osmolarity/Osmolality: Solute concentration in a solution (per kg of solution/solvent, respectively).
      • Osmotic Pressure: Pressure to prevent osmosis (pure solvent).
      • Oncotic Pressure: Osmotic pressure due to proteins (draws water in).
      • Hydrostatic Pressure: Pressure difference across a membrane (driving water into/out of capillaries).

    DNA

    • Structure and Location: Double helix with complementary base pairing; found in nucleus and mitochondria; coiled around histone proteins to form nucleosomes, supercoils and chromosomes.
    • Karyotype: Chromosomes arranged by size; 46 human chromosomes (22 pairs autosomes, 1 pair sex chromosomes).
    • DNA Functions: Storing genetic information; regulating transcription and protein synthesis.
    • Structure of Nucleic Acids: Nucleotides; free phosphate groups.
    • Mutations: Changes in DNA sequence (deletions, duplications, point mutations, expansions of trinucleotide).

    Replication, Transcription, and Translation

    • Replication: Creating two identical copies of DNA; involves initiation, elongation, RNA primer synthesis, and termination (DNA polymerase, ligase, primase).
    • Transcription: Synthesizing mRNA from DNA; involves preparation, production, termination, and modification (RNA polymerase, topoisomerase, helicase).
    • Translation: Synthesizing proteins from mRNA; involves mRNA binding to ribosomes, tRNA (with amino acids) binding to codons, peptide bond formation, and termination (ribosomes, tRNA, enzymes).

    Meiosis and Mitosis

    • Mitosis
    • Results in genetically identical diploid cells.
    • One division.
    • Somatic cell division or gamete formation.
    • Stages include Interphase, Prophase, Prometaphase, Metaphase, Anaphase, Telophase, and Cytokinesis
    • Meiosis
    • Results in genetically different haploid gametes.
    • Two divisions
      • Stages include Interphase, Prophase I, Metaphase I, Anaphase I, Telophase I, Cytokinesis I, Prophase II, Metaphase II, Anaphase II, Telophase II and Cytokinesis II

    Inheritance and Disease

    • Mendelian Inheritance: Homozygous (identical alleles), Heterozygous (different alleles). Types include Autosomal Dominant (one affected allele), Autosomal Recessive (two affected alleles), X-linked (carried on X chromosomes), and Mitochondrial (inherited maternally).
    • Disease Categories: Autosomal recessive, autosomal dominant, X-linked recessive, X-linked dominant, chromosomal, multifactorial, environmental
    • Causes of Disease: Combination of genetic and environmental factors.
      • Numerical and structural variations of chromosomes are chromosomal diseases.

    Energy Production

    • Glycolysis: Occurs in the cytosol; produces 4 ATP, 2 NADH (enters electron transport chain).
    • Krebs Cycle: Occurs in the mitochondrial matrix; produces ATP and electron carriers (NADH and FADH2).
    • Electron Transport Chain: Occurs on the inner mitochondrial membrane; generates ATP through oxidative phosphorylation.
    • Beta Oxidation: Breaking down fatty acids into acetyl CoA; generates NADH and FADH2 for ATP production.
    • Ketone Synthesis: Production and utilisation of ketone bodies (alternative fuel source) when carbohydrate levels are low.

    Fatty Acids Metabolism

    • Citrate Shuttle: Moving acetyl-CoA out of the mitochondria for fatty acid synthesis.
    • Carnitine Shuttle: Transporting long-chain fatty acyl-CoA into mitochondria for beta-oxidation.
    • Beta-Oxidation: Breaking down fatty acids into acetyl-CoA, producing NADH and FADH2 (used in electron transport chain to generate ATP).
    • Ketone Bodies: Molecules produced when acetyl-CoA outpaces the Krebs cycle; used as a fuel source in preference to carbohydrates.

    Oxygen Toxicity

    • Reactive Oxygen Species (ROS): Highly reactive oxygen-containing compounds contributing to aging, homeostasis, and certain cancers. Examples include superoxide, hydrogen peroxide, and hydroxyl radical.
    • Haber-Weiss Cycle: Set of reactions involving transition metals and generate hydroxyl radicals from oxygen and hydrogen peroxide.
    • Fenton Reaction: Reaction involving hydrogen peroxide and a transition metal (e.g., iron) to generate hydroxyl radicals.
    • Cellular Damage: ROS damage proteins, lipids, carbohydrates, and nucleic acids leading to cell membrane damage, increased permeability (influx of calcium, water, sodium), DNA damage, with subsequent mutations.
    • Respiratory Burst: Immune response mechanism involving the generation of ROS to kill bacteria.
    • Protection Against Oxygen Toxicity: Antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase) and antioxidant vitamins (vitamin E, vitamin C).

    Acid-Base Balance

    • Definitions: Acid (proton donor), base (proton acceptor), pH (measure of H+ concentration), acidosis (low pH), alkalosis (high pH), bicarbonate, proteins.
    • Production of H+ Ions: Result of metabolism and especially CO2 release during respiration.
    • Buffer Systems: Bicarbonate, phosphate, proteins (including hemoglobin) to regulate pH shifts.
    • Henderson-Hasselbalch Equation: Describes the relationship between pH, pKa, and the concentrations of acid and conjugate base.
    • Davenport Chart/Diagram: Graphical representation of buffer systems & how they work as a dynamic relationship and how these are related to compensation in the respiratory and renal systems.
    • Compensation: Respiratory and renal systems compensate for deviations from normal pH using the HCO3- and PCO2 systems.
    • Anion Gap: Difference in serum concentrations of cations and anions; can indicate certain metabolic imbalances.

    Other

    • Insufficient context; the information may relate to other subjects.

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