Carbohydrates and Lipids
Honors Biology
• The sugar in your soda and the starch and fiber in your bread, fruit and vegetables are all carbohydrates.
• You consume more carbohydrates than any other organic biomolecule.
• A carbohydrate is an organic macromolecule.
• QUESTION: Do you remember what ORGANIC means???
• QUESTION: Do you remember a synonym for “macromolecule?”
• Carbohydrates are composed of carbon, hydrogen and oxygen in a 1:2:1 ratio.
•Short-term energy storage•Fiber In Animals
In Plants•Energy storage
•Structure of Cell Wall
Carbohydrate Formula:
C6H12O6
Notice the ratio of 1:2:1 for carbon, hydrogen and oxygen
atoms.
CC22HH44OO22 CC33HH44OO55 CC33HH66OO33
CHCH44OO22 CC66HH1212OO66 CC3636HH7272OO3636
CC22HH44OO22 CC33HH66OO33
CC66HH1212OO66 CC3636HH7272OO3636
Notice the ratio of 1:2:1?
For every one carbon there are two hydrogens and one oxygen!
1. Short-term energy storage in animals (glycogen)2. Used to create energy (glucose) in all organisms3. Plant cell walls (cellulose) and plant energy
storage (starch)
What is dietary fiber?
Parts of a plant that we eat but cannot digest. Fiber acts like a broom in our gut, cleaning out decaying food particles.
Celery, popcorn, and whole wheat are high in fiber
• All carbohydrates can be categorized by size
• Three main sizes of carbohydrates—
• Monosaccharides (“one sugar”)• Disaccharides (“two sugars”)• Polysaccharides (“many sugars”)
Glucose
Building block of all carbohydratesBuilding block of all carbohydrates
•It is also called a single or simple sugar.
•Six-sided, diamond-like shape
•Polysaccharides are composed of hundreds or thousands of monosaccharide molecules bound together.
Glucose is the primary energy source for most organisms.
•Energy is stored in the chemical bonds of the glucose molecule.
•The energy is released during cellular respiration in organisms.
Thousands of glucose molecules make up the starches found in the foods you eat.
Sucrose
Glucose Fructose+
“two sugars”
Sugar
Monosaccharides
• Polysaccharides are made of long chains of glucose molecules.
• Glycogen and starch are broken down into glucose molecules during digestion
• The glucose molecules then go to your cells where they are broken down to release energy during cellular respiration.
• Glucose molecules are created by plants during photosynthesis. The glucose molecules are bound together in long chains to make starch.
• Starch, a polysaccharide, is stored in plants until the plant needs to use it. When you eat starchy foods, like potatoes, you break the starch down into glucose.
• Your body will bind glucose molecules together to make glycogen. Glycogen, a polysaccharide, is stored in your muscles and liver for later use by you!
Starch
Energy storage in plants!
Grains
Glycogen
Energy storage in you!
Carbs stored in muscles
• Ever wonder why plants have stiff and rigid stems and leaves? Every plant cell is surrounded by a rigid cell wall made of cellulose.
Cellulose is a tough polysaccharide that most organisms cannot digest. The chemical bonds in cellulose make it hard to digest.
Structure in plant cell walls!
Cellulose
1. What is the C:H:O ratio found in all carbohydrates?
2. True or false: Glycogen is used to store energy in plants.
3. True or false: Starch is a source of dietary fiber
4. True or false: Glucose is a disaccharide
5. True or false: Polysaccharides are composed of two monosaccharides bound together
Nonpolar, organic molecules
Composed of hydrogen (H), carbon (C), and oxygen (O)
Lipids consist of two types of molecules - glycerol & fatty acids
Glycerol - an alcohol - Serves as backbone of the molecule
3 Fatty acids Long hydrocarbon
chains
All lipids are insoluble in water
Lipids are a more efficient energy storage system than carbohydrates – become FAT STORAGE
Energy stored in bonds of lipids – fats store 2.5 times as much energy per unit as carbs
Major component of cell membrane
Cell membrane = Phospholipid bilayer
Phospholipids have a hydrophyllic
end and a hydrophobic end
“Hydrophobic” – water fearing
“Hydrophillic” – water loving
These ends give the membrane many of its properties!!!
1. Would it be more efficient to store energy as glycogen or as fat? Why???
2. Why are lipids considered an organic molecule?
3. What does it mean to be hydrophobic?
4. What is the name of the lipid that makes up the cell membrane?
Saturated fats have long chains with no double-bonds
Unsaturated fats have double bonds between hydrogen and carbon
Triglycerides:
composed of 3 molecules of fatty acids and 1 molecule of glycerol
Oils - lipids that are liquid at room temperature – Unsaturated fats
Fats - lipids that are solid at room temperature – saturated fats
Waxes – lipid that gives many
substances a waterproofing cover
Examples:
surface of plant leaves, ear wax
Steroids – lipids that cause
changes within an organism
Examples:
nerve tissue,plant poisons, hormones, and
venoms
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