Roles of lipids in organisms

• What is the role of hormone-sensitive lipase in energy storage?

  • Breaks down stored triglycerides
  • Converts triglycerides into fatty acids
  • Releases fatty acids into capillaries
• If you wanted to study the detailed 3D structure of the cell membrane, which microscope technique would you use?

  Scanning electron microscope (SEM)
• What is the function of the phospholipid bilayer in the cell membrane?

  It creates a selective barrier
• What is the purpose of the cytoskeletal filaments in the cell membrane?

  To provide structural support
• Where do lipid hormones bind within the cell?

  To intracellular receptors in the cytoplasm or nucleus
• How do lipid hormones interact with cell membranes?

  They can directly diffuse through cell membranes
• What are the key components of the cell membrane?

  1. Integral membrane proteins
  2. Cholesterol molecules
  3. Glycoproteins/glycolipids
  4. Cytoskeletal filaments
• What is the middle layer of the skin called?

  Dermis
• What is the role of integral membrane proteins in the cell membrane?

  They form channels that span the bilayer
• What is the outermost layer of the skin called?

  Epidermis
• How does the function of lipid hormones differ from non-lipid hormones in terms of their cellular targets?

  Lipid hormones bind to intracellular receptors, while non-lipid hormones bind exclusively to portions of receptors in the plasma membrane
• What is the function of the hormone-sensitive lipase shown in the image?

  Glycerol phosphate
• What are the three main types of hormones mentioned in the image?

  Proteins, amino-acid derivatives, and steroids
• What type of hormones are lipid hormones primarily classified as?

  Steroid hormones
• What orientation do hydrophobic tails have in the phospholipid bilayer?

  They face inwards
• Why is the lipid storage and release system important for organisms?

  It maintains a consistent energy supply
• How do glycoproteins and glycolipids differ in their structure and function?

  Glycoproteins:

  • Proteins with carbohydrates attached
  • Involved in cell-cell recognition, adhesion, and signaling

  
  

  Glycolipids:

  • Lipids with carbohydrates attached
  • Involved in cell-cell recognition and as markers on cell surfaces
• What are the main signaling molecules derived from lipids?

  1. Arachidonic acid produces eicosanoids (inflammatory signals)
  2. Phospholipids in membranes convert to signaling molecules
• What is a glycolipid?

  Lipid with carbohydrate attached
• How do free fatty acids and glycerol get transported in the adipocyte?

  • Free fatty acids are transported by albumin
  • Glycerol is transported by albumin
• What do cytoskeletal filaments do in relation to the cell membrane?

  They support the membrane shape
• What are the key differences between lipid and non-lipid hormones?

  • Lipid hormones:
  • Diffuse through membrane
  • Bind intracellularly
  • Directly affect gene expression
  • Non-lipid hormones:
  • Bind to extracellular receptors
  • Require signal transduction
• What are the main steps in lipid hormone signaling?

  • Lipid hormones diffuse through plasma membranes
  • Bind to intracellular receptors
  • Trigger signal transduction
  • Induce metabolic response
  • Elicit gene expression response
• Where do lipid hormones commonly bind inside cells?

  Intracellular receptors (either in the cytoplasm or nucleus)
• What is the role of cholesterol in the cell membrane?

  To regulate fluidity and permeability
• What is the purpose of the hair in the skin?

  The hair provides protection and insulation for the skin.
• What is the function of glycoproteins and glycolipids on the cell membrane?

  They are involved in cell recognition
• How do lipid hormones and non-lipid hormones differ in their mechanism of action?

  Lipid hormones:

  • Diffuse through plasma membranes
  • Bind to intracellular receptors
  • Trigger signal transduction and metabolic/gene expression responses

  
  

  Non-lipid hormones:

  • Bind exclusively to portions of receptors in plasma membrane
• What do non-lipid hormones bind exclusively to?

  Portions of receptors in plasma membrane
• What is the structure of the cell membrane primarily based on?

  Phospholipid bilayer
• What are lipid hormones derived from?

  Cholesterol
• What are the main layers of the skin?

  • Epidermis
  • Dermis
  • Subcutaneous tissue (fat)
• What are the key differences between lipid hormones and non-lipid hormones?

  Lipid Hormones:

  • Derived from cholesterol
  • Bind to intracellular receptors

  
  

  Non-Lipid Hormones:

  • Bind exclusively to portions of receptors in plasma membrane
• What orientation do hydrophilic heads have in the phospholipid bilayer?

  They face outwards
• What is the primary effect of lipid hormones on gene expression?

  They directly affect gene expression
• How do cholesterol molecules contribute to the cell membrane?

  They maintain membrane fluidity
• What is the function of the sweat gland in the skin?

  The sweat gland helps regulate body temperature through the production and release of sweat.
• What is the innermost layer of the skin called?

  Subcutaneous tissue (fat)
• What is the role of cAMP in the adipocyte?

  • Activates hormone-sensitive lipase to break down triglycerides
  • Leads to release of free fatty acids and glycerol
• How do the different layers of the skin work together?

  • Epidermis provides a protective barrier
  • Dermis contains blood vessels, nerves, and connective tissue
  • Subcutaneous tissue insulates and cushions the body