Revisison Handout ** Flashcards
Put these forms of bonding in order of strength fro, strongest to weakest?
Covalent bonds
H-bonds
Van der waals forces
List 5 characteristic of living things?
- High degree of complexity
- Use of energy to maintain structure
- Co-ordination
- Sense and response
- Precise self-replication
Put the following structures into size order from lowest to highest ?
1-animal cell
2-bacteria cell
3-nucleus
4-animal ribosomes
5- bacterial ribosomes
There are many ways of speeding up a chemical reaction. For example, higher temperatures and higher concentration of reactants. Why are these two methods not employed in biological systems?
High temperatures - stability of macromolecules is limited
Higher concentration of reactants - costly as more valuable starting material is needed
What two main methods are employed and state two reasons why these are more suited to employment in biological systems ?
Change in reaction by coupling to a fast one
Lower activation barrier by catalysis
Less energy is required, they can occur at body temp.
Besides carbon, name 6 other elements essential to life state which are required in bulk?
BULK
Carbon Hydrogen Oxygen Phosphate Sulphur
potassium K+,,,Sodium NA+,,, Calcium ca++ ARE metal ions
What are the trace elements?
Magnesium mg++
Zinc zn++
Iron fe++
Copper cu
Iodine I
Mag,zinc and iron play important roles in metabolism
Which two trace elements are required in greatest quantity? And why?
Calcium and sulfur
Calcium - is used in bones which are significant components of total body mass also used in ion channels as an electrolyte
Sulfur - is used in amino acid sequences as disulfide bridges giving many proteins their tertiary structure
Water is a good solvent for many biological molecules. It is as close to a universal solvent we can get in biology. However it is not a good solvent for everything,
List 3 things that water is a good solvent for and not good for?
Good
Amino acids
Small alcohols
Carbohydrates
Bad
Non polar gases
Aromatic molecules
Explain hydrogen bonding of water?
Hydrogen bonding occurs when an atom of hydrogen is attracted strong forces of two atoms instead of one acting as a bond between them
Typically hydrogen bonding occurs where the positively charged hydrogen atom lies between negatively charged oxygen and or nitrogen atoms
Hydrogens are vital for life, give examples why?
Source of unique properties of water
- high specific hear capacity
- high cohesion
- high adhesion
Exists in all three states of matter at normal temp
Forms a less dense structure as a solid than liquid (ice floats)
Water is also vital in?
Structure and function of proteins,DNA, polysaccharide,
Binding of sub straights to enzymes
Binding of hormones to receptors
Matching mRNA and tRNA
The hydrophobic effect makes some molecules poorly soluble in water. Explain this effect?
Bulk water has little order has high entropy (not ordered)
Water near a hydrophobic solute is highly ordered (low entropy)
Low entropy is thermodynamically unfavourable
What are the mathematical equations for PKa and ph?
PH=log10[H+]
PKa=log10ka
What would you look for to identify following R groups in aliphatic side chain?
Aliphatic side chain has a long chain of amino acids