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Science - Living Earth > Ch2 - The Chemistry of Life > Flashcards

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
Q

What is meniscus?

A

A curve on the surface of a molecular substance when it touches another material

26
Q

What is capillary action? Example?

A

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
Q

Solution vs Solvent vs Solute vs Suspension

A

Solution - liquid, homogeneous mixture of 2+ substances
Solvent = dissolving agent (liquid)
Solute = dissolved substance
Water = versatile solvent
Suspension = water + nondissolved material

28
Q

Why is water a good solvent?

A

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
Q

Hydrophilic vs Hydrophobic

A

Hydrophilic: attracted to water
ex. charged molecules
Hydrophobic: scared of water
Ex. fats, oils, wax

30
Q

How does water for ions?

A

Water can split to make Hydrogen ion (H+) and Hydroxide ion (OH-)

31
Q

More acidic vs more basic

A

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
Q

What are buffers & how do they work?

A

Solutions that prevent sudden changes in ph levels (keep it stable)
Remove H+ or OH- ions that could cause change in ph

33
Q

Expand on ocean acidification

A

CO2 from atmosphere reacts with water to form carbonic acid – changing chemistry of seawater to become more acidic

34
Q

What is high heat capacity? Example?

A

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
Q

What is high heat of vaporization?

A

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
Q

What is high heat of vaporization?

A

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
Q

What is Organic Chemistry?

A

study of compounds between carbon atom

38
Q

Why is carbon special?

A

It can form 4 bonds with Hydrogen, Oxygen, Phosphorus, Nitrogen, Sulfate, & itself
Can make long chain & ring structures

39
Q

What are macromolecules? How/what are they formed from?

A

Large molecules formed from monomers through polymerization

40
Q

What are carbohydrates made of? Monomers & Polymers? Examples?

A

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
Q

Function of carbohydrates? In animals vs plants?

A

Plants store carbs - starch
Animals store carbs - glycogen

Store & produce energy (breaking down sugars)
Structure

42
Q

What are lipids made of? Monomers & Polymers? Examples?

A

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
Q

Function of lipids?

A

Store energy
Insulate body
Chemical messenger (steroids)

44
Q

What is hydrogenation?

A

saturation of oils/other unsaturated fats

45
Q

What are nucleic acids made of? Monomers & Polymers? Examples?

A

Hydrogen, Oxygen, Nitrogen, Carbon, Phosphorus
Monomer: Nucleotide
Polymer: Polynucleotide
Ex. DNA, RNA

46
Q

Function of Nucleic Acids?

A

Store & transmit genetic information

47
Q

What are proteins made of? Monomers & Polymers? Examples?

A

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
Q

Structure of proteins?

A

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
Q

Function of proteins?

A

Structure role – hair, nails
Control rate of reactions (enzymes)
Form bones & muscle
Transport substances in & out of cells
Fight diseases

50
Q

What is a chemical reaction?

A

process that changes one set of chemicals to another

51
Q

Reactants vs Products

A

Reactants: what goes into the reaction – what enters
Products: element that is produced – what exits

52
Q

Exergonic vs Endergonic reaction

A

Exergonic: breaking down of compounds – cellular respiration
Endergonic: building compounds (requires energy) – photosynthesis

53
Q

Expand on energy changes? Examples?

A

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
Q

What is activation energy?

A

Energy needed to “kick” start a reaction

55
Q

What is a catalyst?

A

substance that speeds up rate of chemical reaction

56
Q

What are enzymes? Example?

A

biological catalysts
Ex. lactase, sucrase

57
Q

What would happen if enzymes were not there?

A

molecules have to collide with each other with enough energy to break bonds & form new bonds – reactions would go too slow (dangerous)

58
Q

What are substrates?

A

reactant of an enzyme-substrate reaction

59
Q

What is the enzyme-substrate complex?

A

formed when substrates bind to the enzyme at its active site

60
Q

How is enzyme activity regulated?

A

Proteins in cells
Temperature, pH level

61
Q

What does it mean to be denatured?

A

enzyme has been used so much that the active site is not an exact match to the substrates anymore – after prolonged use

Science - Living Earth (11 decks)

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