Biomolecules discussion Biology Unit 3 Biomolecules discussion

What is a Biomolecule? Organic molecule made by living organisms Consist mostly of carbon (C), hydrogen (H), and oxygen (O) Pose a question to students first. Talk about “bio” and “molecule”. Then, discuss the correct definition. Image citation: http://commons.wikimedia.org/wiki/File:Uridine_diphosphate_2.png

But wait…What is an Organic Molecule? Organic Molecules: Contain carbon Covalently Bonded Considered the “chemicals of life” 5 classes of organic molecules Carbohydrates, Lipids, Proteins, Nucleic Acids (DNA, RNA,ATP), Vitamins Cells could not function w/o organic molecules Ask students if they know the difference between organic and inorganic molecules before showing the definitions. Students may link this to “organic foods”. Distinguish between organic foods and organic molecules, if students mention this.

Inorganic Molecules: Do not contain carbon Inorganic Molecules important to living things: Water CO2 Acids and Bases Minerals Salts O2 (oxygen)

Monomers vs. Polymers Macromolecule: Large, complex molecule made of many smaller molecules Monomers: Molecules that may react with similar molecules to form a chain; a single, repeating unit of a macromolecule. Polymers: A chain of many monomers that are chemically bonded together. Ask students to think about the root words “mono” and “poly” to try and determine what the difference between these two molecules is. Then, show the correct definitions.

Formation of Polymers Animation How are polymers formed? Dehydration Synthesis (Condensation): Two hydrogen atoms and one oxygen atom are removed from the monomers to form water, and the two monomers are joined together. Show at least one animation of Dehydration Synthesis (Condensation), such as the one located here: http://www.phschool.com/science/biology_place/biocoach/bioprop/monomers.html (hyperlinked above) or here: http://academic.cengage.com/biology/discipline_content/animations/reaction_types.html. You will need Adobe Shockwave to view this animation. You can download Adobe Shockwave for free at this website: http://get.adobe.com/shockwave/. Then, ask students to describe what happened before showing the definition.

Breakdown of Polymers Animation How are polymers broken down? www.youtube.com/watch?v=ZMTeqZLXBSo How are polymers broken down? Hydrolysis—the reverse of dehydration synthesis (condensation) Water added to the polymer, un-linking the chain and breaking it back down to its original monomer units Show an animation of hydrolysis, such as the one here: http://academic.cengage.com/biology/discipline_content/animations/reaction_types.html (hyperlinked above). Then, ask students to describe what happened before showing them the definition.

Carbohydrates What are they? Group of organic molecules that includes sugars, starches and cellulose. Allow students to share what they remember from the Explore activity, before explaining each piece to them. Discuss with students about what types of foods have carbohydrates. Discuss that when we eat carbohydrates, our body has to break them down into simpler sugars that our cells can actually use. Image citation: http://commons.wikimedia.org/wiki/File:Carbohydrates.jpeg

Carbohydrates Structure: Carbon, hydrogen and oxygen in a 1:2:1 ratio (CH2O)n – n is an integer such as 5 (C5H10O5) Subunits {Monomer}: Monosaccharides, such as glucose or fructose Most often in a ring shape Subunits are connected with covalent bonds Allow students to share what they remember from the explore activity, before explaining each piece to them.

Monosaccharide Example

Disaccharide Example

Polysaccharide Example

Carbohydrates Function: Energy – Primary fuel for cells (Glucose) Structural Support Plants store food as starch Animals store glucose as glycogen Cell Wall – Cellulose makes plant cell walls rigid Cell Membrane Marker Allow students to share what they remember from the Explore activity, before explaining each piece to them.

Lipids What are they? Organic molecule group including fats and phospholipids Allow students to share what they remember from the explore activity, before explaining each piece to them. Discuss with students about what types of foods have lipids. Discuss with students that the lipids we eat must be broken down and processed by our body before being used for energy or being stored as fat within our cells. Image citation: http://commons.wikimedia.org/wiki/File%3AFatty_acids.png

Lipids Structure: Lots more H than O Subunits {Monomer}: Glycerol and 3 fatty acids (triglyceride) Glycerol and fatty acids plus phosphate group Contains the elements C H O Insoluble in water Do not form large polymers (2 or 3 fatty acids with glycerol) Examples: diglyceride and triglyceride Allow students to share what they remember from the Explore activity, before explaining each piece to them. Image citation: http://commons.wikimedia.org/wiki/File%3AFatty_acids.png

Triglyceride Example

Phospholipid Example

Lipids Function: Energy storage – fat stores a large amount of energy Insulation in animals Part of cell membrane (phospholipids) Hormones Seeds store fats as oils Some fats are waxes Cholesterol is important in animal cell membranes

Proteins What are proteins? Group of organic molecules that provides structure and facilitates chemical reactions. Allow students to share what they remember from the Explore activity, before explaining each piece to them. Again, discuss with students which types of foods have proteins (Don’t let them forget about milk, nuts, legumes, and eggs.) and how our body must break down the proteins we eat into components that can be used by our cells. Image citation: http://upload.wikimedia.org/wikipedia/commons/b/b3/Protein_Z.png

Proteins Structure: Subunits{Monomer}: Amino acids Elements: C H O N & sometimes S & P Amino acids connect via peptide bonds Very large molecules Globular or structural Allow students to share what they remember from the explore activity, before explaining each piece to them.

Amino Acid

Proteins Function: Lots of functions! Enzymes (speed rate of chemical reactions) Structural components in cells Important in cell membranes Mechanical functions in muscles and cytoskeleton (internal cell framework) Cell signaling Immune response – Antibodies are proteins Most hormones are proteins Antibodies are proteins

Nucleic Acids What are Nucleic Acids? Group of organic molecules including DNA and RNA ATP is a Nucleic Acid Allow students to share what they remember from the explore activity, before explaining each piece to them. Image citation: http://upload.wikimedia.org/wikipedia/commons/b/b8/DNA-structure-and-bases.png

Nucleic Acids Structure: Subunits {Monomer} are nucleotides—5-Carbon sugar, Nitrogen base and one or more Phosphate groups Contain C H O N P

Nucleic Acids Function: Storage and retrieval of information: Encode genes Gene expression DNA Controls all cell activities Controls Protein Synthesis Controls heredity RNA 1. Makes proteins