Carbon: Transformations in Matter and Energy Environmental Literacy Project Michigan State University Animals Unit Activity 4.1: Molecular Models for Cows Growing: Digestion and Biosynthesis

All animals eat. What happens to the food that they eat? 2

Animals use food in two ways 3 FoodDigestion Materials for growth: Biosynthesis Energy: Cellular respiration

How does a cow get food to a cell in its leg? 4 1.What is food made of? 2.What are animals made of? 3.How can cows get food to a cell in its leg? 4.How can cows use this food to build their bodies?

What are the inputs and outputs of a cow’s body? 5

Matter entering and leaving animals Materials in grass (entering cow) Materials in a cow Materials leave a cow by breathing, urination and perspiration. feces H2OH2O H2OH2O Carbohydrates minerals Protein Fat H2OH2O CO 2 minerals H2OH2O Carbohydrates minerals Fat Protein 6 From lungs

Food is mostly water and large organic molecules LIPIDS (FAT) STARCH CELLULOSE (FIBER) GLUCOSE (SUGAR) 7 CARBOHYDRATES: PROTEINS

Animals are mostly water and different large organic molecules How can animals make these molecules from molecules in the food they eat? LIPIDS (FAT) PROTEINS

Place penny here: large food molecules (grass). Food molecules are in the grass 9

Materials for growth: Biosynthesis Energy: Cellular respiration Step 1: Digestion 10 FoodDigestion

Digestion occurs in stomach and small intestines Put penny here: Large food molecules break into small molecules in intestines 11

During digestion, large organic molecules are broken down into small organic molecules LARGE = Polymer 12 SMALL = Monomers STARCH GLUCOSE (SUGAR)

What happens to food that animals can’t digest? 13 Our digestive systems cannot break down some large organic molecules (such as fiber). These molecules leave our bodies as feces.

How Atoms Bond Together in Molecules Atoms in stable molecules always have a certain number of bonds to other atoms: – Carbon: 4 bonds – Oxygen: 2 bonds – Hydrogen: 1 bond Oxygen atoms do NOT bond to other oxygen atoms if they can bond to carbon or hydrogen instead. Chemical energy is stored in bonds between atoms – Some bonds (C-C and C-H) have high chemical energy – Other bonds (C-O and O-H) have low chemical energy

Breakdown Protein Molecules (Digestion) Let’s focus on what happens to PROTEIN in food. (Put the other food molecules to the side for now.) Digest PROTEIN molecules by cutting the protein into individual amino acids. Notice that after you cut the protein apart there are bonds without atoms. Cut up water molecules to tape an –H and –OH to every amino acid. 15 Chemical change

ProductsReactants Protein polymer (+ water) 16 What happens to carbon atoms and chemical energy in digestion? Amino acid monomers

Chemical change ProductsReactants Protein polymer (+ water) 17 What happens to carbon atoms and chemical energy in digestion? Amino acid monomers Carbon atoms stay in organic molecules with high-energy bonds

Breakdown of Starch Molecules (Digestion) Digest STARCH molecules by cutting the starch into individual glucose monomers. Notice that after you cut the starch apart there are bonds without atoms. Cut up water molecules to tape an –H and –OH to every glucose. 18 Chemical change

Products Glucose monomers Reactants Starch polymer (+ water) 19 What happens to carbon atoms and chemical energy in digestion?

Chemical change Products Glucose monomers Reactants Starch polymer (+ water) What happens to carbon atoms and chemical energy in digestion? 20 Carbon atoms stay in organic molecules with high-energy bonds

Breakdown of Fat Molecules (Digestion) Digest FAT molecules by breaking the fat into individual fatty acid and glycerol monomers. Notice that after you cut the fat apart there are bonds without atoms. Cut up water molecules to tape an –H and –OH to each fatty acid and glycerol. 21 Chemical change

Products Fatty acids + glycerol Reactants Fat (+ water) 22 What happens to carbon atoms and chemical energy in digestion?

Chemical change Products Fatty acids + glycerol Reactants Fat (+ water) 23 What happens to carbon atoms and chemical energy in digestion? Carbon atoms stay in organic molecules with high-energy bonds

Where do digested monomers go? glucose glycerol amino acid fatty acid 24

Where are atoms moving from? Where are atoms moving to? Blood carries digested monomers to all parts of animal bodies.

FoodDigestion Materials for growth: Biosynthesis Energy: Cellular respiration Step 2: Biosynthesis 26

Move Markers: Small molecules move through circulatory system Small molecules move from intestines to blood, and the heart pumps blood and small molecules to all parts of the body. 27

Place your marker here: Large molecules are built here Biosynthesis is the process of small organic molecules becoming large organic molecules in all body parts 28

What’s in cow muscles (BEEF)? PROTEIN FAT 29

Biosynthesis: Building Cow Muscles Build PROTEIN molecules by taping 4 amino acid monomers together. Notice you will need to remove an –H and –OH from each amino acid. Tape these back together to make water. 30 Chemical change

Products Protein polymer (+ water) Reactants 31 What happens to carbon atoms and chemical energy in biosynthesis? Amino acid monomers

Chemical change Products Protein polymer (+ water) Reactants 32 What happens to carbon atoms and chemical energy in biosynthesis? Amino acid monomers Carbon atoms stay in organic molecules with high-energy bonds

Build Cow Muscles (Biosynthesis) Build FAT molecules by taping 3 fatty acid monomers to 1 glycerol molecule. Notice you will need to remove an –H and –OH from each fatty acid and glycerol. Tape these back together to make water. 33 Chemical change

Products Fat (+ water) Reactants 34 What happens to carbon atoms and chemical energy in biosynthesis? Fatty acids + glycerol

Chemical change Products Fat (+ water) Reactants 35 What happens to carbon atoms and chemical energy in biosynthesis? Fatty acids + glycerol Carbon atoms stay in organic molecules with high-energy bonds

How do animal cells use sugar? The diets of most animals—including mealworms, cows, and humans—include lots of carbohydrates (starch, fiber, sugar) This means that lots of sugar travels to animal cells in the blood. BUT animal cells don’t make starch or cellulose. How do they use the sugar? 36

Animal cells use sugar in two ways 1.Animal cells can make fat molecules from sugar molecules. – Glycerol and fatty acids are made of the same atoms—C, H, and O—as sugar molecules – Animals use fats to store chemical energy in C-C and C-H bonds 2.Animal cells can combine sugar molecules with oxygen to release chemical energy. – This is how all cells get the energy they need for their functions. 37

FoodDigestion Materials for growth: Biosynthesis Energy: Cellular respiration Coming up: How Animals Use Food for Energy 38