Cell Membrane Don't Burst My Bubble
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Transcript of Cell Membrane Don't Burst My Bubble
Structure and Function of Cells:Don’t Burst My Bubble
All About YouTeacher Education Course
2016-17
Don’t Burst My BubbleNGSS 3D Learning GoalStudents carry out an investigation using a soap
film model of a cell membrane to explain how the structure of the membrane causes it to function as the boundary that controls what enters and leaves the cell.
ObjectivesDescribe how a cell membrane’s structure relates to
how the membrane functions and the cell functions Evaluate the limitations of the models used to
represent a cell membrane.
How are these organisms similar to each other?
White and Black Variations on Lichen- Free Trees
Cells are the Basic Unit of Life
All Cells Have Certain Characteristics
All cells are surrounded by a cell membrane.
Small Group Self-Managing RolesFacilitator makes sure every voice is heard
Reporter shares group’s ideas in the time given
Recorder writes official team worksheet
Timekeeper keeps group aware of time remaining
Functions of the Cell Membrane
1. Forms the flexible outer boundary of the cell and holds it together.
2. It controls what is allowed to enter and leave the cell and what is not allowed to enter and leave the cell
Don’t Burst My BubbleWork as a table group to sketch the potential
structure of A Cell Membrane given the functions listed on the worksheet.• Timekeepers: 5 minutes
Next, complete the observations and inferences listed in questions 1-3 as you explore the soap film as a Cell Membrane Model.• Timekeepers: 5 minutes
Don’t Burst My BubbleNow explore the What Passes Through? section.
• Investigate with different objects (Question 4)• Complete the table
• Create a rule or rules for what passes through (Question 5)• Consider possible structural changes that provides new
function (Question 6)• Timekeepers: 15 minutes
Next in Changing the Model use the new structure discussed to pass objects through the film.• Revise the scientific drawing (Question 7)• Timekeepers: 5 minutes
Don’t Burst My BubbleAnything unexpected or interesting?
Don’t Burst My Bubble
Graphic Organizer
selectively permeable
phospholipid bilayer
transport (in & out)
structures
cell membrane
proteins
functions
barrier, support, protection, identity
Don’t Burst My BubbleWhat is the function of a cell membrane?
• A cell’s outer boundary which is flexible and fluid, and separates the cells interior from the exterior environment
• Regulates what comes in and goes out of the cell and is its first line of defense
Don’t Burst My BubblePhospholipids
• Cell membranes are composed of molecules with two distinct sides• Hydrophilic head
• Water “loving” phosphate• Hydrophobic tails
• Water “fearing” fatty acidsForms bilayer due to interaction with water inside & outside of cell
Don’t Burst My BubbleSelectively Permeable
• Structure of cell membrane allows certain substances to pass through, while making other substances require help, or not allowing them to pass.
• https://www.pbslearningmedia.org/asset/tdc02_int_membraneweb/
Don’t Burst My BubbleFluid Mosaic Model
• Mosaic = proteins & other structures placed within lipid bilayer
• Fluid = proteins & other structures can move across lipid bilayer
Don’t Burst My BubbleAll models have limitations
prot
ein
Cel
l Mem
bran
eSo
ap B
ubbl
e
water
water
~ nm (10-9 m)
~ µm (10-6 m)~1,000x thicker
Bacteria, viruses and toxic chemicals sometimes have the ability to get into a cell despite the cell membrane’s defensive structures.
What ideas do you have about what cells can do to further protect themselves from an especially harmful environment?
Further Cell Defense Mechanisms
Increasing the cholesterol in the cell membrane makes it much more rigid and difficult for invading molecules to get through.
Cells insert a structure (amino acid) into the protein channels, protecting it against harmful invading molecules.