Topic 1 Flashcards
(121 cards)
What is the extent of the variety of life, both past and present?
The variety of life, both past and present, is extensive, but the biochemical basis of life is similar for all living things.
What are monomers?
Monomers are the smaller units from which larger molecules are made.
What are polymers?
Polymers are molecules made from a large number of monomers joined together.
Give examples of monomers.
Examples of monomers include monosaccharides, amino acids, and nucleotides.
What is a condensation reaction?
A condensation reaction joins two molecules together with the formation of a chemical bond and involves the elimination of a molecule of water.
What is a hydrolysis reaction?
A hydrolysis reaction breaks a chemical bond between two molecules and involves the use of a water molecule.
What are monosaccharides?
Monosaccharides are the monomers from which larger carbohydrates are made, such as glucose, galactose, and fructose.
Which common monosaccharides are there?
Glucose, galactose, and fructose.
how is a glycosidic bond formed between two monosaccharides
condensation reaction removing a molecule of water
How is maltose formed?
Maltose is a disaccharide formed by the condensation of two glucose molecules.
How is sucrose formed?
Sucrose is a disaccharide formed by the condensation of a glucose molecule and a fructose molecul
How is lactose formed?
Lactose is a disaccharide formed by the condensation of a glucose molecule and a galactose molecule.
What are the two isomers of glucose and how do they differ?
The two isomers of glucose are α-glucose and β-glucose.
alpha glucose has a hydroxyl group below and beta glucose has a hydroxyl group above
How are polysaccharides formed?
Polysaccharides are formed by the condensation of many glucose units.
Which polysaccharides are formed by the condensation of α-glucose?
Glycogen and starch.
Which polysaccharide is formed by the condensation of β-glucose?
Cellulose.
Describe the basic structure and function of glycogen.
Polysaccharide of a-glucose;
OR
polymer of a-glucose;
(Joined by) glycosidic bonds
OR
Branched structure;
Hydrolysed (to glucose);
Glucose used in respiration;
describe the basic structure and function of starch.
Starch is a mixture of amylose (unbranched)
and amylopectin (branched) used by plants to store glucose for energy.
Describe the basic structure and function of cellulose.
Cellulose is a linear polysaccharide that provides structural support in plant cell walls due to its high tensile strength.
Straight chains of cellulose interact with each other with hydrogen bonds.
This forms structures known as microfibrils.
These microfibrils provide strength to the cellulose
structure..
test for reducing sugars
- Heat with Benedict’s reagent (1);
- colour change from blue to brick-red (1)
test for non-reducing sugars
- Heat with Benedict’s reagent and no colour change (1);
- boil with acid (HCl) and then neutralise with (NaHCO3) (1);
- re- heat with Benedict’s reagent and colour change from blue to brick-red (1)
test for starch
add iodine
should turn blue-black
What are the two main groups of lipids?
Triglycerides and phospholipids.
How are triglycerides formed?
Triglycerides are formed by the condensation of one molecule of glycerol and three molecules of fatty acid.