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Human Body > 1.3 - Chemistry for Biologists > Flashcards

1.3 - Chemistry for Biologists Flashcards

1
Q

What are organisms made of?

A

Organisms are composed of matter, which is anything that takes up space and has mass

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2
Q

What is matter made of?

A

Matter is made up of elements (substances that cannot be broken down to other substances by chemical reactions)

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3
Q

What is a compound?

A

A compound is a substance consisting of one or more elements combined in a fixed ratio

  • A compound’s characteristics differ from those of its element (ex: sodium and chloride characteristics (elements) vs sodium chloride (compound) characteristics)
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4
Q

T/F: Everything around you, living or non-living, solid, liquid, or gas, is made up of chemical elements

A

True

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5
Q

How many chemical elements exist?

A

There are at least 118 chemical elements

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6
Q

What are elements?

A

Elements are chemical substances made of atoms

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7
Q

How many chemical elements does life require?

A

25 chemical elements

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8
Q

What are the 6 essential elements?

A

Nitrogen, carbon, hydrogen, oxygen, phospohorus, sulfur

AKA “N-CHOPS”

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9
Q

Which 4 of the 6 essential elements make up 96% of living matter? (And describe their behaviour)

A

Carbon, hydrogen, oxygen, and nitrogen

  • They are chemically reactive due to having unfilled valence shells
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10
Q

What are atoms composed of?

A

Atoms are composed of even smaller parts called subatomic particles

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10
Q

What are the 3 relevant subatomic particles?

A
  • Neutrons (with no electrical charge - think ‘neutral’)
  • Protons (with a positive charge)
  • Electrons (with a negative charge)
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11
Q

Where are protons and neutrons found?

A

They are found in the atomic nucleus

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12
Q

Where are electrons found?

A

They surround the atomic nucleus in a ‘cloud’

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13
Q

What does the atomic number represent?

A

The atomic number represents the # of protons an element has

  • Also, in an atom, e = p, so if you know the atomic number, you know how many protons AND electrons there are
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14
Q

What does the atomic mass represent?

A

The atomic mass represents the # of protons and neutrons an element has

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15
Q

How are compounds formed?

A

When 2 atoms approach each other, their outermost (valence) electrons interact. Valence electrons of one atom can interact with valence electrons of other atoms to form chemical bonds.

  • This process is called chemical bonding
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16
Q

How do atoms with filled electron shells (valence) behave?

A

Atoms whose electron shells are filled are chemically unreactive

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17
Q

How do atoms with unfilled electron shells (valence) behave

A

Atoms whose electron shells are unfilled are chemically reactive

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18
Q

What is a covalent bond?

A

A covalent bond is formed if the valence electrons are shared between the 2 atoms

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19
Q

What is a nonpolar covalent bond?

A

Nonpolar covalent bonds are formed when electrons are shared equally

20
Q

What is a polar covalent bond?

A

Polar covalent bonds are formed when electrons are not shared equally; one atom is more electronegative than another (pulls electrons more strongly)

Ex: water (H20)

21
Q

What is an ionic bond?

A

An ionic bond is formed when the two atoms are so unequal that the more electronegative atom strips the electron completely away from its partner

The resulting atoms are called ions

22
Q

What are positive ions called?

A

Cations

23
Q

What are negative ions called?

A

Anions

24
Q

What are ionic compounds called?

A

Salts

25
Q

Describe the strength of ionic bonds in different states of matter

A

Ionic bonds are very strong in solid phases

They tend to be weaker than covalent bonds when in aqueous phases

26
Q

What is hydrogen bonding?

A

Hydrogen bonding is a weak attraction between one molecule and another. Hydrogen will bind weakly to other electronegative atoms (like oxygen, nitrogen). Unlike other bonds, hydrogen bonds are very easy to break, and form/re-form quickly (like a square dance). However, even though they are weak and transient, they are extremely important biologically

27
Q

How do hydrogen bonds form?

A

A hydrogen bond forms when a hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom

28
Q

What is considered to be the universal solvent?

A

Water

29
Q

What is polarity, and how is it used in hydrogen bonding?

A

Polarity occurs when a molecule’s electric charge is split into two distinct poles (positive and negative) that either attract or repel others.

Polarity causes water molecules to form weak (hydrogen) bonds between water molecules

30
Q

What is cohesion?

A

The process by which water sticks to itself

31
Q

What is adhesion?

A

The process by which water stick to other substances

32
Q

Why does water sit atop a glass, instead of spilling over, when filled very high?

A

High surface tension and cohesion: the bonds offset gravity in a very full glass (which is also the reason for droplet formation)

33
Q

What is a capillarty?

A

Capillarty is the thin tube that plants use to get water and nutrients to its leaves

34
Q

What are water’s important thermal properties?

A
  • High freezing and boiling points because of H-bonding and van der Waals’ forces
  • High heat capacity - gains/loses more heat than other substances without greatly increasing/decreasing temperature
  • High latent heat of vaporization (evaporation)
  • High latent heat of melting
  • Calorie - amount of heat required to raise the temperature of one gram of water by 1°C (requires lots of energy to increase water by 1°C)
35
Q

Why does water’s temperature increase/decrease more slowly than other materials?

A

Water’s temperature increases/decreases more slowly than other materials to maintain internal constancy; water has a high specific heat because the hydrogen bonds absorb heat. This protects organisms (made of water) from rapid temperature changes, and causes a swimming pool to stay cold even when it’s hot outside

36
Q

What is latent heat capacity?

A

Latent (hidden) heat is energy that is either absorbed or released as water changes state

37
Q

What is a neutral pH on the pH scale?

A

7

38
Q

What does it mean to be acidic on the pH scale?

A

To be acidic on the pH scale, a solution must fall between 0-6

39
Q

What does it mean to be basic on the pH scale?

A

To be basic on the pH scale, a solution must fall between 8-14

40
Q

What are buffers?

A

Buffers allow solution to resist changes in pH by soaking up excess H+ (percent hydrogen aka pH) or donating H+ when scarce

41
Q

What are hydrophilic chemicals?

A

Solutes (ex: sugar, salt)

42
Q

What does it mean to be hydrophilic?

A

To love water; if something is hydrophillic, it will easily interact with water molecules

43
Q

What are some hydrophobic molecules?

A

Oil, cell membranes, wax

44
Q

What does it mean to be hydrophobic?

A

To hate water; if something is hydrophobic, it will repel water and avoid interacting with it at all costs

45
Q

How are ionic bonds in other substances split up?

A

Water reduces the attraction of ionic bonds in other substances and splits them up by dissolving them (particularly dissolving solutes like salt/sugar)

46
Q

What is the #1 way that water is crucial to life?

A

The most important property of water to the existence of life has to do with the ability of water to dissolve some substances and exclude others

47
Q

How is water crucial for cell life? (6)

A
  • Used as reactant (ex: needed for photosynthesis)
  • Used as solvent (for inorganic/organic substances)
  • Acts as medium for transportation (flows from one area to another)
  • Acts as medium for chemical reaction (many chemicals can dissolve in it)
  • Provides support (some organisms need water to live in (ex: buoyancy for aquatic organisms))
  • Other misc. stuff (medium for fertilization of eggs/sperm in mammals, necessary for forming body secretion (ex: digestive juice), decreases body temperature through evaporation of water from body surface (ex; sweat))

Human Body (22 decks)

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