Unit A – Cells and Systems

1. Unit A – Cells and Systems

2. Chapter 1 - Cells

3. Cells – Key Ideas • Living things share many characteristics • All living things are made of up of one or more cells • Animal and plant cells are similar in some ways and different in others • Technology helps us learn about the structure and function of cells • Substances move in and out of cells

4. 1.1 – Characteristics of Living Things How do you know if something is alive?

5. Organism – any individual living thing • Before something can be classified as an organism, it must show all of the characteristics of living things • (see Table 1 p5)

6. Characteristics of Living Things • Living things are composed of cells • Living things reproduce, grow, and repair themselves. • Living things require energy • Living things respond to their environment • Living things have a life span • Living things produce waste

7. Why isn’t a Solar Calculator Alive? • What characteristic’s of life does it have?

8. Is a Star Fish Living? • What characteristics does a star fish have? • Require energy? • Respond to environment? • Reproduce? Grow? And repair? • Have a lifespan? • Produce waste? • Is it made of cells?

9. Cell Theory • Cells are the basic unit of all living things • The Cell Theory: • All living things are composed of one or more cells • All new cells arise only from cells that already exist (new cells come from old cells)

10. 1.2 – Using a Microscope Be careful…please

11. The Parts of a Microscope

13. Microscope – Field of View • The Field of View – is the circle of light you see when you look through the eyepiece of a microscope • Ratio = magnification of high-power lens/magnification of low-power lens • Diameter of field (high power) = diameter of field (low power)/ratio

14. 1.3 – Plant and Animal Cells What’s the Difference?

15. Plant and Animal Cells • The cells of all plants and the cells of all animals have many structures in common • Using a microscope it is easy to tell between plant and animal cell but it is hard to tell which plant cell came from which plant and which plant cell came from which animal

16. Animal Cell Structures

17. The Nucleus • The NUCLEUS is the control centre. It directs all of the cell’s activities. • In plant and animal cells, the nucleus is surrounded by a membrane. • Cells with a nuclear membrane are known as EUKARYOTIC CELLS

18. The Nucleus • In some one-celled organisms, such as bacteria, the nucleus is not surrounded by a membrane. These cells are known as PROKARYOTIC cells

19. The Nucleus Eukaryotic Prokaryotic

20. Chromosomes • inside the nucleus • Contain DNA or genetic information, which holds “construction plans” for all the pieces of the cell. • This genetic information is duplicated and passed on to other identical cells.

21. Cell Membrane • holds the contents of the cell in place • Controls the movement of materials(nutrients and waste) into and out of the cell. • consists of a double layer of fat molecules.

22. Cytoplasm • watery fluid that contains everything inside the cell membrane and outside the nucleus. • Allows materials to be transported quickly • Stores wastes until they can be disposed of

23. Vacuole • Used to store water and nutrients • Also used to store wasteand move excess water out of the cell

24. Animal Cell - Movement • Some animal cells may have special structures that help them move in their environment • Flagellum • Cilia

25. The Flagellum • Flagellum- a whip-like tail that helps a cell to move

26. Cilia • Cilia- tiny hairs that work to move a cell or the fluid around a cell

27. Plant Cell Structures

28. Vacuole • Just like animal cells except usually much larger

29. Cell Wall • Provides protection and support to the plant cell

30. Chloroplasts • Are the food factories of the cell • Contain many molecules of a green pigment called chlorophyll • Chlorophyll is necessary for photosynthesis

31. 1.4-Technological Advances of the Microscope

32. The Single – Lens Microscope • Anton van Leeuwenhoek’s (1660’s) single lens microscope magnified things 10 x’s • (made objects 10 times bigger than their normal size)

33. The Compound Light Microscope • Single lens were not enough for scientists who wanted to see things in greater detail • Eventually a second lens was added to magnify the image ( 10x’s X 10 x’s = 100 x’s) • Light microscope is limited to about 2000 x’s (image becomes too blurry) • Greater magnification is needed to see the details of a human cell

34. Compound Light Microscope

35. The Transmission Electron Microscope • Are capable of 2 000 000 x’s magnification • Use electrons instead of light • Limitations • Must use extremely thin specimens • Only dead cells can be observed

36. The Transmission Electron Microscope

37. The Scanning Electron Microscope • It uses electrons that are deflected of a specimen to create a digital three-dimensional image • Because it uses only reflected electrons the thickness of the specimen does not matter • Limitations • Only the outside of the specimen can be seen • Cannot magnify as high as the transmission electron microscope

38. The Scanning Electron Microscope

39. 1.6 – Parts of a Cell Seen with an Electron Microscope

40. Organelles • organelle -a tiny structure within the cytoplasm of a cell; specialized to carry out a function

41. Mitochondria: Energy Production • mitochondria (sing. mitochondrion) - circular or rod-shaped organelles that provide the cells with energy through a process called cellular respiration.

42. Cellular Respiration • cellular respiration - a process in which mitochondria release energy by combining sugar molecules with oxygen to form carbon dioxide and water • Sugar + O2 CO2 + ENERGY

43. Ribosomes: Protein Manufacturing • ribosome - a very small organelle that uses information from the nucleus and molecules from the cytoplasm to produce proteins • Proteins are needed for • Cell growth • Repair • Reproduction

44. Endoplasmic Reticulum: Material Transport • endoplasmic reticulum (ER) - a cell structure that consists of a series of folded membranes that act as canals to carry materials through the cytoplasm • Rough – with ribosomes (proteins) • Smooth – without ribosomes (lipids (fats))

45. The Golgi Apparatus: Protein Storage • Golgi apparatus - an organelle that stores proteins and puts them into packages, called vesicles

46. Lysosomes: Recycling • lysosome - an organelle formed by the Golgi apparatus to control and clean the cytoplasm; contains special proteins used to break down large molecules into smaller molecules; also destroys damaged or worn-out cells • Also destroy harmful substances and bacteria that enter the cell.

47. 1.7 – Cells in Their Environment

48. Cell Membranes • Cells allow some materials to enter and leave but not others • Permeable = permitting passage • Impermeable = not permitting passage • The cell membrane is said to be selectively permeable

49. Selectively Permeable • A membrane that allows certain substances to enter or leave

50. Diffusion • DIFFUSION- the movement of molecules from an area of high concentration to an area of low concentration • Molecules are constantly in motion, when they collide, they bounce off each other which causes the molecules to spread out