Chapter 2 - Biochemistry Organic Compounds Chapter 2 - Biochemistry

Lipids, Carbohydrates, and Proteins Chapter 2 - Biochemistry

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

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)

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…

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

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

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)

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)

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)

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

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

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

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

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

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!)

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

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

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

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

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. http://www.youtube.com/watch?v=XTUm-75-PL4

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

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.