BIOL 1441 1st Edition Exam 2 Study Guide Lectures 11 18 Lecture 11 February 17 1 What is the protein that makes up microfilaments Microtubules Intermediate filaments Microfilaments Actin Microtubules Tubulin Intermediate filaments Keratin 2 What are the major functions of microfilaments Microtubules Intermediate filaments Microfilaments muscle contraction cell motility pseudopodia cell division cleavage furrow Microtubules cell motility cilia flagella separate chromosome division Intermediate filaments make up nuclear lamina 3 What is extracellular matrix ECM Is it found in animal cells plants cells or both The ECM is found in animal cells covers because they lack cell walls it repairs divides and rebuilds tissue instead of scarring i Functions support adhesion movement tissue regeneration 4 What are the 4 main protein or carbohydrate structures in the ECM How are they connected 5 What is the main structural protein in the ECM Fibronectin 6 What are the 3 intercellular junctions in animal cells Tight junction membranes of neighboring cells are pressed together preventing leakage of extracellular fluid prevents things from going in between cells Desmosomes anchoring junctions fasten cells together into strong sheets hold cels together keep things from going in between Gap junctions provide cytoplasmic channels between adjacent cells RARE things moving between cells i Ex Heart intestines 7 What is the intercellular junction in plant cells Plasmodesmata 8 What intercellular junctions are similar in plant and animal cells 9 What happens to an animal cell in a hypertonic solution Hypotonic Isotonic Hypertonic fluid rushes OUT and it shrivels Hypotonic fluid rushes IN and it bursts lysed Isotonic GOOD WHERE IT SHOULD BE 10 What happens to a plant cell in a hypertonic solution Hypotonic Isotonic Hypertonic plasma membrane pulls away plasmolyzed Hypotonic GOOD WHERE IT SHOULD BE TURGID Isotonic flaccid wilted 11 What happens to a red blood cell in a hypotonic solution bursts 12 Explain diffusion 13 14 15 16 17 18 19 When molecules spread out evenly into the available space natural movement of anything from high to low concentration doesn t have to be across a membrane How does heat molecule size and concentration gradient affect the rate of diffusion Heat Increase heat increase molecular colisions increased diffusion rate i DIRECT RELATIONSHIP Size smaller molecules move faster than large molecules smaller molecules will diffuse faster i INVERSE RELATIONSHIP Concentration gradient steeper gradient higher concentration on one side compared to low concentration on other side faster diffusion i DIRECT RELATIONSHIP What are the major biological molecules that make up cell membranes Lipids mostly proteins carbohydrates How does temperature affect the fluidity of a membrane As temperatures cool membranes switch from a fluid state to a solid state molecules start slowing down and pack tightly into a solid How do cell membranes remain fluid in cold temperatures In cold temperatures CHOLESTEROL helps maintain fluidity by preventing tight packing by inserting itself between tails to keep them from packing too tightly How do cell membranes prevent too much fluidity in cell membranes when it s too hot In hot temperatures CHOLESTEROL restrains movement of phospholipids which makes them less fluid Cholesterol acts as a speed bump and slows molecules down when they hit cholesterol What are the 6 functions of membrane proteins Transport enzymatic activity signal transduction cell to cell recognition intercellular joining attachment to cytoskeleton ECM What is an amphipathic molecule Containing hydrophobic and hydrophilic regions Lecture 12 February 19 1 What is the difference between active and passive transport Passive transport requires no energy from the cell to make it happen i High to low concentrations natural movement ii Channel proteins carrier proteins Active transport requires energy usually ATP i Low to high concentrations ii ONLY carrier proteins 2 What is the difference between diffusion and facilitated diffusion Diffusion molecules spread out evenly into the available space Facilitated diffusion passive diffusion aided by transport proteins channel carrier proteins and ion channels 3 What is an electrogenic pump Give 2 examples Electrogenic pump transport protein that generates the voltage across a membrane i Sodium potassium pump ii Proton pump 4 Where is the Na K pump located in a cell 5 6 7 8 9 10 11 Cell membrane How does the Na K pump work What are the gradients set up meaning there is Na high and where is it low Where is K high and where is it low Inside of the cell is NEGATIVE Inside of the cell has LOW sodium concentration NA Inside of the cell has HIGH potassium concentration K If NA channels are opened NA diffuses INTO the cell i Pumps 3 NA OUT of cell If K channels are opened K diffuses OUT of the cell i Pumps 2 K INTO cell The concentration gradient is the ENERGY SOURCE Sodium potassium pump maintains these gradients What types of molecules can cross the cell membrane and why Hydrophobic Nonpolar no charge hydrocarbons steroids diffusion passive transport What types of molecules cannot cross the cell membrane and why Hydrophilic Polar ions charged molecules water facilitated diffusion active transport What is the difference between channel and carrier proteins Which can do passive transport Which can do active transport Channel proteins provide corridors that allow a specific molecule or ion to cross the membrane Carrier proteins undergo change in shape that translocates the solute binding site across the membrane Passive transport uses BOTH Active transport ONLY carrier What is osmosis Diffusion of water across a selectively permeable membrane Water is diffusing on its OWN concentration gradient From an area of low solute concentration high water to an area of high solute concentration low water i WATER WILL ALWAYS FLOW TO A HIGH SOLUTE CONCENTRATION LOW WATER What is voltage Electrical potential energy separation of opposite charges What is membrane potential Why is it important in cells Voltage difference across a membrane separate charges across a membrane Lecture 13 February 21 1 What is metabolism All chemical reactions in an organism at one time 2 What is the difference between open and closed systems Open systems energy and matter are being exchanged with surroundings living organisms o Never reaches equilibrium continues to do work Closed systems nothing being