Transcript Carbohydrates, proteins, lipids, and nucleic acids

Carbohydrates,
proteins, lipids, and
nucleic acids
macromolecules
Organic compound
contain carbon
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Carbohydrates
 Contain
elements: hydrogen, oxygen, and
carbon
 Hydrogen and oxygen are found in the same
ratio as water 2:1
Three types of carbohydrates:
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1. Monosaccharides (simple sugars)
 Glucose,
fructose, galactose
 Have same molecular formula C6H12O6
 Differ in their structural formulas
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Disaccharides
 Two
simple sugars joined together by
dehydration synthesis
 Sucrose, maltose
 Have same formula C12H22O11
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Polysaccharides
 Hundreds
of simple sugars bonded together
 Cellulose (supporting material found in cell
walls of plant cells)
 Starch (plant storage of sugar)
 Glycogen (animal storage of sugar, found in
muscle and liver cells)
Dehydration synthesis
(Condensation reaction)
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Building up of complex molecules from
simpler molecules, with the release of
water
Hydrolysis
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Reverse process, large molecules are
broken down to their building blocks,
with the addition of water
Polymer
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Collection of many similar, repeating
units to form a large molecule
Lipids
Fats, oils, and waxes, contain hydrogen,
carbon, and oxygen
 Typically consists of a glycerol molecule
bonded to 3 fatty acids known as a
triglyceride
 Formed by dehydration synthesis
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Saturated fats
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Role in heart disease
Have animal origins
Butter, lard, whole milk, and milk products
Solid at rm temp
Saturated with hydrogen atoms which are
attached to each of the carbon atoms
Unsaturated fats
Have at least one carbon to carbon
double bond
 Missing hydrogen atoms
 Liquid at rm temp
 Plant oils such as corn oil, olive oil,
sunflower oil, and fish oils
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Proteins
Contain carbon, hydrogen, oxygen, and
nitrogen and in many instances, sulfur
 Large polymers of many repeating amino
acid units
 20 different types of amino acids
 More than 3,000 amino acids in a
protein
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Bond between amino acids is called a peptide
bond
A chain of amino acids is a polypeptide
Shape of protein molecule itself depends on
the nature of the attraction between the
different parts of the polypeptide chain
Formed by dehydration synthesis
Polypeptide, not necessarily same
as a protein
Example
 Polypeptide would be a strand of yarn
 Protein would be a sweater
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Shape of protein
Sequence of amino acids determines
proteins shape
 Shape determines how protein functions
 Function of protein depends on its
ability to recognize and bind to some
other molecules
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4 levels of protein structure
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1. Primary=sequence of covalently joined
amino acids in a polypeptide (linear)
2. Secondary=bending and hydrogen bonding
of a polypeptide to form helices and pleated
sheets
3. Tertiary=overall shape of polypeptide
4. Quaternary=association between 2 or more
polypeptides
Nucleic acids
Contain carbon, hydrogen, oxygen,
nitrogen, and phosphorus
 Largest organic molecules known
 Made up of thousands of repeating units
called nucleotides
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Nucleotides consist of three parts:
 1.
phosphate
 2. a five carbon sugar (ribose or deoxyribose)
 3. nitrogen base
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DNA plays key role in determination of
heredity
RNA important in the synthesis of protein
Enzymes
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Organic catalysts, they affect the rate of a
chemical reaction w/out being changed
Can be used over and over again
Protein in nature and specific to their action
Often work with coenzymes which are smaller
and not protein, and are active only with
enzymes
 Example
of coenzymes (B-complex vitamins)
How enzymes function:
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Enzymes are huge compared to the molecules on which they
interact
Only a small portion of the enzyme functions when it is active,
called the active site
The molecule on which the enzyme acts is called the substrate
They work like a “lock and key”
The name of the enzyme usually has the ending –ase, added to
the stem of the word which is taken from the substrate
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Examples:
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Enzyme Maltase; substrate Maltose
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Lipase;
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Lipids
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Protease; “
Protein
Factors affecting enzyme action:
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pH
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Temperature
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Depends on enzyme; maltase functions best in a pH of 7; pepsin, found in the
stomach at a pH of1.5-2.2; trypsin, in the small intestine, pH 7.9-9.0
Most function best at body temperature 370 C
Lower temp activity of enzyme decreases
As temp is raised activity increases until a maximum is reached at about 400
C; beyond this point enzyme becomes distorted and enzyme deactivation
occurs
Relative amounts of enzyme and substrate
Amt of enzyme increased, while substrate remains constant; rate of
reaction is increased to a point; after that rate remains constant
 Amt of substrate is increased, while concentration of enzymes remains the
same; rate of reaction will increase and will continue up to the point where
every available enzyme molecule is actively involved in the reaction
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