A complete summary of the book 'Human Biology'. All images are present and all necessary information is included.
A complete summary of the book “Human Biology”. All images are present in the summary and all necessary information is included.
Biologie en ziekteleer
Profs D’Hooge, Vegh en Lagae
1. The chemistry of living things
Functional foods (nutraceuticals): products with benefits beyond basic nutrition
➔ Vb. Red Bull
Dietary supplements: products normally part of your diet
➔ Vb. Multivitamins
1.3 Life depends on water
Essential to life itself, functions:
• Excellent solvent
• Liquid at body temperature
• Absorb and hold heat energy
• Evaporation of water uses up heat energy
• Participates in essential chemical reactions
Solvent:
Water = polar liquid at body temperature (ideal solvent)
Solvent = liquid in which other substances dissolve
Solute = dissolved substance
Sodium chloride (NaCl)/ table salt: water keeps
ions (Na+ and Cl-) dissolved
Hydrophilic molecules = polar molecules,
attracted to water and interact easily
Hydrophobic molecules = nonpolar molecules, do
not dissolve in water, do not interact easily (e.g. oil)
Body temperature:
Below 0°C: stable, unchanging rigid lattice structure
Above 100°C: hydrogen bonds water molecules broken
and water molecules escape into atmosphere as gas
Good for transport in our body (mainly blood)
Also helps regulate body temperature
➔ Holding or releasing heat (sweating)
Chemical Reactions:
Synthesis and breakdown of carbohydrates, lipids and proteins → essential
,1.4 The importance of hydrogen ions (H+)
Covalent bonds rarely broken, but when they do
➔ H2O → OH- (hydroxide) and H+ (hydrogen)
➔ Acid can give up H+ and make acidic solution
➔ Base can accept H+ and make basic or alkaline solution
pH scale: indicates acidity or alkalinity of a solution (pure water: 7, blood: 7.4)
measure of hydrogen ion concentration of a solution
→ homeostasis (maintenance of low concentration) is very important to maintain good transport throughout the
body and chemical reactions
➔ To do that: buffers
Buffers
• Minimize pH change
• Help maintain stable pH (homeostasis) in body fluids
Carbonic acid and bicarbonate act as one of the body’s most important buffer pairs: chemical equilibrium
HCO3– + H+ → H2CO3
(reversible reaction)
If blood is too acidic: HCO3– + H+ → H2CO3
If blood is too alkaline: H2CO3 → HCO3– + H+
1.5 The organic molecules of living organisms
Organic molecules < carbon + other elements held together by covalent bonds
Carbon = ideal building block (can form strong covalent bonds with other atoms)
➔ Wants to make 4 covalent bonds with other molecules (4 electrons on second shell)
➔ Can form bonds with hydrogen, nitrogen, oxygen, or another carbon
➔ Double bonds with oxygen or another canbon
➔ No limit to size of molecules → Macromolecules (vb. eiwitten)
Macromolecules are built within the cell itself with dehydration synthesis
Dehydration synthesis (condensation reaction)
• Removes the equivalent of a water molecule (dehydration) to link molecular units
• Requires energy
• Builds macromolecules from smaller subunits
,Hydrolysis
• Adds the equivalent of a water molecule to break apart macromolecules
• Releases energy
Dehydration synthesis is the reverse of hydrolysis
1.6 Carbohydrates: used for energy and structural support
General formula: Cn(H20)n (niet kennen)
Monosaccharides: most important simple sugars
carbon, hydrogen, oxygen
1.6.1 Glucose
1.6.2 Fructose
1.6.3 Galactose
1.6.4 Ribose
1.6.5 Desoxyribose (one oxygen less than ribose)
Oligosaccharides
Monosaccharides can be linked together via dehydration synthesis
Some oligosaccharides are covalently bonded to certain cell-membrane proteins (glycoproteins)
Disaccharides: two monosaccharides linked together
Thousands of monosaccharides joined in linear and/or branched chains
➔ Often to store energy
Examples
• Starch: made in plants; stores energy
• Glycogen: made in animals; stores energy
• Cellulose: indigestible polysaccharide made in plants for
structural support → celwand
1.7 Lipids: insoluble in water
Three important classes of lipids
• Triglycerides
• Energy storage molecules
• Also known as (neutral) fats and oils
• Composed of glycerol and three fatty acids
Fatty acids: chains of hydrocarbons → carboxyl group
➔ Saturated (in fats)—all single bonds between carbons
➔ Unsaturated (in oils)—include some double bonds between carbons
• Stored in adipose (fat) tissue
• Stored energy
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