Ms. Frost  A world of biology.....
  • Welcome
    • Data bases for labs
    • IB Calendar
  • IB: Introduction to cells
    • Origin and Division of Cells
    • Membrane Structure and transport
    • Structure of DNA and RNA
    • DNA Replication
    • Transcription and gene expression
    • Translation
    • Genetic modification and biotechnology
  • Molecules to Metabolism
    • Molecular diagrams
    • Water
    • Carbohydrates and Lipids
    • Proteins and Enzymes
    • Lactase / Enzyme Inhibition
    • Cellular Respiration
    • Phases of Cellular Respiration
    • Earth atmosphere / Color
    • Photosynthesis
  • Digestion and absorption
    • The kidney and osmoregulation
    • Neurons and synapses
    • Muscle and Movement
    • The blood system
    • Gas exchange
    • Defense against infectious disease
    • Antibody production and vaccination
    • Hormones, Homeostasis
    • Sexual reproduction
  • Genetics and Genes
    • Chromosomes
    • Meoisis
    • Inheritance
    • MORE Inheritance
  • Evidence of evolution
    • Natural selection
    • Gene pools and speciation
    • Classification of biodiversity
    • Cladisitics
  • Ecology Species, communities and ecosystems
    • Energy Flow
    • Carbon Cycling
    • Climate change
  • Option C: Species and communities
    • Option C: Communities and ecosystems
    • Option C: Impacts of human on ecosystems
    • Option C: Conservation of biodiversity
  • Plants: Transport in the xylem of plants
    • Transport in the phloem of plants
    • Growth in plants
    • Reproduction in plants
  • Anatomy Language
    • Epithelial/Connective/Skeletal
    • Muscular / Nervous Tussue
    • Heart
  • Western Hills Website
  • Science in the News
  • World Population Clock

Movement across membranes

Membrane structure

Understandings:
Phospholipids form bilayers in water due to the amphipathic properties of phospholipid molecules.
​
Amphipathic phospholipids have hydrophilic and hydrophobic properties.
Membrane proteins are diverse in terms of structure, position in the membrane and function.
Cholesterol is a component of animal cell membranes.


Application: Cholesterol in mammalian membranes reduces membrane fluidity and permeability to some solutes.
Skill: Drawing of the fluid mosaic model.
Skill: Analysis of evidence from electron microscopy that led to the proposal of the Davson-Danielli model.
Skill: Analysis of the falsification of the Davson-Danielli model that led to the Singer-Nicolson model.
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Drawings of the fluid mosaic model of membrane structure can be two dimensional rather than three dimensional. Individual phospholipid molecules should be shown using the symbol of a circle with two parallel lines attached. A range of membrane proteins should be shown including glycoproteins.
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Membrane Game!
Can  you create a membrane, in the time frame allowed, that will work correctly ? Can you identify organelles with lightning speed? 
Do you know your organelles?

Membrane transport

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Na+ K+ pump

Application: Structure and function of sodium–potassium pumps for active transport and potassium channels for facilitated diffusion in axons.
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Passive transport

Particles move across membranes by simple diffusion, facilitated diffusion, osmosis and active transport.
• The fluidity of membranes allows materials to be taken into cells by endocytosis or released by exocytosis. Vesicles move materials within cells.

how vesicles move cargo
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Osmosis

Application: Tissues or organs to be used in medical procedures must be bathed in a solution with the same osmolarity as the cytoplasm to prevent osmosis.
Skill: Estimation of osmolarity in tissues by bathing samples in hypotonic and hypertonic solutions.
 (Practical 2)


Design your experiment!
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Surface area to volume - why are cells so small?

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  • Welcome
    • Data bases for labs
    • IB Calendar
  • IB: Introduction to cells
    • Origin and Division of Cells
    • Membrane Structure and transport
    • Structure of DNA and RNA
    • DNA Replication
    • Transcription and gene expression
    • Translation
    • Genetic modification and biotechnology
  • Molecules to Metabolism
    • Molecular diagrams
    • Water
    • Carbohydrates and Lipids
    • Proteins and Enzymes
    • Lactase / Enzyme Inhibition
    • Cellular Respiration
    • Phases of Cellular Respiration
    • Earth atmosphere / Color
    • Photosynthesis
  • Digestion and absorption
    • The kidney and osmoregulation
    • Neurons and synapses
    • Muscle and Movement
    • The blood system
    • Gas exchange
    • Defense against infectious disease
    • Antibody production and vaccination
    • Hormones, Homeostasis
    • Sexual reproduction
  • Genetics and Genes
    • Chromosomes
    • Meoisis
    • Inheritance
    • MORE Inheritance
  • Evidence of evolution
    • Natural selection
    • Gene pools and speciation
    • Classification of biodiversity
    • Cladisitics
  • Ecology Species, communities and ecosystems
    • Energy Flow
    • Carbon Cycling
    • Climate change
  • Option C: Species and communities
    • Option C: Communities and ecosystems
    • Option C: Impacts of human on ecosystems
    • Option C: Conservation of biodiversity
  • Plants: Transport in the xylem of plants
    • Transport in the phloem of plants
    • Growth in plants
    • Reproduction in plants
  • Anatomy Language
    • Epithelial/Connective/Skeletal
    • Muscular / Nervous Tussue
    • Heart
  • Western Hills Website
  • Science in the News
  • World Population Clock