Cellular Processes: What do cells do anyway? 8.L.5-Understand the composition of various substances as it relates to their ability to serve as a source of energy and building materials for growth and repair of organisms. 8.L.5.1-Summarize how food provides the energy and the molecules required for building materials, growth and survival of all organisms (to include plants).

Essential Questions  How do cells produce food and energy?  How do the different cell functions ensure the survival of the entire organism?

The student will be able to…  Explain the function of different cell organelles and how they work to produce food and energy.  Explain the different cellular functions needed to sustain the life of the cell and the life of the entire organism.

Important Vocabulary  Photosynthesis  Chloroplasts  Respiration  Mitochondria  Selectively permeable  Active transport  Passive transport  Fermentation  Anaerobic respiration  Aerobic respiration  transpiration

Cell Organelle Review  Cell membrane  Endoplasmic reticulum  Nucleus  Cytoplasm  Vacuole  Mitochondria  Golgi apparatus/bodies  Chloroplast  Cell wall

Moving Cellular Materials  All materials exchanged between a cell and its environment takes place at the cell membrane.  Selective permeability: some substances ability to move through the cell membrane while other materials cannot

How cells make energy for active transport  Photosynthesis  Cellular respiration

Passive Transport  Remember, the cell membrane is selectively permeable. This means it is picky about what it let’s across! (How many of you are picky eaters?)  Some things move across the cell membrane easily; so easy in fact that no energy is required for it to cross! This is passive transport.

Photosynthesis  In plant cells, photosynthesis happens, where a plant cell captures energy from the sun and uses it to make food.  The chloroplast (found in the cells of leaves) absorb sunlight, CO 2 enters the leaves and H 2 O enters through the roots. The CO 2 and H 2 O react with the captured sun energy to make glucose (sugar) and oxygen. The glucose is used as food for the plant.

Photosynthesis Chemical Formula  Light energy + 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 (sugar)

Draw Photosynthesis (in journal)

Making Energy  Cellular respiration changes glucose into energy inside the mitochondria.  The energy created during respiration is what powers the cell and its organelles.  Cellular respiration takes place in both plant and animal cells.

Making Energy  During respiration, the chemical reaction creates water and carbon dioxide along with the energy, ATP.  What does the cell do with the water created?  Stores it in the vacuole  Eliminates it from the body as either sweat or urine (animal cells only)

Cellular Respiration Chemical Formula  C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O + energy What do you notice about this chemical formula? Yes, it’s the reverse of the photosynthesis chemical formula!!!! The two processes, photosynthesis and respiration, need each other to continue.

Fermentation  Why do you sometimes get sore muscles from physical exercise?  It’s simple. Even if you’re breathing hard, your cells may not be receiving enough oxygen. When that happens, the cells will go through a process called fermentation to get energy when there is not enough oxygen for respiration.

Fermentation  Fermentation is the cellular process that cells use to release some of the energy stored in glucose molecules if they do not have enough oxygen for respiration.  Fermentation takes place in the cytoplasm; the reaction releases energy and produces wastes.  The wastes are lactic acid (in animal cells) or alcohol and CO 2 (in plant cells).

Fermentation  The lactic acid produces sore muscles, yogurt, and some cheeses.  Another name for fermentation is anaerobic respiration meaning it takes place without oxygen to make energy.  Another name for cellular respiration is aerobic respiration meaning it uses oxygen to make energy.

Active Transport  Okay, if passive transport does not require energy, what do you think active transport requires?  Yes! Active transport requires energy to move things across the membrane.  Some molecules, like the sugar molecule, require energy to move across the membrane.

Active and Passive Transport Analogy  Think about riding a bike. If you are at the top of a hill and coast down it, is that like active transport or passive transport?  If you are at the bottom of a hill and need to pedal to the top of the hill, is that like active transport or passive transport?

Transpiration  First, what is transpiration?  Yes, it is the water vapor being released from the leaves.  Go back and look at your respiration chemical formula. What are the products (things made) in that chemical reaction?  Yes, carbon dioxide and water are made.  The plant can either store the water (where?) or can release the water during transpiration.

Active Transport  Osmosis  Diffusion Transpiration  Passive Transport Types of Transport

Diffusion  Diffusion is a passive movement of particles across the cell membrane.  Things move from high concentration (crowded, like the hallways in-between classes) to low concentration (less crowded like the classroom).  Example: The smell of a pie baking in the oven filling the air with its scent.  Cells like to be in equilibrium or homeostasis. This means the cell likes the same amount of the material on the outside as on the inside.

Osmosis  Osmosis is the diffusion of water across the cell membrane  It is passive transport  Examples: A plant wilting—the water needs to diffuse into the cells when it is watered. You getting wrinkly in water—there is more water outside of your body (high concentration) than inside your body (low concentration).

Mitosis  Mitosis is cell reproduction.  Occurs in the nucleus of a cell  Allows the cell to make an exact copy of itself  Produces two daughter cells from one parent cell  The daughter cells are identical to one another and the original parent cell  Is needed for growth, replacement, and asexual reproduction.

Mitosis Drawings  Use textbook, p , Figure 4  Drawings must be accurate, colorful, and labelled.

Meiosis  Meiosis is a cellular process used to produce sex cells (gametes)  Gametes are different from all other cells; they only contain half the number of chromosomes found in other body cells  It is important for gametes to only have half the number of chromosomes; when two gametes (one from the male, one from the female) join, the correct number of chromosomes is present in the new organism

Meiosis vs. Mitosis Similarities  Both go through interphase— replication of the chromosomes Differences  Mitosis produces two daughter cells  Meiosis produces four daughter cells

Summary  Answer the EQ’s.  How do cells produce food and energy?  How do the different cell functions ensure the survival of the entire organism?