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How are organelles isolated from animal tissues?
- Tissue is mechanically homogenized in aqueous buffer
- Large/small particles are separated by centrifugation at varying speeds
- Isopycnic centrifugation (using a solution gradient) is used to separate similarly sized particles by density
Define: in vitro, chiral, enantiomer, diasteromer, stereoisomer
- in vitro: "In glass", No interference from other molecules
- chiral: C w/ 4 diff attachments, can have 2 stereoisomers
- enantiomer: stereoisomers that are mirror images of eachother
- diasteromer: stereoisomers that are not mirror images of eachother
- stereoisomer: same chemical bonds w/ different configuration
List 4 differences between plant and animal cells
- Cell walls/plasmodesmata in plants
- Lysosome in animals
- Chloroplast/thylakoids/starch granules in plants
- Vacuole in plants
- Secondary metabolites in plants
Why is cell size limited by diffusion?
- Metabolism requires O2 diffusion
- If SA:V ratio increases too much the diffusion cannot match need
What is a kilodalton? What does it represent?
- a measurement of molar mass (moles/g)
- 1 dalton = 1/12 mass of C-12
Conformation vs configuration
- Conformation: spatial arrangement of substituents that can be formed without breaking bonds (staggered vs eclipsed)
- Configuration: the way the molecules are connected together (stereoisomerism)
How do living organisms get energy?
- Take up chemical fuels and oxidize them
- Absorb energy from sunlight
Gibbs free energy equation
- ΔG = ΔH - TΔS (spontaneous (exergonic) if ΔG is -)
- ΔH: enthalpy (#/types of bonds)
- ΔS: entropy (measure of disorder in a system)
- T: absolute temp (in K)
- aA + bB <-> cC + dD
Relationship between Keq and ΔG?
- If Keq >> 1, ΔG is large and negative (more likely to occur)
- If Keq << 1, ΔG is large and positive (less likely to occur)
How enzymes alter reactions? Affect Keq?
- Enzymes increase the raterxn by decreasing activation energy required
- Enzymes do not affect equilibrium
Name for the precise 3D structure of a protein?
When does the fossil record show first eukaryotic fossils?
4 differences between prokaryotes and eukaryotes?
- Discrete complexes of protein/DNA (chromosomes)
- Membrane-bound organelles
homolog vs Ortholog vs paralog
- Homolog: proteins from genes that contain sequence similarities
- Paralog: homologs in the same species
- similar, but often have different functions
- Ortholog: homologs in different species
- often has the same function in both species
What percentage of genes has no assigned function?
How identical are human and chimpanzee genomes?