carbohydrates Flashcards
What is meant by monomers? (1)
Smaller units from which larger molecules are made
What is meant by polymers? (1)
Molecules that are made from a large number of repeating units joined together
What is a condensation reaction? (3)
A chemical reaction that joins up two molecules;
With the formation of a chemical bond;
And the loss of a water molecule
What is a hydrolysis reaction? (2)
A chemical reaction that breaks up the chemical bond between two molecules;
And the addition of a water molecule
What chemical elements do carbohydrates contain? (3)
Carbon (C), Hydrogen (H), Oxygen (O)
What chemical elements do lipids contain? (3)
Carbon (C), Hydrogen (H), Oxygen (O)
What chemical elements are found in all amino acids (and therefore all proteins)? (5)
Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N);
Some also contain Sulphur (S)
What are the monomers of carbohydrates? (1)
Monosaccharides
What are three examples of monosaccharides? (3)
Glucose, Fructose, Galactose
What type of monosaccharide is glucose? (2)
Hexose sugar
Which means it contains 6 carbon atoms
What are the two forms of glucose? (2)
α-glucose
β-glucose
How do you draw the two isomers of glucose? (2)
α-glucose: hydroxyl group above the ring on carbon 1
β-glucose: hydroxyl group below the ring on carbon 1
What type of monosaccharide is ribose? (2)
Pentose sugar;
Because it has 5 carbons
How is the structure of glucose related to its function as the main energy source in animals and plants? (2)
It is soluble, so it can be easily transported
Its chemical bonds contain a lot of energy.
What type of bond joins monosaccharides together? (1)
Glycosidic bonds
How is a disaccharide formed? (3)
When two monosaccharides are joined together;
By a glycosidic bond;
During a condensation reaction
How is a polysaccharide formed? (3)
When more than two monosaccharides are joined together;
By a glycosidic bond;
During a condensation reaction
What is maltose made of? (2)
Alpha glucose + Alpha glucose
What is sucrose made of? (2)
α-glucose + fructose
What is lactose made of? (2)
α-glucose or β-glucose + galactose
What is the main energy store in plants? (2)
Starch;
Excess glucose is stored as starch
Why is starch a good molecule for storage in plants? (3)
Insoluble so osmotically inert;-
Therefore, does not affect water potential;
So does not draw in water into plant cells
What are the two polysaccharides that make up starch? (2)
Amylose
Amylopectin
Describe the structure of amylose (3)
Long unbranched chain of α-glucose molecules;
Joined by 1-4 glycosidic bonds;
Which give it a coiled structure so compact
Describe the structure of amylopectin? (3)
Long branched chain of α-glucose molecules;
It has 1-4 glycosidic bonds and branches formed by 1-6 glycosidic bonds;
Resulting in a branched rather than helical structure
Why is the branched structure of amylopectin important? (2)
Allows enzymes to easily access the glycosidic bonds;
Which enables quick release of glucose
What is the main energy store in animals? (1)
Glycogen
Describe the structure of glycogen (2)
Highly branched chain of α-glucose molecules;
Which allows enzymes to access the glycosidic bonds easily and hydrolyse glucose quickly
Why is glycogen a good storage molecule in animals? (3)
Compact;
Has a high energy content for its mass;
Insoluble, so it does not affect the cell’s water potential
What is the major component of cell walls in plants? (1)
Cellulose
Describe the structure of cellulose (2)
Made up of long, straight, unbranched chains;
Of β-glucose molecules inverted by 180 with each molecule
How are cellulose chains held together, and what function does this serve? (3)
By hydrogen bonds to form microfibrils;
Which are strong fibers;
That provide structural support for plant cells
