Observing Living Things

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1 Observing Living Things Textbook pages 8 21 Before You Read Section 1.1 Summary This section describes the signs that scientists look for to help them decide if something is living or non-living. On the lines below, list two living things and then list two non-living things. Mark the Text Identify Details As you skim the section, use one colour to highlight the text or labels that talk about parts of a microscope. Use another colour to highlight facts about microscopes. Reading Check 1. What are two things that a microscope does? How can you tell if something is living or non-living? All living things have certain characteristics in common. Something is living if it has all of these characteristics: responds to its environment needs energy grows reproduces gets rid of wastes that build up in its body Another name for a living thing is organism. All organisms are made up of cells. A cell is the smallest living part of a living thing. Single-celled organisms are called unicellular. Organisms made of many cells are called multicellular. How can you see cells? Most cells are too small to see with just your eyes. You need a microscope to see them. At school you use a compound light microscope. It is a compound microscope because it combines two lenses. It is a light microscope because it uses light to view an object. A compound light microscope is shown on the next page. A microscope helps you focus two objects or details that are close together. This is called resolving power. A microscope also makes an object seem larger than it is. This is called magnification power. When you look into a microscope, the object you see is magnified, reversed, and turned upside down (inverted). 2 MHR Section 1.1 Observing Living Things 2006 McGraw-Hill Ryerson Limited

2 Analyzing Information Section 1.1 Use with textbook page 11. Characteristics of living things List five characteristics of living things. Give an example for each characteristic. Characteristic of living things Example MHR Section 1.1 Observing Living Things 2006 McGraw-Hill Ryerson Limited

3 Cells Textbook pages Before You Read How might the cells of a plant be like the cells of an animal? How might they be different? Write your ideas in the space below. Section 1.2 Summary Mark the Text Identify Definitions Highlight the definition of each word that appears in bold type. Reading Check 1. How is a prokaryotic cell different from a eukaryotic cell? What is the cell theory? The cell theory states three important facts about cells. 1. The cell is the basic unit of all life. 2. All living things are made up of one or more cells. 3. All cells come from other living cells. How are prokaryotic cells different from eukaryotic cells? There are two main types of cells. Eukaryotic cells are cells with organelles that have a membrane around them. You will find out more about organelles below. Plant cells and animal cells are eukaryotic cells. Prokaryotic cells are cells that do not have organelles with membranes around them. Bacteria are prokaryotic cells that live just about everywhere on Earth. Some bacteria cause diseases. It is easy to confuse bacteria with another type of tiny thing that causes disease: viruses. Viruses are non-living things that are able to reproduce. Viruses are not cells. Viruses must be present inside the cell of a living thing in order to reproduce. What is inside a cell? All cells have organelles that carry out specific tasks that help the cell to survive. Most of the organelles in animal cells are also found in plant cells. However, animal cells do not have a cell wall or chloroplasts. 8 MHR Section 1.2 Cells 2006 McGraw-Hill Ryerson Limited

4 Typical Cell Structures mitochondria Section 1.2 Summary continued cell membrane cytoplasm nucleus chloroplasts vacuole cell wall Plant cell cell membrane: This structure is like a skin that surrounds the whole cell. The cell membrane keeps the inside of the cell separate from what is outside it. The cell membrane also controls what enters and leaves the cell. nucleus: The nucleus of the cell controls all the cell s activities. cytoplasm: This clear, jelly-like fluid holds the organelles of the cell in place. mitochondria: These bean-shaped structures are the energy producers. vacuoles: Vacuoles store materials such as wastes for a short time. Plant cells usually have one large vacuole. Animal cells have many small vacuoles. cell wall: The cell wall surrounds the cell membrane of plant cells. The cell wall gives the plant cell protection and supports its box-like shape. chloroplasts: These green-coloured structures in plant cells trap the Sun s light energy and change it to chemical energy for use by the cell. Reading Check 2. Name two organelles that are found in plant cells but not in animal cells. cell membrane cytoplasm nucleus vacuoles mitochondria Animal cell 2006 McGraw-Hill Ryerson Limited Section 1.2 Cells MHR 9

5 Use with textbook page 27. Parts of cells Vocabulary cell membrane nucleus cell wall chloroplast vacuole vacuoles cytoplasm mitochondria Interpreting Illustrations Section 1.2 Use the terms in the box to label the parts of an animal cell and a plant cell. Terms may be used more than once. A. E. B. C. D. F. G. I. H. J. K. L. 10 MHR Section 1.2 Cells 2006 McGraw-Hill Ryerson Limited

6 Use with textbook pages Inside a cell Vocabulary bacteria cell theory cell membrane cell wall chloroplasts cytoplasm eukaryotic living thing mitochondria organelle prokaryotic nucleus vacuoles viruses Cloze Activity Section 1.2 Use the terms in the vocabulary box to fill in the blanks. Each term may be used only once. You will not need to use all the terms. 1. A(n) is a cell structure in which functions are carried out to ensure the cell s survival. 2. Each cell is surrounded by a that separates the interior of the cell from its surroundings. 3. Within the cell is a jelly-like substance called. 4. The is the organelle that controls all the activities within the cell. 5. The are the energy producers in the cell. 6. are temporary storage compartments that sometimes store waste. 7. The is a tough, rigid structure that surrounds the cell membrane and protects the cell. 8. The trap the energy from the Sun and change it into chemical energy. 9. Plant and animal cells are examples of cells. 10. cells are cells that do not have organelles with membranes around them. 11. are examples of prokaryotic cells that can cause disease. 12. are examples of non-living things that are able to reproduce McGraw-Hill Ryerson Limited Section 1.2 Cells MHR 11

7 Comprehension Section 1.2 Use with textbook pages True or false? Read the statements given below. If the statement is true, write T on the line in front of the statement. If it is false, write F and rewrite the statement to make it true. 1. The cell is the basic unit of life. 2. All organisms are composed of only one cell. 3. Animal cells use chloroplasts to trap the Sun s energy. 4. Prokaryotic cells are cells that are surrounded by a cell wall. 5. Eukaryotic cells are cells that are surrounded by a cell membrane. 6. Some bacteria cause diseases. 7. Viruses are non-living things. 8. Bacteria are an example of eukaryotic cells. 12 MHR Section 1.2 Cells 2006 McGraw-Hill Ryerson Limited

8 Assessment Section 1.2 Use with textbook pages Cells Circle the letter of the best answer. 1. Cell membranes are found in A. plant cells only B. animal cells only C. neither plant or animal cells D. both plant and animal cells 2. Which comparison between plant and animal cells is correct? Plants 3. Which of the following describes the cell theory? A. I, II, and III only B. I, II, and IV only C. I, III, and IV only D. II, III, and IV only Animals A. no chloroplasts chloroplasts B. no mitochondria mitochondria C. nucleus no nucleus D. cell wall no cell wall I. The cell is the basic unit of life. II. III. IV. All organisms are composed of one or more cells. Two or more cells are necessary to produce new cells. All cells come from other living cells. 4. Which of the following statements is true? A. A eukaryotic cell has organelles surrounded by membranes. B. A prokaryotic cell has organelles surrounded by membranes. C. All eukaryotic cells are surrounded by a cell wall. D. All prokaryotic cells are surrounded by a cell wall. 5. Bacteria are examples of A. organelles B. viruses C. prokaryotic cells D. eukaryotic cells 6. Plant cells are examples of A. organelles B. bacteria C. prokaryotic cells D. eukaryotic cells Match each Term on the left with the best Descriptor on the right. Each Descriptor may be used only once. Term 7. cell membrane 8. nucleus 9. cytoplasm 10. mitochondria 11. vacuoles 12. cell wall 13. chloroplasts Descriptor A. produces energy B. controls all the cell s activities C. protects and supports plant cells D. traps light energy E. stores materials such as wastes F. controls what enters and leaves a cell G. organelles without a membrane around them H. holds the organelles in place 2006 McGraw-Hill Ryerson Limited Section 1.2 Cells MHR 13

9 Section 1.3 Summary How does osmosis move substances through the cell membrane? Osmosis is a special kind of diffusion that involves water. Osmosis is the diffusion of water through a selectively permeable membrane. Osmosis happens when water particles move from a place where their concentration is higher to a place where their concentration is lower. Osmosis is important to cells. Cells contain water and need it to survive. Cells also live in water or in watery surroundings. What will happen if the concentration of water inside a cell is higher than outside a cell? Water will move out of the cell by osmosis. What will happen if the concentration of water inside a cell is lower than outside a cell? Water will move into the cell by osmosis. In A, the rate at which water particles move into the cell is the same as the rate at which they move out of the cell. A plant cell, shown in B, is normal and healthy. In C, the concentration of water particles outside of the cell is higher than inside the cell. Water particles move into the cell by osmosis. A plant cell, shown in D, is swollen with extra water. A water particle sugar particle B continued Reading Check 2. If the concentration of water outside a cell is higher than it is inside a cell, in which direction will water move? C water particle sugar particle D In E, the concentration of water particles outside of the cell is lower than inside the cell. Water particles move out of the cell by osmosis. A plant cell, shown in F, loses water. If you could see the whole plant, it would be wilted. E water particle sugar particle F 2006 McGraw-Hill Ryerson Limited Section 1.3 Diffusion, Osmosis, and the Cell Membrane MHR 15

10 Vocabulary Section 1.3 Use with textbook pages Crossing the cell membrane Vocabulary diffusion concentration osmosis a selectively permeable membrane Use the terms in the vocabulary box to fill in the blanks. Each term may be used as often as necessary. 1. refers to the amount of a substance in a given space. 2. is the movement of particles from an area of higher concentration to an area of lower concentration. 3. allows some materials to pass through it but keeps other materials out. 4. is the diffusion of water molecules through a selectively permeable membrane. 5. moves wastes from inside a cell to outside a cell. 6. can be compared to a window screen. 7. happens when water particles move from a place where their concentration is higher to a place where their concentration is lower. 8. is the process by which oxygen is moved into a cell. 9. is the process by which carbon dioxide is moved out of a cell. 16 MHR Section 1.3 Diffusion, Osmosis, and the Cell Membrane 2006 McGraw-Hill Ryerson Limited

11 Use textbook pages Examples of osmosis Interpreting Illustrations Section 1.3 To predict the direction of water flow through a cell membrane, you have to compare the concentration of particles on both sides of the membrane. Examine the diagrams below. Explain why the plant cell looks different in each illustration. Diagram A. Explanation B. C. 18 MHR Section 1.3 Diffusion, Osmosis, and the Cell Membrane 2006 McGraw-Hill Ryerson Limited

12 Assessment Section Use with textbook pages Diffusion, osmosis, and the cell membrane Circle the letter of the best answer. 1. Diffusion is A. the movement of particles from an area of low concentration to an area of high concentration B. the movement of particles to the inside of a cell only C. the movement of particles from an area of high concentration to an area of low concentration D. when the particles do not move through the cell membrane at all Use the following diagram to answer questions 4 and 5. water particle sugar particle water particle sugar particle water particle sugar particle A B C 4. In which diagram(s) does water move into and out of the cell at the same rate? A. A B. B C. C D. both A and B 2. Osmosis is A. the movement of water from an area of low concentration to an area of high concentration B. the movement of water to the inside of a cell only C. the movement of water from an area of high concentration to an area of low concentration D. when the water does not move through the cell membrane at all 3. A selectively permeable membrane A. keeps substances out of the cell B. keeps substances in the cell C. has many small openings D. allows only water to pass through it 5. In which diagram(s) will the cell begin to swell? A. A B. B C. C D. both A and C Match each Term on the left with the best Descriptor on the right. Each Descriptor may be used only once. Term 6. concentration 7. diffusion 8. osmosis 9. selectively permeable membrane Descriptor A. moves oxygen into cells B. moves water into and out of cells C. allows some substances through D. surrounds the cell with water E. amount of a substance in a certain place 2006 McGraw-Hill Ryerson Limited Section 1.3 Diffusion, Osmosis, and the Cell Membrane MHR 19

Observing Living Things

Observing Living Things Textbook pages 8 21 Before You Read Section 1.1 Summary This section describes the signs that scientists look for to help them decide if something is living or non-living. On the