Transcript Chemistry of Life

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Organic Compounds
&
Inorganic Substances
in Living Things
ksuweb.kennesaw.edu/~vking2/Chemistry%20of%20Life%20Post.ppt
www.wyalusingrams.com/53942041017952357/lib/53942041017952357/UNIT_2_chemistry.ppt
faculty.sgc.edu/asafer/BIOL1107/chapt02_lecture.ppt
Introduction
a) Organic compounds are
carbon-based and are the
key substances that make
up living things.
b) Inorganic substances also
are important to organisms,
but do NOT contain carbon
c) Organic (Carbon) Compounds
1.
2.
All living things are made MOSTLY of
organic compounds!
Yes, you’re organic! 
The 4 Types of Organic (C) Compounds
3. Organic compounds are made of
repeating units called monomers
4. Organic compounds FORM by
dehydration synthesis
(condensation)
5. Organic compounds are BROKEN
DOWN by hydrolysis
(decomposition)
Part 1:
Types of Organic (C) Compounds
1) Carbohydrates
Main Use: immediate energy
– contain C, H, and O
– polysaccharide is a long chains of
monomers
Examples of carbohydrates:
sugars & starches
a) Monosaccharides:
• glucose (main source of
energy for cells)
• fructose (in fruit)
b) Disaccharides
• sucrose (table sugar)
• lactose (in milk)
c) Polysaccharides (starches)
•
•
glycogen starch stored in liver
cellulose fibers in plants
2) Lipids (fats; triglycerides)
Main Use: long term energy storage
– contains C, H, and O
– composed of glycerol + long fatty
acid chains
a) Saturated fats – contain single
bonds
- solid fats (related to heart disease)
e.g. butter, lard, coconut oil, palm oil
b) Unsaturated fats – contain double
bonds
- liquid oils (healthier)
e.g. peanut, corn, olive oils
c) Steroids – have a four ring structure
Examples:
 cholesterol (LDL, HDL)
 sex hormones (testosterone,
estrogen),
 cell membrane
 bile
3) Proteins
Main Uses:
Structural –muscle protein fibers
Enzymes – catalysts to speed up
chemical reactions
Energy– only if starvation occurs
– contains
C, H, O, N
– monomer = amino acids
– polypeptide is a long chain of amino
acids linked by peptide bonds
Examples of proteins

hemoglobin (in red blood cells)
 digestive enzymes
Enzymes speed up
chemical reactions!
hydrolysis or
decomposition
(e.g. digestion)
dehydration synthesis
- assembles larger organic
compounds
4) Nucleic Acids
Main Use: store and carry genetic
information
C, H, O, N and P
– monomer = nucleotide
–
Examples of nucleic acids
 DNA (deoxyribonucleic acid) is double
stranded
 RNA (ribonucleic acid) is single stranded
MATCHING
Monomer
Organic compound
1. nucleotides
carbohydrates
2. monosaccharides
lipids
3. amino acids
proteins
4. glycerol + fatty
acid chains
nucleic acids
Part 2: Inorganic Substances
in Living Things
(no carbon)
I. Water & Organisms

about two-thirds (2/3) of the human body is
water!!!

Water is essential for cell function; it is
required in chemical reactions to sustain life

Water is the only common substance in
nature in all 3 physical states of matter–
solid, liquid and gas
A) Polarity of Water
Water is a polar molecule with positive
(+) and negative (-) ends
 this leads to easy formation of hydrogen
(H) bonds between water molecules

Water is a polar molecule
Oxygen
H
H
H
Hydrogen (H) bonds
form between water
molecules
H
Oxygen
H bond
H
H bond
H
H
H
B) Properties of Water
1. cohesion--water molecules H
bond to one another easily and
“cling” together
cohesion  surface tension
water strider (or skater)
2. adhesion--water molecules easily
form H bonds to other non-water
substances
e.g. water travels
UP through plant
stems & tree
trunks
adhesion  capillary action
3. high specific heat!
Water has high specific heat and
resists changes in temperature
e.g. sweat absorbs some of the heat
of your body
4. high heat of vaporization
* It takes a significant temperature
increase for water to evaporate!
5. Water is less dense as a solid!

water E X P A N D S when it freezes
 Therefore, ice FLOATS in water!!
 and cells die when the cytoplasm
(fluid) inside freezes!
e.g. frostbite
Euphausid shrimp under ice
Ice fishing
6. High solubility
 water molecules surround
molecules
 water is practically a universal
solvent
•
Many substances are dissolved in
biological fluids (vitamins, glucose,
oxygen, salts, carbon dioxide, wastes)
• Detection by blood & urine tests
II. Acids & Bases
1.
Acids are substances that form
hydrogen ions (H+) in water
2. Bases are substances that form
hydroxide ions (OH-) in water
3. The pH scale measures the acidity &
alkalinity.
pH scale
_________________________________________
0
7
14
acids
bases
pH < 7
pH > 7
neutral
pH = 7
III. Oxygen (O2)
•
•
•
cells use O2 to breakdown food
into ATP energy molecules during
cellular aerobic respiration
You need to breathe O2 for energy!
No O2, no energy, no life!
IV. Salts
– dissolve easily in water
– form ions (electrolytes) for metabolism
(chemical reactions for cell activities)
e.g. Na+, Mg2+, Ca2+, K+, Cl-
Assignment #27:
Create a thinking map entitled,
“Chemicals in Living Things”
Enzymes


Enzymes are proteins that function as catalysts for
chemical reactions
– they speed up the rate of reactions by lowering the
activation energy needed for a chemical reaction to
happen
Lock and Key Model
–
–
Each enzyme has a specific shape (lock)
Substrate (key)
 the
–
reactant that must fit into active site of
enzyme for reaction to occur
 One enzyme  one specific reaction
Enzymes are not changed during the reaction; “reusable”

Coenzymes – smaller organic molecules that are
needed for a proper fit of an enzyme to substrate
e.g. vitamins

Cofactors – ions needed for proper fit of
enzyme/substrate
e.g. Minerals
Denaturation – the change of a protein’s shape

–
–
Change the shape, change (usually ruin) the function
possible causes: high temperatures, wrong pH or salt
concentration