Chapter Two Flashcards
1
Q
What are the four main elements that make up a majority of our bodies?
A
- O-Oxygen (most abundant)
- C- Carbon
- H- Hydrogen
- N- Nitrogen
2
Q
Atoms
A
- chemical elements are composed of units of matter of the same type called atoms
- smallest unit of matter that retain properties and characteristics of an element
- Composed of:
- Protons +
- Neutrons 0
- Electrons -
3
Q
Atomic number
A
number of protons in its nucleus
4
Q
Mass number
A
number of protons and neutrons in its nucleus
5
Q
Ion
A
atoms gain or lose an electron to become an ion
6
Q
Molecule vs. compound
A
- Molecule: composed of 2 or more atoms that share electrons
- Ex. O2
- Compound: substance that can be broken down into 2 or more different elements
- Ex. H2O
7
Q
Free radical
A
- an atom or group of atoms with an unpaired electron in the outermost shell
- Ex. superoxide
- vey unstable
8
Q
3 types of chemical bonds
A
- ionic bonds
- covalent bonds
- hydrogen bonds
9
Q
Ionic bond
A
- an atom loses an electron it become positively charged (cation)
- When an atom gains an electron it becomes negatively charged (Anion).
- Oppositely-charged ions attract to each other and form ionic bonds.
- An ionic compound that breaks apart into positive and negative ions in a solution is called an electrolyte.
• Most ions in the body are dissolved in body fluids as electrolytes.
10
Q
Covalent bonds
A
- when two or more atoms share electrons
- can share up to 3 pairs of electrons
- The larger the number of electron pairs shared, the stronger the covalent bond.
- Sometimes when atoms share electrons, they do not share equally.
- The nucleus of one atom attracts shared electrons more strongly.
- When this happens, the shared electrons move to one end of the molecule, forming a polar molecule.
• The end with more electrons becomes negative.
• The end with less electrons becomes positive.
11
Q
Hydrogen bonds
A
- Polar covalent bonds that form between hydrogen atoms and other atoms.
- Hydrogen bonds result from the attraction of oppositely charged parts of molecules rather than from sharing electrons as in covalent bonds.
- Example = water
• The oxygen end of the compound is slightly negative
• The hydrogen ends are slightly positive
12
Q
Chemical Reactions
A
- A chemical reaction occurs when new bonds are formed or old bonds are broken.
• Reactants = starting substances
• Products = ending substances - Metabolism= sum of all chemical reactions occurring in the body
• Products = ending substances
13
Q
Forms of energy
A
- Energy is the capacity to do work.
• Kinetic energy = energy associated with matter in motion
• Potential energy = energy stored by matter due to its position
• Chemical energy = form of potential energy that is stored in chemical bonds.
• When chemical bonds are formed or broken the overall result is absorbing energy or releasing energy.
• Law of conservation of energy:
• Energy can neither be created nor destroyed.
• It may be converted from one form to another.
14
Q
Synthesis reaction vs decomposition reaction
A
- Synthesis: A + B → AB
- Decomposition: AB → A + B
- Rate can be sped up by introducing a catalyst (catalyst reduces activation energy)
15
Q
Inorganic compounds
A
- Inorganic compounds lack carbon and are structurally simple.
- Their molecules also have only a few atoms and cannot be used by cells to perform complicated biological functions.
- They include:
- Water, many salts, acids, and bases.
- Water is the most abundant and important inorganic compound in all living things.
- Makes up 55-60% of an adults lean body mass
- 1-2% are from all other inorganic compounds combined
