Download Chemistry of Life - El Camino College

8/7/2013
Chemistry of Life
Why study chemistry in Biology?
Life is organized
Cells are considered to be the smallest structure that is alive
Atoms are the smallest unit of matter
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Atoms come in different flavors (elements)
There are 92 naturally occurring elements
Each element is abbreviated with a chemical symbol
Which are the most common elements in living things? _______
Atoms joined by a chemical bond form molecules
Molecules have a 3-D shape,
Shape is determined by
___________________
This shape will determine the molecule’s
function
Predict:
two molecules with similar shape:
if the molecule’s shape is changed:
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Chemical reactions: atoms change partners
By breaking existing bonds and forming new ones
2 H + O  2H O + energy
Reactants
Products
Is matter or energy created during a chemical reaction?
Matter and energy can not be created nor destroyed ONLY transformed!
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Living things are made of organic molecules
• This molecules have a backbone of carbon atoms joined
by chemical bonds
• There are some inorganic molecules
present in living things
• Smaller organic molecules (monomers)
are joined together
to form bigger ones called _______________
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Cells make a great number of large molecules
from a small set of small molecules
Carbohydrates:
can be grouped into three classes
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Carbohydrates: are the source of cells energy and
structural material
Lipids: diverse group of molecules
that don’t mix with water
• Fats and oils
•Steroids
• •Phospholipids
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Lipids and Your Health:
Saturated versus unsaturated fats
Lipids: provide long term energy storage,
cell membrane components and hormones
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Nucleic Acids are chains of nucleotides
Nucleic Acids:
like letters on a sentence carry information
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Proteins: chains of amino acids
A protein’s sequence of amino acids determines its shape which determines …
A protein’s shape is sensitive to changes
in its surroundings
Changes in temperature, salt or acid concentration
can lead to denaturation
Why does a denatured protein no longer function normally?
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Proteins: essential to the structure and activities of life
• Structure (keratin)
• Movement
• Transport (Hemoglobin)
• Hormones (insulin)
• Defense (antibodies)
• Enzymes (lactase)
An enzyme speeds up a cell’s chemical reaction
- A specific enzyme catalyzes each cellular reaction
- Enzymes are not consumed or affected during a chemical reaction
- Surrounding environment affects enzyme activity
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Enzyme Lab
Reactants (substrate) ----------- products
Part 1: Observing Catalase Enzyme Activity
2(H2O2) ---------- 2H2O + O2
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Room
temp
H202
Record how rapidly the solution bubbles
0= no reaction
1= slow….. 5= very fast
At room temp assume rate is 4!
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Part 2: Effect of Temperature on Enzyme Activity
Ice bath
two tubes, one with liver and one with peroxide
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ICE
BATH
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ROOM
TEMP
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BOILING
TEMP
H202
H202
H202
Part 3. Enzyme specificity
A
B
C
D
Enzyme
water
enzyme
water
milk
Milk
sucrose
sucrose
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Test strips for presence of glucose
Part 4.
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