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Transcript
Chapter 1 – Cells Page 17 1. Living things are i) made up of cells ii) they reproduce, grow and repair iii) they require energy iv) the respond to the environment v) they have a set life span vi) they produce waste 2. No they are not because they do not show ALL of the characteristics listed in #1. 3. a) responding to the environment b) growing d) need food and energy e) reproduce c) producing waste Pg. 21 1. Structure Nucleus Plant Cell Y Animal Cell Y Chromosomes Y Y Cell Membrane Y Y Cytoplasm Y Y Vacuole Y (large) Y (small) Cell Wall Y N Function Control center of the cell Contains DNA. What make up the DNA. They contain all of the info needed to make an organism. Protects the cell and controls what goes in and out of the cell. “Selectively permeable” The gel like water based material inside of the cell. All organelles are found in here. Used for storage in a cell. Protects plant cells and gives plants support Chloroplasts Y N Flagellum N Y Cilia N Y Centrioles N Y Used to collect sun’s energy in plants. Contain chlorophyll – a green pigment in plants. Used by cells to move around their environment. Used by cells to move around their environment. Used by animal cells in cell division. 2. All genetic information for a cell is found in the nucleus. 3. If a cell looks like it has two nuclei, then it was probably just getting ready to divide. 4. If a cell membrane was replaced by a plastic coat, the cell would slowly get poisoned by its own waste. In addition, the cell would “starve” to death as there would be no nutrients getting into the cell. Pg. 27 1. organelles are tiny structures inside of a cell. They do everything from digesting food, to creating energy, to determining when a cell divides. 3. If a cell’s mitochondria stop working then the cell would no longer be able to create the energy needed for cellular processes. 4. Many Golgi apparatus are found in the stomach cells due to the fact that the Golgi are protein “sorting centers”. They are responsible for taking basic forms of protein found in the cells, processing the protein in the apparatus and then releasing it as an enzyme. Pg. 29 1. Diffusion is the passing of materials across a cell membrane without using any energy. This is always done by movement from an area of high to low concentration. Once the concentrations are in balance, diffusion DOES NOT stop….it is just in balance or equilibrium. 2. Impermeable means that nothing can pass. Permeable means that everything can pass and selectively permeable means that certain substances can pass while others cannot. 3. All cells have selectively permeable membranes. The membranes are designed to block some substances from crossing into or out of the cell. Likewise, the are designed to let certain substances specifically into and out of the cell. 4. The pores are different sizes due to the fact that the molecules or substances being allowed into and out of the cell are also of different sizes. Each pore fits a specific substance. 5. a) Imagine a mechanism that looks like a lock and a key. b) The sugar in their blood would be too high as it is not being used by their cells due to the pores not being opened. c) Mitochondria are affected as they need sugar to create energy for the cell. Pg. 33 1. Both osmosis and diffusion are the passage of materials across a selectively permeable membrane without using any of the energy in the cell. Osmosis is the special name given to the movement of water across the cell membrane. 2. The concentration of salts either inside or outside of a cell determines the movement of water both in and out of a cell. The water will always move from an area of high concentration to low until a balance is reached. 3. The cell wall is what prevents a plant cell from bursting as water flows into it by osmosis. 4. Animal cells are more likely to burst due to the fact that they do not have a cell wall to provide extra support. 5. Turgor pressure is the pressure that develops in plant cells due to water moving in and out of it. If a plant cell is filled up with water then it has a high turgor pressure. When a plant is in need of being watered, then it has a low turgor pressure and a plant looks wilted. 6. Grocery stores spray their vegetables so that the plant cells can take up water and increase the turgor pressure. Then the vegetables look fresh and not like they have been sitting there for a week! 7. The red blood cells burst due to the fact that the concentration of salts inside if the cell is larger than the dilute blood, due to all of the extra water that the person had. To try to balance out the concentrations, water enters the blood cells through osmosis and eventually bursts them. This is why man sport drinks have electrolytes in them which are basically salts. Pg. 37 1. Irrigation with salt water would be harmful to plants as it would draw all of the water OUT of a plant cell, causing it to wilt and die. 2. These potatoes taste better due to the fact that minerals get drawn up with the water into the plant and become part of the plant tissue. This makes for a better tasting potato. Pg. 41 1. Tissues make up organs and organs make up organ system. For instance a group of heart cells make up tissue and together the make up your heart, which is an organ. Then the heart along with another group of organs make up the circulatory system. 2. molecule – cell – tissue – organ – organ system 5. Large multicellular organisms are more complex and cannot depend on just basic cells to carry out all life processes. They need cells to specialize into organs that do what a single cell would do in a unicellular organism. For example, instead of having lysosomes to break down food, multicellular organisms have digestive systems. Pg. 45 1. Bacteria are more “primitive” due to the fact that they do not have any organelles inside of them surrounded by membranes. In other words, they do not have a nucleus, ribosomes, lysosomes, etc ….Having organelles form is a marker of more modern cells. 2. They are called plant like due to the fact that they have chlorophyll inside of them. Chlorophyll is the green pigment found in plants. 3. Euglena has chlorophyll and can make its own food just like a plant if it needs to. It also has a large vacuole to get rid of water. However, it can “eat” like an animal also so it kind of sits on the fence between plant and animal. 4. A paramecium uses the cilia (tiny hairs) on it to draw food into its “oral grove”. An amoeba extends “pseudopods” also called “fake feet” around its food, creates a membrane around the food and then digests it with lysosomes. 5. Many microorganisms cause disease if they are taken in with food or water. Bacterial can cause infections that we need to take antibiotics to get rid of, when travelling, amoeba’s and other protists in water often cause stomach upset and the need to run to the bathroom. 6. All three, the amoeba, euglena and paramecium, live in fresh water. As a result, water is continually trying to flow into the organism to maintain “balance”. If there were not contractile vacuoles present to “squirt” out the extra water flowing across the membrane, these organisms would burst. 7. Diagram will be different for each student. You just have to show the wall slowly breaking down and then bacterial cell eventually bursting. Pg. 47 1. The smaller a cell is the faster communication is inside of it. Messages travel from the nucleus through the cytoplasm much faster than in a larger cell. This is why cell size has a “cap” on it. Once the cell gets too large to communicate quickly, the message to divide gets sent out and the cell splits. 2. The cell the with larger surface area – translation…largest cell membrane – is the most efficient at getting rid of waste. This is due to the fact that there are multiple sites on the membrane to get rid of waste as the cell pushes it out through the membrane using vacuoles. 3. These cells are small due to the fact that they have to create such large amounts of energy . The small size allows the cell to carry out the chemical processes very quickly that produce the energy needed to run the rest of the cell. The small size means that this energy can quickly be released outside of the cell without losing too much of it. 4. a) A cell that is a cube would have a larger surface area. This is why cells are circular. They want a large surface area, but they also do not want to waste too much material making up the cell membrane. b) A cell with a smooth membrane has the smallest surface area as the projections on a cell would use up more membrane and increase the surface area. CELL ORGANELLES - NOTES CELL THEORY Cells are the basic unit of life. The Cell Theory states that: 1) All organisms are made up of one or more cells and the products of those cells. 2) All cells carry out life activities ( require energy, grow, have a limited size). 3) New cells arise only from other living cells by the process of cell division. THE THREE MAIN COMPONENTS OF ANY PLANT OR ANIMAL CELL ARE: 1. PLASMA MEMBRANE/ CELL MEMBRANE Structure- a bilipid membraneous layer composed of proteins and carbohydrates. It is fluid like. Function - the cell membrane separates the cell from its external environment, and is selectively permeable (controls what gets in and out). It protects the cell and provides stability. Proteins are found embedded within the plasma membrane, with some extending all the way through in order to transport materials. Carbohydrates are attached to proteins and lipids on the outer lipid layer. 2. CYTOPLASM Structure - The jelly-like substance composed of mainly water and found between the cell membrane and nucleus. The cytoplasm makes up most of the "body" of a cell and is constantly streaming. Function - Organelles are found here and substances like salts may be dissolved in the cytoplasm. 3. NUCLEUS Structure - The largest organelle in the cell. It is dark and round, and is surrounded by a double membrane called the nuclear envelope/membrane. In spots the nuclear envelope fuses to form pores which are selectively permeable. The nucleus contains genetic information (DNA) on special strands called chromosomes. Function - The nucleus is the "control center" of the cell, for cell metabolism and reproduction. THE FOLLOWING ORGANELLES ARE FOUND IN BOTH PLANT AND ANIMAL CELLS. 1. "ER" OR ENDOPLASMIC RETICULUM The Endoplasmic Reticulum is a network of membranous canals filled with fluid. They carry materials throughout the cell. The ER is the "transport system" of the cell. There are two types of ER: rough ER and smooth ER. Rough Endoplasmic Reticulum is lined with ribosomes and is rough in appearance and smooth endoplasmic reticulum contains no ribosomes and is smooth in appearance. 2. RIBOSOMES Ribosomes are small particles which are found individually in the cytoplasm and also line the membranes of the rough endoplasmic reticulum. Ribosomes produce protein. They could be thought of as "factories" in the cell. 3. GOLGI BODY / APPARATUS Golgi bodies are stacks of flattened membranous stacks (they look like pancakes!). The Golgi Body temporarily stores protein which can then leave the cell via vesiciles pinching off from the Golgi. 4. LYSOSOMES Lysosomes are small sac-like structures surrounded by a single membrane and containing strong digestive enzymes which when released can break down worn out organelles or food. The lysosome is also known as a suicide sac. 5. MITOCHONDRIA The mitochondria are round "tube-like" organelles that are surrounded by a double membrane, with the inner membrane being highly folded. the mitochondria are often referred to as the "powerhouse" of the cell. the mitochondria releases food energy from food molecules to be used by the cell. This process is called respiration. Some cells( muscle cells) require more energy than other cells and so would have many more mitochondria. 6. VACUOLES Vacuoles are fluid filled organelles enclosed by a membrane. They can store materials such as food, water, sugar, minerals and waste products. ANIMAL CELLS ORGANELLES NOT FOUND IN PLANT CELLS: CILIA AND FLAGELLA Both cilia and flagella are hair-like organelles which extend from the surface of many animal cells. the structure is identical in both, except that flagella are longer and whiplike and cilia are shorter. There are usually only a few flagella on a cell, while cilia may cover the entire surface of a cell. The function of cilia and flagella ionclude locomotion for one-celled organisms and to move substances over cell surfaces in multi-celled organisms. ORGANELLES AND OTHER FEATURES FOUND ONLY IN PLANT CELLS: 1. CELL WALL The cell wall is a rigid organelle composed of cellulose and lying just outside the cell membrane. The cell wall gives the plant cell it's box-like shape. it also protects the cell. The cell wall contains pores which allow materials to pass to and from the cell membrane. 2. PLASTIDS Plastids are double membrane bound organelles. It is in plastids that plants make and store food. Plastids are found in the cytoplasm and there are two main types: Leucoplasts - colorless organelles which store starch or other plant nutrients. ( example - starch stored in a potato) Chromoplasts - contain different colored pigments. The most important type of chromoplast is the chloroplast, which contains the green pigment chlorophyll. This is important in the process of photosynthesis. 3. CENTRAL VACUOLE The central vacuole is a large fluid-filled vacuole found in plants.