1.2 important principles in biology
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1.2 Important principles in biology. Organisms are ‘living’ things Living things: Store energy – in cells, tissues and organs Release energy – cellular respiration, photosynthesis - PowerPoint PPT PresentationTRANSCRIPT
1.2 Important principles in biology
Organisms are ‘living’ things• Living things:– Store energy – in cells, tissues and organs– Release energy – cellular respiration, photosynthesis– Use energy – to move, grow, repair structures, reproduce, detect
and respond to changes, keep internal conditions within limits– Exchange matter with their surroundings – waste products exit,
essential materials enter– Are made of cells
*No non-living thing possesses ALL of these attributes.
Waterfall – non living thing
Elephant – living thing
Candelabra tree – living thing
•All organisms are made up of cells (and the products of cells)
•All cells come from pre-existing cells
•The cell is the smallest living organisational unit
Evolution explains diversity:
• Organisms have changed through time – diversity of living things, fossil record, geographic distribution of organisms, DNA information
• Over time, species become structurally, physically, physiologically and behaviourally adapted to the particular environment in which they live.
• Individuals with features most suited to their environment are likely to survive and produce more offspring than those with less favourable features.
• Over many generations, favoured features become more frequent in the population and undesirable features become less frequent.
• Questions 5 – 8
Compounds
• 92 different elements on Earth• Compounds are molecules containing different
different elements • Organisms produce characteristic complex
compounds that contain carbon and hydrogen• These are called organic compounds • All other compounds are called inorganic
compounds (water, oxygen, Carbon Dioxide, Nitrogen & minerals)
water
• Most organisms are usually 70-90% water• Has important properties –
• pH – enzymes• Cohesiveness – “sticky” allows movement of water up
stems• high heat capacity – absorbs heat without a change in
temperature (temperature regulation)
O2 & CO2
• O2 - Used for release of energy from food molecules
• CO2 - Used in photosynthesis
Nitrogen
• Key component of all proteins• Atmosphere is about 78% nitrogen gas
Minerals
• Biologically important minerals• Phosphorous, potassium, calcium, magnesium, iron, sodium,
iodine, sulfur
Organic molecules
• Carbohydrates• Important source of energy for living organisms• Basic subunits is a monosaccharide (‘single sugar’) • Two sugars join to form a disaccaride• Long chains are called polysaccarides
• Lipids• Fats and oils • Energy stores • Phospohlipids make up the cell membrane
• Proteins• More complex, thousands of different ones • Each organisms proteins are unique• Composed of smaller subunits called amino acids• Linked together with a peptide bond• 20 different amino acids
• Nucleic acids• Genetic material of all organisms• Two types - DNA and RNA
– DNA carries the instructions for protein assembly– RNA plays a roll in the manufacture of proteins within cells
Organic molecules
• Vitamins• Required by animals in small amounts for normal
functioning• Some can be synthesised, others must be obtained in
the diet (Vitamin C) • Some are water soluble (not storable), some are lipid
soluble (storable)
Organic molecules
• Q 9 – 11• Chapter Summary • Key terms – cards or list• Chapter review questions 1 - 11