POB Lectures 13-23 Flashcards
What are plasmids?
Small ‘chromosomes’ in prokaryotic bacteria
How do bacterial cells split?
Binary Fission (to make one into two daughter cells)
Bacterial Gene Transfer
Horizontal (F plasmid) and vertical (down genetic tree)
Phospholipids
Amphipathic - hydrophobic and hydrophilic parts
Cell Membrane
Cholesterol (stops solidifying and liquefying)
Membrane Permeability
Number double bonds, cholesterol in membrane,
Membrane Proteins
Integral proteins (middle nonpolar - outer polar) and peripheral proteins (attached to the surface of the lipid bilayer) (used for transport, enzymes, and signal transduction)
Tonicity
Hypotonic (high internal concentration, low external concentration), hypertonic (low internal concentration, high external concentration)
Facilitated diffusion
Channel proteins, carrier proteins
Types of active transport
Uniport (one item, one direction), Symport (two items, one direction), Antiport (two items two directions)
What are common cell structures?
DNA, Ribosomes, plasma membrane, cytosol
DNA replication
Starts at origin of replication - helicase splits, single stranded binding proteins prevent recoiling, topoisomerase prevents supercoiling, primase creates a primer, and DNA polymerase 1 synthesizes 5’–> 3’ New nucleotides are added onto the 3’ OH group by dehydration synthesis The lagging strand is discontinuously synthesized in okazaki fragments going in the 5’ to 3’ direction (the lagging strand comes out of the replication fork in the 5’ to 3’ direction, and they’re antiparalell strands). DNA polymerase 3 then comes in and replaces the primer with the corresponding nucleotides, and dna ligase connects the phosphodiester bonds.
Types of transfer
Horizontal (transduction - from a virus) (transformation - from the environment) (conjugation - bacteria to bacteria) Vertical (down from parent –> daughter cell)
Redox
Reduction - gaining an electron Oxidation - losing an electron Oxidation agent - electron acceptor (electronegative) - gains an electron Reducing agent - electron donor - loses an electron
What is the equation for photosynthesis?
6CO2+6H20–>C6H12O6+6H2O
Electron transfer
Less electronegative to more electronegative - exergonic
What are the parts of photosynthesis?
Light reactions and the calvin cycle (light independent reactions)
Pigments
Chlorophyll a, Chlorophyll b, Carotenoids
Light reactions of photosynthesis
Photosystems (light harvesting complexes, reaction center) inside the thylakoid membrane - cytochrome complex between PS2 and PS1 - transfers by electron transport chain
Photosynthesis
(in PS2) Photon + electron from H20 (hydrogen goes to the other side of gradient) - O2 is released - ATP created by electron transport chain to cytochrome complex (more H+ is transferred against the concentration gradient), goes to PS1, then the electron is captured in NADPH - ATP synthase uses the concentration gradient oh H+ outside the cell and turns it into ATP as the H+ gradient moves towards equilibrium
Calvin cycle
Fixation (CO2 and RuBP (5 carbon sugar) –> 2 3-PG molecules Reduction Needs to be done 3 times! to create 63PG molecules so regeneration can happen Final product 1G3P (RuBP is regenerated with 5G3P) Net energy 6NADPH + 9ATP
Carbon fixation (taking carbon from CO2 and making it into a ring structure CO2+ATP+NADPH–>sugar Carbon is reduced Anabolic reaction
Redox reaction example
a. A redox reaction: 6 CO2 + 12 H2O + light energy → C6H12O6 + 6 O2 i. CO2 gains e- (and a proton, H) – is reduced ii. H2O loses e- (and a proton, H) – is oxidized
How many times does the calvin cycle run?
3
What are the inputs in the calvin cycle?
ATP and NADPH from the light-independent reactions in photosynthesis - phosphorylated by ATP, reduced by NADPH
What is the catalyst in the calvin cycle?
RubisCO
How is the calvin cycle regenerated?
RuBP gets hydrolyzed in regeneration - one ATP per RuBP molecule
Oxidative phosphorylation
Powered by redox of the electron transport chain
Substrate-level phosphorylation
enzyme puts a P group onto an ADP
Glycolysis
Breakdown of sugar- catabolic reaction - energy investment and energy payoff
What is the net output of glycolysis?
2ATP, 2NADH, 2 Pyruvate (2H2O, 2H+)
Does glycolysis require oxygen?
No - it doesn’t care
Where does glycolysis happen?
In the cytosol
What happens after glycolysis?
It depends on oxygen. If there is oxygen, aerobic respiration will happen. If not, either fermentation or anaerobic respiration
What is fermentation?
Regenerates NAH+ from NADH so glycolysis can happen again. Either alcohol (releasing CO2) or lactic acid (produces lactate - no CO2 is produced)
What is anaerobic respiration?
Respiration that uses another electron acceptor other than oxygen - may use nitrogen or sulfur - no electron transport chain
Aerobic respiration
O2 - electron transport chain - pyruvate is oxidized into acetyl CoA - each pyruvate loses a CO2
Respiration
Pyruvate oxidation (pyruvate –> acetyl CoA) - gives off CO2, NAD+ to NADH, Coenzyme A added
Citric Acid Cycle - each acetyl CoA combines with oxaloacetate –> citrate (CoA is released) –> needs to regenerate oxaloacetate
Citric Acid Cycle
Citric Acid Cycle - each acetyl CoA combines with oxaloacetate –> citrate (CoA is released) –> needs to regenerate oxaloacetate
