Two Organic Biomolecules: Carbohydrates and Lipids Honors Biology

Everyday Carbohydrates 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.

What Is A Carbohydrate? 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.

Functions of Carbohydrates Short-term energy storage Fiber In Animals Energy storage Structure of Cell Wall In Plants

C6H12O6 Carbohydrate Formula: Notice the ratio of 1:2:1 for carbon, hydrogen and oxygen atoms.

Which of the following look like formulas for carbohydrates? Notice the ratio of 1:2:1? For every one carbon there are two hydrogens and one oxygen!

Chief Functions of Carbs Short-term energy storage in animals (glycogen) Used to create energy (glucose) in all organisms 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

Three main types of carbohydrates All carbohydrates can be categorized by size Three main sizes of carbohydrates— Monosaccharides (“one sugar”) Disaccharides (“two sugars”) Polysaccharides (“many sugars”)

Building block of all carbohydrates Monosaccharide: Building 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

Glucose Is Very Important! 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.

Disaccharides “two sugars” Sucrose + Monosaccharides Glucose Fructose

Poly—“many”, saccharide—“sugar” 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.

Plants and Polysaccharides 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!

Energy storage in plants! Grains Starch Energy storage in plants!

Carbs stored in muscles Glycogen Energy storage in you!

Cellulose 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 Structure in plant cell walls!

Carbohydrates Review What is the C:H:O ratio found in all carbohydrates? True or false: Glycogen is used to store energy in plants. True or false: Starch is a source of dietary fiber True or false: Glucose is a disaccharide True or false: Polysaccharides are composed of two monosaccharides bound together

What are Lipids? Nonpolar, organic molecules Composed of hydrogen (H), carbon (C), and oxygen (O) Lipids consist of two types of molecules - glycerol & fatty acids

Glycerol Glycerol - an alcohol - Serves as backbone of the molecule

Fatty Acid 3 Fatty acids Long hydrocarbon chains

Biological Importance: 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

Lipids in the Cell Membrane Phospholipids have a hydrophyllic end and a hydrophobic end “Hydrophobic” – water fearing “Hydrophillic” – water loving These ends give the membrane many of its properties!!!

Checkpoint – Questions Would it be more efficient to store energy as glycogen or as fat? Why??? Why are lipids considered an organic molecule? What does it mean to be hydrophobic? What is the name of the lipid that makes up the cell membrane?

Types of fats Saturated fats have long chains with no double-bonds Unsaturated fats have double bonds between hydrogen and carbon

Special Lipids Triglycerides: composed of 3 molecules of fatty acids and 1 molecule of glycerol

Special Lipids Oils - lipids that are liquid at room temperature Fats - lipids that are solid at room temperature

Special Lipids Waxes – lipid that gives many substances a waterproofing cover Examples: surface of plant leaves, ear wax Steroids – lipids that cause changes within an organism nerve tissue,plant poisons, hormones, and venoms