Lesson 4 (Week 5) 4 March 2014

1. Lesson 4 (Week 5)4 March 2014 Biochemical molecules and cellular transport

2. Pop Quiz

3. Today’s lesson We will be looking at • Basic chemistry principles • Biochemical molecules • Carbohydrates • Proteins • Lipids • Passive transport in cells • Diffusion • Osmosis • Facilitated diffusion

4. Some basic chemistry • All matter is made up of atoms • Atoms combine to form molecules • Compound- is a molecule with more than one type of atom.

5. Basic chemistry

6. More basic chem • All particles are in motion (Brownian motion) • Motion of particles depends on energy available to them (ie heat increases motion) • Atoms stick together due to chemical bonds • Bonds store energy- when a bond is broken, energy can be released

7. Organic compounds • Derive from life and living things • Contain carbon atoms in chains or ring molecular structures

8. Carbohydrates • Include substances such as sugars, starches, cellulose • Are made up of Carbon (C), Hydrogen (H) and Oxygen (O) • Carbons form chains or rings (rings are more common) • Often a repeat sequence of a simple saccharide (or two)

9. Carbs • Monosaccharides have the simplest molecular structure • Include simple sugars (eg glucose) & taste sweet • 3,5 or 6 carbon atoms

10. Carbs • Disaccharides are also sugars and include sucrose (cane sugar) • Made us of 2 monosaccharide subunits eg sucrose=glucose + fructose subunits

11. Carbs • Polysaccharides are the most complex carbs include starch and cellulose • Contain many hundreds of subunits in long chains eg starch contains many glucose subunits (300-600) in long chains

12. Lipids • Include fats, waxes, steroids and phospholipids • Usually repel water and form globules

13. Fats • Act as an energy store • Have long chains of carbons in their structure

14. Phopho lipids • A molecule with a polar head and non polar tail • Allows formation of the cell membrane- a phospho lipid bilayer

15. Proteins • Include enzymes, cell structure, antibodies, toxins, hormones • Are made up of chains of amino acids in complex structures

16. Protein synthesis

17. DNA and RNA • Made up of chains of nucleotides • Nucleotides are made up of rings if carbon, a phosphate group and a nitrogenous base

18. Movement across cell membranes • Substances have to move in and out of cells • Small particles such as O2, CO2, H2O can diffuse across cell membranes • Larger particles such as glucose need to be facilitated • Membrane impermeable to proteins, nucleotides

19. Concentration gradients • These occur when there is a difference between concentrations of solutions between two regions • Diffusion occurs ‘down’ the conc gradient, from high to low

20. Diffusion • Movement of ions down a concentration gradient (ie from high  low) Homework: where does diffusion occur in a biological organism and for what purpose?

21. Osmosis • Movement of water across a semipermeable membrane Homework: can you find examples of osmosis occurring in a biological organism?

22. Isotonic, hypotonic and hypertonic • Movement of water via osmosis is dependent on concentration of solutes (dissolved substances) on either side of the membrane. Intercellular fluid can be isotonic (same concentrated), hypotonic (less concentrated) or hypertonic (more concentrated)

23. Facilitated diffusion • Movement of molecules across the cell membrane down a concentration gradient, via a specific carrier protein