Biological Molecules 1 Flashcards
What is an organic compound?
Contains carbon atoms.
What is the basic structure of all carbohydrates?
Made up of carbon, hydrogen and oxygen
What are the 3 main groups of carbohydrates?
Monosaccharides
Disaccharides
Polysaccharides
What are the main 2 monosaccharides?
Alpha glucose + beta glucose
What is the structure of glucose?
6 carbons
What is the difference between the structure of alpha glucose and beta glucose?
(Hydrogen at carbon 1)
Alpha = hydrogen above A=Above
Beta = hydrogen below B=Below
What reaction happens when 2 monosaccharides join to form a disaccharide?
A condensation reaction
Results in a molecule of water (H2O) being removed
What type of bond is the link between 2 monosaccharides?
A glycosidic bond (a type of covalent bond)
What are the 3 main types of disaccharide?
Sucrose - stored in plants e.g. sugarcane (a glucose + fructose)
Lactose - milk sugar, main carb in milk (a glucose + b galactose)
Maltose - malt sugar, in germinating seeds e.g. barley (a glucose + a glucose)
What is the structure of polysaccharides?
-Compact, good for storage
-Glycosidic bonds are easily broken, allowing rapid release of monosaccharides for cellular respiration
-Not soluble in water so have little effect on water potential
What is the reaction when a glycosidic bond splits?
Hydrolysis reaction
What is the reaction when a glycosidic bond splits?
Hydrolysis reaction
Water is added to the bond
What compounds is starch a mixture of?
Amylose + amylopectin
What is starch used as?
An energy store in plants
Sugars produced by photosynthesis are rapidly converted into starch which is insoluble and compact but can be broken down rapidly to release glucose when it is needed
Amylose
An unbranched polymer made up of between 200 and 5000 glucose molecules. As the chain gets longer the molecules spiral making it good for storage.
1-4 glycosidic bonds (only alpha glucose)
Amylopectin
A branched polymer of glucose molecules
The branching chains have many terminal glucose molecules that can be broken off when energy is needed
1-4 and 1-6 glycosidic bonds
Glycogen
‘Animal starch’ as it is the only carbohydrate store found in animals
Similar to amylopectin molecules and starch however has more 1-6 glycosidic bonds giving it more branches therefore making it easier to be broken down quickly
Cellulose
Makes up most of the cell wall
Made up of beta glucose
1-4 glycosidic bonds however every other glucose has to be inverted
What chemical are fats and oils made up of and what is the bond called?
Fatty acids and glycerol
Forms an ester bond
How do fatty acids vary?
The length of the carbon can differ
It can be saturated or unsaturated
Forming ester bonds
Forms in a condensation reaction between the carboxyl group of a fatty acid and the hydroxyl group of the glycerol
It is called esterification
When is a phospholipid formed?
When glycerol undergoes esterification with a phosphate group instead of a fatty acid
How is a phospholipid bilayer or a micelle formed?
The polar phosphate head is hydrophilic and the lipid tail is hydrophobic
What are proteins made up of?
Amino acids
What is the basic structure of amino acids?
An amino group (-NH2) and a carboxyl group (-COOH) attached to a carbon atom. The R group varies between amino acids
How do amino acids join together?
The amino group of one joins with the carboxyl group of another. This forms a peptide bond and relies on a dipeptide.
What bonds can form between amino acids?
Peptide
Hydrogen
Disulfide
Ionic
How do hydrogen bonds form?
When the opposite charges of an amino acid attract
There are lots of hydrogen bonds however they break easily meaning the protein can easily change shape if there is a change in pH or temperature
When do disulfide bonds form?
When 2 cysteine molecules are close together. Disulfide bonds are very strong but occur much less often
When do ionic bonds form?
Between the strongly positive and negative amino acids
What are the 4 types of protein structure?
Primary
Secondary
Tertiary
Quaternary
What are fibrous proteins and what is their structure?
They have little or no tertiary structure
Long parallel polypeptide chains
Insoluble and very tough
Collagen is an example of this
What is a globular protein and its structure?
Have complex tertiary and sometimes quaternary structures that fold into globular shapes. They hold molecules in position in the cytoplasm. They are also important in the immune system.
What is a conjugated protein?
Some proteins are conjugated with a prosthetic group. Chlorophyll and haemoglobin are conjugated.
