Chapter 1 + 2 Flashcards
Importance of water
- Most abundant compound in our bodies
- Main solvent for many organic molecules present
- Ideal medium for metabolism
H2O structure
- Single oxygen atom (negative charge) covalently bonded with two hydrogen atoms (positive charge)
Water molecules are highly…
Cohesive
Water molecules are cohesive meaning
Individual molecules of water are highly attracted to another
Causes of water being cohesive
- Hydrogen bonding
- Slight positive/negative charges
Properties of water (8)
- Boils at 100 degrees Celsius
- Less dense as ice
- Transparent
- High specific heat capacity
- Evaporative cooling
- pH of 7 (pure)
- Surface tension
- Naturally exists in 3 states
Reasons for boiling point at 100 degrees
Hydrogen bonds no longer hold together molecules
Reasons for ice being less dense
- Less movement within molecule when frozen
- Lattice shape
Hydrophilic definition
Substances that dissolve readily in water
Other terms for hydrophilic
Polar, lipophobic
Hydrophobic definition
Substances that do not dissolve readily in water, but dissolve readily in lipids
Other terms for hydrophobic
Non-polar, lipophilic
Examples of hydrophobic substances
Alcohol, ether
How substances dissolve
The positive and negative charge of water attracts ions in substance and break substance apart causing it to ionise.
How pH is worked out
Ratio of OH- and H+ ions
Neutral pH
7
Acidic pH
Less than 7
Basic pH
More than 7
How pHis kept constant by body
Cells produce and use hydrogen ions
Hydrogen bonds maximum partners (in water)
4
Main types of organic molecules
Carbohydrates, lipids, proteins, nucleic acids
Monomers definition
Smaller molecules (subunits) that give rise to the polymer
Polymer definition
Molecules that consist of many repeating subunits
How polymers are formed
Condensation reactions,
Anabolic, endergonic
How polymers are broken down
Hydrolysis reaction
Catabolic, exergonic
Carbohydrates elements
Carbon, hydrogen, oxygen
Ratio of elements in carbohydrates
1:2:1
Subunits of carbohydrates
Monosaccharides, disaccharides
Polymer of carbohydrates
Polysaccharides
Monosaccharides
A molecule that is comprised of a single sugar unit
Polysaccharides
A molecule that is comprised of many sugar units
Disaccharides
Molecule that is comprised of two sugar units
Monosaccharide examples (4)
Glucose, fructose, galactose, mannose
Glucose
- hexose sugar
- most common source of energy
- C6H12O6
Two types of glucose
Alpha and beta glucose
Fructose
Pentose sugar, in fruit
Disaccharide examples (3)
Sucrose, maltose, lactose
Sucrose
Glucose + fructose
Processed sugar
Form in plants (phloem)
Lactose
Glucose + galactose
Maltose
Glucose + glucose
Polysaccharide examples (6)
Starch, glycogen, cellulose, chitin, pectin, inulin
Starch properties (branched or not, role, solubility, type of glucose)
Branched
Storage of energy in plants (granules)
Slightly soluble
Alpha glucose
Glycogen properties (branched or not, role, solubility, type of glucose)
Highly branched (more than cellulose)
Energy storage in animals
Slightly soluble in water
Alpha glucose
Cellulose properties (branched or not, role, solubility, type of glucose)
Unbranched
Structural component in cell walls of plants used for structure and strength
Insoluble
Beta glucose
Energy storage in plants (not just starch)
Granules in amyloplasts
Simple carbohydrates
Carbohydrates containing one or two sugar units
Complex carbohydrates
Many sugar units
Inorganic compounds examples
Salts, water, O2, CO2, minerals
Bonding that holds together carbohydrates
glycosidic linkages
Lipid elements
carbon, hydrogen, oxygen
How to tell difference between lipid and carbohydrate
in lipid, there is usually much less oxygen
Do lipids or carbohydrates produce more energy
lipids as they are more dense
Examples of lipids (4.5)
fats and oils, phospholipids, waxes, steroids
Fats and oils are known as
triglycerides/triacylglycerols
Triglycerol comprised of
single glycerol molecule bonded to 3 fatty acid tails
Are lipids polymers
no, as their subunits are discrete and non-repeating
Are lipids soluble in water
no
How are triglycerides stored in the body
adipose tissue
Purpose of adipose tissue
protects vital organs by cushioning, absorbs impact, insulator, source of fats, energy
Cholesterol structure
4 rings
Purpose of cholesterol in phospholipid bilayer
fluidity to prevent solidification, keeps in place, acts as barrier between phospholipids
Use of steroids
signalling molecules, muscle repair
Use of wax
surface coating
Phospholipids definition
A lipid molecule found in the membranes of cells, that are comprised of a glycerol molecule attached to a hydrophilic phosphate head, and a two hydrophobic fatty acids tails.
Phospholipids structure
phosphate group, glycerol molecules, two fatty acid molecules
Are fatty acids of phospholipids saturated or unsaturated
one is saturated, one is unsaturated
Unsaturated meaning
if have one or more double carbon bonds
Saturated meaning
are saturated with hydrogens; have the maximum possible number of hydrogens
Is phospholipid hydrophilic or hydrophobic
head is hydrophilic, tails are hydrophobic
Why do fatty acid tails face in
because they are hydrophobic
Amino acid elements
C, H, O, N, generally S
Subunits of proteins
amino acids
How many naturally occurring amino acids are there
20
Amino acids can be (polarity e.t.c.)
nonpolar, polar, electrically charged, acidic or basic
Structure of amino acid
carboxyl group (-COOH), amino group (-NH2), variable R/Z group
Dipeptide
2 amino acids
Tri-peptide
3 amino acids
Polypeptide
many amino acids
When to call it protein vs polypeptide
it’s a protein if it’s extremely long, multiple separate amino chains, globular
Globular proteins
soluble, lock and key
Examples of globular proteins (5)
enzymes, messenger molecules, membrane channel/carrier proteins, regulatory proteins, defensive
Fibrous proteins
insoluble, structural use
Amino acids are….
directional
Type of bonding amino acids use
peptide bonding