Chapter 2- Biochemistry- chemical elements and water Flashcards
Most frequent element- carbon, what it its percentage?
19%
What are the 4 most frequently occurring chemical elements?
Carbon
Hydrogen
Oxygen
Nitrogen
Most frequent chemical, hydrogen, what is its percentage?
10%
Most frequent chemical, oxygen, what is its percentage?
65%
Most frequent chemical, nitrogen, what’s its percentage?
3%
What are the 5 other main elements needed by living organisms?
Sulphur Calcium Phosphorus Iron Sodium
Where is sulphur (0.25%) found and what does this allow?
Found in certain amino acids (cysteine and methionine) - allowing for proteins to form disulphides bonds.
Where is calcium (1.5%) found and what’s its involved with ?
Found in bones and teeth and involved in neurotransmitter release in synapses.
What is phosphorus (1%) a component of?
Nucleic acids and cell membranes.
Where is iron (0.7%) found and what’s its purpose?
Found in haemoglobin (red protein responsible for transporting oxygen) and allows oxygen transport.
What is sodium (0.15%) involved in the generation of?
Generation of nerve impulses in neurones.
What is chemical polarity?
Describes how equally bonding electrons are shared between atoms.
What is cell polarity?
Differences in shape, structure and functions of cells.
What does oxygen atoms have more of?
More protons (+ve)
If oxygen has more protons what does it attract more of and what does this equal too?
Attracts more electrons (-ve) which equals it to become slightly negative while hydrogen becomes slightly positive.
Covalent bonded molecules that have slightly potential charge are what?
Polar
Slightly charged regions of water can attract other polar or charged compounds therefore water molecules can associate with what?
Weak hydrogen bonds
What are the 3 thermal properties of water?
High specific heat capacity
High heat of vaporisation
High heat of fusion
What does specific heat capacity measure?
Measure of energy required to raise the temp of 1g of substance by 1•C
What does heat of vaporisation measure?
amount of energy absorbed per gram as it changes from a liquid to a gas/vapour
What does heat of fusion measure?
amount of energy required to be lost to change 1g of solid at 0•C
Why do all these thermal properties of water occur?
Result of extensive hydrogen bonding between water molecules
Allows water to absorb considerable amounts of energy with little change ( hydrogen bonds need to be broken first)
Is water strongly cohesive (stick to one another)? If so what do they stick too?
Yes- tend to stick to other molecules that are charged or polar (adhesion)
Why is water strongly cohesive (stick to one another)?
Result of polarity of a water molecule and its ability to form hydrogen bonds with appropriate molecules.
