1.2 Important principles in biology

1. 1.2 Important principles in biology

2. 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.

3. Waterfall – non living thing

4. Elephant – living thing

5. Candelabra tree – living thing

6. 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

7. 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.

8. Questions 5 – 8

9. 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)

10. 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)

11. O2 & CO2 • O2 - Used for release of energy from food molecules • CO2 - Used in photosynthesis

12. Nitrogen • Key component of all proteins • Atmosphere is about 78% nitrogen gas Minerals • Biologically important minerals • Phosphorous, potassium, calcium, magnesium, iron, sodium, iodine, sulfur

13. 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

14. Organic molecules • 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

15. 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)

16. Q 9 – 11 • Chapter Summary • Key terms – cards or list • Chapter review questions 1 - 11