1 / 11

Chapter 8

Chapter 8. Cells and Their Environment. Plasma = liquid portion of blood It’s a aqueous solution. (H 2 0) It’s the cell’s environment Contains: CO 2 , O 2 , glucose, enzymes, salts, proteins like hormones and insulin and platelets among other things. 8-1 Cell Membrane.

rowdy
Download Presentation

Chapter 8

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 8 Cells and Their Environment

  2. Plasma = liquid portion of blood It’s a aqueous solution. (H20) It’s the cell’s environment Contains: CO2, O2, glucose, enzymes, salts, proteins like hormones and insulin and platelets among other things

  3. 8-1 Cell Membrane • How does a cell membrane (CM) help a cell maintain homeostasis? • How does the CM restrict the exchange of substances? • What are some functions of membrane proteins? A simple defect in a cell membrane protein can make a life or death difference, in people who have cystic fibrosis, the cell membrane does not work properly.

  4. Roles of the CM • Surrounds every cell (support; contain) • Protects the cell (identification; antigens) • Regulates transport(gate keeper; pores and channels) • moves substances in and out • blocks substances from entering/exiting • Moves messages between cells (communication) • Maintains consistency and order

  5. Homeostasis • The maintaining of a constant, steady internal state while the outside environment fluctuates (ex: environment moves between hot and cold while thermostat maintains constant room temp) • Cells live in an aqueous (water filled) environment – must constantly regulate amount of water inside cell • Cells spend LOTS of energy maintaining homeostasis

  6. Structure of membraneYou should be able to draw and label this pictureHolt pg. 177

  7. Lipid bilayer • Called the “phospholipid bilayer” • Phosphates (PO4-3) represented by circles • Lipid “tails” represented as squiggly lines • Two rows of phospholipids = bilayer • Phosphate areas are polar (charged) and attract water. This are called hydrophilic • Lipid areas are nonpolar and repel water. This is called hydrophobic • CM idea of “water balloon”, really made of WAXY or OILY layer

  8. Functions of lipid bilayer • Water is inside cell (cytoplasm is mostly water) • Water is outside cell (extracellular fluid) • Chemical reactions in cells take place in water • Waxy CM keeps everything in the right place • Only certain substances can pass through the membrane (usually small and nonpolar like CO2, oxygen and simple sugars)

  9. Membrane Proteins • CMs are also made of proteins • Some proteins run throughout the depth of the membrane and are called Integral Proteins • “something that is integrated is throughout a process, program or structure”….. Rebar in integrated into concrete roads; academic vocabulary is integrated into GLHS • Other proteins are just on the outside edge or the inside edge and are called Peripheral Proteins • “ something at the periphery is at the edge”…. Like your peripheral vision. • Proteins are made of amino acids with polar and non-polar regions so they are three dimensionally ‘locked’ in the membranes by their charge and their shape.

  10. Types of CM Proteins • Cell-Surface Markers • Special chains of sugars • Used for Identification (like a name tag or bar code) • Receptor Proteins • Sense cells surroundings • Cause changes to the cell (different shape or chemical reaction) • Junctions • Connect cells to other cells (velcro or rivet); tight junction, gap junctions, plasmodesmata • Enzymes • Help to coordinate and regulate chemical reactions • Transport Proteins • Move substances across CM • Especially if substance is required but is large, polar or charged.

  11. Review - Proteins • Made of amino acids • Made in the RIBOSOMES • Coded for by DNA directions • Contain C,H,O and N and S • Used by organisms/cells for: • Storage (egg white stores amino acids) • Movement (muscle contractions) • Structure (hair, nails, hooves and cytoskeleton) • Transport (hemoglobin carries oxygen and move substances into cells ) • Regulation (enzymes cause reactions) • Defense (antigens and surface markers) • Communication (neurotransmitters between nerves) • Hormonal proteins (important compounds like insulin are protein)

More Related