The Chemistry of Life

Question 1

Organic Elements

Answer 1

Carbon, Nitrogen, Oxygen and Hydrogen

Question 2

Carbon

Answer 2

• has a high versatility (forms many different compounds)
• part of carbohydrates, lipids, nucleic acids and proteins
• energy is released when the bonds are broken
• can form rings or long chains

Question 3

Carbohydrates

Answer 3

• contain C, H, O
• sugars and starches
• join with glycosidic bond (condensation reaction, releases water, covalent)
• breaking down is called hydolysis (requires water)
• form long chains, the more the less sweet and less soluble
• store of energy
• C-2H-O
• used in plants for structure

Question 4

Sugars

Answer 4

• Monosaccharides: Glucose, Fructose, Galactose

- Disaccharides: Maltose (glucose+glucose), Lactose (galactose+glucose), Sucrose (glucose+fructose)

Question 5

Starches

Answer 5

Amylose:
- plant starch
- energy store
Cellulose:
- plant starch 
- structural
Glycogen: 
- animal starch 
- liver as energy store

Question 6

Lipids

Answer 6

• glycerol molecule and three fatty acid molecules
• generally insoluble
• fats, oils, waxes

Question 7

Lipid Functions

Answer 7

• waterproofing
• energy store (37000 J per gram)
• heat insulation
• buoyancy
• steroids

Question 8

Fats

Answer 8

• animals
• solid at room temperature
• saturated (no double bonds)
• more energy

Question 9

Oils

Answer 9

• plants
• liquid at room temperature
• unsaturated (double bonds)

Question 10

Nucleic Acids

Answer 10

• made up of nucleotides (5-carbon sugar+phosphate group (PO4-)+nitrogenous base)
• store and transmit hereditary information
• Deoxyribonucleic Acid (DNA)
• Ribonucleic Acid (RNA)

Question 11

Nitrogenous Base

Answer 11

Adenine
Guanine
Cytosine
Thymine

Question 12

Adenine

Answer 12

Thymine

Question 13

Guanine

Answer 13

Cytosine

Question 14

Purines

Answer 14

Adenine and Guanine

Larger

Question 15

Pyramidines

Answer 15

Thymine, Cytosine and Uracil

Smaller

Question 16

Proteins

Answer 16

• macromolecules
• made of amino acids
• most of the body is protein

Question 17

Amino Acids

Answer 17

• made of Amino Group (NH2), Carboxyl Group (COOH) and C bonded with H and R Group
• 20 different R Groups
• bond with peptide bond (condensation reaction, covalent)

Question 18

Protein Functions

Answer 18

• Catalysts (enzymes e.g. Amylase)
• Storage (ovalbumen)
• Transport (hemoglobin)
• Communication (hormones)
• Contractile (actin and myosin)
• Protective (Immunoglobulin)
• Toxins (snake venom)
• Structural (cell membrane)

Question 19

Globular Proteins

Answer 19

• large
• transportable
• soluble
• proteins with binding sites
• membrane receptor sites

Question 20

Fibrous Proteins

Answer 20

• involved in structure (tendons and ligaments e.g. collagen and keratin)
• contractile

Question 21

Less Common Elements

Answer 21

• Sulfur
• Calcium
• Phosphorus
• Iron
• Sodium

Question 22

Sulfur Uses

Answer 22

• needed for the synthesis of two amino acids (Cysteine and Metathione)

Question 23

Calcium Uses

Answer 23

• used to strengthen bones and teeth
• used for synaptic transmission of nerve impulses
• used for muscle contraction
• blood clotting

Question 24

Phosphorous Uses

Answer 24

• part of DNA and ATP molecules

- works with calcium to maintain bones and teeth

Question 25

Iron Uses

Answer 25

- part of the protein hemoglobin used to transport oxygen | - used as part of many enzymes

Question 26

Sodium Uses

Answer 26

- helps to regulate osmosis in cells

Question 27

Thermal Properties of Water

Answer 27

- water has a high specific heat capacity (4.2 Joules to raise one gram of water by one dress Celsius) - it is thermally stable - high heat of evaporation meaning that is can absorb a lot of heat without changing its temperature too much - doesn't change its temperature like its environment - wide range between boiling and freezing points

Question 28

Cohesive Properties of Water

Answer 28

- very cohesive - due to hydrogen bonding - the permanent positive charge es make water molecules slightly polar - this polarity causes the hydrogen atoms to bond with the oxygen - this is why water has a high specific heat capacity - surface tension - forms crystal when frozen, less dense - capillary action

Question 29

Cohesion

Answer 29

When molecules of the same type are attracted to each other

Question 30

Solvent Properties of Water

Answer 30

- due to the polarity of water it can dissolve other polar molecules - like dissolves like - a lot of molecules found on the body are polar - water is abundant in the body to dissolve organic molecules (not fats)

Question 31

Adhesion

Answer 31

When molecules of different types are attracted to each other