biochem notes

7/21/2019 Biochem Notes

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BIOCHEMISTRY



½ cup of CHEX MIX

contains 13 g of carbs = 4%

daily value….

How much more can you have

the rest of the day???



½ cup of CHEX MIX

contains 13 g of carbs = 4%

daily value….

How much more can you have

the rest of the day???

_ _ = 13

100 X

X= 325 g



These spinach imposters contain less than 2 percent of “spinach powder” seasoning. Yum! And thewraps’ green color? Courtesy of food dyes yellow #5 and blue #1.

When was the last time you saw a flowering field of disodium phosphate? Or how about a freshcrop of maltodextrin? Didn’t think so. These cheese puffs consist largely of corn, but they’ve been

processed to the point that no 20th-century farmer would ever recognize them as food.



Carbon

Can form large and complex structures

Can bond with other non metals likeoxygen and hydrogen

Organic Chemistry - study of carboncompounds



Organic vs. Inorganic Compounds

Organic Compounds –Compounds that containcarbons.

Lipids, proteins, nucleicacids, carbohydrates

Inorganic Compounds –Compounds that do NOTcontain carbon.

Salts, water, oxygen



Macromolecules

Macromolecules –“Giant molecules” madefrom smaller molecules

Formed by a processknown aspolymerization, (thesmaller units, or

monomers, join

together to formpolymers.)



Organic Compounds

Four groups found in living things are:

1. Carbohydrates

2. Lipids

3. Proteins

4. Nucleic acids



Carbohydrates (carbo =carbon hydrate = H20)

Compounds made up of carbon,hydrogen, and oxygen atoms

Ratio of 1 : 2 : 1.



Uses of Carbohydrates

Living things use carbohydrates as:

1. Main source of energy (starches and sugars)

2. Plants and some animals also use

carbohydrates for structural purposes



Uses of Carbohydrates

Plants

Store excess sugar in the form of starch forenergy

Use tough, flexible cellulose fibers to givethem their strength and rigidity

Animals

Store excess sugar in the form of glycogen

Located/made in liver and muscles

Both

Glucose is main energy source for cells



Classification of Sugars

Monosaccharides (monomer) – Single(simple) sugar molecules

Examples: Glucose, Galactose, Fructose

Disaccharides – Double sugar molecules Examples:

Glucose + Fructose = Sucrose

Glucose + Galactose = Lactose

Glucose + Glucose = Maltose

Polysaccharides (polymer) – More thantwo monosaccharide molecules

Examples: Starch, Cellulose, Chitin, Glycogen



Classification of Sugars



Composition of Lipids

Made mostly from carbon, hydrogen and

oxygen atoms Usually has relatively small amounts of

oxygen

Monomer :Glycerol molecule+ fatty acids

Steroid (4 rings)



Saturated and Unsaturated Lipids

Saturated - If each carbon atom in alipid's fatty acid chains is joined toanother carbon atom by a single

bond. “ Saturated ” means it has the maximum

possible number of hydrogen atoms

Solid at room temperature

Examples – Cholesterol, butter, chocolate



Saturated and Unsaturated Lipids

Unsaturated- If there is at least onecarbon-carbon double bond in a fattyacid. Liquid at room

temperature

Examples - Corn oil,sesame oil, canola oil,

and peanut oil



Lipids

Common categories of lipids are1. Fats

2. Oils

3. Waxes Functions:

1. Can be used to store energy

2. Some lipids are important parts of biological

membranes and waterproof coverings3. Can serve as chemical messengers (steroids

only)

Generally not soluble in water



Protein Proteins - Macromolecules that contain

nitrogen as well as carbon, hydrogen,oxygen and nitrogen

Made up of chains of amino acids foldedinto complex polypeptides.

Amino Acids - Compounds with an aminogroup (−NH2) on one end and a carboxyl

group (−COOH) on the other end.



Amino Acids

There are more than 20 different aminoacids.

What distinguishes one amino acid from

another is the R-group (functional group)section of the molecule.



Functions of Proteins

Each protein has a specific

role.1. Some proteins control the rate

of reactions and regulate cellprocesses.

Enzymes2. Some are used to form bones

and muscles and tissues.

Structurally = collagen and keratin

3. Others transport substances intoor out of cells or help to fightdisease. Antibodies

Transport channels in the cellmembrane



Nucleic Acids

Nucleic acids - Macromoleculescontaining hydrogen, oxygen, nitrogen,carbon, and phosphorus.

Made up of repeating units callednucleotides

Each nucleotide contains:

1. 5-Carbon Sugar

2. Phosphate Group3. Nitrogenous Base



Nucleic Acids

Function: Store genetic information

Transmit genetic information

Two Kinds of NucleicAcids:1. Ribonucleic acid (RNA)

Contains the sugar ribose

Single stranded

2. Deoxyribonucleic acid (DNA) Contains the sugar deoxyribose

Double stranded



Dehydration Synthesis

Dehydration synthesis – A chemical reaction that buildsup molecules by losing water molecules.

Used to put together monomers to build polymers.

The “dehydration” part is the removal of water

The “synthesis” part is the joining of the two smallercompounds to create one larger one

TRICK: There will always be one less water produced thanthe number of monomers joining together.

http://www.youtube.com/watch?v=UyDnnD3fMaU






Hydrolysis

Hydrolysis – The breaking of chemical bonds bythe addition of water. (lysis= break)

Used to break down polymers into theirmonomers.



Chemical Reactions

Chemical Reaction - A process thatchanges one set of chemicals into anotherset of chemicals.

Always involve the breaking of bonds inreactants and the formation of new bonds inproducts.



Chemical Reactions

Reactants - The elements or compoundsthat enter into a chemical reaction.

Products - The elements or compounds

produced by a chemical reaction.

Na + Cl NaClReactants Products



Energy in Reactions Because chemical reactions involve

breaking and forming bonds, they involvechanges in energy.

Did you know? ( Not in notes) Chemical reactions that release energy often

occur spontaneously.

Energy is released in the form of heat, light, and

sound. Chemical reactions that absorb energy will not

occur without a source of energy.

Every organism must have a source of energy tocarry out necessary chemical reactions.



Organisms and Energy

Plants Get their energy by trapping and storing the

energy from sunlight in energy-richcompounds.

Animals Get their energy when they consume plants or

other animals.

They release the energy needed to grow tall,

to breathe, or to think through the chemicalreactions that occur when humans metabolize,or break down, digested food.



Activation Energy

Activation Energy - Theenergy that is needed toget a reaction started.

The peak of each graphrepresents the energyneeded for the reaction togo forward.

The difference between thisrequired energy and theenergy of the reactants isthe activation energy.



Catalysts

Some chemical reactions that make lifepossible are too slow or have activationenergies that are too high to make them

practical for living tissue and cells.

Catalyst - A substance that speeds up therate of a chemical reaction by lowering areaction’s activation energy.



Enzymes

Enzymes - Proteins that act as biologicalcatalysts.

Speed up chemical reactions that take place in

cells. (by lowering activation energy) Very specific, generally catalyzing only one

chemical reaction.

Part of an enzyme's name is usually derived

from the reaction it catalyzes.



Enzyme Substrate Complex

Active site



How Do Enzymes Work?

Substrates - The reactants of enzyme-catalyzedreactions.

The Enzyme-Substrate Complex

Enzymes provide a site where reactants can be brought

together to react.

This site reduces the energy needed for reaction.

Each protein has a specific, complex shape.

Active Site – The site on the enzyme where substratesbind.

The active site and the substrates have complementaryshapes, which is often compared to a lock and key model.



Regulation of Enzyme Activity

Enzymes can be affected by any variablethat influences a chemical reaction suchas:

1. pH2. Temperature

3. Cells contain proteins that help to turn keyenzymes “on” or “off ”



Animations to help explain:

http://www.lpscience.fatcow.com/jwanamaker/animations/Enzyme%20activity.html





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