Cells

1. Cells Organelles

2. The plasma membrane • This is the membrane surrounding all animal cells.

3. The plasma membrane • This is the membrane surrounding the cell. • Fluid inside the cell is very different from fluid outside the cell, so must be kept separate.

4. The plasma membrane • This is the membrane surrounding the cell. • Fluid inside the cell is very different from fluid outside the cell, so must be kept separate. • Membranes are semi-permeable – they let some things through but not others.

5. The plasma membrane • This is the membrane surrounding the cell. • Fluid inside the cell is very different from fluid outside the cell, so must be kept separate. • Membranes are semi-permeable – they let some things through but not others. - small molecules like O2 and CO2 can pass freely through ________ - larger molecules such as starch have to be actively transported across the membrane.

6. Membrane structure • Membranes are made up of a phospholipidbilayer.

7. Membrane structure • Membranes are made up of a phospholipidbilayer. • The bilayer has ‘heads’ of hydrophillic (water-loving) phosphates, and ‘tails’ of hydrophobic (water-hating) fatty acids.

8. Membrane structure • Membranes are made up of a phospholipidbilayer. • The bilayer has ‘heads’ of hydrophillic (water-loving) phosphates, and ‘tails’ of hydrophobic (water-hating) fatty acids. • This structure allows the membrane to assemble itself and also seal itself off if damaged. (Basically creates flexibility)

9. Membrane structure • Membranes are made up of a phospholipidbilayer. • The bilayer has ‘heads’ of hydrophillic (water-loving) phosphates, and ‘tails’ of hydrophobic (water-hating) fatty acids. • This structure allows the membrane to assemble itself and also seal itself off if damaged. (Basically creates flexibility) • The surface of the membrane contains proteins which ‘communicate’ with the cell’s surroundings and the cell can respond accordingly.

10. Nucleus • Controls the cell and carries the genetic code - _____

11. Nucleus • Controls the cell and carries the genetic code – DNA • DNA is scattered throughout the nucleus as chromatin – these only form visible structures called chromosomes just before the cell is about to divide.

12. Chromatin - Chromosome Different levels of DNA condensation. (1) Single DNA strand. (2) Chromatin strand . (3) Condensed chromatin during interphase. (4) Condensed chromatin during prophase. (Two copies of the DNA molecule are now present) (5) Chromosome during metaphase.

13. Cytoplasm • Where most chemical reactions occur in the cell.

14. Cytoplasm • Where most chemical reactions occur in the cell. • The fluid portion is called the cytosol (this consists mainly of water, ions in solution, small molecules and proteins).

15. Cytoplasm • Where most chemical reactions occur in the cell. • The fluid portion is called the cytosol (this consists mainly of water, ions in solution, small molecules and proteins). • The rest of the cytoplasm has organelles in it and other cell structures.

16. Organelles: Endoplasmic reticulum • Endoplasmic – ‘within the cytoplasm’

17. Organelles: Endoplasmic reticulum • Endoplasmic – ‘within the cytoplasm’ • Reticulum – ‘a network’

18. Organelles: Endoplasmic reticulum • Endoplasmic – ‘within the cytoplasm’ • Reticulum – ‘a network’ • Takes up most of the space in the cytoplasm.

19. Organelles: Endoplasmic reticulum (ER) • Endoplasmic – ‘within the cytoplasm’ • Reticulum – ‘a network’ • Takes up most of the space in the cytoplasm. • Consists of a vast network of tubes which are filled with fluid and encased in membranes.

20. Functions of the E.R. • Acts as a transport system – carrying various chemicals around the cell, and outside of the cell.

21. Functions of the E.R. • Acts as a transport system – carrying various chemicals around the cell, and outside of the cell. • The E.R. Membranes can act as a surface where some biochemical reactions take place.

22. Functions of the E.R. • Acts as a transport system – carrying various chemicals around the cell, and outside of the cell. • The E.R. Membranes can act has a surfaces where some biochemical reactions take place. - These include the synthesis of lipids, proteins, and carbs.

23. Types of E.R - Smooth • Smooth outer surface

24. Types of E.R - Smooth • Smooth outer surface. • Produces steroids.

25. Types of E.R - Smooth • Smooth outer surface. • Produces steroids. • Helps with calcium storage in muscle cells and affects muscle contraction.

26. Types of E.R - Smooth • Smooth outer surface. • Produces steroids. • Helps with calcium storage in muscle cells and affects muscle contraction. • Lipids (fats and oils) are produced on smooth E.R

27. Types of e.r - Rough • Rough appearance due to the presence of ribosomes (site for protein synthesis).

28. Types of e.r - Rough • Rough appearance due to the presence of ribosomes (site for protein synthesis). • Makes secretory proteins which are kept apart from other proteins.

29. Types of e.r - Rough • Rough appearance due to the presence of ribosomes (site for protein synthesis). • Makes secretory proteins which are kept apart from other proteins. • These leave the ER membrane as ‘transport vesicles’ and carry secretory proteins to other parts of the cell.

31. Golgi apparatus/bodies • Most animal cells only have one golgi apparatus.

32. Golgi apparatus/bodies • Most animal cells only have one golgi apparatus. • Consists of stacks of membrane sheets – Cisternae.

33. Golgi apparatus/bodies • Most animal cells only have one golgi apparatus. • Consists of stacks of membrane sheets – Cisternae. • The G.A recieves the transport vesicles from the E.R and fuse onto the cis side of the G.A. Then, the contents are released into the G.A.

34. Golgi apparatus/bodies • Most animal cells only have one golgi apparatus. • Consists of stacks of membrane sheets – Cisternae. • The G.A receives the transport vesicles from the E.R and fuse onto the cis side of the G.A. Then, the contents are released into the G.A. • After passing through, these molecules are modified and completed and then ‘pinched off’ from the other side of the G.A.

35. Golgi apparatus/bodies • Most animal cells only have one golgi apparatus. • Consists of stacks of membrane sheets – Cisternae. • The G.A receives the transport vesicles from the E.R and fuse onto the cis side of the G.A. Then, the contents are released into the G.A. • After passing through, these molecules are modified and completed and then ‘pinched off’ from the other side of the G.A. • This is how cells secrete molecules such as enzymes and hormones.

36. LYsosomes • Tough, membranous sacs which contain digestive enzymes.

37. LYsosomes • Tough, membranous sacs which contain digestive enzymes. • Lysosomes are pinched off from the ‘shipping’ side of the Golgi Ap.

38. LYsosomes • Tough, membranous sacs which contain digestive enzymes. • Lysosomes are pinched off from the ‘shipping’ side of the Golgi Ap. • They contain enzymes which are discharged into food vacuoles in order to digest the food.

39. LYsosomes • Tough, membranous sacs which contain digestive enzymes. • Lysosomes are pinched off from the ‘shipping’ side of the Golgi Ap. • They contain enzymes which are discharged into food vacuoles in order to digest the food. • Help to renew the cell – by breaking down old worn-out mitochondria and other cells.

40. Cool example - lysosomes • Tail of a tadpole is dissolved before it turns into a frog – lysosomes do this. • Also! We have webbed fingers in the womb, and lysosomes break down the skin cells so our fingers are separated.

41. Vacuoles • Refers to a membrane bag with no inner structure. (In general, animal vacuoles are small, and plant vacuoles are large).

42. Vauoles • Refers to a membrane bag with no inner structure. (In general, animal vacuoles are small, and plant vacuoles are large). • Animal cells – Food is engulfed by vacuoles and then digested by ___________.

43. Vauoles • Refers to a membrane bag with no inner structure. (In general, animal vacuoles are small, and plant vacuoles are large). • Animal cells – Food is engulfed by vacuoles and then digested by ___________. • Plant cells – Vacuoles take up most of the space and provide a place to store organic compounds.

44. Vauoles • Refers to a membrane bag with no inner structure. (In general, animal vacuoles are small, and plant vacuoles are large). • Animal cells – Food is engulfed by vacuoles and then digested by ___________. • Plant cells – Vacuoles take up most of the space and provide a place to store organic compounds. Some store pigments that colour petals, or store poison as defence.

45. Vauoles • Refers to a membrane bag with no inner structure. (In general, animal vacuoles are small, and plant vacuoles are large). • Animal cells – Food is engulfed by vacuoles and then digested by ___________. • Plant cells – Vacuoles take up most of the space and provide a place to store organic compounds. Some store pigments that colour petals, or store poison as defence. Vacuoles in plants play an important role in keeping the cells in a turgid (swollen) state.

46. mitochondria • Converts food into energy – ATP.

47. mitochondria • Converts food into energy – ATP. • Cells which use a large amount of energy (such as muscle cells and sperm cells) have a lot of mitochondria.

48. mitochondria • Converts food into energy – ATP. • Cells which use a large amount of energy (such as muscle cells and sperm cells) have a lot of mitochondria. • Place where aerobic cell respiration occurs – breaking down glucose/fats to produce CO2, H20 and energy (ATP)

49. Chloroplasts (only in plant cells) • Function is to manufacture glucose in the photosynthesis process.

50. Centrioles (only in animal cells) • Appear as a tiny dot next to the nucleus