Chapter 2: Introduction to the chemistry of life Flashcards
The smallest unit of an element that exists as a stable entity.
Atom
A substance containing only one type of atom
Element
A substance containing two or more different types of atoms
Compound
How many naturally occurring elements?
92
Living tissue composed of
Carbon, hydrogen, oxygen and nitrogen
Atom structure
A nucleus containing protons and neutrons
* With electrons orbiting the outside
Neutrons are
Neutral and carry no electric charge
Protons are
Positively charged
Electrons are
Negatively charged
What makes one element different from another?
The atomic number
The atomic number
Is the number of protons in the nuclei
The atomic weight
Of an element is the sum of the protons and neutrons in the nucleus
The electron configuration
Describes the distribution of the electrons in each element
Electron shells
2 in the first
8 in the second
18 in the third, and
32 in the fourth
Isotopes
These are atoms of an element in which there is a different number of neutrons in the nucleus. This does not effect the activity of the atom just the atomic weight.
Molecules
Consist of two or more atoms that are chemically combined
Compound
two or more elements combined the molecule is referred to as
Compounds that contain carbon and hydrogen are classified as
Organic
Covalent bonds
Are formed when atoms share their electrons with each other
Ionic bonds
Are weaker and are formed by electrons being transferred from one atom to another
Cation
Positive charge
Anion
Negative charge
Electrolyte
an ionic compound dissolved in water and can conduct electricity
Mole
Molecular weight in grams of a substance
Chloride (normal plasma levels)
97-106 mmol/L or
97-106 mEq/l
Sodium (normal plasma levels)
135-143 mmol/L or
135-143 mEq/l
Glucose (normal plasma levels)
3.5-5.5 mmol/L or
60-100 mg/100ml
Iron (normal plasma levels)
14-35 mmol/L or
90-196 mg/100ml
PH
The concentration of hydrogen ions in a solution is the measure of the acidity of the solution
PH scale
0-14
0-6.9 acid
7 neutral
7.9-14 alkaline
Ph value of blood
7.35-7.45
Ph value of Saliva
5.4-7.5
Ph value of Gastric Juice
1.5-3.5
Ph value of Bile
6-8.5
Ph value of Urine
4.5-8
PH equation
CO2 + H2O H2CO3 H+ + HCO3-
Carbon Water Carbonic Hydrogen Bicarbona
dioxide acid ion -te ion
Acid base balance
Maintained by the buffer and excretory systems so that the ph range of blood stays within normal, narrow range limits
Acidosis
Ph falls below 7.35
Alkalosis
Ph rises above 7.45
Carbohydrates
Sugars and starches composed of carbon, oxygen and hydrogen.
* Arranged in a ring
Glycosidic linkage
two sugars combine to form a bigger sugar and a water molecule is expelled
One unit of sugar
Monosaccharide
Two sugar units
Disaccharide
Many sugar units
Polysaccharide
Proteins
Made from amino acids joining together
20 amino acid types
Amino acids always contain
carbon, hydrogen, oxygen and nitrogen and many contain sulphur
Peptide bond
two amino acids combine to form a bigger molecule and a water molecule is expelled
Protein
is an alternate energy source
Glucose is the
prefered source of energy for the cells
Lipids are
a diverse group of substances with an inability to mix with water
Carbon, hydrogen and oxygen
Phospholipid
Double layer Cell membrane with a hydrophilic head and hydrophobic tail
Fat soluble vitamins
Vitamin A, D, E and K
Fats (triglyceride) stored in
Adipose tissue
Fats are classified as
Saturated or Unsaturated
Saturated
Are solid at room temperature
Unsaturated
Are liquid at room temperature
Prostaglandins
Important chemicals derived from fatty acids and are involved in inflammation and other processes
Cholesterol
is a lipid made in the liver and available in the diet. It is an integral part of cell membranes and is used to make steroid hormones
Nucleic acids
Largest molecule in the body and are built from nucleotides.
DNA - deoxyribonucleic acid
RNA - ribonucleic acid
ATP - Adenosine triphosphate
is a nucleotide that contains ribose (the sugar unit), adenine (the base and three phosphate groups
‘The energy currency of the body’
Enzyme
Proteins that are catalysts for biochemical reactions
Substrate
molecule entering an enzyme reaction
Active site
the substrate will bind to a specific part of the enzyme
Anabolic reaction
When an enzyme catalyses the combination of two or more substances into a larger product
Catabolic reaction
Involves the breakdown of the substrate into smaller products, as occurs in digestion of food
Diffusion
Movement of molecules down its concentration gradient
Passive
requiring no energy
Active Transport
requiring energy
Osmosis
diffusion of water down its concentration gradient
Isotonic
solution equal on both sides of the membrane
Hypotonic
a dilute solution
Hypertonic
A concentrated solution
The total amount of body water in an adult
60% of body weight
40 litres
Extracellular water
22%
12 litres
Intracellular water
38%
28 litres