KINE 2011 Chapter Notes - Chapter 2: Ribose, Disulfide, Active Transport

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Chapter 2
Pg 19
Atoms
- A unit of matter that forms all chemical substances
- Atomic nucleus is the small volume at the center of the atom
- Protons are located in the atomic nucleus
- The nucleus has a net positive charge equal to the number of protons it contains
- The atomic number is how many protons each element has
- Atomic weight scale indicates an atoms mass relative to the mass of other atoms
- Atomic weight scale is a ration of atomic masses, it has no absolute units. The unit of atomic
mass is known as a dalton. One Dalton (d) equals one-twelfth the mass of a carbon atom
(carbon has an atomic weight of 12, and a carbon atom has an atomic mass of 12 daltons)
- Table 2-1 Essential Chemical elements in the body:
- Major elements are: Hydrogen (63%), Oxygen (26%), Carbon (9%) and Nitrogen (1%). These
elements make up 99.3% of total atoms in the body
Pg 20
- Many chemical elements can exist in multiple forms called isotopes
- One gram atomic mass of a chemical element is the amount of the element in grams, equal to
the number value of its atomic weight (example on pg 20)
- 6x10 to the power of 23 is Avogadro’s number
Atomic composition of the body
- The seven essential mineral elements are the most abundant substances dissolved in the
extracellular and intracellular fluids
- Trace elements are present in small quantities, but are essential for growth
Molecules
- Two or more atoms bonded together make up a molecule
Covalent chemical bonds
- Atoms in molecules are held together by chemical bonds, which form when electrons transfer
from one atom to another or when two atoms share electrons.
- A covalent bond is when one electron in the outer electron orbit of each atom is shared
between the two atoms
Ions (explanation of page 20)
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- A single atom is electrically neutral because it contains equal numbers of negative electrons and
positive protons
- As an atom gains or lose one or more electrons, it acquires a net electric charge and becomes an
ion
- Some atoms can gain or lose more than one electron to become ions with two or even three
units if net electric charge. (e.g the calcium ion Ca 2+)
Pg. 21
- Ions that have a net positive charge are called cations while those that have a net negative
charge are called anions.
- Electrolytes have the ability to conduct electricity when dissolved in water
- If an atom has more protons than electrons, the charge is positive +
- If an atom has less protons than electrons, the charge is negative -
- Two commonly encountered groups of atoms that undergo ionization are the carboxyl group
( -- COOH) and the amino group (-- NH2)
- Shorthand formula RCOOH
- R signifies the remaining portion of the molecule.
- R never changes, it stays the same. It cannot gain or lose
- The amino group gains a hydrogen in the example, or it can lose it reversed.
- Ionization of each of these groups can be reversed
Free Radicals
- An atom containing a single (unpaired) electron in its outermost orbital is known as a free
radical usually oxygen
- Goes around in your body trying to find something to bond to. It will steal electrons from other
molecules and screw up their functions.
- Antioxidants make free radicals natural because it bonds or will supply extra electrons for them
to bond to
- Pg 22
- Free radicals are unstable molecules that can react with other atoms, through the process
known as oxidation
- Pg 23
- Free radicals are highly reactive, removing electrons from the outer orbits of molecules present
in the pathogen cell membrane
- It is important that free radicals be inactivated by molecules that can donate electrons to free
radicals without becoming free radicals themselves.
- A free radical configuration can occur in either an ionized (charged) or an un-ionized molecule
Polar molecules
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- There are bonds in which the electrons are not shared equally between two atoms, but instead
reside closer to one atom of the pair. The atom acquires a slight negative charge, while the
other atom, because it partly lost an electron becomes slightly positive.
- These bonds are polar covalent bonds because the atoms at each end of the bond have an
opposite electric charge
- δ- and δ+ refer to atoms with a partial negative or positive charge
- Molecules containing significant numbers of polar bonds or ionized groups are known as polar
molecules, whereas molecules composed predominantly of electrically neutral bonds are known
as non-polar molecules
- The electrical attraction between the hydrogen atom in a polar bond in one molecule and an
oxygen or nitrogen atom in a polar bond of another molecule forms a hydrogen bond
- Hydrogen bonds are dashed or dotted lines and are weak
Pg 24
- The shape of large molecules often determines their functions
Water
- The oxygen in water has a slight negative charge and each hydrogen has a slight positive charge
Example:
R1 R2 + H O H R1 OH + H R2
- In this reaction, the covalent bond between R1 and R2 and the one between a hydrogen atom
and oxygen in water are broken and the hydroxyl group and hydrogen atom are transferred to
R1 and R2 .
- Hydrolyic reactions are called hydrolysis
- Large molecules are broken down by hydrolysis with assistance of enzymes
- Dehydration is when one net water molecule is removed to combine two small molecules into a
larger one.
- Dehydration reactions are responsible for building proteins and other polymers required by the
body
- Water moves between fluid compartments by osmosis where water moves from regions of low
solute concentrations to regions of high solute concentrations
Solutions
- Substances dissolved in a liquid are known as solutes and the liquid in which they are dissolved
is the solvent
- Solutes dissolve in a solvent to form a solution
- Water is a solvent
Molecular solubility
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Document Summary

A unit of matter that forms all chemical substances. Atomic nucleus is the small volume at the center of the atom. Atomic weight scale indicates an atoms mass relative to the mass of other atoms. Atomic weight scale is a ration of atomic masses, it has no absolute units. The nucleus has a net positive charge equal to the number of protons it contains. The atomic number is how many protons each element has mass is known as a dalton. One dalton (d) equals one-twelfth the mass of a carbon atom (carbon has an atomic weight of 12, and a carbon atom has an atomic mass of 12 daltons) Table 2-1 essential chemical elements in the body: Major elements are: hydrogen (63%), oxygen (26%), carbon (9%) and nitrogen (1%). These elements make up 99. 3% of total atoms in the body. Many chemical elements can exist in multiple forms called isotopes.

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