Cell Structure and Function - ReviewCell Structure and Function - Review

Cell “plasma” Membrane

Nucleus

Mitochondrion

Endoplasmic reticulum

Golgi Body

Lysosome

ribosomescytoplasm cytoskeleton

View cell structure function

The cell membrane regulates what enters and leaves the cell and also The cell membrane regulates what enters and leaves the cell and also provides protection and support. The composition of nearly all cell provides protection and support. The composition of nearly all cell membranes is a double-layered sheet called a lipid bilayer. As you can see in membranes is a double-layered sheet called a lipid bilayer. As you can see in Figure 7-12,Figure 7-12,there are two layers of lipids, hence the name bilayer. The lipid bilayer gives there are two layers of lipids, hence the name bilayer. The lipid bilayer gives cell membranes a flexible structure that forms a strong barrier between the cell membranes a flexible structure that forms a strong barrier between the cell and its surroundings.cell and its surroundings.

Figure 7-12Figure 7-12

Cell BoundariesCell Boundaries

Identification makersIdentification makers

The Plasma Membrane

Biology – Homeostasis

Topics

• Investigate and analyze the cell as a living system including:

• Maintenance of homeostasis.

• Movement of materials into and out of cells.

Essential QuestionsEssential Questions

1.1. How is homeostasis maintained? How is homeostasis maintained? How are temperature, pH, blood How are temperature, pH, blood glucose and water balanced? glucose and water balanced?

2.2. What is the difference between What is the difference between active and passive transport? active and passive transport? What is a semi permeable What is a semi permeable membrane?membrane?

3.3. What is osmotic pressure; can What is osmotic pressure; can you predict changes? (isotonic, you predict changes? (isotonic, hypotonic, and hypertonic)hypotonic, and hypertonic)

HomeostasisHomeostasis

Homeostasis Overview

HomeostasisHomeostasis is the property of a system that regulates its is the property of a system that regulates its internal environment and tends to maintain a stable, internal environment and tends to maintain a stable, constant condition of properties like temperature, water constant condition of properties like temperature, water balance or pH. balance or pH.

Cellular Homeostasis

The Cell MembraneThe Cell Membrane

Overview of the cell “plasma” membrane structure

Phospholipid bilayer

Channel protein

Protein with marker Receptor protein

cholesterol

Active transport protein

Cell Membrane Rap

Why are the Why are the tails moving tails moving away?away?

Hydrophilic – Hydrophilic – “water loving” “water loving” phosphate head phosphate head regionregion

Hydrophobic –Hydrophobic –““water fearing”water fearing”Lipid tail regionLipid tail region

DiffusionDiffusion describes the spread of describes the spread of particles through particles through randomrandom motion motion from regions of higher from regions of higher concentration to regions of lower concentration to regions of lower concentration. concentration.

Passive TransportPassive Transport

Diffusion Definition

Diffusion Explained

OsmosisOsmosis is the movement of is the movement of water water moleculesmolecules through a selectively permeable through a selectively permeable membrane into a region of higher solute membrane into a region of higher solute concentration, aiming to equalize the solute concentration, aiming to equalize the solute concentrations on the two sides concentrations on the two sides

Passive TransportPassive Transport

How osmosis works

Passive TransportPassive TransportFacilitated diffusion is a type of passive is a type of passive transport that allows substances to cross transport that allows substances to cross membranes with the assistance of membranes with the assistance of special special transport proteinstransport proteins..  

Gummy Bear Lab Gummy Bear Lab The Method:The Method:Set up the experiment as shown below using Set up the experiment as shown below using your chosen gummiesyour chosen gummies

Osmosis Rap

Vitual lab - diffusion

TonicityTonicity is a measure of the osmotic pressure gradient (as defined by is a measure of the osmotic pressure gradient (as defined by the water potential of the two solutions) of two solutions separated by a the water potential of the two solutions) of two solutions separated by a semipermeable membrane. It is commonly used when describing the semipermeable membrane. It is commonly used when describing the response of cells immersed in an external solution. response of cells immersed in an external solution.

Hypotonic SolutionHypotonic Solution If water molecules continue to diffuse into the cell, it If water molecules continue to diffuse into the cell, it will cause the cell to swell, up to the point that cytolysis (rupture) may will cause the cell to swell, up to the point that cytolysis (rupture) may occur occur

Isotonic solutionIsotonic solution isotonic environment happens when an equal isotonic environment happens when an equal concentration exists inside and outside the cell concentration exists inside and outside the cell

Hypertonic SolutionHypertonic Solution If water molecules continue to diffuse out of the cell, If water molecules continue to diffuse out of the cell, it will cause the cell to shrink, or crenate. it will cause the cell to shrink, or crenate.

Animal cellAnimal cell Plant cellPlant cell

Osmosis Demo

Passive Transport – Passive Transport – Comparing Osmosis and DiffusionComparing Osmosis and Diffusion

Active and Passive Transport

is the movement of a substance against its concentration is the movement of a substance against its concentration gradient (from low to high concentration) requiring the use of gradient (from low to high concentration) requiring the use of Energy.Energy.

Active TransportActive Transport

Proton Pump

Active TransportActive Transportis the movement of a substance against its concentration is the movement of a substance against its concentration gradient (from low to high concentration) requiring the use of gradient (from low to high concentration) requiring the use of Energy.Energy.

Endocytosis and Exocytosis Endocytosis and Exocytosis

EndocytosisEndocytosis“ “ Entering the Cell”Entering the Cell”

Phagocytosis“Cell Eating”

Pinocytosis“Cell Drinking”

ExocytosisExocytosis““Exiting the Cell”Exiting the Cell”