Greek Roots in Biology
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Questions and Answers

What is the characteristic feature of eicosanoids in terms of their carbon chain?

  • They have a 20-carbon chain (correct)
  • They have a 10-carbon chain
  • They have a 15-carbon chain
  • They have a varying number of carbons

    • What is the term used to describe the type of signaling that eicosanoids are involved in?

  • Paracrine signaling (correct)
  • Endocrine signaling
  • Synaptic signaling
  • Autocrine signaling

    • What is the precursor molecule for eicosanoids?

  • Cholesterol
  • Arachidonic acid (correct)
  • Fatty acid
  • Sterol

    • What is the characteristic feature of sterols in terms of their molecular structure?

    <p>They are planar in shape</p> Signup and view all the answers

    What is the term used to describe lipids that contain both polar and nonpolar parts?

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

    What is the function of bile salts based on their molecular structure?

    <p>They are involved in lipid digestion</p> Signup and view all the answers

    What is the relationship between sterols and other lipids?

    <p>Sterols are a basis for other lipids</p> Signup and view all the answers

    What is the term used to describe the type of bonds found in sterols?

    <p>No rotation around the carbon bonds</p> Signup and view all the answers

    What is the immediate precursor of fatty acids in lipid synthesis?

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

    What was the reason behind the Air Ministry's claim that British pilots were eating lots of carrots during WW2?

    <p>To improve their night vision</p> Signup and view all the answers

    Where does the synthesis of longer chain fatty acids take place?

    <p>Smooth Endoplasmic Reticulum</p> Signup and view all the answers

    What is the function of vitamin D in the body?

    <p>Regulating calcium metabolism</p> Signup and view all the answers

    What is the intermediate in the synthesis of sterols from acetate?

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

    Which type of cells do not have an Endoplasmic Reticulum?

    <p>Prokaryotic cells</p> Signup and view all the answers

    What is the connection between a lack of vitamin D or calcium and a specific bone disorder?

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

    What is the medical use of vitamin K?

    <p>Countering the effects of rat poison</p> Signup and view all the answers

    What is the building block of lipids?

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

    What is the precursor molecule for vitamin D?

    <p>7-Dehydrocholesterol</p> Signup and view all the answers

    How are fatty acids built?

    <p>Two carbons at a time</p> Signup and view all the answers

    What is the enzyme responsible for making Palmitate?

    <p>Fatty acid synthase</p> Signup and view all the answers

    What is the primary function of bile salts in the digestive system?

    <p>To solubilize and absorb dietary lipids</p> Signup and view all the answers

    What is the resulting compound formed from the modification of 7-dehydrocholesterol?

    <p>1,25-Dihydroxycholecalciferol</p> Signup and view all the answers

    What is the primary function of bile salts in the digestive system?

    <p>Emulsifying fats</p> Signup and view all the answers

    What is the structure of Palmitate?

    <p>16:0</p> Signup and view all the answers

    What is the characteristic feature of amphipathic lipids?

    <p>They contain both polar and nonpolar parts</p> Signup and view all the answers

    Which type of vitamins are fat-soluble?

    <p>Vitamins A, D, E, and K</p> Signup and view all the answers

    What is the characteristic feature of amphipathic lipids?

    <p>Polar and non-polar regions</p> Signup and view all the answers

    What is the primary function of steroid hormones in the body?

    <p>To act as cellular messengers</p> Signup and view all the answers

    What is the characteristic feature of Vitamin A (Retinol)?

    <p>It is essential for vision and skin health</p> Signup and view all the answers

    What is the relationship between sterols and other lipids?

    <p>Sterols are derived from sterol molecules</p> Signup and view all the answers

    What is the function of steroid drugs?

    <p>To treat inflammatory and autoimmune disorders</p> Signup and view all the answers

    What is the primary difference between water-soluble and fat-soluble vitamins?

    <p>Their solubility in water or fat</p> Signup and view all the answers

    What is the primary function of eicosanoids in the body?

    <p>Hormone signaling</p> Signup and view all the answers

    Which type of lipid is characterized by the presence of a hydrocarbon chain and a carboxyl group?

    <p>Fatty acids</p> Signup and view all the answers

    What is the primary function of bile salts in the body?

    <p>Emulsification of fats</p> Signup and view all the answers

    Which of the following is an example of an amphipathic lipid?

    <p>Bile salts</p> Signup and view all the answers

    What is the primary function of sterol derivatives in the body?

    <p>Cell membrane structure</p> Signup and view all the answers

    Which type of lipid is responsible for the absorption of lipid-soluble vitamins?

    <p>Dietary fat</p> Signup and view all the answers

    What is the energy yield of each gram of fat when oxidized?

    <p>9 kcal</p> Signup and view all the answers

    What is the primary function of fatty acid derivatives in the body?

    <p>Hormone signaling</p> Signup and view all the answers

    What is the primary purpose of cell-cell signalling?

    <p>To communicate between cells and change gene expression</p> Signup and view all the answers

    What is the role of the responding cell in cell signalling?

    <p>To detect the signal and trigger a response</p> Signup and view all the answers

    What is the difference between paracrine and autocrine signalling?

    <p>Autocrine signalling acts on the secreting cell, while paracrine signalling acts on nearby cells</p> Signup and view all the answers

    What is the result of a cell responding to a signal?

    <p>The cell changes its gene expression</p> Signup and view all the answers

    How do some signals affect the responding cell?

    <p>By forming gradients that influence cell fate</p> Signup and view all the answers

    What is the purpose of signal transduction?

    <p>To translate the signal into changes in cell physiology or gene expression</p> Signup and view all the answers

    What is the difference between endocrine and paracrine signalling?

    <p>Endocrine signalling acts on distant cells, while paracrine signalling acts on local cells</p> Signup and view all the answers

    How does the signal enter the cell?

    <p>Through the plasma membrane</p> Signup and view all the answers

    What type of receptors are activated by signals that can pass through the plasma membrane?

    <p>Nuclear receptors</p> Signup and view all the answers

    What is the role of Hsp chaperones in nuclear receptors?

    <p>To release the receptor</p> Signup and view all the answers

    What is the result of GDP being replaced by GTP in G-protein linked receptors?

    <p>Ga dissociates from Gbg</p> Signup and view all the answers

    What is the role of type II receptors in serine/threonine kinase receptors?

    <p>To phosphorylate type I receptors</p> Signup and view all the answers

    What is the result of ligand binding to nuclear receptors?

    <p>The receptor-ligand complex moves to the nucleus</p> Signup and view all the answers

    What is the role of Ga in G-protein linked receptors?

    <p>To activate downstream 'second messengers'</p> Signup and view all the answers

    What is the result of Smads being phosphorylated in serine/threonine kinase receptors?

    <p>They move to the nucleus to act as transcription factors</p> Signup and view all the answers

    What is the characteristic of signals that activate nuclear receptors?

    <p>They can pass through the plasma membrane</p> Signup and view all the answers

    What is the primary purpose of cell-cell signalling?

    <p>To influence the behaviour of other cells</p> Signup and view all the answers

    What is the role of the responding cell in cell signalling?

    <p>To detect and respond to signals</p> Signup and view all the answers

    What is the main difference between paracrine and autocrine signalling?

    <p>The cell that receives the signal</p> Signup and view all the answers

    What is the result of a cell responding to a signal?

    <p>All of the above</p> Signup and view all the answers

    How do some signals affect the responding cell?

    <p>By forming gradients that influence cell fate</p> Signup and view all the answers

    What is the purpose of signal transduction?

    <p>To translate the signal into a cellular response</p> Signup and view all the answers

    What is the main difference between endocrine and paracrine signalling?

    <p>The distance over which the signal acts</p> Signup and view all the answers

    How do signals that can pass through the plasma membrane bind to their receptors?

    <p>Through a nuclear receptor</p> Signup and view all the answers

    What type of receptors are involved in signaling through steroids or retinoids?

    <p>Nuclear receptors</p> Signup and view all the answers

    What is the function of Hsp chaperones in nuclear receptors?

    <p>To prevent receptor activation</p> Signup and view all the answers

    What happens to the G-protein in G-protein linked receptors after ligand binding?

    <p>It releases GDP and takes up GTP</p> Signup and view all the answers

    What is the role of Smads in serine/threonine kinase receptors?

    <p>To act as transcription factors</p> Signup and view all the answers

    What is the difference between type I and type II receptors in serine/threonine kinase receptors?

    <p>Type I receptors phosphorylate type II receptors</p> Signup and view all the answers

    What is the result of G-protein activation in G-protein linked receptors?

    <p>The activation of downstream second messengers</p> Signup and view all the answers

    What is the role of Ga in G-protein linked receptors?

    <p>It dissociates from Gbg and activates downstream second messengers</p> Signup and view all the answers

    What happens to the GTP bound to the G-protein in G-protein linked receptors?

    <p>It is hydrolyzed to GDP</p> Signup and view all the answers

    Study Notes

    Lipids

    • Refers to a collection of organic molecules of varying chemical composition: fatty acids, glycerides, nonglyceride lipids, and complex lipids.
    • Includes sterol derivatives.

    Biological Functions of Lipids

    • Energy source: each gram of fat releases 9 kcal of energy.
    • Energy storage: in the form of triglycerides (TAG) in adipocytes.
    • Cell membrane structural components: phosphoglycerides, sphingolipids, and steroids make up the basic structure of all cell membranes.
    • Hormones: eicosanoids and steroid hormones.
    • Vitamins: lipid-soluble vitamins (A, D, E, and K).
    • Vitamin absorption: dietary fat serves as a carrier of lipid-soluble vitamins.
    • Protection: fats as shock absorbers.
    • Insulation: subcutaneous fat.

    Eicosanoids

    • Act as paracrine signals.
    • Derived from arachidonic acid.
    • Are drug targets.

    Sterols and Derivatives

    • Sterols are amphipathic (contain polar and nonpolar parts) and planar (flat).
    • No rotation around carbon bonds.
    • Cholesterol is a sterol derivative.
    • Bile salts: derived from cholesterol, amphipathic, and enable fat absorption.

    Synthesis of Lipids

    • Lipids are built from acetate.
    • Acetate is converted to Acetyl-Coenzyme A (Acetyl-CoA).
    • Fatty acids and sterols are made from Acetyl-CoA.
    • Fatty acids are built two carbons at a time.
    • Palmitate is the precursor of fatty acids.
    • Longer chain fatty acids are made by fatty acid elongation systems in the smooth ER.

    Steroid Hormones

    • Derived from sterol.
    • Act as cellular messengers.
    • Many drugs are steroid analogues.
    • Examples: sex hormones (e.g., progesterone) and corticosteroids.

    Vitamins

    • Water-soluble vitamins: B class (1, 2, 3, 5, 6, 7, 9, 12) and C.
    • Fat-soluble vitamins: A, D, E, and K.
    • Vitamin A (Retinol): important in skin cells and vision.
    • Vitamin D: made from 7-dehydrocholesterol, controls calcium metabolism.
    • Vitamin K: used as an antidote against rat poison and as a treatment for anticoagulant overdose.

    Cell Signalling

    • Cell signalling is the communication between cells, involving a chemical messenger (signal/ligand) released by the signalling cell.
    • The signal is detected by the responding cell (receptor), triggering intracellular reactions that influence the behaviour of the responding cell.

    Tasks of Cell Communication

    • Signal release: synthesis and excretion of the signalling molecule by the signalling cell.
    • Signal detection: interaction of signal and receptor.
    • Signal transduction: translation of detection to changes in cell physiology or gene expression.

    Types of Signals

    • Paracrine signals: act on a local set of cells.
    • Autocrine signals: act on the secreting cell itself.
    • Endocrine signals: long-range signals moving through the bloodstream.

    Signalling and Control of Gene Expression

    • Cell-cell signalling can change the repertoire of transcription factors in the responding cell, resulting in different gene expression.
    • Some signals can form gradients, and cell fate depends on signal concentration.

    Signal Entry into the Cell

    • Two strategies for signal entry:
      • The signal can pass through the plasma membrane (e.g., nuclear receptors).
      • The signal can activate a membrane receptor (e.g., G protein linked receptors, Serine/threonine kinase receptors).

    Nuclear Receptors

    • Signals are steroids or retinoids.
    • These signals can pass through the plasma membrane and encounter nuclear receptors in the cytoplasm.
    • The receptor-ligand complex then enters the nucleus to activate genes.

    Signalling through Nuclear Receptors

    • Nuclear receptors like the glucocorticoid receptor are cytoplasmic proteins.
    • In their inactive form, they are bound to Hsp chaperones.
    • Ligand binding releases the Hsp, and the receptor-ligand complex moves to the nucleus to activate the transcription of target genes.

    G-Protein Linked Receptors

    • Transmembrane receptors are linked to a G-protein.
    • Upon ligand binding, the G protein releases GDP and takes up GTP.
    • Ga dissociates from Gbg and activates downstream 'second messengers' (e.g., cAMP).
    • GTP is hydrolyzed to GDP, and Ga reassociates with Gbg.

    Serine/Threonine Kinase Receptors

    • Transmembrane receptors that bind the TGFb family of signals.
    • Ligand brings together type I and type II receptors.
    • Type II phosphorylates type I.
    • Smads become phosphorylated and move into the nucleus to act as transcription factors.

    Cell Signalling

    • Cell signalling is the communication between cells, involving a chemical messenger (signal/ligand) released by the signalling cell.
    • The signal is detected by the responding cell (receptor), triggering intracellular reactions that influence the behaviour of the responding cell.

    Tasks of Cell Communication

    • Signal release: synthesis and excretion of the signalling molecule by the signalling cell.
    • Signal detection: interaction of signal and receptor.
    • Signal transduction: translation of detection to changes in cell physiology or gene expression.

    Types of Signals

    • Paracrine signals: act on a local set of cells.
    • Autocrine signals: act on the secreting cell itself.
    • Endocrine signals: long-range signals moving through the bloodstream.

    Signalling and Control of Gene Expression

    • Cell-cell signalling can change the repertoire of transcription factors in the responding cell, resulting in different gene expression.
    • Some signals can form gradients, and cell fate depends on signal concentration.

    Signal Entry into the Cell

    • Two strategies for signal entry:
      • The signal can pass through the plasma membrane (e.g., nuclear receptors).
      • The signal can activate a membrane receptor (e.g., G protein linked receptors, Serine/threonine kinase receptors).

    Nuclear Receptors

    • Signals are steroids or retinoids.
    • These signals can pass through the plasma membrane and encounter nuclear receptors in the cytoplasm.
    • The receptor-ligand complex then enters the nucleus to activate genes.

    Signalling through Nuclear Receptors

    • Nuclear receptors like the glucocorticoid receptor are cytoplasmic proteins.
    • In their inactive form, they are bound to Hsp chaperones.
    • Ligand binding releases the Hsp, and the receptor-ligand complex moves to the nucleus to activate the transcription of target genes.

    G-Protein Linked Receptors

    • Transmembrane receptors are linked to a G-protein.
    • Upon ligand binding, the G protein releases GDP and takes up GTP.
    • Ga dissociates from Gbg and activates downstream 'second messengers' (e.g., cAMP).
    • GTP is hydrolyzed to GDP, and Ga reassociates with Gbg.

    Serine/Threonine Kinase Receptors

    • Transmembrane receptors that bind the TGFb family of signals.
    • Ligand brings together type I and type II receptors.
    • Type II phosphorylates type I.
    • Smads become phosphorylated and move into the nucleus to act as transcription factors.

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    Description

    Learn how Greek roots like 'eikosi' and 'para' are used to describe biological concepts like eicosanoids, which are fatty acid derivatives with a 20-carbon chain.

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