View
220
Download
1
Category
Tags:
Preview:
Citation preview
Introduction
Living things are composed of an array of molecules We need to classify them
Certain qualities The more common biochemically important molecules
are:
Molecule Subcomponents
Carbohydrates Monosaccharides
Lipids Glycerol & fatty acids
Proteins (polypeptides) Amino acids
Nucleic acids Nucleotides
Common biochemicals & their structure
Classified as organic or inorganicAll organic molecules contain the element
carbonHowever, not all carbon-containing
molecules are organic Example = carbon dioxide (not organic)
Some of the most important categories …
Category Subcategory Example molecule
Carbohydrates Monosaccharides Glucose, galactose, fructose
Disaccharides Maltose, lactose, sucrose
Polysaccharides Starch, glycogen, cellulose
Proteins Enzymes, antibodies
Lipids Triglycerides, phospholipids
Nucleic Acids DNA, RNA
You should learn to recognize the structures of common molecules
BUT you do not need to draw them (yea!) Wait till organic chemistry …
Open your book to page 57Look at figures 3.2, 3.3, 3.4, and 3.5 Answer question 4
Carbohydrates
Different “sizes” Monosaccharides, disaccharides, polysaccharides
All serve many functions in living organisms Contain only three elements: C, H, O
Hydrogen and oxygen in a 2:1 ratio FYI: many of the carbons in food you eat (carbs)
will be eliminated from your body in carbon dioxide that you breath out
Monosaccharide – simple sugar
Relatively small; taste sweet and soluble in water
Examples: Glucose: made by green leaves using light
energy, our bodies transport it in our blood, respiration (chemical fuel), building block for larger molecules
Galactose Fructose (found in fruits – makes them sweet)
Disaccharides
Made of 2 monosaccharide molecules Examples:
Sucrose (glucose + fructose) Maltose (glucose + glucose) Lactose (galactose + glucose)
Polysaccharides
Built from many monosaccharide molecules connected by glycosidic links
Examples Starch (polymer of glucose) Glycogen (polymer of glucose)
Stores glucose in liver and muscles Cellulose (polymer of glucose)
Component of cell walls
Lipids
Lipids occur in living things as animal fats, plant oils, phospholipids of cell membranes, and steroids
At room temperature, oils are liquid and fats are solid
Contain C, O, and H (like carbs), but proportion of oxygen is much less
Insoluble in water; hydrophobic Can be dissolved in organic solvents (alcohol)
Lipids
Fats and oils are compounds called triglycerides Formed when water is removed between fatty acids and
glycerol
Long hydrocarbon tails
The Role of Lipids
Energy storage Lipids store about twice as much chemical
energy as carbohydrates
If you eat more food than you burn, your body will store much of the excess as fat in adipose tissue
Other important roles of lipids
1. Energy storage Less oxygen atoms/more concentrated source
2. Metabolic water source3. Thermal insulation and buoyancy 4. Water proofing of hair and feathers 5. Electrical insulation
Myelin sheath
Amino Acids, peptides, and proteins
Contain nitrogen, sulphur, hydrogen, carbon and oxygen Amino group: NH2 Carboxyl group: COOH
Amino acids peptides and proteins Polypeptide and protein are used interchangeably
Once the chain is constructed, it takes a specific shape – shape matters with proteins Shape function
Amino acids
Proteins are made from 20 amino acids Also attached is an R group
Differ different chemical characteristics
Most macromolecules are polymers
Carbohydrates, lipids, and proteins are chainlike molecules called polymers Polymer is a long molecule consisting of many
similar or identical building blocks linked by covalent bonds
Monomers
Condensation and hydrolysis
Many organisms rely on food to gain the building block molecules
When animals eat, food is digested (or hydrolyzed) into the building blocks Going from polymers to monomers
These building blocks are transported to body cells and bonded together to form larger molecules
What happens when you eat?
Foods are chemically digested in your alimentary canal
Hydrolyzing enzymes are required Each reaction is called a hydrolysis and
requires a molecule of water as a reactant Think about the word hydrolysis:
Hydro = water Lyse = split
Examples of hydrolysis
Hydrolysis of a disaccharide in two …
Hydrolysis of a triglyceride lipid to …
Hydrolysis of a polypeptide to …
Condensation reactions
Are the reverse of hydrolysis Condensation reactions occur to re-form
larger biochemical molecules Water molecules are products rather than
reactants Also requires a different type of enzyme
Condensation Reaction (or Dehydration Synthesis)
The process of connecting monomers to create a polymer This process requires
energy and is aided by enzymes
Removes water molecules
One monomer provides a hydroxyl group and the other provides a hydrogen
Wrap Up
All organic molecules contain the element _________ Carbohydrates exist as _______, _______, & _______ The smallest carbohydrates are ___________ The subcomponents of other biochemically important
organic molecules are: _____________, which make up proteins _____________, which make up lipids (fats and oils) _____________, which make up nucleic acids (DNA and RNA)
Subcomponents are bonded together by ___________ Larger molecules are split by ____________ Although carbohydrates and lipids are used for energy
storage …
Recommended