carbohydrates, proteins, lipids, and nucleic acids macromolecules
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Carbohydrates, proteins, lipids, and nucleic acids
macromolecules
Organic compoundcontain carbon Carbohydrates
Contain elements: hydrogen, oxygen, and carbon
Hydrogen and oxygen are found in the same ratio as water 2:1
Three types of carbohydrates:
1. Monosaccharides (simple sugars)Glucose, fructose, galactoseHave same molecular formula C6H12O6
Differ in their structural formulas
DisaccharidesTwo simple sugars joined together by
dehydration synthesisSucrose, maltoseHave same formula C12H22O11
PolysaccharidesHundreds of simple sugars bonded
togetherCellulose (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)
Building up of complex molecules from simpler molecules, with the release of water
Hydrolysis
Reverse process, large molecules are broken down to their building blocks, with the addition of water
Polymer
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
Saturated fats
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
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
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
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
4 levels of protein structure
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
Nucleotides consist of three parts: 1. phosphate 2. a five carbon sugar (ribose or deoxyribose) 3. nitrogen base
DNA plays key role in determination of heredity
RNA important in the synthesis of protein
Enzymes
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: 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 Examples:
Enzyme Maltase; substrate Maltose “ Lipase; “ Lipids “ Protease; “ Protein
Factors affecting enzyme action: pH
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
Temperature 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