Chapter Three: Biological Molecules Flashcards
What are the roles of these anions?:
1. nitrate ions
2. phosphate ions
3. hydroxide ions
4. chloride ions
5. hydrogen carbonate ions
- nitrogen supply to plants for amino acid and protein formation
- cell membrane formation, bone nuclei acid and ATP formation
- catalysis of reactions and pH determination
- balance positive charge of sodium and potassium ions in cells
- maintenance of blood pH
What are the roles of these cations?:
1. calcium ions
2. sodium ions
3. hydrogen ions
4. potassium ions
5. ammonium ions
- nerve impulse transmission and muscle contraction
- nerve impulse contraction and kidney function
- catalysis of reactions and pH determination
- nerve impulse transmission and stomatal opening
- production of nitrate ions by bacteria
How does hydrogen bonding occur between water molecules?
- oxygen is more electronegative than hydrogen so it attracts the electrons
- forms a slightly negative oxygen, and slightly positive hydrogens, making water a polar
- intermolecular forces of attraction between lone pair on oxygen and one atom of hydrogen on a nearby molecule
What are the six most biologically important properties of water?
- universal solvent
- high specific heat capacity
- high latent heat of vaporisation
- density
- cohesion between molecules
- high surface tension
why is it important that water is a universal solvent?
- things dissolve easily in water because it’s polar
- the slightly positive hydrogens attract negative solutes
- the slightly negative oxygen attracts positive ions in solutes
why is it important for prokaryotes and eukaryotes that water is a universal solvent?
- cytosol in those cells is mainly water so many solvents can dissolve with the cell and be transported
why is water important as a transport medium?
- cohesion (water molecules ‘sticking’ together by hydrogen bonds) allows water to move up xylem as a continuous column of water which is an advantage as it’s easier to move than individual molecules
why does water have a high specific heat capacity and why is it important?
- has a high specific heat capacity because hydrogen bonds between molecules need lots of energy to be broken
- it’s important because it allows internal temps in animals and plants to stay relatively the same so enzymes won’t denature or reduce activity because of temp changes
why does water have a high latent heat of vaporisation and why is it important?
- has a high latent heat of vaporisation because lots and f energy is needed to break hydrogen bonds between water molecules and turn it into a gas
- it’s important because it gives animals a cooling effect
why is water important as a habitat and why is it important that it has a high surface tension?
- it buffers temperature which allows a stable environment
- cohesion gives water a high surface tension which allows small invertebrates to move and live on surface, and give them a habitat away from predators
why is density as a property of water important?
- ice is less dense than water because of hydrogen bonds so it floats on water and gives animals a surface habitat
what is a monomer and what is a polymer? give the examples.
- monomer: smaller units which can create larger molecules. examples are glucose (and other monosaccharides), amino acids, and nucleotides
- polymer: lots of monomers bonded together. examples are starch (and other polysaccharides), cellulose, glycogen, protein, DNA and RNA
what are carbohydrates?
- a group of substances used as both energy sources and structural materials in organisms
what are the chemical elements that make up biological molecules?
- carbohydrates: C, H, and O
- lipids: C, H, and O
- proteins: C, H, O, N, and S
- nucleic acids: C, H, O, N and P
what are the main three groups of carbohydrates? what do they consist of?
- monosaccharides: simple sugars. general formula (CH2O)n, where ‘n’ can be 3-7.
- disaccharides: ‘double’ sugars, formed from two monosaccharides.
- polysaccharides: large molecules formed from many monosaccharides.
