biological molecules

Question 1

What is a monomer?

Answer 1

Monomers are the smaller units from which larger molecules are made

Question 2

What is a polymer?

Answer 2

Polymers are molecules made from a large number of monomers joined together in a chain.

Question 3

What are the examples for monomers?

Answer 3

Glucose, amino acid and nucleotide

Question 4

What are the examples for polymers ?

Answer 4

Starch, glycogen, cellulose, protein, DNA and RNA

Question 5

What are the 3 monosaccharides?

Answer 5

Glucose,Fructose and Galactose

Question 6

What are the 3 disaccharides ?

Answer 6

Sucrose, Maltose and lactose

Question 7

What are the 3 polysaccharides ?

Answer 7

Starch, cellulose and glycogen

Question 8

What are the three different types of carbohydrates called?

Answer 8

Monosaccharides , disaccharides and polysaccharides

Question 10

What is a carbohydrate?

Answer 10

Carbohydrates are molecules which consist only of carbon, hydrogen and oxygen and they are long chains of sugar units called saccharides.

Question 11

Why is water such an important molecule and a major component of cells?

Answer 11

Water is a polar molecule due to uneven distribution of charge within the molecule
- the hydrogen atoms are more positive than the oxygen atom causing one end of the
molecule to be more positive than the other
It is a metabolite in metabolic reactions such as condensation and hydrolysis which are used in forming and breaking of chemical bonds
It is a solvent in which many metabolic reactions occur
It has a high heat specific capacity meaning that a lot of energy is required to warm
water up therefore minimising temperature fluctuations in living things therefore it acts as a Durier
It has a relatively large latent heat of vaporisation, meaning evaporation of water provides a cooling effect with little water loss
Strong cohesion between molecules enables effective transport of water in tube-like transport cells as the strong cohesion supports columns of water. As a result of strong cohesion the surtace tension at the water-air boundary is high
Maximum density of water is at 4 degrees - this means that ice is less dense than water and floats on top of it creating an insulating layer, this increases the chance of survival of organisms in large bodies o water as it prevents them from freezing
Water is incompressible therefore it provides good support

Question 12

What are saturated lipids?

Answer 12

saturated lipids don’t contain any carbon-carbon double bonds

Question 13

What are unsaturated lipids?

Answer 13

unsaturated iDids contain carbon-carbon
double bonds and melt at lower temperatures than saturated fats

Question 14

What are triglycerides?

Answer 14

are lipids made of one molecule of glycerol and 3 fatty acids joined by ester bonds formed in condensation reactions

Question 15

When do hydrolysis reactions take place?

Answer 15

Hydrolysis Reactions occurs when larger molecules are broken down into smaller molecules with the addition of water.

Question 16

What is the test for reducing sugars?

Answer 16

Add Benedict’s reagent + heat and should produce a red/orange precipitate

Question 17

What is the test for non-reducing sugars?

Answer 17

hydrochloric acid+ heat should produce a red/orange precipitate

Question 18

What is the test for starch?

Answer 18

Add iodine should turn blue/black

Question 19

What is the test for proteins?

Answer 19

Add sodium hydroxide should turn purple

Question 20

What is the tests for lipids?

Answer 20

Add ethanol+water should turn cloudy white

Question 21

What’s a covalent bond?

Answer 21

A covalent bond is the sharing of two or more electrons between two atoms

Question 22

What is a condensation reaction?

Answer 22

A condensation reaction occurs when monomers combine together by covalent bonds to form polymers (polymerisation) or macromolecules (lipids) and water is removed

Question 23

What is a hydrolysis reaction?

Answer 23

In the hydrolysis of polymers, covalent bonds are broken when water is added

Question 24

What are Nucleic Acids?

Answer 24

Like carbohydrates, lipids and proteins, all nucleic acids contain the chemical elements C, H and O
However, all nucleic acids also contain N (nitrogen) in their bases and P (phosphorous) in the form of phosphate groups

Question 25

What is the function of nucleic acids?

Answer 25

Carrying the genetic code in all living organisms
Nucleic acids are essential in the control of all cellular processes including protein synthesis

Question 26

What’s a macromolecule?

Answer 26

-Macromolecules are very large molecules
-They contain 1000 or more atoms and so have a high molecular mass
Polymers can be macromolecules, however, not all macromolecules are polymers as the subunits of polymers have to be the same repeating units

Question 27

state the name of the bond that holds water molecules together

Answer 27

hydrogen bonds

Question 28

DNA is one of many substances which will dissolve in water. Explain why water is a good solvent

Answer 28

molecules are polar,enabling water molecules to attract to solute molecules

Question 29

What role does hydrogen and sodium play in helping cut flowers last longer

Answer 29

hydrogen ions used to regulate pH
Sodium ions used to regulate water potential

Question 30

Explain why mammals store glycogen instead of glucose?

Answer 30

-They can’t store glucose because it is soluble- it can effect the water potential of the cell.
-Metabolically inactive.
-Compact/lots can be stored in a small space.

Question 31

How is glucose’s structure related to its function as the main energy source in animals and plants?

Answer 31

-Its structure makes it soluble, so it can be easily transported.