Topic 3: Life's elements, water, and organic chemistry

Question 1

What are the top 4 elements?

Answer 1

Hydrogen, Oxygen, Nitrogen, and Carbon

Question 2

Why are HONC the top 4 elements?

Answer 2

Because they are the main elements found in organic molecules in organisms.

Question 3

Why are chemical bonds necessary?

Answer 3

Because elements bond in order to be stable, stable meaning having a full valence energy level.

Question 4

What is a compound?

Answer 4

Two or more elements combined in a fixed ratio.

Question 5

What are three types of chemical bonds?

Answer 5

Ionic, covalent, and hydrogen.

Question 6

The type of bond formed is due to what?

Answer 6

Electronegativity: attraction for electrons of the atoms involved.

Question 7

Describe Ionic bonding.

Answer 7

One atom strips valence electrons away from another atom (due to high electronegativity difference). Electron transfer creates ions (charged atoms).

Question 8

What are the two types of ions?

Answer 8

Cation (positive ion) and anion (negative ion).

Question 9

What is an example of ionic bonding?

Answer 9

Salts (sodium chloride)

Question 10

Describe covalent bonding.

Answer 10

Sharing pair of valence electrons. Number of electrons required to complete an atom’s valence shell determines how many bonds will form.

Question 11

What is an example of covalent bonding?

Answer 11

Hydrogen and oxygen bonding in water, bonding in organic molecules.

Question 12

Define molecule.

Answer 12

When elements covalently bonded.

Question 13

What is nonpolar covalent and an example of it?

Answer 13

Nonpolar covalent: electrons shared equally.

Ex: O2, C-H bonds.

Question 14

What is polar covalent and an example of it?

Answer 14

Polar covalent: one atom more electronegative than the other (creates partial charges).
Ex: water

Question 15

Describe a hydrogen bond.

Answer 15

Attraction between a partially positive hydrogen atom of one polar molecule and a partially negative atom (like oxygen or nitrogen) of another polar molecule.

Question 16

What are water’s properties due to?

Answer 16

Due to its polarity and the resultant of hydrogen bonds.

Question 17

What are the thermal properties of water?

Answer 17

High Specific heat: amount of heat absorbed or lost to change temperature by 1 degree Celsius (water=1cal/g/degree C).
High Heat of vaporization: quantity of heat required to convert 1g from liquid to gas states. (Evaporative cooling/sweat).
High boiling point: 100 degrees Celsius

Question 18

Explain water’s cohesive properties.

Answer 18

Cohesion: H bonds holding water molecules together.

Surface tension: measurement of the difficulty to break or stretch the surface of a liquid.

Question 19

Describe water’s solvent properties.

Answer 19

Water is a very good solvent (sometimes called the “universal solvent”).

Question 20

What is a solution?

Answer 20

A completely homogenous mixture.

Question 21

What is sodium chloride’s mode of transport?

Answer 21

Dissolved in plasma (ions).

Question 22

What are amino acids’ mode of transport?

Answer 22

Dissolved in plasma (sufficient solubility due to charged regions)

Question 23

What is glucose’s mode of transport?

Answer 23

Dissolved in plasma (polar)

Question 24

What is oxygen gas’ mode of transport?

Answer 24

Carried by hemoglobin (nonpolar)

Question 25

What are fats' mode of transport?

Answer 25

Transported in lipoprotein complexes (nonpolar)

Question 26

What is cholesterol's mode of transport?

Answer 26

Transported in lipoprotein complexes (nonpolar)

Question 27

Modes of transport in blood depends on what?

Answer 27

Solubility

Question 28

Describe water's adhesion property.

Answer 28

Adhesion: H bonds holding molecules to another substance (water droplets hanging onto a leaf)

Question 29

Describe water's density properties.

Answer 29

Water is less dense as a solid than a liquid due to hydrogen bonding. e

Question 30

What are chemical reactions?

Answer 30

Making and breaking of chemical bonds leading to the changes in the composition of matter.

Question 31

Acid does what to the hydrogen concentration of a solution?

Answer 31

Increases it.

Question 32

Base does what to the hydrogen ion concentration of a solution?

Answer 32

Reduces it.

Question 33

What is the focus of molecular biology?

Answer 33

To explain living processes in terms of the chemical substances involved.

Question 34

What is vitalism?

Answer 34

Vitalism is the belief that living organisms possess a non-physical inner force or energy that gives them the property of life. It was thought that organic compounds could NOT be produces without this vital force.

Question 35

What helped to falsify vitalism?

Answer 35

The artificial synthesis of urea (1828 urea an organic compound produced in the liver was first synthesized artificially)

Question 36

What does organic mean?

Answer 36

Organic = carbon compounds that are found in living organisms. Almost all carbon compounds are organic.

Question 37

What does inorganic mean?

Answer 37

Inorganic = all compounds that do NOT contain carbon and CO2, carbonates, bicarbonates.

Question 38

Why is carbon so important?

Answer 38

Carbon is tetravalent (can form four covalent bonds). This allows it to produce a great variety of stable organic compounds.

Question 39

What is metabolism?

Answer 39

The web of all the enzyme-catalysed reactions in a cell or organism.

Question 40

What is anabolism?

Answer 40

The synthesis of complex molecules from simpler molecules. (Ana=and, so synthesis)

Question 41

What is catabolism?

Answer 41

The breakdown of complex molecules into simpler molecules (cata=cut, so breakdown)

Question 42

What are polymers?

Answer 42

Covalent bonding of monomers. Formed through condensation reaction (dehydration synthesis).

Question 43

Describe the process of condensation reaction (dehydration synthesis).

Answer 43

One monomer provides a hydroxyl group while the other provides a hyrdrogen to form a water molecule.

Question 44

What happens in Hydrolysis?

Answer 44

Bonds between monomers are BROKEN by adding water (digestion).