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