Chapter 2 - Chemical Basis of Life

Question 1

Chemistry

Answer 1

the branch of science that studies the composition, properties and interactions of matter

Question 2

Atomic Number

Answer 2

the number of protons

Question 3

Mass Number

Answer 3

the total number of protons plus neutrons

Question 4

Isotopes

Answer 4

atoms with the same atomic number but different mass numbers due to differing amounts of neutrons

Question 5

Radioactive Isotopes

Answer 5

unstable isotopes that experience atomic degradation which releases energy
- Releases atomic radiation

Question 6

Forms of Radiation

Answer 6

• Alpha: consists of particles from atomic nuclei which includes two protons and two neutrons which move slowly and cannot penetrate matter
  
  • Beta: consists of electrons(smaller) that travel faster and can more deeply penetrate matter
  • Gamma: a form of energy similar to X-radiation and is the most penetrating form of radiation

Question 7

Octet rule

Answer 7

8 electrons are required to fill the shells in most of the atoms important for living organisms, besides if atoms only have 1 shell

Question 8

Inert

Answer 8

used to describe atoms who cannot form chemical bonds due to having outermost shells being stable

Question 9

Ionic Bond

Answer 9

the attraction of two oppositely charged ions which are charged due to the movement of electrons

Question 10

Covalent Bond

Answer 10

the sharing of electrons between two atoms to fill their valence shells and become stable

Question 11

Nonpolar Covalent Bond

Answer 11

covalent bonds where atoms are shared equally due to both atoms having similar electronegativity

Question 12

Polar Covalent Bond

Answer 12

covalent bonds between two atoms where 1 is more electronegative than another, resulting in a pull of electrons towards the more electronegative atom, creating an uneven distribution of charges

Question 13

Hydrogen bond

Answer 13

he weak polar covalent bond between a hydrogen atom and a oxygen or nitrogen atom

Question 14

Electrolytes

Answer 14

compounds that ionize in water due to the positive and negative ends in water molecules causing atoms to dissociate
- E.g. sodium chloride in water will dissociate into sodium and chloride ions
- Electrolyte means they can conduct an electrical current in water

Question 15

Types of Electrolytes

Answer 15

• Acid: substance which releases hydrogen ions
  • Base: substances that releases ions which combine with hydrogen ions
  • Salt: substances formed by the reaction between an acid and a base

Question 16

pH Scale

Answer 16

measures H+ concentration in grams of ions per litre from 0-14
- It tracks the number of decimal places in 10 fold differences
- pH less than 7 is acidic due to increase in H+
- pH greater than 7 is alkaline due to Decrease in H+

Question 17

Blood pH normal levels and disease levels

Answer 17

• Blood pH is between 7.35 to 7.45
  
  • Alkalemia: blood pH above 7.5
  • Acidemia: blood pH below 7.3

Question 18

Alkalosis

Answer 18

a disease someone encounters when their pH of body fluids exceeds above 7.45 making them feel agitated and dizzy

Question 19

Acidosis

Answer 19

a disease when pH of body fluids decreases below 7.35 making them feel disoriented, fatigued and difficulty breathing.

Question 20

Buffer

Answer 20

chemical systems which resist pH change by donating H+ when they are depleted or by combining with them when they are in excess

Question 21

Types of Chemicals in Metabolism

Answer 21

• Organic: molecules which contain both carbon and hydrogen molecules
  ○ Non electrolytes as they don’t dissolve in water
  - Carbs, proteins, lipids, nucleic acids
  • Inorganic: substances which don’t contain either carbon or hydrogen atoms
    ○ Usually dissolve in water forming ions(electrolytes)
    - e.g. water, oxygen, C02, nitric acid, Carbon Monoxide, inorganic salts

Question 22

Inorganic substances: water

Answer 22

• Most metabolic reactions occur in water as when water dissociates, it turns into ions which are more likely to react
  • Water is important in transporting chemicals in the body
    ○ Blood made up of mostly water, carries oxygen, sugars, salts and vitamins
  • Water absorbs and carries heat
    ○ Blood brings heat released from muscle cells to the surface
    ○ Skin cells secrete water as sweat which releases heat by evaporation

Question 23

Inorganic substances: Nitric oxide

Answer 23

harmful to health yet are important to physiology in small concentrations
- They are biological messenger molecules:
○ NO is involved in digestion, memory, immunity , respiration and circulation
- found in smog, cigarette smoke and acid rain

Question 24

Inorganic substances: oxygen

Answer 24

• Cells use oxygen to release energy from nutrient molecules
• O2 drives metabolism

Question 25

Inorganic Substances: Carbon Monoxide

Answer 25

harmful to health yet are important to physiology in small concentrations - They are biological messenger molecules: ○ CO functions in the spleen recycling old red blood cells and in the brain which controls memory, smell and other functions - a colorless, odorless gas that is deadly when it leaks from exhaust pipes, home heating systems

Question 26

Inorganic Substances: Inorganic salts

Answer 26

- The sources of many necessary ions which play a role in metabolism, maintaining water concentration, controlling pH, blood clotting, bone development, energy transfer in cells and muscle and nerve functions

Question 27

Organic Substances: Carbs

Answer 27

functions: - Provide cellular energy - Materials for cell structure Subunit: - Monosaccharides Examples

Question 28

Organic Substances: Lipids

Answer 28

Functions: - Provide cellular energy - Provide structure for membranes - Assist in hormone synthesis Subunits: - Triglycerides: * 1 glycerol head * 3 fatty acid tails - Phospholipids: * 1 glycerol head * 2 fatty acids * 1 phosphate - Steroids: * 4 carbon rings Example: - oil - butter - cell membrane - cholesterol

Question 29

Organic Substances: Protein

Answer 29

Function: - Cell structure - Transport substances - Assist in hormone synthesis - Enzymes - Movement Subunits: - Amino acids: * Amino group(NH2) * Central carbon * R group * Carboxyl group(CO=OH) Examples: - Keratin - hemoglobin - Actin/myosin - Phenalene

Question 30

Organic Substances: Nucleic Acids

Answer 30

Function: - Holding genetic code - Building proteins Subunits - nucleotides: * Deoxyribose sugar * Phosphate group * Nitrogenous base Example: - DNA - RNA

Question 31

Types of reactions:

Answer 31

- Synthesis reaction: building large molecules by bonding smaller ones - Decomposition: breakdown of large molecules into smaller ones - Exchange reaction: parts of two different types of molecules trade positions as bonds are broken and new ones are formed