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Biology > Chapter 2 > Flashcards

Chapter 2 Flashcards

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1
Q

Chemistry

A

The science that studies the composition and properties of substances and various elementary forms of matter.

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2
Q

Biochemistry

A

The chemistry of living matter

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3
Q

Matter

A

Anything that has mass and takes up space

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4
Q

Atoms

A

The smallest functional units of matter that form all chemical substances

Cannot be further broken down into other substances by ordinary means

Each specific type of atom is a chemical element

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5
Q

Three subatomic particles

A

Protons
Neutrons
Electrons

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6
Q

Protons

A

Subatomic particles with a positive charge found in the nucleus of an atom

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7
Q

Neutrons

A

Subatomic particles with a neutral charge found in the nucleus of an atom

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8
Q

Electrons

A

Subatomic particles with a negative charge found in orbitals of an atom

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9
Q

When protons and electrons are present in equal numbers in an atom, it has ________ charge.

A

no net/a neutral

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10
Q

Orbital (“electron cloud”)

A

Region in space where there is a 90% probability of finding an electron

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11
Q

Orbitals

A

s, p, d, f

s orbitals are spherical
p orbitals are propeller or dumbbell shaped, 4 lobed
d orbitals are belt shaped, 6-8 lobed
f orbitals

each orbital can hold 2 electrons

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12
Q

Energy levels/shells

A

Atoms with more electrons have orbitals with electron shells that are at greater and greater distances from the center of a nucleus.

Energy levels of electrons are labeled by principal quantum numbers (n).

1st shell:
1 spherical orbital (1s) - holds one pair of electrons

2nd shell:
1 spherical orbital (2s) - holds one pair of electrons
3 dumbbell shaped orbitals (2p) - three pairs of electrons
Can hold four pairs of electrons = 8 electrons

etc.

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13
Q

Valence electrons

A

Electrons in the outer shell available to combine with other atoms

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14
Q

Dimitri Mendeleev

A

Developed the periodic table

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15
Q

Periodic table

A

Organizes chemical elements by atomic mass

Rows correspond to number of electron shells

Columns, from left to right, indicate the number of electrons in the outer shell (valence electrons)

Similar properties of elements within a column occur because they have the same number of electrons in their outer shells, and therefore they have similar chemical bonding properties

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16
Q

Atomic number

A

The sum of protons that the atom contains

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17
Q

Atomic mass number

A

The average sum of protons and neutrons in an element

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18
Q

How to calculate number of neutrons

A

Atomic mass - atomic number

(protons + neutrons) - protons = neutrons

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19
Q

Dalton

A

Unit of measurement for atomic mass

Also known as atomic mass unit (amu)

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20
Q

Mole

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A

Unit of measurement

The amount of a substance that contains 6.022 x 10^23 atoms/particles

1 mole of any element contains the same number of atoms—6.022 x 10^23 (Avogadro’s number)

21
Q

Isotopes

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A

Multiple forms of the same element that have different numbers of neutrons

e.g.
Carbon-12 contains 6 protons and 6 neutrons
Carbon-14 contains 6 protons and 8 neutrons

22
Q

Radioactive isotopes

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A

An isotope that has an unstable nucleus that decomposes spontaneously and gives off energy

Carbon-12 is a stable isotope
Carbon-14 is an unstable (radioactive) isotope

23
Q

Tracers

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A

Radioactive isotopes used in scientific research to track metabolic processes

Radioactivity, coming from the area in which the metabolic processes are taking place using the tracers, can be detected by instruments

24
Q

Positron-emission tomography (PET)

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A

An imaging instrument that uses PET detects the location of injected radioactive materials

PET scans are useful for diagnosing heart disorders and cancer

25
Carbon, Hydrogen, Oxygen, and Nitrogen (C, H, O, N)
Make up 95% of the atoms in living organisms Hydrogen and oxygen occur primarily in water Nitrogen is found in proteins Carbon is the building block of all living matter Mineral elements - less than 1% Trace elements - less than 0.01%
26
Oxygen
A major component of both organic and inorganic molecules; as a gas, essential to the oxidation of glucose and other food fuels, during which cellular energy (ATP) is produced.
27
Carbon
The primary element in all organic molecules, including carbohydrates, lipids, proteins, and nucleic acids.
28
Hydrogen
A component of most organic molecules; as an ion (a charged atom), it influences the pH of body fluids.
29
Nitrogen
A component of proteins and nucleic acid (genetic material).
30
Molecule
Two or more atoms of the same element combined chemically ex. O2, H2
31
Compound
Two or more atoms of different elements combined chemically ex. NaCl, H2O
32
Covalent bond
Atoms share a pair of electrons Occurs between atoms with unfilled valence electron shells Covalent bonds are strong, because the shared electrons behave as if they belong to each atom Can share: 1 pair of electrons (single bond) 2 pairs of electrons (double bond) 3 pairs of electrons (triple bond) Can be polar or nonpolar
33
Hydrogen bond
Hydrogen atom from one polar molecule is attracted to an electronegative atom from another molecule Represented by dashed or dotted lines Individually, these are weak bonds that can form or break easily Collectively, many H bonds can be strong H bonds hold DNA strands together
34
Ionic bond
Electrons are transferred, forming ions that are attracted to each other Occurs when a cation binds to an anion by electrostatic attraction Ionic compounds are called salts ex. NaCl, KCl, CaCl2
35
Octet rule
Atoms are stable when their outer shell is full, and for many atoms, the outer shell is filled when there are 8 electrons An exception is hydrogen, which fills its outer shell with just 2 electrons
36
Polar covalent bonds
Form between atoms of different electronegativity (attraction to electrons) Shared electrons are more likely to be closer to the more electronegative atom The uneven distribution of electrons creates a polarity (difference in electrical charge) across the molecule
37
Nonpolar covalent bonds
Occur between atoms with similar electronegativity (attraction to electrons) Equal sharing of electrons No charge difference across molecule
38
Ion
An ion is an atom that has gained or lost one or more electrons
39
Cations
Ions with a net positive charge
40
Anions
Ions with a net negative charge
41
Hydrophilic
“Water-loving” Readily dissolved in water Molecules with ionic and/or covalent bonds
42
Hydrophobic
“Water-fearing” Do not dissolve in water Nonpolar molecules like hydrocarbons, oils
43
Amphipathic
“Both loves” Have both polar/ionized and nonpolar regions May form micelles in water Detergent is an amphipathic molecule
44
Functions of water in living organisms
Participates in chemical reactions (hydrolysis or condensation) Provides force or support Removes toxic waste components Evaporative cooling Cohesion and adhesion Surface tension Lubrication
45
Acids
Molecules that release hydrogen ions in solution A strong acid releases more H+ than a weak acid
46
Bases
Molecules that lower the H+ concentration Some release OH- Others bind H+
47
pH scale
Acidic solutions are pH 6 or below pH 7 is neutral Alkaline/basic solutions are pH 8 or above
48
The pH of a solution can affect what?
The shapes and functions of molecules The rates of many chemical reactions The ability of two molecules to bind to each other The ability of ions or molecules to dissolve in water
49
Buffers
Buffers are substances that help to maintain a constant pH Organisms usually tolerate only small changes in pH An acid-base buffer system can shift to remove or release H+ to adjust for changes in pH

Biology (8 decks)

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