BIOL 235 Chapter 3 Quiz with correct solutions | Latest 2023/2024

BIOL 235 Chapter 3 Quiz with correct solutions | Latest 2023/2024 Define Cell --Living structural and functional units enclosed by a membrane Cell Biology --Study of cellular structure and function 3 major components of a cell --Plasma Membrane, Cytoplasm, Nucleus Plasma Membrane --Forms cell's flexible outer surface separating internal and external environment Regulates flow in and out of cell Plays role in communication among and between cells and external environment Cytoplasm --Cellular contents between membrane and nucleus has 2 parts 1) Cytosol --> fluid portion; contains H2O, dissolved solutes, and suspended particles 2) Organelles --> within cytosol Nucleus --House's cell DNA Lipid Bilayer --2 back to back layers made up of 3 types of lipids 1) phospholipids (75%) 2) Cholesterol (20%) 3) Glycolipids (5%) Occurs because lipids are amphipathic --> polar and non polar molecules and have hydrophobic centers Cholesterol are weakly amphipathic Integral Membrane Proteins --extends into or through lipid bilayer among fatty acid; tails are embedded -Most are transmembrane proteins -Some are attached to 1 side of the bilayer by covalent bonding to fatty acids -Amphiphatic Peripheral Membrane Proteins --Attached to polar heads of lipids or integral proteins @ inner and outer surface Glycoproteins --Integral -Have carbohydrate group attached at the ends that protrude into Extracellular Fluid ---Carbohydrates are oligosaccharides chains of 2-60 monosaccharides that may be straight or branched --- Carbohydrate portions of glycolipids and glycoproteins form sugary coat called glycolax Glycolax --acts as molecular signature that enables cells to recognize one another Enables cells to adhere to one another in some tissues Protects cells from being digested by enzymes in Extracellular Fluid Hydrophilic properties attract fluid to surface --> makes Red Blood Cells slippery Functions of Membrane Proteins --Ion channels formed by Integral proteins -- holes/pores that specific ions flow through -- most are selective Carriers (integral proteins) --selectively moving polar ion/substance from one side of the membrane to the other Receptors --serve as cellular recognition sites --Each type recognizes and binds a specific type --Specific molecule that binds is a ligand Enzymes --Catalyze specific chemical reactions Linkers --anchor proteins to one another (neighboring in plasma membrane or to protein filaments) Cell-Identity Marker (glycolipids and glycoproteins --Enable cell to -- 1) recognize other cells of the same kind during tissue formation -- 2) recognize and respond to potentially dangerous foreign cells Peripheral Proteins ---Help support plasma membrane -Anchor integral Proteins -Participate in mechanical activities ---moving materials and organelles within cell ---changing cell shape in dividing and muscle cell ---Attaching cells to one another Membrane Fluidity ---Depends on number of double bonds in fatty acid tails of the lipids that make-up bilayer and amount of cholesterol present -Each double band puts a kink in the Fatty Acid tail --- Increases membrane fluidity by preventing lipid molecules from packing tightly in the membrane -Allows interaction to occur within plasma membrane -Enables movement of membrane components responsible for cellular processes What is Selective Permeability? ---When some substances pass more readily -Lipid Bilayer Portion --- permeable to non-polar, uncharged molecules (Oxygen, Carbon Dioxide, Steroids) --- impermeable to ions and large, uncharged polar molecules (glucose)