Section 1: Discovering Cells What are Cells?

1. Section 1: Discovering CellsWhat are Cells? • Cells are the basic units of structure and function in living things

2. How can we see cells? • Cells are two small to be seen with the naked eye so we must use a microscope

3. What is a Microscope? • A microscope is an instrument that makes small objects look larger • A compound microscope contains more than one lens

4. How do Microscopes Work? • Some microscopes use lenses to focus light onto an object • The lenses in light microscopes are similar to the clear curved pieces of glass used in eyeglasses

5. Who was Robert Hooke? • He was one of the first people to observe cells • He observed cork cells using a microscope he had built himself

6. Who was Anton van Leeuwenhoek? • He was a Dutch businessmanwho observed water from a pond and was the first person to see what are now called bacteria

7. What is the cell theory? • A widely accepted explanation of the relationship between cells and living things

8. For a light microscope to be useful what two properties must be combined? • Magnification • Resolution

9. What is Magnification? • The ability to make things look larger than they are

10. How do light microscopes make things look bigger? • The lens or lenses in a light microscope magnify an object by bending the light that passes through them

11. What is a Convex Lens? • A lens with a curved shape • These lenses cause the light passing through the sides to bend inward; when this light hits the eye the object seems larger

12. How does a compound microscope magnify an object even more? • It has more than one lens • Light passes through a specimen and then through two lenses

13. How do you calculate total magnification? • The total magnification is equal to the magnification of the two lenses multiplied together • Example: First lens(10) second lens(40) total = 400

14. What is resolution? • The ability to clearly distinguish the individual parts of an object • Another term for sharpness

15. What other kind of microscopes are there? • Electron Microscopes – use a beam of electrons instead of light to examine a specimen

16. Section 2: What is inside a cell? • Organelles – tiny cell structures that carry out specific functions within the cell

17. What is the structure surrounding the cell? • Cellwall - a rigid layer of nonliving material that surrounds the cells of plants and some other organelles

18. What is the cell wall made of? • Cellulose – a tough, yet flexible, material • Wood contains a lot of cellulose

19. What is the function of the cell wall? • A plant’s cell wall helps to protect and support the cell • Cell walls allow trees to stand so tall

20. If the cell wall is so stiff can materials still pass through the cell wall? • Yes, many materials, including water and oxygen, can pass through the cell wall

21. What is just inside the cell wall? • Cellmembrane– controls what substances come into and out of a cell • All cells have cell membranes

22. How does the cell membrane allow things to pass through? • There are tiny pores in the membrane that allow things to pass through like a windowscreen

23. What is the large, oval structure located within the cell? • Nucleus – the cell’s control center, directing all of the cell’s activities

24. What is found within and surrounding the nucleus? • Nuclear Membrane • Chromatin • Nucleolus

25. What structure surrounds the nucleus? • The nuclearmembrane –protects the nucleus

26. How does the nucleus know how to direct the cell? • Chromatin– strands the contain genetic material, the instructions that direct the functions of a cell

27. What is the smaller structure located within the nucleus? • Nucleolus – where ribosomes are made (ribosomes are the organelles where proteins are produced)

28. What is the clear, thick, gel-like fluid outside of the nucleus? • Cytoplasm – the region between the cellmembrane and the nucleus

29. Where are most cell organelles found? In the Cytoplasm: • Mitochondria • Endoplasmic Reticulum • Ribosomes • Golgi Bodies • Chloroplasts • Vacuoles • Lysosomes

30. What are the rod-shaped structures located within the cytoplasm? • Mitochondria – known as the “powerhouses”of the cell because they produce most of the energy the cell needs to carry out its functions

31. What forms a maze of passageways? • The endoplasmicreticulum– the passageways carry proteins and other materials from one part of the cell to another

32. What is attached to the outer surface of the endoplasmic reticulum? • Ribsomes – Small grainlike bodies • Can also be found floating in the cytoplasm • Function as factories to produce proteins

33. What are the structures that look like a flattened collection of sacs and tubes? • GolgiBodies – receive proteins and other new materials, package them, and distribute them to other parts of the cell • Known as the cell’s mailroom

34. What are the large green structures in the cytoplasm? • Chloroplasts – capture energy from sunlight and use it to produce food for the cell • Animal cells do not have these; plant cells do • These give plants their color

35. What is the large, round, water-filled sac in the cytoplasm? • Vacuoles – The storage area of the cell • Most plant cells have one large vacuole

36. What else can be found in the cytoplasm? • Lysosome - Small, round structures that contain chemicals that break down large food particles into smaller ones

37. How are bacterial cells different from plant and animal cells? • Smaller • No nucleus - genetic material is found in the cytoplasm

38. Are we made up of all the same cells? • No, we are made up of many differentcells(skin, bone, etc.) • Cells are structured to suit their unique function