Transcript Chapter 2 - Biochemistry

Biochemistry
To be used with Biochemistry
Guided Notes
Gaccione/Bakka
Organic vs. Inorganic Molecules
Organic
Inorganic
Contains Carbon (C), Hydrogen (H), Does not contain C, H, and O
and Oxygen (O)
at same time (Example: H20)
(Example: C6H12O6)
Carbon is the key element—
the element of life
Carbon can bond with itself and form
many times for bonds (single,
double, triple and rings)
Water: makes up 60 to 98% of living
things—necessary for chemical
activities and transport
Salts: help maintain water balance
Example: Gatorade—electrolytes
4 Organic Molecules:
1. Carbohydrates
2. Lipids
3.Proteins
4. Nucleic Acids
Acids and Bases:
-pH Scale
-Important for enzyme function
Carbohydrates give us instant energy
• Sugars and starches(complex carbohydrates)
• Contains 3 elements: carbon,
hydrogen, and oxygen
In all carbs the hydrogen is in a 2:1 ratio to oxygen)
• Most carbohydrates end in -ose
Monosaccharides - means one sugar
•
•
•
•
AKA Simple sugars
All have the formula C6H12O6
Have a single ring structure
Example: Glucose
Fructose
Disaccharides - means two sugars
• All have the formula C12H22O11
• Example:
glucose + fructose = sucrose (table sugar)
Isomers
• Example: Glucose & Galactose
• Isomers - compounds that have same
formula different 3-D structure
Polysaccharides (polymers)means many sugars
• Three or more simple sugar units
• Examples:
– Glycogen: animal starch stored in the liver and muscles
– Cellulose: indigestible in humans: forms cell wall in plants
– Starches: used as energy storage
Comparing saccharides
Monosaccharides
Polysacchrides
Disaccharides
How are complex carbohydrates
(polysaccharides) formed?
• Condensation (Dehydration) synthesis:
combining simple molecules to form a more
complex one with the removal of water
• Example:
– monosaccharide + monosaccharide  disaccharide + water
– C6H12O6 + C6H12O6  C12H22O11 + H2O
• Polysaccharides are formed from repeated
dehydration synthesis
Monosaccharide + Monosaccharide 
Disaccharide
+ Water
How are complex carbohydrates
broken down?
• Hydrolysis: the addition of water to a
compound to split it into smaller subunits
– also called chemical digestion
• Example:
– disaccharide
+ water  monosaccharide + monosaccharide
– C12H22O11 + H2O  C6H12O6 + C6H12O6
Lipids
• Lipids (Fats): lipids 4 function
1. energy storage
2. protection
3. insulation
4. found in cell membranes
• Three elements found in lipids
1. carbon
2. Hydrogen
3. oxygen
The H:O is not in a 2:1 ratio
Lipids
– Examples:
1. meat
2. bacon
3. cheese
• Lipids tend to be the largest of organic
molecules
Lipids
• Lipids are composed of
one glycerol molecule and 3 fatty acids
Lipid formular
• glycerol +
3 fatty acids  lipid (fat)
• Condensation (Dehydration) synthesis:
combining simple molecules to form a lipid
with the removal of water
• Hydrolysis: the addition of water to a lipid
splits it into smaller subunits
Four Types of Lipids
1.Fats: from animals
• Saturated: solid at room temperature
• All single bonds in the fatty acid tail make it very
difficult to break down
4 Types of Lipids
2. Oils: from plants
•
Unsaturated: liquid at room temperature
•
•
Presence of a double bond in the fatty acid tail
Ex. Vegetable oils
Four Types of Lipids
3. Waxes: ear wax & bees wax

4 Types of Lipids
4. Steroids:
• Examples:
1. Cholesterol - High levels could lead to heart disease
2. Estrogen - female hormone
3. Testosterone - male hormone
Proteins
• Proteins: contain the elements
1. carbon
2. hydrogen
3. oxygen
4. Nitrogen
– Made at the ribosomes
– Composed of subunits called amino acid
– 20 amino acids
Proteins
• Major Protein Functions:
Growth and repair & Energy
• Usually end with -in:
• Example:
1. Hemoglobin (blood)
2. Insulin (breaks down glycogen)
3. Enzymes(speeds up chemical reactions)
Making Proteins
• Condensation (Dehydration) synthesis of
a dipeptide.
Breaking down Proteins is call Hydrolysis
dipeptide + water
amino acid + amino acid
• Dipeptide: formed from two amino acids
• amino acid + amino acid  dipeptide + water
Proteins
• Polypeptide: composed of three or more amino
acids
• Examples of proteins:
1. muscle
5. insulin
2. Skin
6. hemoglobin
3. Hair
7. enzymes
4. Nails
• There are a large number of different types of
proteins:
– The number, kind and sequence of amino acids lead to
this large variety
Enzymes
• Catalyst: inorganic or organic substance
which speeds up the rate of a chemical
reaction without entering the reaction itself
– Examples: enzymes (organic) and heat
(inorganic)
• Enzymes: organic catalysts made of
protein
– most enzyme names end in –ase
– enzymes lower the energy needed to start a
chemical reaction (activation energy)
How enzymes work
1. Enzyme forms a temporary association with a
the substance it affects
•
These substances are known as substrates.
2. The association between enzyme and
substrate is very specific—like a Lock and Key
•
This association is the enzyme-substrate complex
3. While the enzyme-substrate complex is formed,
enzyme action takes place.
4. Upon completion of the reaction, the enzyme
and product(s) separate
5. The enzyme is now able to be reused
Enzyme-Substrate Complex
Enzyme Terms
• Active site: the pockets in an enzyme
where substrate fits
– Usually enzyme is larger than substrate
• Substrate: molecules upon which an
enzyme acts
• All enzymes are proteins
• Coenzyme: non-protein part attached to
the main enzyme
– Example: vitamins
Proteins in action
enzyme
substrate -------------> product
Lock and
Key Model
Factors Limiting Enzyme Action
• pH: pH of the environment affects enzyme
activity
– Example: pepsin works best in a pH of 2 in stomach
Amylase works best in a pH of 6.8 in mouth--saliva
Factors Limiting Enzyme Action
•
Temperature: as the temperature
increases the rate of enzymes increases
–
Optimum Temperature: temperature at
which an enzyme is most affective
•
•
Humans it is 37 degrees C or 98.6 degrees F
Dogs between 101 and 102 F
When Temperatures Get Too High
• Denature:
– Change in their shape so
the enzyme active site no
longer fits with the
substrate
– Enzyme can't function
– Above 45 C or 130 F most
enzymes are denatured
• Why do we get a fever
when we get sick?
General Trend vs. Denaturing
Factors Limiting Enzyme Action
• Concentration of Enzyme and Substrate
– With a fixed amount of enzyme and an excess of
substrate molecules
• the rate of reaction will increase to a point and then
level off
– Leveling off occurs because all of the enzyme is used up
• Excess substrate has nothing to combine with
– Add more enzyme reaction rate increases again
Enzyme-Substrate Concentration
Nucleic Acids
• Nucleic Acids: found in the
chromosomes in every nucleus of all cells.
DNA: contains the genetic code of instructions.
found in the chromosomes
of the nucleus
Consists of 3 parts called a nucleotide:
1. phosphate
2. sugar
3. nitrogen base
– RNA: directs protein synthesis
• found in nucleus, ribosomes & cytoplasm.