Name_______________KEY______________ Cells Unit Study Guide Biology Cell Unit Study Guide 1. List some difference between prokaryotic and eukaryotic cells. eukaryotes • • • • • • Much larger Much more complex Contain a true nucleus to house the genetic material (DNA) Linear DNA packaged into chromatin found inside the nucleus Contains specialized structures in the cytoplasm called organelles to carry out various functions Not all have a cell wall prokaryotes • • • • • • Much smaller Less complex No true nucleus Circular DNA that is found in the cytoplasm No organelles found in the cytoplasm Surrounded by a cell wall 2. Organelle means "little organ." How are organelles similar to organs? -they have a specific structure and function to carry out a specific job- just like organs in our bodies 3. What are the levels of organization in a eukaryote? - list them. -cell, tissue, organ, organ system, organism 4. All large organisms have cells with organelles. What advantage do organelles give the cell? Eukaryotic cells are larger and can not pass nutrients as quickly. They require specialized organelles to: i. carry out metabolism ii. provide energy iii. transport chemicals throughout the cell 5. The cell requires instructions in order to function correctly; where are these instructions found? - the DNA in the cytoplasm 6. How are the functions of mitochondria and chloroplasts similar? Which kinds of cells can each be found in? -they both provide energy for the cell -mitochondria in all types of cells – chloroplasts are only in plant cells 7. By comparing a bee's body mass to its wing span, it has been calculated that a bee should not be able to fly. Cell biologists have since found that the muscles which control the wings of the bee have a huge number of mitochondria. Explain why this discovery may help explain why bees are able to fly. -the mitochondria provide energy for cells- the cells of a bee’s wings must be able to have ample amounts of energy needed to operate. 8. What is the function of the ER? Location: Function: In the cytoplasm around the nucleus Modifies materials needed in the cell Name_______________KEY______________ Cells Unit Study Guide Biology Aka: “Fashion designers” 9. Describe the function of the Golgi apparatus. Location: In the cytoplasm Function: Sorts and ships materials to the correct parts of the cell Aka: “the post office” 10. What is the function of the ribosome? Location: In the cytoplasm and on the rough ER Function: Makes protein Aka: “Protein packs” 11. Cells of the stomach lining have large numbers of ribosomes and Golgi. Explain why this is true. Golgi Function: Sorts and ships materials to the correct parts of the cell ribosomes: Function: Makes protein The stomach is a major site of digestion. Food material needs to be absorbed in the cells and packaged to be sent wherever it needs to go throughout the cells of the body. 12. What are the functions of lysosomes? Location: In the cytoplasm Function: Destroys worn out cell parts Aka: “the death chamber: 13. A Biology student has observed an amoeba (animal cell) and made a drawing. You are marking the drawing and notice that he has drawn in a chloroplast. Do you take marks off or not? Explain. – an amoeba is an animal cell, and therefore does not have any chloroplasts 14. What is the function of the cell wall? organisms that have cell walls. Name some types of Location: Around the cell membrane of plant cells Function: Gives the cell shape and protection Aka: “plant cell armor” ex: oak tree, apple tree, apples, onions, leaves of any type 15. How does a cell membrane differ from a cell wall? -materials can pass through a cell membrane- it determines what can come into and out of the cell; both plant and animal cells have a cell membrane -cell walls provide support and protection for the cell- only plant cells have them 16. List the organelles that are only found in plants. List those found only in animals. found only in plants: cell wall, chloroplasts only in animal cells: cilia, flagella Name_______________KEY______________ Cells Unit Study Guide Biology The Cell Membrane Diffusion is the movement of particles from areas of higher concentration to areas of lower concentration. It is a natural, random process. This means that it does not require extra energy input. 1a. These are pictures of molecules frozen at two different times. Draw arrows to show the direction each particle might travel due to diffusion in diagrams A and B. A. B. Random arrows Random arrows 1b. Describe the way the particles of a gas move. Randomly 1c. Diagram A shows the same number of particles as in Diagram B except most particles start out on one side of the box. Explain why after a while, Diagram A resembles Diagram B. Molecules move randomly and reach equilibrium 2. Give an everyday example of diffusion in air and in water. AIR: e.g. Scents and Smells WATER: e.g. Colored dye in a glass of water 3. Complete the following sentence: Diffusion is the -Random- movement of particles from -High- concentration to a -Lowconcentration until they are Evenly spread out. 4. Moths emit chemicals called pheromones to attract a mate. a) Which process is responsible for the distribution of these chemicals through the air? Diffusion b) If a moth detects pheromones, how might it work out which direction they are coming from? Detect the higher concentration of pheromones c) What would be the advantage of a moth releasing the pheromones on a night when there was little wind? The pheromones aren’t blown away from a potential mate 5a. Osmosis is the diffusion of water across a semi permeable membrane. The semi permeable membrane acts like a filter that lets only the water through. Water always goes from the area of higher water concentration to the area of lower water concentration. Confused? Then imagine the particles (or solute) are salt and follow the rule - SALT SUCKS! On the diagram on the next page label the: • Semi permeable membrane (M) • Area of higher water concentration (HC) • Area of lower water concentration (LC) Name_______________KEY______________ Cells Unit Study Guide Biology • Direction of osmotic flow (arrow) M LC HC 5b. What happens to the number of water particles on the left hand side? Increase What happens to the concentration of the solution on the right hand side? Stays the same What happens to the concentration of the solution on the left hand side? Decreases Explain why the concentrations of solution on either side of the semi-permeable membrane change? Water passes through the membrane until in equilibrium, the Salt does not 6. Complete the following sentence: Osmosis is the passage of Water molecules from a LOW concentrated solution to a HIGH concentrated solution through a Semi permeable Membrane 7. The roots of a plant have root hair cells that absorb water from the soil. The diagram below shows two different kinds of roots. The concentration of the solution inside the cell is higher than the concentration of the solution in the soil. a) Explain why water moves from the soil into the root hair cell. Water equilabrates through the semi permeable membrane moving from a high concentration of H20 outside to a low concentration of H2O inside the cell b) Suggest why root hair cells are long and thin and not short and stubby? More membrane surface area so more water can be taken up by the plant. 8. Label the following diagrams of Red Blood Cells and Plant Cells as being examples of cells contained in Isotonic, Hypertonic and Hypotonic solutions. Hypo Iso Hyper Name_______________KEY______________ Cells Unit Study Guide Biology 9. Strawberry jelly is a very strong solution of sugar. By contrast the cytoplasm in a bacteria is a Much weaker solution. (a.) The cell wall of a microbe is made up of a semi-permeable membrane. Would water flow from the microbe to the jam, or from the jam to the microbe by osmosis? Microbe to Jam (b.) Explain why bacteria find it difficult to survive in jam. They can’t keep water inside of their cell which they need for their metabolism. 10. Why is a cell membrane considered “selectively permeable”? The cell membrane controls what, when, and how materials can pass through the membrane 11. What is the function of proteins in cell membranes? • Proteins act as passageways for nonpolar (hydrophobic) molecules to pass through. • Without proteins embedded in the bilayer, essential molecules needed for communication, energy, etc., would not reach the interior of the cell. 12. What is the function of carbohydrates (such as cholesterol) in cell membranes? • Carbohydrates are attached to the proteins. – Allow for cell recognition and communication. 13. What is active transport? – the movement of molecules through a cell membrane using energy 14. If a substance cannot be passed through the cell membrane via osmosis or diffusion, how is it still able to be moved into or out of the cell? Facilitated Diffusion - Diffusion through pores or channel proteins 15. When would the cell perform: Name_______________KEY______________ Cells Unit Study Guide Biology Endocytosis: process of cells engulfing large particles by forming a vesicle around them Phagocytosis: (cell eating) - If the particles are cell fragments or organic matter Pinocytosis: (cell drinking) -occurs if the particles have been partially broken down into a liquid of tiny dissolved molecules Exocytosis: -process by which wastes or secretions (hormones) are brought to the cell membrane, packaged into vesicles and sent out of the cell – the reverse of endocytosis 16. What is a receptor? How does it allow cells in multicellular organisms to communicate? • are often found on the outside of cells where they bind chemical signaling molecules and influence cellular activity.