biochemistry to be used with biochemistry guided notes
TRANSCRIPT
Biochemistry
To be used with Biochemistry Guided Notes
Organic vs. Inorganic MoleculesOrganic Inorganic
Does not contain C, H, and O at same time (Example: H20)
Carbon is the key element—the element of life
Water: makes up 60 to 98% of living things—necessary for chemical activities and transport
Salts: help maintain water balance
Example: Gatorade—electrolytes
Carbon can bond with itself and form many times for bonds (single, double, triple and rings)
4 Organic Molecules:
Carbohydrates Lipids
Nucleic Acids Proteins
Contains Carbon (C), Hydrogen (H), and Oxygen (O) (Example: C6H12O6)
Acids and Bases: -pH Scale -Important for enzyme function
Carbohydrates
• Sugars and complex carbohydrates (starches)
• Contain the carbon, hydrogen, and oxygen (the hydrogen is in a 2:1 ratio to oxygen)
• End in -ose
Monosaccharides
• Simple sugars
• All have the formula C6H12O6
• Have a single ring structure
• Example: Glucose
Disaccharides
• Double sugars
• All have the formula C12H22O11
• Example: sucrose (table sugar)
Polysaccharides• 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
How are complex carbohydrates formed?
• 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 chiefly function in energy storage, protection, and insulation– contain carbon, hydrogen, and oxygen but the
H:O is not in a 2:1 ratio– Examples: fats, oils, waxes, steroids
• Lipids tend to be large molecules
Lipids
• Lipids are formed from one glycerol molecule and 3 fatty acids
• 3 fatty acids + glycerol lipid (fat)
4 Types of Lipids1.Fats: from animals
• Saturated: solid at room temperature• All single bonds in the fatty acid tail• 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:• One important molecule that is classified in
this category is cholesterol• High levels could lead to heart disease
Proteins
• Proteins: contain the carbon, hydrogen, oxygen, and nitrogen– Made at the ribosomes– Composed of amino acid subunits
Proteins
• Major Protein Functions: – Growth and repair– Energy
• Usually end with -in:– Example: Hemoglobin
Making Proteins
• Dehydration synthesis of a dipeptide– Dipeptide: formed from two amino acids
• amino acid + amino acid dipeptide + water
Breaking down Proteins
• Hydrolysis of a dipeptide • dipeptide + water amino acid + amino acid
Proteins
• Polypeptide: composed of three or more amino acids– These are proteins
• Examples: insulin, hemoglobin, and enzymes
• There are a large number of different types of proteins:– The number, kind and sequence of amino
acids lead to this large variety
Nucleic Acids
• Nucleic Acids: present in all cells – DNA: contains the genetic
code of instructions throughthe synthesis of proteins
• found in the chromosomesof the nucleus
– RNA: directs protein synthesis
• found in nucleus, ribosomes & cytoplasm
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 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