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Bio > Chapter 2 > Flashcards

Chapter 2 Flashcards

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Biology 101 flashcards
1
Q

wood ants

A

shoot formic acid to defend against invaders

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2
Q

Matter consists of ___ in pure form and in combinations called ___.

A

chemical elements, compounds.

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3
Q

element

A

substance that can’t be broken down to other substances by chemical reactions

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4
Q

How many naturally occurring elements are there?

A

92 elements

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5
Q

compound

A

substance consisting of 2+ different elements combined in a fixed ratio. (eg. NaCl)
has different characteristics from that of its elements

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6
Q

essential elements

A

20-25% of the natural elements

needed by an organism to live a healthy life and reproduce

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7
Q

What elements make up 96% of living matter?

A

carbon, oxygen, hydrogen, nitrogen

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8
Q

trace elements

A

required by an organism only in minute quantities

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9
Q

What elements are trace elements?

A

boron, chromium, cobalt, copper, fluorine, iodine, iron, manganese, molybdenum, selenium, silicon, tin, vanadium, zinc

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10
Q

goiter

A

when the thyroid gland swells to abnormal size due to lack of iodine

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11
Q

arsenic

A

poisonous to humans

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12
Q

serpentine

A

jade-like material with elevated concentrations of chromium, nickel, cobalt

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13
Q

evolution of tolerance to serpentine

A

some plants evolved over time (natural selection) to survive in serpentine soils

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14
Q

An element’s properties depend on the ____.

A

structure of its atoms.

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15
Q

atom

A

smallest unit of matter that still retains properties of an element

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16
Q

subatomic particles

A

make up atoms

neutron, proton (+), electron (-)

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17
Q

atomic nucleus

A

dense core made of protons and neutrons, surrounded by cloud of electrons (attracted by charge)

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18
Q

mass of proton/neutron

A

1.7 x 10^-24 g/1 Dalton

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19
Q

dalton

A

unit of measurement same as 1 amu

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20
Q

atomic number

A

number of protons of a certain element
written in subscript on the left of the symbol
usually indicates number of electrons as well, IF atom isn’t an ion

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21
Q

mass number

A

sum of protons + neutrons

superscript to the left of the symbol

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22
Q

atomic mass

A

total mass of an atom

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23
Q

isotopes

A

different atomic forms of the same element, with different neutron number
have greater masses

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24
Q

radioactive isotope

A

unstable, nucleus decays spontaneously, gives off particles and energy

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25
Q

radioactive tracers

A

radioactive atoms put into bloodstream to diagnose certain disorders (eg. kidney disease)

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26
Q

PET scanners

A

monitor growth and metabolism of cancers in the body

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27
Q

dangers of decaying isotopes

A

radioactive fallout

severity depends on amount/type of radiation

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28
Q

radiometric dating

A

used to date fossils

measure ratio of different isotopes and calculate how many half-lives have passed since an organism was fossilized

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29
Q

half-life

A

parent isotope decays into daughter isotope

amount of time for 50% of parent to decay

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30
Q

Which subatomic particles are responsible for chem reactions?

A

electrons

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31
Q

energy

A

capacity to cause change (eg. by doing work)

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32
Q

potential energy (PE)

A

energy matter possesses b/c of its location/structure

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33
Q

What is matter’s natural tendency?

A

to move towards the lowest possible state of potential energy

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34
Q

Skills Exercise: Neanderthal Extinction

A
  • used carbon-14 dating to determine age of Neanderthal fossil from most recent layer
  • half-life of carbon-14 is 5,730 years
  • fossil had ~ 0.0078 as much carbon-14 as the atmosphere
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35
Q

potential energy of an electron is from:

A
  • their distance from the nucleus; the more distant an electron is from the nucleus, the greater the potential energy
  • energy level; can’t exist between energy levels, only at certain ones
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36
Q

electron shells

A

have characteristic average distance and energy level
where electors are found
represented by concentric circles
first shell = closest to nucleus (lowest PE)
contain electrons at a particular energy level

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37
Q

Can electrons move between shells? How?

A

Yes, but only by absorbing/losing amount of energy equal to the difference in PE between its position in the old and new shell

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38
Q

When an electron absorbs energy:

A

it moves to a shell further from the nucleus

39
Q

When an electron “falls back” to a shell:

A

the lost energy is released into the enviro as heat

40
Q

Chemical behavior of an atom is determined by the:

A

distribution of electrons in the electron shells

41
Q

How many electrons can the first shell hold?

A

2 electrons

42
Q

How many electrons can the second, third, etc shells hold?

A

8 electrons

43
Q

The outermost shell determines:

A

the chemical behavior of an atom, based on the NUMBER of electrons in it

44
Q

valence shell/valence electrons

A

the outermost shell and outermost electrons

unpaired electrons react

45
Q

Atoms with full valence shells will:

A

not react w/ other atoms; inert

46
Q

Each concentric circle in a 2D drawing:

A

represents only the average distance between an electron in that shell and then nucleus

47
Q

orbital

A

3D space where an electron is found 90% of the time
component of an electron shell
no more than 2 electrons can occupy a single orbital
4 orbitals of the second electron shell = up to 8 electrons

48
Q

types of orbitals

A

1st electron shell: only one spherical s orbital (1s)

2nd electron shell: 4 orbitals, 1 large spherical s orbital (2s), 3 dumbbell-shapped p-orbital (2p orbitals)

49
Q

Formation and function of molecules depend on ____ between ___

A

chemical bonding, atoms.

50
Q

chemical bonds

A

attractions between atoms that interact

51
Q

covalent bonds

A

sharing of a pair of valence electrons by 2 atoms

52
Q

molecule

A

2+ atoms held togeterh by covalent bonds

53
Q

molecular formula

A

indicates how many atoms in the molecule (eg. H2)

54
Q

Lewis Dot structure

A

element symbols are surrounded by dots that represent the valence electrons (eg. H:H)

55
Q

structural formula

A

line represents single bond; double bond is two lines (eg. H-H, or O=O)

56
Q

valence

A

bonding capacity of an atom corresponding to # of covalent bonds they can form; equals # of unpaired electrons required to complete the atom’s outermost shell

57
Q

electronegativity

A

attraction of a particular atom for the electrons of a covalent bond; more electronegative = more strongly it pulls shared electrons toward itself

58
Q

nonpolar covalent bond

A

electron is shared equally between 2 atoms; same electronegativity

59
Q

polar covalent bond

A

electron not shared equally b/c differing electronegativities (eg. water = very polar b/c oxygen is very electronegative)

60
Q

partial negative

A

caused by polar covalent bonds

indicated w/ delta signs

61
Q

ions

A

two oppositely charged atoms (b/c electron stripped away from another)
applies to molecules that are electrically charged

62
Q

cation

A

positively charged ion

63
Q

anion

A

negatively charged ion

64
Q

ionic bond

A

bond between any two oppositely charged ions (eg. sodium and chlorine)

65
Q

ionic compounds/salts

A

compounds formed by ionic bonds
often found as crystals in nature
made of vast #s of cation ions and anions bound by electrical attraction and arranged in 3D lattice
*IS NOT a molecule

66
Q

importance of weaker bonds

A
  • two molecules can come together, respond, then separate

eg. water and ionic bond, hydrogen bonds and van der Waals

67
Q

hydrogen bond

A

attraction between a hydrogen and an electronegative atom (when covalently bonded w/ electroneg atom, has slight pos charge that allows it to be attracted to diff electroneg atom nearby)

68
Q

van der Waals interactions

A

individually very weak; occur only when atoms and molecules are very close together
constantly changing regions of pos/neg charge in molecules

69
Q

linear shape

A

molecule consisting of two atoms

70
Q

Molecule shape is determined by:

A

position of atoms’ orbitals
(eg. atoms w/ valence electrons in both s and p orbitals form 4 new hybrid orbitals shaped like teardrops from region of atomic nucleus; if connect larger ends w/ lines, have a tetrahedron)

71
Q

importance of molecular shape

A

determines how biological molecules recognize and respond to one another / specificity (only bind temporarily if their shapes are complementary)
(eg. opiates, which relieve pain and alter mood by weakly binding to specific receptor mollies on brain cell surfaces; have shapes similar to endorphins)

72
Q

Chemical reactions ___ and ____ chemical bonds.

A

make, break

73
Q

chemical reactions

A

making/breaking of chemical bonds, leading to changes in composition of matter (eg. hydrogen and oxygen reaction forms water by breaking covalent bonds of H2 and O2 and forming new bonds for H2O)

74
Q

reactants

A

starting materials, on L of equations

75
Q

products

A

ending materials, on R of equations

76
Q

In chemical reactions, matter is:

A

conserved. Reactions can only rearrange electrons

77
Q

All chemical reactions are:

A

reversible

78
Q

factor that affects rate of reaction

A

concentration of reactants; greater concentration = more collisions = more opportunities to react and form products

79
Q

chemical equilibrium

A

point at which the reactions offset one another exactly
is a dynamic equilibrium (reactions still going on) w/ no net effect on reactant/product concentrations
*equilibrium does NOT mean reactants and products are equal in concentration, but that their concentrations have stabilized at a particular ratio (eg. ammonia)

80
Q

strongest chemical bonds

A

ionic and covalent

81
Q

glucose

A

C6H12O6

alpha glucose vs beta glucose = reversal of H and OH on first carbon

82
Q

fructose

A

C6H12O6, placement of C atoms = diff

83
Q

glycosidic linkage

A

connects 2 sugar molecules, disaccharide, loses water molecule as does so –> condensation reaction, dehydration reaction

84
Q

starch

A

polymer of alpha glucose molecules; energy storage in plant cells

85
Q

glucogen

A

polymer of alpha molecules; differs in pattern of polymer branching; energy storage in animal cells

86
Q

cellulose

A

[polymer of beta glucose; structural molecule in walls of plants, major componenet of wood

87
Q

chitin

A

beta glucose molec w/ N containing group attached to ring; structural molecule in walls of fungus cells; exoskeletons

88
Q

tryglycerides

A

fats and oils, 3 fatty acids attached to glycerol molecule

  • fatty acids = hydrocarbons (covalently bonded C and H w/ carboxyl group (COOH) at end)
  • double bond in fatty acid creates bend –> saturated fats
89
Q

saturated fats

A

packed tightly, higher melting point

-single covalent bond btwn each pair of C, each C has 2 H bonded to it (saturated w/ H)

90
Q

unsaturated fats

A
  • liquid at room temp

- lower melt temp

91
Q

monounsaturated fatty acid

A

1 double covalent bond, each of 2 C in bond has only 1 H bonded to it

92
Q

polyunsaturated fatty acid

A

2+ double covalent bonds

93
Q

phospholipid

A

looks like triglyceride

-one of fatty acid chains replaced by phosphate group

Bio (10 decks)

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