Download Lipids - Biology

Lipids
Lipid Structure
Plasma Membrane
Cell Transport
Cell Communication
Lipids
Carbon and hydrogen
Store energy
Waterproof coverings on plants and animals
Cell membrane
Steroids/Hormones
Lipids
• Fats, Oils, Waxes
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Glycerol + 2 fatty acids = Triglyceride
Fats – animal, solid, saturated fatty acids (straight)
Oils – plant, liquid, unsaturated fatty acids (kinked)
Waxes – highly saturated solids for waterproofing
• Phospholipids
• Hydrophilic phosphate head and hydrophobic fatty tail
• Cell membranes
• Steroids
• Carbon rings
• Cholesterol
• Estrogen (female sex hormone), testosterone (male sex hormone), bile (fat digestion)
Checkpoint #1
(You should also use your four fold notes to answer these.)
1. What are the primary functions of lipids?
2. Differentiate the three types of lipids.
3. Create a diagram showing the differences between saturated and
unsaturated fats.
4. How are lipids different than carbohydrates?
5. Why are lipids insoluble?
Plasma Membrane
• A layer of phospholipids
Plasma Membrane Video Link
Checkpoint #2
1. Describe the primary functions of the cell membrane.
2. Describe the primary structure of the cell membrane.
3. Explain why the “fluid mosaic model” is used to explain the cell
membrane.
4. Polar molecules need help getting through the cell membrane.
Why?
5. What role do proteins play in the cell membrane?
Cell Transport to maintain homeostasis
Cell
Transport
Passive
Transport
Simple
Diffusion
Facilitated
Diffusion
Active
Transport
Osmosis
Endocytosis
Exocytosis
Transport
Pumps
Passive Transport
• Passive Transport: the process of particles
moving through a membrane with NO ENERGY
(high to low concentration)
• Water, lipids, and some lipid soluble substances can
move by passive transport.
• Molecules can move through proteins or the
membrane itself.
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http://www.bmb.psu.edu/courses/bisci004a/cells/faciltat.jpg
Passive: Diffusion
• Diffusion : movement of particles from an area of
high to low concentration (no energy required)
• continues until there is no more concentration gradient.
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Passive: Facilitated Diffusion
• Facilitated Diffusion: proteins helping large molecules across the
plasma membrane.
• No energy is used by the cell or its parts! (passive)
• Movement is powered by the concentration gradient. (hi to lo)
• See p. 187 Fig. 7.17
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http://www.mhhe.com/biosci/genbio/enger/student/olc/art_quizzes/genbiomedia/0086.jpg
Passive: Osmosis
• Osmosis: The diffusion of water across a selectively
permeable membrane.
• Review:
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•
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Plasma Membrane- Phospholipid Bilayer
Concentration Gradient
Homeostasis
Fig. 8.1 p. 202
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3 Types of Solutions
• Isotonic Solution: Concentration of solutes is the
same inside and outside the cell.
• No osmosis occurs
• dynamic equilibrium: molecules are moving across
membrane but no concentration gradient created.
• Dynamic: Movement or change
• Equilibrium: An equality or balance
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Types of Solutions
• Hypotonic Solution: The concentration of solutes is
less outside the cell than inside the cell. See p. 186,
Fig. 7.16
• Water moves by osmosis into the cell!
• The cell tends to swell.
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Types of Solutions
• Hypertonic Solution: The concentration of solutes
is more outside the cell than inside the cell. See p.
186 Fig. 7.16
• Osmosis causes water to flow out of the cell.
• Cells will shrink or shrivel
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Comparison of Hypo, Iso, and Hypertonic Solutions
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• Turgor Pressure: The pressure in a plant cell
that results from water flowing into the cell.
• Occurs with a hypotonic solution.
• Gives plants their shape and ability to stand up.
Without it they wilt!
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Plasmolysis: Loss of pressure within a cell causing it to shrivel
• Occurs with a hypertonic solution
• In plants turgor pressure is lost (wilting occurs), animal cells
just shrivel
http://www.apsnet.org/online/feature/xmasflower/images/figure22sm.jpg
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http://www.biology.arizona.edu/cell_bio/problem_sets/membranes/graphics/hypertonic_plt.gif
Cell Membrane Proteins
• Carrier Proteins: Span through plasma membrane (transport
proteins) and change shape to help molecules get from one
side to the other.
• Their exposed ends open and close like a gate.
• Channel Proteins: Span through plasma membrane (transport
proteins) and create an opening where molecules can pass
through.
• They do not change shape.
Carrier
Channel
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http://images.google.com/imgres?imgurl=io.uwinnipeg.ca/~simmons/cm1503/Image132.gif&imgrefurl=http://io.uwinnipeg.ca/~simmons/cm1503/membranefunction.htm&h=311&w=800&sz=42&tbnid=CfM5o08rCDgJ:&tbnh=55&tbnw=141&prev=/images%3
Fq%3Dcarrier%2Bproteins%26start%3D20%26svnum%3D10%26hl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3DUTF-8%26sa%3DN
Active Transport
• Active Transport: cell uses energy to move molecules
across plasma membrane against the concentration
gradient.
• These molecules are moving the opposite way they would
naturally move due to diffusion. (low-high)
http://www.bmb.psu.edu/courses/bisci004a/cells/active.jpg
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Active: Ion Pumps
• Ion pumps use ATP to move ions against the concentration gradient.
• From a low concentration to a high concentration
Active: Endo and exocytosis
• Endocytosis
• Movement into cell
• Phagocytosis and Pinocytosis is a form of endocytosis
• Phagocytosis: one cell engulfing another.
• Pinocytosis: tiny pockets form along the cell membrane fill with
liquid and pinch off to form vacuoles
• Exocytosis
• Movement out of cell; waste or messengers (hormones)
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Endocystosis (amoeba eats two paramecia)
Checkpoint #3
1.
2.
3.
4.
5.
6.
How are active and passive transport different?
Where do cells get the energy required to perform active transport?
What role do you suppose DNA plays in active transport?
What is a concentration gradient?
How would transport help maintain homeostasis for the cell?
*Amoeba video – Once inside the cell, how do you think the
paramecia are broken down?
(review video on transport to follow)
All you want to know about transport