BIOL 120 1st Edition Lecture 10Outline of Last Lecture I. Prokaryotic Cells (cont.)a. flagellaII. Eukaryotic Cells a. nucleolus, nuclear envelope, nuclear pore, chromatin, Rough ER, endocytosis, pinocytosis, thylakoids, grana, stromaIII. Cell to cell interactions and connections Outline of Current LectureI. Membrane StructureII. Membrane ProteinsIII. Cell division (beginning) Current LectureI. Membrane Structure1. it is a phospholipid bilayer2. Has proteins that go through the membrane i.e. Globular proteins3. the environment influences the fluidity A. saturated fatty acids make the membrane less fluidi. straight tail  forms from single carbon bondsii. Bent tail forms from double bonded carbons (kinks)B. Most membranes contain cholesterol which can increase or decrease membrane fluidity based on temperature These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.I. warmer is more fluid than cold II. Membrane Proteins 1. hydrophobic interior of membrane makes it hard for molecules to pass through proteins function as transport proteins A. nonpolar molecules can easily move through because phospholipids are mostly non-polar and wont form bonds B. Smaller polar molecules have limited permeability  proteins moves these across the membrane2. Functions:A. Transporters: selective, allow only certain molecules to move acrossB. Enzymes: perform many chemical reactions on the surface of PM (membrane) using enzymes attached to it.1. Cristae gives more surface area where ATP is made C. Cell-surface receptors: Receptor proteins in PM receives chemical messages.2. Can bring chemicals/ molecules into the cell by binding to them to start a cell function D. Cell-surface identity markers: PM membrane proteins which identify cell types.E. Cell-to-cell adhesion proteins: Cells use specific proteins to glue them togetherF. Attachments to the cytoskeleton: Anchored to the cytoskeleton by PM proteins3. Help keep cell shape and placement within the cell 3. Transmembranal A. integral membrane proteins i. span the lipid bilayer  nonpolar regions are embedded in the interior and polar regions are protruding from both sidesB. Peripheral proteins--. Found on the surface of the membrane 4. Pore (transporter role)A. a extensive nonpolar region within a trasnmembrane protein i. made from beta barrel ii. the interior is polar --. Allows water and small molecules to pass through membrane 5. Channel ProteinsA. ion channels: act as a gate that allows ions to pass throughB. Gated channel: open or close in response to a stimulus that can be chemical orelectrical6. Carrier ProteinA. transports ions and other solutes  needs a concentration difference across the membrane i. has a net gain of 0 ii. gradient goes from high to low B. has to bind to the molecule to transport iti. saturation- rate of transportation is limited by numbers of transporters 7. Active TransportA. requires energy (ATP) directly or indirectly B. moves substance against the concentration gradient from low to high concentrations C. needs selective carrier proteinsi. uniporters: move one molecule at a timeii. Symporters: move two molecules in the same directioniii. Antiporters: move two molecules in opposite directions (one in and one out)8. Passive TransportA. no energy input neededB. follows the concentration gradient from high to low 9. Sodium- potassium pumpA. uses ATP for active transport B. uses antiporters to move 2 K+ into the cell and 3Na+ out of the celli. going against the gradient10. EndocytosisA. movement of substances into the celli. Phagocytosis: cell takes matter inii. Pinocytosis: cell takes in fluid and solutes11. receptor mediated endocytosisA. receptor proteins bond to molecules then caves in on itself to bring them into the cellB. in the disease familial hypercholesterolemia  receptors lack tails and cannot function correcting letting bad cholesterol build up in arteries 12. Exocytosis:A. the discharge of materials out of the cellB. plants use: export cell wall materialC. Animals use: to secrete hormones, neurotransmitters and digestive enzymes III. Cell division (beginning) 1. Key ConceptsA. Eukaryotes divide to reproduce through the Cell Cycle (G1, S or synthesis, G2 &M or mitosis)i. chromosomes are duplicated during the S phase from 46 to 92ii. then moved to the middle of the cell during the M phaseiii. chromosomes distributed to two daughter cells and cytokinesis begins (division of cytoplasm)iv. also duplicated and divides organelles B. This process produces two cells identical (genetically) to the parent celli. diploid: 46 chromosomes (2 sets)ii. haploid 23 chromosomes (1 set for reproduction) 2. Bacterial Cell DivisionA. bacteria divides through binary fission (no sexual life cycle  reproduce by cloning)B. The circular bacterial chromosomes is replicated and then Septum forms to divide the cell into 2 3. MutationsA. the cell cycle needs to be carefully controlled otherwise can lead to the development of cancer 4. Meiosis and MitosisA. both are followed by cytokinesis B. Meiosis: leads to the production of gametes (egg and sperm)C. Mitosis: leads to the production of all other cell types (somatic cells)5. functions of MitosisA. GrowthB. Wound repairC. Asexual