Chapter 7 - Biological Molecules

Question 1

What is a polymer?

Answer 1

A large molecule formed by bonding together many smaller basic units.

Question 2

What is a monomer?

Answer 2

It is a basic unit that can be bonded to other basic units to form a polymer.

Question 3

Name the monomer and the bond btween monomers in thee following polymers:
- starch (polysaccharide)
- lipid
- protein (polypeptide)
- DNA

Answer 3

• glucose (glycosidic bond)
• 3 fatty acids & glycerol (ester bond)
• amino acids (peptide bond)
• nucleotides (hydrogen bonds)

Question 4

Name the chemical elements that compose carbohydrates.

Answer 4

• carbon
• hydrogen
• oxygen

Question 5

Name the 3 monosaccharides of carbohydrates.

Answer 5

Glucose
Fructose
Galactose

Question 6

Name the 3 disaccharides of carbohydrates.

Answer 6

Maltose
Sucrose
Lactose

Question 7

Name the 3 polysaccharides of carbohydrates.

Answer 7

Starch
Glycogen
Cellulose

Question 8

How are lipid molecules formed and how can they be broken up?

Answer 8

Formed by condensation reaction
Broken up by hydrolysis

Question 9

Through what process does 2 monosaccharides combine?

Answer 9

Condensation reaction

Question 10

Through what process is disaccharides split up?

Answer 10

Hydrolysis

Question 11

Through what process can many monomers be linked to form a polymer?

Answer 11

Polymerisation

Question 12

Through what process can polysaccharides be broken down into monomers?

Answer 12

Hydrolysis

Question 13

What is the difference between plant fats and animal fats?

Answer 13

Plant fats are composed of unsaturated fatty acids, they have lower melting point and are usually liquids at room temperature.
Animal fats are composed of saturated fatty acids, have higher melting points and are usually solids at room temperature.

Question 14

What are the monomers of proteins?

Answer 14

Amino acids

Question 15

Of how many amino acids does one molecule of protein consist of?

Answer 15

A few hundred of a few thousand amino acids.

Question 16

With what process does amino acids combine with?

Answer 16

Condensation reaction with a peptide bond.

Question 17

What process. Is used to split up proteins into polypeptides and amino acids?

Answer 17

Hydrolysis by adding water molecules.

Question 18

Nam the uses of glucose.

Answer 18

• it is the main source of energy for cells
• it is the building blocks for larger molecules
• it is the starting block for building other molecules such as fatty acids
• glucose is the carbohydrates which is transported in blood around the bod of humans

Question 19

What is the uses of sucrose?

Answer 19

• it is the transport molecule that can be transported through translocation in plants
• the human body break down sucrose into fructose and glucose, which is then metabolized to release energy to cells in the body

Question 20

What are the uses of starch?

Answer 20

• it’s main function if to act as an energy source
• it is insoluble and has no osmotic effect
• it can easily be hydrolysed into glucose
• animals break it down into glucose and use it as energy

Question 21

What are the uses of glycogen?

Answer 21

• it acts as energy storage in animal tissue
• it is insoluble and has no osmotic effect and can easily by hydrolysed into glucose when needed

Question 22

What is the advantage of storing glycogen rather than glucose?

Answer 22

Glycogen is a compact molecule, so larger quantities can be stored.

Question 23

What are the uses of cellulose?

Answer 23

• it is the main material for production of plant cell walls
• cell walls of cellulose support the plant and prevents the cell from bursting

Question 24

What is the role of proteins?

Answer 24

• Proteins help to create cells needed for growth, repair and maintain tissues
• proteins have an energetic role
• proteins have an enzymatic role
• proteins have structural role
• protein have support role
• proteins have a hormonal role
• proteins have a transport role
• proteins are integral parts of cell membranes
• proteins is also an important part of the immune system

Question 25

What is the roles of lipids?

Answer 25

• lipids are energy sources
• lipids act as storage
• it serves as structural component of cell membranes
• it helps with the formation of the outer covering of nerve cells
• lipids have a protection role for organs
• lipids acts as an insulating layer against heat loss, as it is a poor conductor of heat

Question 26

What is the role of water?

Answer 26

• water is a universal solvent
• water is a very efficient transport medium

Question 27

With how many bonds are cytosine bonded to guanine?

Answer 27

3 hydrogen bonds

Question 28

With how many bonds are adenine bonded to thymine?

Answer 28

2 hydrogen bonds

Question 29

What are the subunits of DNA molecules calles?

Answer 29

Nucleotides

Question 30

What two bases are thee purines of DNA molecules?

Answer 30

Adenine and Guanine

Question 31

What two bases are the pyrimidines of DNA molecules?

Answer 31

Cytosine and Thymine