Biology I. Chapter 7

Transcription

1 Biology I Chapter 7

2 Interest Grabber NOTEBOOK #1 Are All Cells Alike? All living things are made up of cells. Some organisms are composed of only one cell. Other organisms are made up of many cells. 1. What are the advantages of a onecelled organism? 2. What are the advantages of an organism that is made up of many cells?

3 Discovery of the Cell There are several scientists that are responsible for understanding the cell. They are: 1. Robert Hooke - Observed a piece of cork and saw thousands of empty spaces. Coined the cell because they reminded him of the small rooms in the monastery. 2. Anton van Leeuwenhoek - first person to observe living cells. 3. Matthias Schleiden - All plants are made of cells. 4. Theodor Schwann - All animals are made of cells. 5. Rudolf Virchow - New cells come only from other cells.

4 The Cell Theory 1.All living things are composed of cells. 2.Cells are the basic units of structure and function in living things. 3.New cells are produced from existing cells.

5 Microscopes Compound light microscope - uses two lenses to focus on an image through which light passes through. Transmission Electron Microscope (TEM) - sends a beam of electrons through a microscopic slice of a specimen. Scanning Electron Microscope (SEM) - sends a beam of electrons over the surface of an object to produce a 3-D image.

6 Prokaryotes They are cells that have genetic material that is not contained in a nucleus. Example - bacteria

7 Eukaryotes Usually larger and more complicated than prokaryote cells. Contain a nucleus in which their genetic material is separated from the rest of the cell. Contain dozens of structures and internal membranes.

8 Prokaryotic and Cell membrane Cytoplasm Prokaryotic Cell Cell membrane Cytoplasm Eukaryotic Cell Nucleus Organelles

9 NOTEBOOK #2 1. What were the following scientists credited with: Hooke, Leeewenhoek, Schleiden, Schwann, Virchow 2. What are the three kinds of microscopes? 3. What is a prokaryote? 4. What is a eukaryote?

10 NOTEBOOK #3 Division of Labor Interest Grabber A cell is made up of many parts with different functions that work together. Similarly, the parts of a computer work together to carry out different functions. Working with a partner, answer the following questions. 1. What are some of the different parts of a computer? What are the functions of these computer parts? 2. How do the functions of these computer parts correspond to the functions of certain cell parts?

11 Comparing the Cell to a Factory The cell is made up of many tiny structures that act similar to specialized organs. The structures are known as organelles. Biologist split the eukaryotic cell into two parts: Nucleus Cytoplasm

12 Nucleus The nucleus is compared to the main office of the factory. It is the control center. The nucleus contains nearly all the cell s DNA and with it the coded instructions for making proteins and other important molecules.

13 Parts of the nucleus The nucleus is surrounded by a nuclear envelope. The envelope contains many different pores that allow materials such as proteins, RNA, and other molecules to travel to and from the rest of the cell. Just like the memos, instructions and blueprints move in and out of the office.

14 Parts of the nucleus The nucleus contains granular material made up of DNA bound to proteins called chromatin. During cell division, this chromatin condenses to form thread-like structures called chromosomes. The nucleus also contains a small, dense region called the nucleolus which is responsible for the assembly of ribosomes.

15 Ribosomes One of the most important products of the cell is the making of proteins. Proteins are assembled on ribosomes. Ribosomes are small particles of RNA and protein found in two places throughout the cell: 1. Endoplasmic Reticulum 2. Cytoplasm In the factory, they are the machines that produce the product.

16 Endoplasmic Reticulum The endoplasmic reticulum is the site where lipid components of the cell membrane are assembled, along with proteins and other materials that are exported from the cell. There are two types of ER s: 1.Rough ER 2.Smooth ER

17 Rough ER Rough ER is responsible for producing proteins that are exported from the cell. It is called rough because there are ribosomes found on the surface of the ER which gives it a bumpy surface. The proteins made by these ribosomes enter the ER where they are modified.

18 Smooth ER Ribosomes are not found on its surface. Contains enzymes that perform specialized tasks such as the synthesis of membrane lipids and the detoxification of drugs. Liver cells have large amounts of smooth ER.

19 NOTEBOOK #4 1. What is the nucleus? 2. What is it surrounded by? 3. What is found in the nucleus? 4. What is the job of the ribosomes? 5. Where are the ribosomes found? 6. What is the job of the ER? 7. What are the two kids of ER and explain the difference.

20 Golgi Apparatus Proteins that are made in the rough ER move into the golgi apparatus. They are a stack of apposed membranes. The function of the golgi apparatus is to modify, sort, and package proteins and other materials from the ER for storage in the cell or secretion outside the cell. Golgi is the customization shop where the finishing touches are put on the product.

21 Lysosomes They are small organelles filled with enzymes. They have two major jobs: 1. Digest or breakdown lipids, carbohydrates, and proteins into small molecules that can be used by the cell. 2. Ingest and destroy old and worn-out organelles. The lysosome can be compared to the cleanup crew of the factory.

22 Vacuoles Vacuoles are the storage area of the cell. They store things such as water, salts, proteins, and carbohydrates. In plants, there is usually a large central vacuole that is filled with liquid. The pressure built up in the vacuole make it possible to support heavy structures. In single-cell organisms, such as the paramecium, they contain a contractile vacuole that pumps out excess water to help maintain homeostasis. Homeostasis is the maintenance of a controlled internal environment.

23 NOTEBOOK #5 1. What is the gologi apparatus? 2. What is the job of the golgi apparatus? 3. What are lysosomes? 4. What is the job of the lysosome? 5. What is a vacuole? 6. What is the job of the vacuole? 7. What process is maintained by the vacuole?

24 Mitochondria Mitochondria are organelles that convert the chemical energy stored in food into compounds that are more convenient for the cell to use. Mitochondria have two membranes - an outer membrane and an inner membrane that is folded up to create more surface area. Mitochondria are inherited from the cytoplasm of the ovum, or egg. Called the Powerhouse of the cell. ATP is made here.

25 Chloroplasts Chloroplasts are organelles that capture the energy from sunlight and convert it into chemical energy in a process called photosynthesis. They act as solar panels. The chemical that absorbs the sunlight is a green pigment called chlorophyll.

26 Organelle DNA Mitochondria and Chloroplasts contain their own genetic information in the form of small DNA molecules. They are believed to be descendants of ancient prokaryotes. The idea suggests that the ancient prokaryotes developed a symbiotic relationship with the eukaryotes and actually took up residence within the eukaryotic cell. This idea is called the endosymbiotic theory.

27 Cytoskeleton The cytoskeleton is a network of protein filaments that helps the cell to maintain its shape. The cytoskeleton is also involved in movement. The two main types of protein filaments Microfilaments - thread-like structures made of actin. Microtubules - hollow structures made of tubulins. Play an important role in cell division. Make up centrioles, cilia, and flagella.

28 NOTEBOOK #6 1. What is the job of the mitochondria? 2. What is made there? 3. How is mitochondria inherited? 4. What is the job of the choloroplast? 5. What is the chemical that absorbs the solar energy? 6. According to the endosymbiotic theory, how did mitochondira and chloroplasts end up living inside of cells? 7. What is the cytoskeleton and what is its job?

29 NOTEBOOK #7 Animal Cells Venn Diagrams Plant Cells Prokaryotes Cell membrane Eukaryotes Nucleus Endoplasmic reticulum Golgi apparatus Lysosomes Vacuoles Mitochondria Cytoskeleton Centrioles Cell membrane Ribosomes Nucleus Endoplasmic reticulum Golgi apparatus Lysosomes Vacuoles Mitochondria Cytoskeleton Cell Wall

30 Figure 7-5 Plant and Animal Cells Vacuole Chloroplast Cell Cell wall Plant Cell Smooth endoplasmic Ribosome Ribosome Nuclear Golgi apparatus Mitochondrion Nucleolus Nucleus Rough endoplasmic reticulum

31 Figure 7-5 Plant and Animal Cells Animal Cell Rough endoplasmic Nucleolus Nucleus Nuclear Ribosome Ribosome Cell Mitochondrion Smooth endoplasmic Golgi apparatus Centrioles

32 Figure 7-11 Cytoskeleton Cell membrane Endoplasmic Microtubule Microfilament Ribosomes Mitochondrion

33 NOTEBOOK #8 In or Out? Interest Grabber How is a window screen similar to a cell membrane? Read on to find out. 1. What are some things that can pass through a window screen? 2. What are some things that cannot pass through a window screen? Why is it important to keep these things from moving through the screen? 3. The cell is surrounded by a cell membrane, which regulates what enters and leaves the cell. Why is it important to regulate what moves into and out of a cell?

34 Cell Boundaries All cells are surrounded by a thin, flexible barrier known as the cell membrane. The cell membrane regulates what enters and leaves the cell and also provides protection and support. Nearly all cell membranes are composed of a double layered sheet called a lipid bilayer.

35 Cell Walls Cell walls are present in many organisms including plants, algae, fungi, and prokaryotes. The main function of the cell wall is to provide support and protection for the cell.

36 Diffusion Through Cell Boundaries Every living cell exists in a liquid environment that it needs to survive. One of the most important functions of the cell membrane is to regulate the movement of dissolved molecules from the liquid on one side of the membrane to the liquid on the other side.

37 Diffusion Through Cell Boundaries Concentration- the mass of solute in a given volume of solution, or mass/volume. Diffusion- process by which molecules tend to move from an area where they are more concentrated to an area whe they are less concentrated. Equilibrium- when the concentration of the solute is the same throughout the system

38 Diffusion Through Cell Boundaries Because diffusion depends upon random particle movements, substances diffuse across membranes without requiring the cell to use energy.

39 Osmosis Osmosis is the diffusion of water through a selectively permeable membrane. Isotonic - when the concentration of two solutions is the same Hypertonic-when comparing two solutions, the solution with the greater concentration of solutes. Hypotonic- when comparing two solutions, the solution with the lesser concentration of solutes.

40 Figure 7-15 Osmosis

41 Facilitated Diffusion Movement of specific molecules across a membrane

42 Facilitated Glucose High Cell Low Protein

43 Notebook #8 What are most cell membranes composed of? What is the job of the cell membrane? What types of organisms have cell walls? What is diffusion? What is osmosis? Define isotonic, hypertonic, and hypotonic. What is facilitated diffusion?

44 Figure 7-12 The Structure of the Outside Cell Proteins Carbohydrate Inside of cell Protein Lipid bilayer

45 Figure 7-19 Active Transport Molecule to Energy Molecule

46 NOTEBOOK #9 1. What part of the cell membrane aids in facilitated diffusion? 2. What is the structure of the cell membrane? 3. What is osmosis? 4. What is active transport?

47 Interest Grabber From Simple to More Complex Many multicellular organisms have structures called organs that have a specific function and work with other organs. Working together, these organs carry out the life processes of the entire organism.

48 NOTEBOOK #10 Interest Grabber continued 1. Some activities cannot be performed by only one person, but need a team of people. What type of activity requires a team of people to work together in order to complete a task? 2. What do you think are some characteristics of a successful team? 3. How is a multicellular organism similar to a successful team?

49 Levels of Organization Muscle cell Smooth muscle tissue Stomach Digestive system

50 Videos Click a hyperlink to choose a video. Diffusion Osmosis Passive Transport Active Transport Endocytosis and Exocytosis

51 Interest Grabber NOTEBOOK #11 An Important Process While walking along a dusty path, you begin to cough. As you continue your walk, a small insect comes flying toward you. You blink and then duck so that it misses you. These actions are just a few examples of homeostasis. Homeostasis is the process by which organisms keep internal conditions relatively constant 1. List three other examples of homeostasis that occur in organisms. 2. Why is homeostasis important to an organism?

52 Homeostasis The process by which organisms keep internal conditions relatively constant despite changes in external environment.

53 Thermoregulation

54 Water Regulation (Osmoregulation)

55 Oxygen Regulation

56 Video 1 Diffusion Click the image to play the video segment.

57 Video 2 Osmosis Click the image to play the video segment.

58 Video 3 Passive Transport Click the image to play the video segment.

59 Video 4 Active Transport Click the image to play the video segment.

60 Video 5 Endocytosis and Exocytosis Click the image to play the video segment.

61 Go Online The latest discoveries in cell study Cell structure activity Career links on histotechnologists Interactive test Articles on cells For links on cell theory, go to and enter the Web Code as follows: cbn For links on cell membranes, go to and enter the Web Code as follows: cbn-3073.

62 Interest Grabber Answers 1. What are the advantages of a one-celled organism? A one-celled organism has simpler needs and can respond immediately to its environment because its entire cell is immersed in its environment. 2. What are the advantages of an organism that is made up of many cells? In a multicellular organism, different jobs are divided among different groups of cells that work together. Also, a multicellular organism can continue to survive even if it loses some of its cells.

63 Interest Grabber Answers Working with a partner, answer the following questions. 1. What are some of the different parts of a computer? What are the functions of these computer parts? Answers may include: monitor (interfaces with the computer s environment), software (instructions for how to carry out different jobs), CPU (directs the computer's activities), recycle bin or trash can (storage area for wastes), and so on. 2. How do the functions of these computer parts correspond to the functions of certain cell parts? Students should try to link the functions they described in question 1 to the functions of the different cell structures. The cell needs a way to interface with its environment (cell membrane), instructions for carrying out different jobs (DNA), and a CPU to direct the cell s activities (nucleus).

64 Interest Grabber Answers 1. What are some things that can pass through a window screen? Answers may include air, fine dust, and rainwater. 2. What are some things that cannot pass through a window screen? Why is it important to keep these things from moving through the screen? Insects, leaves, and other matter that may fall from trees. The screen keeps out annoying insects and objects that may bring dirt into the home. 3. The cell is surrounded by a cell membrane, which regulates what enters and leaves the cell. Why is it important to regulate what moves into and out of a cell? Materials such as oxygen and food that are needed by the cell have to be able to get inside the cell. At the same time, excess materials have to leave the cell.

65 Interest Grabber Answers 1. Some activities cannot be performed by only one person, but need a team of people. What type of activity requires a team of people to work together in order to complete a task? Answers might include building a human pyramid or constructing an arch out of blocks. 2. What do you think are some characteristics of a successful team? Divide up jobs and cooperate well with one another. 3. How is a multicellular organism similar to a successful team? The functions of the organism are divided up among its parts (organs and organ systems). All the parts cooperate to carry out all the functions of the whole organism.

66 Interest Grabber Answers 1. List three other examples of homeostasis that occur in organisms. Accept all reasonable student examples that show an understanding of homeostasis. 2. Why is homeostasis important to an organism? Homeostasis allows an organism to remain in balance with its environment. If homeostasis is not maintained, it can harm the organism