Biomolecules - Part 1
What are the four major types of biological molecules?
Carbohydrates, lipids, proteins, and nucleic acids.
What is a macromolecule?
A large molecule made of smaller units bonded together
Why are structure and function inseperable in biology?
A molecules shape determines how it works
What are the four most abundant elements in living cells?
Carbon, hydrogen, oxygen and nitrogen
Why is carbon so important in biological molecules?
Carbons can form 4 bonds allowing if to build complex structures
What are functional groups?
They are small groups of atoms that attacj to carbon skeletons and change how molecules behave
How do functional groups affect biomolecules?
They control molecules chemical properties and function
What is meant by carbon skeletons in biological molecules?
Carbon skeletons are the chains or rings of carbon atoms that form the backbone of biomolecules
What are isomers?
Isomers are compounds that have the same molecular formula but different structures and properties
What are structural isomers?
They have different covalent arrangements of their atoms.
What are cis-trans isomers?
They have the same covalent bonds but differ in the spatial arrangement of atoms around the double bond
What are enantiomers?
Isomers that are mirror images of each other
Do biological systems use all isomers?
No, they usually use or produce only one specifc isomer
What is a dehydration reaction in polymer synthesis?
A dehydration reaction occurs when two monomers bond together through the loss of a water molecule
How are polymers broken down into monomers?
By hydrolysis, which is the reverse of a dehydration reaction
What is hydrolysis?
Its a chemical reaction where a bond is broken by adding water
Why is there so much diversity in polymers?
There are thousands of different macromolecules in each cell, and polymer structures vary between cells, species, and individuals.
What are carbohydrates and what do they do?
They serve as both fuel and building material in living organisms
What are the simplest carbohydrates?
Monosaccharides, also known as single sugars
What are polysaccharides?
Carbohydrate molecules made from many monosaccharide units.
What is the general chemical ration in carbs?
Carbon hydrogen and oxyfen in the ration 1:2:1
What is the general molecular formula of monosaccharides?
Monosaccharides usually have molecular formulas that are multiples of CH2O
what is the most common monosaccharide?
Glucose
How are monosaccharides classified?
1. location of carbonyl group
2. number of carbon atoms in carbon skeletons
What is a disaccharide and how is it formed?
When two monosaccharides join in a dehydration reaction. Two sugars link together through a covalent bond called glycosidic linkage
What are polysaccharides?
They are long chains of sugars (polymers) with storage or structural functions
What is starch and where is it stored?
Its a storage polysaccharide in plants made entirely of glucose
What is glycogen and where is it stored?
Glycogen is a highly branched storage polysaccharide in animals. found in liver and muscle cells
What is cellulose and what is its function?
Its a structural polysaccharide that forms the tough walls of plant cells?
Why cant humans difest cellulose?
They lack the enzyme needed to break beta-glycosidic bonds in cellulose?
How do herbivores digest cellulose?
They rely on symbiotic microbes in their stomach or gut that produce enzes to break cellulose?
What is chitin and where is if found?
Its a structural polysaccharide found in rhe exoskeleton and in the cell walls of many fungi
What makes lipids unique compared to other biological molecules?
They arent true polymers and are defined by being hydrophobic
Why are lipids hydrophobic?
Because the contain mainly of hydrocarbons, which form nonpopar covalent bonds
What are the 3 biologically important types of lipids?
Fats
Phospholids
Steroids
What are the main functions of lipids?
Store energy
Insulate the body
Help absorb vitamins
Protect organs
What are lipids made of?
They are composed of triglycerides, which contain carbon, hydrogen and oxygen.
What is the main function of fats?
store energy
What two molecules are fats made from?
Glycerol and fatty acids
What is glycerol?
A three carbon alchohol with a hydroxyl group attached to each carbon
What is a fatty acid?
A long hydrocarbon chain with a carboxyl group at one end.
What is a trans-fat?
An unsaturated fat that has been chemically altered by hydrogenation, causing double bonds to rearrange into trans form
How does hydrogenation create trans-fats?
It adds hydrogen to unsaturated fats, but sometimes only partially - causing the double bonds to flip into trans form instead of cis
Why are trans-fats considered harmful?
Increases risk of cardiovascular disease more than saturated fats
Describe the structure of a phospholid.
Glycerol backbone
Two hydrophobic fatty acid tails
a hydrophilic phosphate head
What is the biological significance of phospholids?
They form the phospholid bilayer, the basic structure of all cell membranes
What are steroids?
Lipids with four ring carbon structure
What is cholesterol and why is it important?
Its a type of steroid found in animal cell membranes and used to make hormones
Why can high cholesterol be dangerous?
It can form plaques that block arteries, increasing risk of heart disease or strokes