Ch2 - The Chemistry of Life Flashcards

1
Q

What parts make up an atom? Where are they located?

A

Proton (+) : center of atom
Neutron (=): center of atom
Electron (-): orbit on electron cloud

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2
Q

What is an element?

A

substance with only 1 atom

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3
Q

What determines the atomic number & atomic mass?

A

Atomic number – # of protons & neutrons
Atomic mass – proton + neutron

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4
Q

What are isotopes? Ex

A

An element with a different # of neutrons
ex. Carbon 14

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5
Q

What are radioactive isotopes?

A

whose nuclei are unstable (bc of change in # of neutrons)
break down at a constant rate - releasing matter/energy as radiation

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6
Q

Uses of radioactive isotopes?

A

treat cancer
find age of rocks/fossils
kill bacteria
track movement of atoms within living tissue

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7
Q

What is a compound?

A

substance formed by 2+ different elements that are bonded chemically

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8
Q

What is a molecule?

A

smallest unit of most compounds
2+ atoms joined chemically (same or different)

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9
Q

What is a mixture? Two types of mixtures?

A

2+ atoms not joined chemically
Homogenous: blended well together – will not separate
Heterogenous: Not uniform

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10
Q

What determines chemical bonds?

A

Valence electrons

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11
Q

What are covalent bonds?

A

Strongest bond - sharing of electrons between 2 atoms

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12
Q

What are ionic bonds?

A

Transfer of 1+ electrons across atoms

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13
Q

What is an ion? Example? Types of ions?

A

Atom that has gained/lost an electron
Ex. NaCl
Cation: Positively charged ion
Anion: Negatively charged ion

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14
Q

What is the octet rule?

A

Atom is most stable with 8 electrons in valence shell

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15
Q

Bond pair vs Lone pair

A

Bond pair: 2 electrons that have fomed a bond
Lone pair: 2 electrons that are not involved in any bond

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16
Q

What is the van der waals force?

A

If two polar molecules are brought together so that atoms touching are opposite charges, their slightly positive and negative charges will cause them to attract (in other words, both surfaces have matching shapes)

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17
Q

What is polarity?

A

Unequal sharing of electrons causing partial positive and negative charges
Ex. Water molecule – O- H+

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18
Q

What is hydrogen bond?

A

Between 2 water molecules
Oxygen of 1 molecule and Hydrogen of another molecule – due to partial positive/negative charge

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19
Q

List the properties of water

A
  1. Cohesion
  2. Adhesion
  3. Good solvent
  4. Acids & bases
  5. High heat capacity
  6. High heat of vaporization
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20
Q

What is cohesion? Example

A

Attraction between molecules of the same substance

Ex. Water striders can walk on water
Ex. Drinking from a straw

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21
Q

What causes high surface tension?

A

In water - cohesion causes high surface tension since the bonds are very strong

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22
Q

Explain why water striders can walk on water

A
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23
Q

Why does ice float?

A

Ice is less dense than water – hydrogen bonds spread apart in order to be more stable

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24
Q

What is adhesion?

A

Bonding between unlike molecules
- can counter force of gravity

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25
What is meniscus?
A curve on the surface of a molecular substance when it touches another material
26
What is capillary action? Example?
Ability of water to move up thin tubes (against the force of gravity) Allows plants to get water from the ground Water climbs up paper towel/cloth Ex. water always moves up xylem vessels of sequoia trees
27
Solution vs Solvent vs Solute vs Suspension
Solution - liquid, homogeneous mixture of 2+ substances Solvent = dissolving agent (liquid) Solute = dissolved substance Water = versatile solvent Suspension = water + nondissolved material
28
Why is water a good solvent?
The positive/negative sides of the water molecule attract other polar molecules - causing molecules of other substances to mix uniformly with the water molecules Solvents (water) dissolve solutes, creating an aqueous solution
29
Hydrophilic vs Hydrophobic
Hydrophilic: attracted to water ex. charged molecules Hydrophobic: scared of water Ex. fats, oils, wax
30
How does water for ions?
Water can split to make Hydrogen ion (H+) and Hydroxide ion (OH-)
31
More acidic vs more basic
More acidic: If H+ ions > OH- ions – ph<7 Ex. HCI, stomach acids, lemon juice More basic: If H+ ions < H+ ions – pH>7 NaOH
32
What are buffers & how do they work?
Solutions that prevent sudden changes in ph levels (keep it stable) Remove H+ or OH- ions that could cause change in ph
33
Expand on ocean acidification
CO2 from atmosphere reacts with water to form carbonic acid – changing chemistry of seawater to become more acidic
34
What is high heat capacity? Example?
It takes a lot of energy to raise the temperature of a certain amt of water by 1 degree Helps to regulate the temperature in the environment Ex. allows the temperature of pond water to stay constant day and night
35
What is high heat of vaporization?
The amt of heat needed to change a certain amt of water into vapor (when heat of vaporization is reached – the state of matter changes)
36
What is high heat of vaporization?
The amt of heat needed to change a certain amt of water into vapor (when heat of vaporization is reached – the state of matter changes)
37
What is Organic Chemistry?
study of compounds between carbon atom
38
Why is carbon special?
It can form 4 bonds with Hydrogen, Oxygen, Phosphorus, Nitrogen, Sulfate, & itself Can make long chain & ring structures
39
What are macromolecules? How/what are they formed from?
Large molecules formed from monomers through polymerization
40
What are carbohydrates made of? Monomers & Polymers? Examples?
carbon + hydrogen + oxygen Monomer: monosaccharide - 1 simple sugar Ex. Glucose, fructose Polymers: disaccharide - 2 simple sugars Ex. Sucrose, Lactose, maltose polysaccharide - >6 sugars Ex. Starch, Glycogen, Cellulose, Chitin
41
Function of carbohydrates? In animals vs plants?
Plants store carbs - starch Animals store carbs - glycogen Store & produce energy (breaking down sugars) Structure
42
What are lipids made of? Monomers & Polymers? Examples?
Carbon & Hydrogen Monomer: Triglyceride (1 glycerol 3 fatty acids) Polymers: Saturated: Only carbon single bonds Ex. butter, cheese Unsaturated: 1+ double/triple bonds Ex. nuts, avocado Polyunsaturated: 1+ double bond Ex. soybean oil, corn oil, sunflower oil
43
Function of lipids?
Store energy Insulate body Chemical messenger (steroids)
44
What is hydrogenation?
saturation of oils/other unsaturated fats
45
What are nucleic acids made of? Monomers & Polymers? Examples?
Hydrogen, Oxygen, Nitrogen, Carbon, Phosphorus Monomer: Nucleotide Polymer: Polynucleotide Ex. DNA, RNA
46
Function of Nucleic Acids?
Store & transmit genetic information
47
What are proteins made of? Monomers & Polymers? Examples?
Carbon, Hydrogen, Nitrogen, Oxygen Monomer: Amino acids - amine group (NH2) & carboxyl group (COOH) & R (variable group that determines acidic/basic level) Linked with peptide bonds
48
Structure of proteins?
Primary Structure: linear chain (# & sequence varies) Secondary Structure: shortening by coiling & pleating Tertiary Structure: further folding to make compact Quaternary Structure: 2+ chains bonded/coiled together
49
Function of proteins?
Structure role -- hair, nails Control rate of reactions (enzymes) Form bones & muscle Transport substances in & out of cells Fight diseases
50
What is a chemical reaction?
process that changes one set of chemicals to another
51
Reactants vs Products
Reactants: what goes into the reaction -- what enters Products: element that is produced -- what exits
52
Exergonic vs Endergonic reaction
Exergonic: breaking down of compounds -- cellular respiration Endergonic: building compounds (requires energy) -- photosynthesis
53
Expand on energy changes? Examples?
Release energy - spontaneous Absorb energy - require source of energy Ex. hydrogen burns/ reacts with oxygen to create water vapor -- this releases a lot of heat, light, and sound energy
54
What is activation energy?
Energy needed to "kick" start a reaction
55
What is a catalyst?
substance that speeds up rate of chemical reaction
56
What are enzymes? Example?
biological catalysts Ex. lactase, sucrase
57
What would happen if enzymes were not there?
molecules have to collide with each other with enough energy to break bonds & form new bonds -- reactions would go too slow (dangerous)
58
What are substrates?
reactant of an enzyme-substrate reaction
59
What is the enzyme-substrate complex?
formed when substrates bind to the enzyme at its active site
60
How is enzyme activity regulated?
Proteins in cells Temperature, pH level
61
What does it mean to be denatured?
enzyme has been used so much that the active site is not an exact match to the substrates anymore -- after prolonged use