Chemical Elements & Biological Compounds Flashcards
Magnesium
- Constituent of chlorophyll
- Needed for photosynthesis
- Lack of leads to chlorosis (yellow leaves)
Iron
- Constituent of haemoglobin
- Involved in transportation of oxygen in blood
- Lack leads to anaemia
Calcium
- Structural component of bones and teeth
Phosphate
- Needed for making nucleotides e.g. ATP
Why is Water Dipolar ?
- Slightly negative charged oxygen, slightly positive charged hydrogen
Why is Water a Good Solvent ?
- Dipolar molecule
- Easily dissolve charged particles
Why can Water form Hydrogen Bonds ?
- Slightly negative oxygen is attracted to slightly positive hydrogen.
Why is there Surface Tension in Water ?
- Water molecules attract each other and create lattices (Cohesion)
- Hydrogen bonds between water molecules creates surface tension
Why does Water have High Latent Heat ?
- Many hydrogen bonds, large amount of heat needed for temperature change
- Requires lots of energy to break bonds
Monosaccharides
- Single sugars containing carbon, hydrogen, oxygen
- Name depends on number of carbons (triose-3)
Disaccharide
- Two monosaccharides bonded together by condensation reaction, loss of water forming a glycosidic bond
Polysaccharide
- Many monosaccharides bonded together forming glycosidic bonds
What makes a Polysaccharide good energy store ?
- Unable to diffuse in and out of cell
- Compact
- Insoluble
Alpha Glucose
Hydroxyl group below C4, H above
Beta Glucose
Hydroxyl group above C4, H below
Isomers
Same chemical formula, different atom arrangement
Starch
- Main energy store in plants
- Made of amylose and amylopectin
Structure of Amylose
- 1-4 glycosidic bonds
- Forms single helix
- Alpha glucose
Structure of Amylopectin
- 1-4 and 1-6 glycosidic bonds
- Forms branched structure increasing surface area for hydrolysis to occur
- Alpha glucose
Glycogen
- Energy store in humans
- Has a more branched structure than amylopectin
- 1-4 and 1-6 glycosidic bonds
- Alpha glucose
Cellulose
- Present in plant cell walls
- Beta glucose
- 180 degree rotations
- Hydrogen bonds between rotated glucose forming microfibrils
Chitin
- Exoskeletons
- Beta glucose
- 180 degree rotation
- Hydrogen bonds between rotated glucose forming microfibrils
- Strong, light, waterproof
Functions of Lipids
- Energy reserve
- Thermal insulation
- Protection
- Waterproofing
- Metabolic Water
Triglycerides
1 glycerol molecule bonded to 3 fatty acids by condensation reaction forming an ester bond
Phospholipid
- Phosphate group and 2 fatty acids
- Phosphate group is hydrophilic
- Fatty acid tails are hydrophobic
Saturated Fats
Hydrocarbon chain fully bonded to hydrogen atoms
Unsaturated Fats
- Hydrocarbon chain includes double bond.
- Not fully bonded to hydrogen atoms
- Creates a kink in the structure
Effect of Saturated Fats on Health
- Atherosclerosis (build up of fatty deposits in arteries)
- LDL - low density lipoproteins
- Leads to angina then heart attack
Effect of Unsaturated Fats on Health
- Results in body manufacturing high density lipoproteins (HDL)
- These carry harmful fats to the liver for disposal
Amino Acids
Order of 20 amino acids determine structure therefore function
Dipeptide
Two amino acids bonded together by a condensation reaction, loss of water forming a peptide bond
Polypeptide
Many amino acids bonded together by peptide bonds
Primary Proteins
Linear sequence of amino acids in polypeptide chain
Secondary Protein
- Alpha helix/Beta pleated sheet
- Hydrogen bonds between =O and -COOH
Tertiary Protein
- Disulphide bridges, Ionic bonds, Hydrophobic interactions
- Gives globular proteins their shape
Quaternary Protein
- 2 or more polypeptide chains in tertiary form combined
Types of Globular Protein
- Antibodies
- Enzymes
- Plasma Proteins
- Hormones
Properties of Globular Proteins
- Compact, folded into spherical molecules
- Insoluble in water
Structural Functions of Fibrous Proteins
- Polypeptides in parallel chains
- Sheets with crosslinks
Properties of Fibrous Proteins
- Insoluble in water
- Strong
- Tough
Example of Globular Protein
- Haemoglobin
- 4 folded polypeptides and a ham group
Example of Fibrous Proteins
- Collagen
- Single fibre containing 3 polypeptide chains interwined
- Very stable