1. Chapter 2 - Biochemistry
Organic Compounds
Chapter 2 - Biochemistry

2. Lipids, Carbohydrates, and Proteins
Chapter 2 - Biochemistry

3. Organic compounds
Organic compounds: contain carbon and are/were part of a living system
Macromolecules/polymers: really large organic compounds
4 main types
Lipids
Carbohydrates
Proteins
Nucleic acids (DNA, RNA)
Protein macromolecule

4. Lipids – what are they? Contain mostly carbon & hydrogen
Include “oils” (liquids), “fats” (solids)
Examples: cholesterol, olive oil, butter, lard
(“Saturated” lipids - more likely to lead to clogged arteries – animation)

5. Lipids – why are they important?
Used to store lots of energy (fat)
Fats more difficult to break down (metabolize), but store more energy than carbohydrates
Form cell membranes (the “skin” of the cell)
Cell communication
Hormones
Many others…

6. Lipids: what do they look like?
Each molecule has a “head” with a “tail”
Tail usually consists of two or three strands

7. Lipids – cell membranes
“Phospholipids” make up cell membranes
Water is polar
Phospholipids have polar and non-polar ends
So water and phospholipids don’t mix well (one end likes water, the other doesn’t)
This end likes water
This end does not like water

8. Lipids – cell membranes
The “head” ends face outside towards water, and the “tail” ends are inside, away from water.
Water
Water Cell Water
This is a cell!
Time to stand up! I need five students (if we have time)

9. Carbohydrates – what are they?
Contain carbon, hydrogen, and oxygen
Include:
Monosaccharides (simple sugars)
Examples:
Fructose (honey, some fruits)
Lactose (dairy products)
Glucose (very common)
Disaccharides (ex: sucrose)
Polysaccharides (ex: starch)

10. Carbohydrates - why are they important?
Glucose - main source of energy for cells.
Plants make their own glucose
Animals ingest glucose in their food
Glucose contains less energy than lipids, but is easier to metabolize
(Blood sugar = glucose in blood)
Important to cell structure
Cellulose (plants: cell walls - fiber)
Chitin (animals: fingernails,
exoskeletons)

12. Carbohydrates - monosaccharides
Main ring of carbon and oxygen atoms
C – O
C C or
C – C

13. Carbohydrates – disaccharides
Two monosaccharides combined = disaccharide
Example: Sucrose (table sugar)
Sucrose = fructose & glucose combined
Plants make sucrose
Fructose + Glucose

14. Carbohydrates – polysaccharides
Many monosaccharides combined = polysaccharide (Pasta makes you row fasta!)
Plants store extra glucose as “starch”
Ex: potatoes
Glucose + Glucose + Glucose = Starch

15. Carbohydrates – polysaccharides
Animals store extra glucose as “glycogen”
Stored in our liver and muscle cells

16. Proteins – what are they?
Contain carbon, hydrogen, oxygen, and nitrogen
Are macromolecules made of amino acids joined together

17. Proteins – why are they important?
Form muscles, bone, other important structures (determine what you look like!)
Move materials in and out of cells
Helps with immune responses
Control the rate of chemical reactions (enzymes!)

18. Proteins – amino acids 20 amino acids exist in nature
Humans cannot create 8 of 20 amino acids
How do we get them?
Eat plants/animals (“essential amino acids”)
Without essential amino acids, you can not produce all proteins you need to survive
Your DNA creates proteins by organizing amino acids in your body

19. Proteins – what do they look like?
Primary structure – the order of the amino acids

20. Proteins – what do they look like?
Secondary and tertiary structure
Refer to how the protein is folded
Secondary – how amino acids twist or fold into something that looks like a chain
Tertiary – how the chain
is folder into a complex
molecule like this one

21. Proteins and chemical reactions
Occurs when one or more chemicals (reactants) react to form different chemicals (products)
Example: glucose and oxygen react to form carbon dioxide and water
Enzymes can speed up chemical reactions in living organisms (cells) – often millions of time faster!
“Catalyze” reactions

22. Proteins and enzymes
Enzymes provide a site for chemicals to come together to react
Kind of like a lock and key
Enzymes are specific – only help certain chemicals react.

23. What affects enzymes reaction rates?
Without enzymes, most reactions in cells would not happen quick enough for life
What affects the speed of enzyme reactions?
pH (the effect varies)
How much are produced by cells (more = faster)
Mixing (better mixed usually = faster)
Temperature (warmer usually = faster)
Too warm = “denatured” (egg white)
Denatured enzymes DO NOT FUNCTION

24. Amylase Amylase is an ENZYME that helps 1 starch molecule…
…get broken down into 3 glucose molecules
Without amylase, your body could not break down starch efficiently.