Presentation on theme: "Chapter 4 Cells Chapter 5 Cell Membrane and Signaling"— Presentation transcript:
1 Chapter 4 Cells Chapter 5 Cell Membrane and Signaling Unit 2 Review AP BiologyChapter 4 CellsChapter 5 Cell Membrane and Signaling
2 1. Calculate surface area to volume ratio 3:53:103:50Reduced0.6 : 10.3 : 10.06 : 1Surface Area = 6 X length squaredVolume = length x length =x length
3 2. Which size cell would be the first to get a toxin in the middle? The smallest cell would be firstWhy?The smallest cell has the greatest surface area relative to its volume.The toxin would have greater opportunity to enter the cell because of this ratio
4 3. Explain how prokaryotes carry out enzymatically catalyzed biochemical conversions without organelles?There are proteins in the cytoplasm moving around.This motion ensures that reactions are taking place at a rate sufficient for the cell to survive.There are also enzymes in the cytoplasm to catalyze reactions.
5 4. Explain whether ribosomes are present only in eukaryotes, only in prokaryotes, or in both. Ribosomes make proteins and proteins are essential in all living things
6 5. Describe the structure and function of as many cellular organelles as you can in regard to the synthesis and secretion of protein signals.RER – proteins are synthesized on the ribosomes and then delivered to GolgiSER – stores Ca+ that trigger the secretion of proteins that are secreted by cellsGolgi Body – concentrates, packages, sorts and modifies proteins to send them to their destinationRibosomes – make proteins from amino acids
8 7. Explain how the structure of the phospholipid is amphipathic and can form a bilayer that is nonpolar in middle and polar on the outsidesMiddle is hydrophobic due to the fatty acidsOutside is hydrophilic due to the phosphate groups.
9 8. What are the 2 primary factors that influence membrane fluidity? Lipid composition and temperature
10 9. Explain how the ink diffused through the gel even though there were no currents. By diffusion its random and it will go until equilibrium.
11 10. Describe 2 differences between passive and active transport Moves materials from high to lowNo energy neededMoves materials from low to highRequires energyAll require proteins
12 11. Define and provide a description IsotonicEqual solute concentrations on each side of membraneNo net movement of water in/out of cellHypotonicLow solute concentration outside the cellCauses enlargement of cellsHypertonicHigh solute concentrations outside the cellCauses shrinking of cells
13 12. Is facilitated diffusion active or passive transport? Explain why. No energy is required even though there are proteins involved.
14 13. Explain how cells are involved in the transition from wilted to normal. Wilted hypertonic resulting in a flaccid appearanceWhen a wilted plant is watered, water moves in to the shrunken cells, expanding them. Cells become plump again and has turgor pressure.
15 19. Complete table. Simple Diffusion Osmosis Facilitated Diffusion Active transportCellular Energy required?NoYesDriving force?Concentration GradientATP hydrolysisMembrane protein required?Yes for some cells, No for othersDirectional?Specificity?
16 20. Explain the Na+K+ Pump 3 sodium ions get pumped OUT 2 potassium ions get pumped INRequires 1 ATP – ATP gets broken down into ADP + inorganic phosphate
17 16. Explain how phagocytosis and pinocytosis are similar and different Both forms of endocytosisBoth involve the folding of the plasma membraneBoth active transportBoth bring materials into the cellPhagocytosis is bringing in large particles/cellsPinocytosis is bringing in fluids and dissolved substances
18 17. Describe each step of cell signaling Signal arrives at target. Signal molecule may be a specific molecule or a physical stimulus.ReceptorSignal molecule fits into the receptor protein and binding occursResponseReceptor changes its 3D shape and this initiates a cellular response
19 18. If a cell had no proteins, will it be able to respond to any environmentally stimuli? Explain Cells must have specific receptors to any environmental stimuli and receptors are always made of protein
20 19. Why doesn’t caffeine enter the cell? Caffeine is largeCaffeine is polar (see nitrogens)It is unlikely to diffuse through the plasma membrane so it likely will bind to a receptor on the surfaces of nerve cells in the brain
21 20. All cells haveCytoplasmPlasma membraneribosomes
22 21. Animals HAVE (and plants don’t) LysosomesCentriolesFlagellaCiliaMore rounder shapeSmaller and more vacuoles
24 23. Prokaryote vs. Eukaryote OlderNo nucleus (nucleiod)No organellesSimpler ribosomesBacteria is an exampleYoungerNucleus and nuclear membraneOrganellesComplex ribosomesPlants, animals, fungi and protists are examples