IB Topic 3 - WikispacesTopic+3+1.pdfIB Topic 3 The Chemistry of Life. 3.1 Chemical Elements & Water....
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IB Topic 3 The Chemistry of Life
Transcript of IB Topic 3 - WikispacesTopic+3+1.pdfIB Topic 3 The Chemistry of Life. 3.1 Chemical Elements & Water....
IB Topic 3The Chemistry of Life
3.1Chemical Elements
& Water
3.1.1 State that the most frequently occurring chemical elements in living things are carbon,
hydrogen, oxygen and nitrogen.
• Atoms Elements Compounds• In Biological Compounds…often form
covalent bonds• Proportions in Living Organisms• C 19%• H 10%• O 65%• N 3%
3.1.2 State that a variety of other elements are needed by living organisms, including...
3.1.3 State one role for each of the elements...
• SULFUR– In some amino acids (disulfide bridges)– Proteins – Chemoautotrophs use it as energy source
3.1.2 State that a variety of other elements are needed by living organisms, including ...
3.1.3 State one role for each of the elements...
• CALCIUM– Cell structure, movement
• Cell walls, cell membranes, muscle contractions– Support of bones (lack osteoporosis)– Neurotransmitter release for nervous system
messages
3.1.2 State that a variety of other elements are needed by living organisms, including ...
3.1.3 State one role for each of the elements...
• PHOSPHORUS– ATP– DNA
3.1.2 State that a variety of other elements are needed by living organisms, including ...
3.1.3 State one role for each of the elements...
• IRON– Some chemoautotrophs—source
of energy– Helps w/formation of chlorophyll
• Fe deficient plants can’t photosynthesize properly
– Component of hemoglobin (RBCs) O2 transport
3.1.2 State that a variety of other elements are needed by living organisms, including ...
3.1.3 State one role for each of the elements...
3.1.2 State that a variety of other elements are needed by living organisms, including ...
3.1.3 State one role for each of the elements...
• SODIUM– Some plants: helps bind CO2
for photosynthesis– Action potential in neurons
• Nerve impulses• Na-K pumps
– Glucose co-transport across membranes
– Prokaryotes—movement of flagellum
3.1.4 Draw and label water molecules to show their polarity and hydrogen bond formation.
• Covalent bonds• 105° angle between H
atoms• Polarity:
– O: 2δ- ; pulls harder on e-
– H: δ+• H bonds form from H
of 1 to O of another
O
H
H
3.1.5 Outline the thermal, cohesive, and solvent properties of water.
• Water’s polar attractive forces cohesive takes a lot of energy!
• THERMAL– High specific heat
• Water requires a lot of energy to warm up; gives off a lot of energy when cooled down
– High heat of vaporization• Water requires a lot of energy to evaporate
3.1.5 Outline the thermal, cohesive, and solvent properties of water.
• COHESIVE– Attraction forces between molecules of same
kind• SOLVENT
– Water’s polar, will dissolve many polar solutes
3.1.6 Explain the relationship between the properties of water [thermal, cohesive, solvent]
and its uses in living organisms as a coolant, medium for metabolic reactions, and transport
medium.
• THERMAL– TRANSPORT: blood carries heat to cold body parts – COOLANT: plants & animals evap water (coolant
effect)• COHESIVE
– TRANSPORT: helps water go UP xylem of plants• SOLVENT
– TRANSPORT: plants (xylem, phloem) & animals (oxygen, glucose, & urea in blood)
– MEDIUM FOR METABOLIC RXNS: rxns involving polar molecules can take place in water
Comparison of air & water temp (24 hrs) from an Oak woodland
during a temperate summer• temp vs. time of day• water remains fairly stable
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