Module 2 Biological Molecules

Question 1

What are anions

Answer 1

Negativity charged ion

Question 2

What are cations

Answer 2

Positively charged ions

Question 3

What is the purpose of calcium

Answer 3

Ca2+, cation, nerve impulses, muscle contractions

Question 4

What is the purpose of sodium

Answer 4

Cation, Na+, nerve impulses, kidney function

Question 5

What is the purpose of potassium

Answer 5

K+, cation, nerve impulses, stomata

Question 6

What is the purpose of hydrogen

Answer 6

Cation, H+, catalysts, PH determination

Question 7

What is the purpose of ammonium

Answer 7

Cation, NH4+, needed to make nitrate ions

Question 8

What is the purpose of nitrate

Answer 8

Anion, NO3-, amino acid formation

Question 9

What is the purpose of hydrogen carbonate

Answer 9

Anion, HCO3-, maintain blood PH

Question 10

What is the purpose of chloride

Answer 10

Anion, Cl-, balance sodium and potassium ions in cells

Question 11

What is the purpose of phosphate

Answer 11

Anion, PO4 3-, cell membranes, nucleic acids and ATP formation, bone formation

Question 12

What is the purpose of hydroxide

Answer 12

Anion, OH-, catalysts, PH determination

Question 13

What is carbohydrate made of

Answer 13

Carbon, hydrogen, oxygen,

Question 14

What is lipids made out of

Answer 14

Carbon, hydrogen, oxygen

Question 15

What is proteins made out of

Answer 15

Carbon, hydrogen, oxygen, nitrogen, sulfur

Question 16

What is nucleic acids made out of

Answer 16

Carbon, hydrogen, oxygen, nitrogen, phosphorus

Question 17

What are polymers

Answer 17

Long chains of molecules made up of monomers, repeating units.

Question 18

What is an example of carbohydrate

Answer 18

Sucrose

Question 19

What is an example of a lipid

Answer 19

Cholesterol

Question 20

What is an example of a protein

Answer 20

Insulin

Question 21

What is an example of a nucleic acid

Answer 21

ATP

Question 22

How is glucose transported around the blood

Answer 22

It’s soluble, so can be dissolved and transported

Question 23

Why is water important

Answer 23

Photosynthesis, regulating temp, maintaining cellular structure, excretion, lubricating joints, transporting nutrients, facilitating metabolic reactions

Question 24

What is water a metabolite for

Answer 24

Hydrolysis reactions, condensation reactions

Question 25

Where does most of water properties come from

Answer 25

Water molecules stick together

Question 26

Describe structure of water

Answer 26

Consists of 2 hydrogen atoms covalently bonded with 1 oxygen. The oxygen has a greater affinity for electrons than the hydrogens so it pulls electrons closer. This makes oxygen slightly negative indicated by S- and the hydrogens slightly positive indicated by S+. This creates different charged regions making water a polar molecule. Because it has 2 charged regions it is dipolar.

Question 27

Describe the hydrogen bonding and importance of it within a water molecule

Answer 27

Many of the properties come from the hydrogen bond. The slightly negative charge on the oxygen atom makes it attract the slightly positive hydrogen atom of another water molecule. The numerous hydrogen bonds make it very stable and cohesive structure.

Question 28

Describe the cohesion between water molecules

Answer 28

At an air-water surface, the cohesion between water molecules produces surface tension, which can make a solid like surface explaining how a pond skater can walk on water. Within a column of water cohesion also explains why the column does not break when water molecules are pulled up a narrow tube e.g in a straw or xylem during transpiration.

Question 29

Describe water as a solvent

Answer 29

It has polar molecules so water is attracted to any substance that is polar. Substances that can become part of water’s hydrogen bonded structure will dissolve water are called hydrophilic. Substances that cannot and will not dissolve in water are hydrophobic. Only triglycerides(lipids and fats) and large polymers eg starch do not dissolve.

Question 30

What does cohesion of water explain

Answer 30

Water absorbs/loses a large amount of heat before its temp change=specific heat capacity. Water absorbs a large amount of heat before it turns into water vapour=latent heat of vaporisation

Question 31

EQ- describe ways in which the physical properties of water allow organisms to survive over a range of temperatures (9 marks)

Answer 31

High latent heat of vaporisation, evaporation is efficient for cooling eg sweating. High specific capacity, thermally stable environment for aquatic organisms, which use less energy on temp control, so internal temp of organism changes slowly so enzyme reactions are at correct rate. Ice is less dense than water so provides habitat for organisms. Water beneath remains liquid, so organism don’t freeze. Effective solvent for reactions. Cohesion eg transpiration in xylem. Surface tension, habitat for insects like pond skater. Transparent for underwater photosynthesis. High density for floating and support. Organisms can still obtain oxygen, food etc form water.