Unit 3 lesson 5 Homeostasis and Cell Processes

I. Homeostasis https://youtu.be/6fhbbFd4icY A. Maintaining Balance Homeostasis= maintenance of an internal balance of conditions in a changing external environment Need to; Obtain energy Use energy Make new cells Exchange materials Eliminate wastes In unicellular organisms the cell membrane will regulate homeostasis by monitoring what goes in and out of the cell

xylem carries water in plants from “roots to shoots” multicellular organisms use the cardiovascular system to transport materials throughout the body carry wastes away and bring nutrients to cells xylem carries water in plants from “roots to shoots” phloem carries “food” glucose from leaves to roots (shoots to roots)

II Cell Energy https://youtu.be/eo5XndJaz-Y A. Photosynthesis Photosynthesis= process by which plants, algae, & some bacteria use sunlight, carbon dioxide (CO2) to make food (sugars) Chlorophyll is a pigment that absorbs energy Gives plants their green color Found in the chloroplasts Plants have cells that open and close on the bottom of their leaves called stomata Stomata allow CO2 to enter the plant

Roots of the plant allow water to enter the plant CO2 plus water with the energy from light creates glucose (sugar) and oxygen Glucose can be stored as starch that we eat in plants Oxygen is released out of plants through the stomata for us to breath The energy from sun is not “used” it is needed to make allow the reactions to happen

B. Cellular Respiration Cellular respiration= process which cells use oxygen to produce energy from food It is NOT breathing Breathing gives the oxygen needed to run cellular respiration Glucose (food) is broken down into CO2 & H2O (water) using O2 (oxygen) ATP is made (ENERGY for the cell) CO2 released goes to plants for photosynthesis Takes place in the mitochondria “Mighty” mitochondria or the powerhouse of the cell

Plants also undergo cellular respiration in their mitochondria to release the energy in the glucose that they made during photosynthesis Plants use CO2 to make sugar & release O2= cycle Animals use O2 to break down sugar and release CO2 = cycle

C. Fermentation Fermentation= the breakdown of food without the use of oxygen Cells need ATP to function & live When there is no available oxygen and the cell is working it must make ATP using fermentation Lactic acid is produced in our cells= causes muscles to be sore https://youtu.be/DGq94gpKEbg Alcoholic fermentation is used in baking with yeast Holes in the bread is from the CO2 being released

III. Cell division A. Purpose To reproduce cells must copy their DNA before they reproduce binary fission asexual reproduction in which a prokaryote copies it’s DNA and splits in two mitosis= eukaryotic cellular division DNA condenses into chromosomes to allow the cell to divide into 2 identical cells

To grow and repair damaged cells mitosis allows for multicellular eukaryotes to replace cells and grow

IV. Exchange with the environment. A IV. Exchange with the environment A. Diffusion- passive transport https://youtu.be/w3_8FSrqc-I The cells have to get rid of waste products and take in materials needed to live Semipermeable membrane= allows certain substances in and out of the cell The cell membrane Particles travel from where they are crowded (high concentration) to where they are less crowded (low concentration)= diffusion Food color in water will move throughout until all of the water is colored

B. Osmosis- passive transport https://youtu.be/7-QJ-UUX0iY Osmosis= the diffusion of water through cell membranes Water is made of particles called molecules Pure water has a lot of water molecules Kool-Aid would have less water molecules than pure water because the sugar takes up some of the water molecule space Like diffusion= water will move from a high concentration (crowded space) to a low concentration (less crowded space) Without osmosis our body would not be able to keep the right amount of water in our cells Plants would wilt without being able to gain or lose water

C. Moving small particles Small particle will move into and out of the cell membrane through proteins that make “tunnels” Passive transport does NOT use energy Particles move from high concentration to low concentration (osmosis) Active transport DOES USE energy Moves from low to high (like a salmon swimming upstream)

D. Moving large particles- active transport Endocytosis= active transport process in which the cell will take in a particle Cell comes into contact with what it is going to bring in Cell membrane wraps around the particle A vesicle pinches off inside of the cell

Exocytosis: the active transport process in which something is being released to the outside of the cell Particle such as waste must leave the cell Vesicle travels to the edge of the membrane Cell releases the particle out https://youtu.be/qpw2p1x9Cic