IB Biology Study Guide
Topic 1: Cell Biology
Name: _______________________________
1.3 – Cell Membrane
Essential Idea – The structure of biological membranes makes them fluid and dynamic.
1.4 – Membrane Transport
Essential Idea – Membranes control the composition of cells by active and passive transport.
I.
Terms:
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active transport
amphipathic
bilayer
cholesterol
cytoplasm
diffusion
endocytosis
exocytosis
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facilitated diffusion
fluid mosaic model
homeostasis
hydrophilic
hydrophobic
hypertonic
hypotonic
isotonic
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molarity
membrane proteins
membrane protein
functions (6)
nonpolar
osmosis
passive transport
phospholipid
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polar
selective permeability
vesicle
concentration
gradient
Homework:
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Read: Pages 19 – 38 in your textbook
Lecture Tutorial: Study the slides for DP 1.3 Membranes & DP 1.4 Membrane Transport
Links also available on teacher class page.
1.3 - http://www.slideshare.net/diverzippy/bioknowledgy-dp-13-membrane-structure
1.4 - http://www.slideshare.net/diverzippy/bioknowledgy-14-membrane-transport?next_slideshow=1
II.
III.
Understandings
Cell Membrane
 Phospholipids form bilayers in water due to the amphipathic properties of phospholipid molecules.
 Membrane proteins are diverse in terms of structure, position in the membrane and function.
 Cholesterol is component of animal cell membranes.
Membrane 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 the cell.
Applications & Skills
Cell Membrane
 Application: Cholesterol in mammalian membranes reduces membrane fluidity and permeability to some
solutes.
 Skill: Draw and label a fluid mosaic model of the cell membrane
 Skill: Analysis of evidence from electron microscopy that led to the proposal of the Davson-Danielli model
(1935).
 Skill: Analysis of the falsification of the Davson-Danielli model that led to the Singer-Nicolson model (1972).
Membrane Transport
 Application: Structure & function of sodium-potassium pumps for active transport and potassium channels for
facilitated diffusion in axons.
 Application: Tissues or organs to be used in medical procedures must be bathed in a solution with the same
osmolarity as the cytosplasm to prevent osmosis.
 Skill: Estimation of osmolarity in tissues by bathing samples in hypertonic and hypotonic solutions. (Practical 2)
IV.
Guidance
Cell Membrane
 Amphipathic phospholipids have hydrophobic and hydrophilic properties.
 Drawings of the fluid mosaic model of the membrane structure can be two dimensional rather than three
dimensional. Individual phospholipid molecules should be shown using a circle and two parallel lines attached. A
range of membrane proteins should be shown including glycoproteins and transport proteins.
Membrane Transport
 Osmosis experiments are a useful opportunity to stress the need for accurate mass and volume measurements
in scientific experiments.
Figures and Diagrams:
Phospholipid
bilayer
Tonicity
Types of
Transport