CELLS

1. CELLS Chapter 2 pp. 44-61 Buchanan 2013

2. Cell Structure • A cell is the smallest unit that is capable of performing life functions. • All cells have a cell membrane (thin outer layer that holds all the goop in) • Inside the cell there is cytoplasm (gelatin-like (jell-o) material that has hereditary material)

3. The shape of a cell may tell you something about the job the cell does. • Most cells are very small; however, some can be seen with the naked eye. (an egg)

4. Comparing Cells • What are some of the different cells in your body? nerve cells egg cells bacteria cells red blood cells

5. Cell Types • Prokaryotic -No Nucleus -No membrane-bound structures • Eukaryotic -Has a Nucleus -Has membrane-bound structures

6. Cell Organization • Each cell has a specific function or job to do. • Compare the cell to a deli that is open 24 hours a day. • Raw materials are brought in, food is eaten in the store, some food is taken elsewhere, waste is created.

7. Cell Wall-the outer defense • Cell walls are tough, rigid outer coverings that protect the cell and give it shape. • Cells walls are found in plants, algae, fungi and most bacteria. • A plant cell wall is made up mostly of a substance called cellulose.

8. Cell walls also have a substance called pectin, which is used to make jelly and jam • Cell walls also have a substance called lignin which is a compound that makes cell walls rigid. • Plant cells usually have alot of lignin to help support the plant.

9. Cell Membrane • The protective layer around ALL Cells is the cell membrane. • If a cell has a cell wall, the cell membrane is located inside the cell wall. • The cell membrane controls interactions between the cell and the environment around the cell.

10. Water is able to move freely into and out of the cell through the cell membrane. • Food particles and some molecules enter through the cell membrane. • Waste products leave the cell through the cell membrane.

11. Cytoplasm • Gelatin-like substance inside the cell • This goop flows inside of the cell membrane • Contains the cytoskeleton, which is the framework that allows a cell to maintain or change its shape.

12. The cytoskeleton allows some cells to move. (The amoeba moves by stretching and contracting its cytoskeleton) • Cytoskeleton is made up of thin, hollow tubes of protein and thin, solid protein fibers. • Proteins are organic (living) molecules made up of amino acids.

13. Most of the cells life processes occur in the cytoplasm • In eukaryotic cells, the cytoplasm contains structures called organelles.

14. Organelles • Some process energy • Some manufacture other substances • Some move materials • Some act as storage sites • Most are surrounded by membranes • The nucleus is usually the largest organelle in a cell.

15. Nucleus-“The Brain” • Directs all cell activities and is separated from the cytoplasm by a membrane called the nuclear membrane. • Materials enter and leave the nucleus through the nuclear membrane. • Contains the instructions for everything the cell does.

16. Nucleolus • The nucleolus is a non-membrane bound structurecomposed of proteins and nucleic acids found within the nucleus of eukaryotic cells. • Its function is to transcribe ribosomal RNA and assemble it within the cell.

17. The instructions are found on long, threadlike, heredity material made of DNA (Deoxyribonucleic Acid) • DNA contains the code for the cell’s structure and activities. • During cell division, the heredity material wraps around proteins to form chromosomes.

18. Energy-Processing Organelles

19. Chloroplast • Cells need energy continuously to process food, make new substances, communicate with one another and eliminate waste • In plants, food is made in green organelles called chloroplast.

20. Chlorophyll captures light energy and stores it as a chemical and uses it to make a sugar called glucose. • Chloroplast contains the pigment chlorophyll which gives many plants their green color. • Animal cells do not have chloroplast and cannot make their own food. We have to get it from the environment around us. (McDonalds, Burger King, Chick-fil-a, etc.)

21. Mitochondria • Energy from food is stored in the mitochondria until it is released. • Energy is released from the breaking down of food into Carbon Dioxide and Water. • Cells, such as muscle cells are very active and require a larger number of mitochondria.

22. Manufacturing Organelles

23. Ribosomes • Proteins are present in almost every cell activity. They are a key part of the different types of membranes located in the cells. • Cells make their own proteins on small structures called ribosomes.

24. Ribosomes are considered organelles but are not bound by a membrane. • Some ribosomes float freely in the cytoplasm; others are attached to the endoplasmic reticulum. • Are made in the nucleolus and move out into the cytoplasm. • Receive directions from the hereditary information in the nucleus on how, when, in what order to make specific proteins.

25. Processing, Transporting, and Storing Organelles

26. Endoplasmic Reticulum- “The E.R.” • Extends from the nucleus to the cell membrane. • A series of folded membranes where material is processed and moved around inside the cell. • In most cells, the E.R. takes up a large amount of space.

27. May be classified as “rough” or “smooth” • E.R. with no attached ribosomes is called “smooth” • Smooth E.R. processes other cellular substances such as lipids that store energy. • Rough E.R. has ribosomes attached to it. • Rough E.R. makes proteins that may be used in the cell or moved out of the cell.

28. Smooth and Rough E.R.

29. Golgi Bodies-a.k.a. Golgi Apparatus • Stacked, flattened membranes • Sort proteins and other cellular substances and package them into membrane-bound structures called vesicles for export.

30. Vesicles deliver materials inside the cell. (Think of them as UPS or FedEx) • They also carry substances to the cell membrane and release them to the outside of the cell.

31. Vacuole-Storage Sites • A temporary storage area that can store water, waste products, food or other cellular material (they are like mini-storage units for all the stuff the cell has) • Plants cells have a large vacuole that makes up most of a plant cells volume. Animal cells do not have a large vacuole.

32. 3 differences between plant and animal cells • Cell Wall • Chloroplast • Large Vacuole Plant cells have these; animal do not!!!

33. Recycling Organelles

34. Lysosomes-Garbage Collectors • Breaks down and recycle substances • Contain digestive chemicals that help break down food molecules, cell wastes and worn-out cell parts. • Membrane keeps digestive material from leaking into the cell causing it to destroy the cell.

35. When a cell dies, the Lysosomes membrane disintegrates allowing the chemicals to release and breakdown the remains of the cell.

36. From Cell to Organism Cell Tissue Organ Organ System

37. Cells group together to form tissue (cardiac cells form heart tissue) • Tissues are a group of similar cells that work together to do one job ( • Tissues are organized into organs. (Heart) • An organ is a structure made up of two or more different types of tissues that work together.

38. A group of organs working together to perform a certain function is an Organ System. • Cardiovascular System-includes heart, arteries, veins and capillaries

39. Viewing Cells Section 2

40. Magnifying Cells • The things you cannot see with your eye outnumber the things you can see • Can you see all of the cells in a leaf? • Can you see all of the cells in your body?

41. Early Microscopes • Late 1500’s, the first microscope was made by a Dutch glass maker

42. In the mid 1600’s, Antonie van Leeuwenhoek made a simple microscope with a tiny glass bead . -Magnified up to 270 times -Saw things in pond water no one ever imagined

43. Modern Microscopes • Simple Microscope-similar to a magnifying glass. Only has 1 lens. • Compound Light Microscope- has two sets of lenses…eye lenses and objective lenses. -Uses lenses and light to direct beams of light.

44. Magnification • Change of size is called magnification • If the eyepiece lens has a power of 10x and the objective lens has a power of 43x=> The total magnification is 430x • This means it makes the object 430 times larger than it really is.

45. Electron Microscopes • Used to view things too small for a regular microscope to see • Uses a magnetic field in a vacuum to direct beams of electrons

46. Some electron microscopes can magnify up to 1 million times • Images must be photographed or electronically produced in order to be seen.

47. Scanning Electron Microscopes (SEM) • Produce a realistic, three-dimensional image • Only the surface of the specimen is observed

48. Transmission Electron Microscopes (TEM) • Produce a two-dimensional image of a thinly sliced specimen • Details of cell parts can be examined using a TEM

49. Cell Theory • 1665, Robert Hooke cut a thin piece of cork to view under his microscope • The sample seemed to be made up of little boxes which Hooke named them cells.