Lecture 10 Flashcards
What are the 4 chemical processes that distinguish life from non-life?
1) enzyme catalysis
2) energy harvesting from redox reactions
3) energetically-coupled reactions
4) transduction of energy from transmembrane ion gradients
What is enzyme catalysis?
accelerates otherwise slow reactions
What is energy harvesting from redox reactions?
oxidation/reduction to generate ATP and NADH
What are Energetically-coupled reactions?
linking favorable and unfavorable reactions
What is Transduction of energy from transmembrane ion gradients?
generating ion gradients to perform work or generate ATP
What are the processes of bacterial growth? (4)
1) Fueling
2) Biosynthesis
3) Polymerization
4) Assembly
What are the 4 macromolecules of cellular structures?
1) Nucleic Acids
2) Proteins
3) Carbohydrates
4) Lipids
What is the most abundant macromolecule in the cell?
proteins 55% of dry weight
What is the the second most abundant macromolecule?
RNA ~20% of total dry weight
What are fueling reactions?
getting precursor metabolites, energy and reducing power the cell needs for biosynthesis
Why do cells need energy?
Motility
Protein secretion
Repair
Sensing and communication
How is energy conserved intracellularly?
ATP
Why is ATP the energy currency of the cell?
1) ATP is small
2) can store a lot of energy
3) phosphate groups are highly negative
3) gamma phosphate is the highest bond
What are the building blocks of macromolecules?
13 precursor metabolites
What is the difference between and autotroph vs heterotroph?
autotroph = CO2
heterotroph = organic
What is the difference between and phototroph vs chemotroph?
phototroph = sunlight
chemotroph = organic
Which have to fix inorganic carbon to organic carbon?
autotrophs
How do chemotrophs harvest energy from oxidation reactions?
electron moves from a high energy level in one chemical molecule to a lower energy level in another molecule (makes ATP)
oxidative phosphorylation
How do autotrophs harvest energy from oxidation reactions?
light energy excites from a low energy level to a higher level and then the ”restless” electron travels downhill (makes ATP)
photophosphorylation
What are the 2 types of reactions of the central pathways?
Oxidation and dehydrogenation
What is oxidation?
electron is extracted alone and passed to an electron receptor
What is dehydrogenation?
electron is removed together when a proton and transferred to a H-accepting molecule (NAD or NADP) generating reducing power (NADH or NADPH)
—links like the TCA cycle and oxidative phosphorylation
What is the Simplest and neatest way to generate ATP?
substrate level phosphorylation
How does substrate level phosphorylation work?
1) Generates ATP from ADP
2) Organic substrate first becomes phosphorylated with inorganic phosphate (no energy needed)
3) Phosphorylated substrate is oxidized (with NAD) and the low-energy bond is transformed to a high-energy bond
4) The high-energy phosphoryl bond can be transferred to ADP to form ATP
makes NADH
occurs in glycolysis
Are the energy requirements to make proteins?
very huge, 29,257 mol of high energy phosphate/gram of cells
What is a proton motive force?
Protons are exported across the inner membrane to generate the proton motive force (PMF) that provides energy for the enzyme ATP synthase to make ATP
What is the composition of ATP synthase?
Two large complexes (F0 and F1)
F0 forms a proton channel
F1 is on the interior
How does ATP synthase work?
1) Passage of 3-4 protons from the exterior to the interior through F0 and rotates the axle
2) Rotation of the axle drives F1 to form one ATP molecule from ADP
3) Reaction can occur in either direction dependent of the concentration of ATP and ion gradient
Phospholipids comprise how much of the cell?
9% of cell’s dry weight
LPS comprise how much of the cell?
3.4%
DNA comprise how much of the cell?
3%
Goal of fermentation?
regenerate NAD+
