BIOL126 Lecture Notes - Lecture 2: Ionic Bonding, Thyroid, Chemical Bond
10 Jun 2018
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Chemistry
1.8 Structure of atoms
Atom: smallest stable unit of matter.
Sub-atomic particles- protons, neutrons, electrons.
1.9 Elements, compounds and molecules
Two or more atoms can interact by chemical bonding to form a molecule;
If all bonding atoms are the same = element,
Combination of different types of atoms = compound.
1.9.1 the roles of biologically important elements!
Oxygen (O): cellular respiration (breaking
down food to water, carbon dioxide and
energy)
Carbon (C): in all organic molecules
Hydrogen (H): in all organic compounds, an
element in water
Nitrogen (N): in amines, proteins and nucleic
acids
Calcium (Ca): for muscle contraction, nervous
impulses, blood clotting, bones and teeth
Phosphorus (P): component of ATP (body’s
chemical energy molecule), nucleic acids
Potassium (K): main intracellular cation (+ve),
in nervous impulses, muscle contraction
Sodium (Na): main extracellular cation, in
nerves impulses, muscle contraction, fluid
balance
Chlorine (Cl): main extracellular anion (-ve)
Magnesium (Mg): cofactor in enzyme reactions
Sulfur (S): in many proteins
Iron (Fe): component of haemoglobin in red
blood cells
Iodine (I): component of hormones of the
thyroid gland!
1.9.2 H, K, Na, C, Ca, Fe
1.10 Electrons
Electrons orbit around atom nucleus in concentric shells. First shell has a maximum of 2 electrons,
remainder have a maximum of 8.
1.10.1 their role in making bonds between atoms
Outer shell = valence shell = electrons involved in bonding with other atoms.
Chemical bonding means potential instability (as bonding makes a new chemical that has distinct
properties from the original forming elements).
1.10.2 distinguish between ionic and covalent bonds
To become more stable during bonding, atoms lose, gain or share valence electrons.
Lose or gain electrons = ionic bonding.
Share electrons = covalent bonding.
1.11 The importance of key organic molecules:
Organic compounds: always contain C and H atoms or
Inorganic compounds: don’t have C as a structural basis
1.11.1 carbohydrates, lipids, proteins, nucleic acids
Sucrase: breaks down sucose
Lipase: breaks down fat
Nuclease: modifies nucleic acids
Protease: breaks down proteins
1.11.2 what is an enzyme
Enzyme: a substance produced by a living organism which acts as a catalyst to bring about a
specific biochemical reaction.
1.12 what pH is, and how it changes
pH is a scale of 0-14 for Hydrogen concentration.
pH value tells us whether substances are acids, bases, or neutral.
Below pH 7- acidic e.g.stomach acid
Above pH 7- basic/alkaline e.g. bleach
Physiological pH- pH is 6.7-7.8, plasma aro9und 7.4
1.12.1 the biological importance of neutral, acidic and basic/ alkaline pH
Buffers: chemical compounds that stop pH changes if H (acid) or OH (alkaline) is formed.
In the body, buffers that work at physiological pH are very important to hold that pH; prevent
acidosis/ alkalosis.
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Document Summary
Two or more atoms can interact by chemical bonding to form a molecule; If all bonding atoms are the same = element, Combination of different types of atoms = compound. Oxygen (o): cellular respiration (breaking down food to water, carbon dioxide and energy) Hydrogen (h): in all organic compounds, an element in water. Nitrogen (n): in amines, proteins and nucleic acids. Calcium (ca): for muscle contraction, nervous impulses, blood clotting, bones and teeth. Phosphorus (p): component of atp (body"s chemical energy molecule), nucleic acids. Potassium (k): main intracellular cation (+ve), in nervous impulses, muscle contraction. Sodium (na): main extracellular cation, in nerves impulses, muscle contraction, uid balance. Iron (fe): component of haemoglobin in red blood cells. Iodine (i): component of hormones of the thyroid gland. Electrons orbit around atom nucleus in concentric shells. First shell has a maximum of 2 electrons, remainder have a maximum of 8. 1. 10. 1 their role in making bonds between atoms.
