1. Biomolecules discussion
Biology Unit 3
Biomolecules discussion

2. 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.
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3. 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.

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

5. 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.

6. 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: (hyperlinked above) or here: You will need Adobe Shockwave to view this animation. You can download Adobe Shockwave for free at this website: Then, ask students to describe what happened before showing the definition.

7. Breakdown of Polymers Animation How are polymers broken down?
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: (hyperlinked above). Then, ask students to describe what happened before showing them the definition.

8. 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.
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9. 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.

10. Monosaccharide Example

11. Disaccharide Example

12. Polysaccharide Example

13. 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.

14. 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.
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15. 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.
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16. Triglyceride Example

17. Phospholipid Example

18. 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

19. 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.
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20. 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.

21. Amino Acid

22. 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

23. 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.
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24. Nucleic Acids Structure:
Subunits {Monomer} are nucleotides—5-Carbon sugar, Nitrogen base and one or more Phosphate groups
Contain C H O N P

25. 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