Chapter 12- Anabolism and Energy in Biosynthesis Flashcards
endergonic (input of chemicals or light energy from catabolism), reduction, catalyzed by enzyme, specific enzymatic regulation, use a carbon source and inorganic molecules, antibiotics inhibit anabolic pathway, lots of energy needed
principles of anabolism
cells would rather take in molecules than synthesize their own
regulation
continual degradation and resynthesis of cell constituents by non-growing cells
turnover
rate of turnover to be balanced by rate of biosynthesis, in response to an organisms environment
metabolism regulation
not all catabolic and anabolic pathways are identical because _______________
some enzymes only function in 1 direction
macromolecules synthesized from limited number of simple structural units, many enzymes play a role, large assemblies form spontaneously from macromolecules by self assembly
principles governing biosynthesis
located in separate compartments, simultaneous but independent pathways
physical separation of catabolic and anabolic pathways
catabolic pathways produce NADH, NADPH used as electron donor in anabolism
different cofactors of pathways
a critical generation in anabolism, carbon skeletons used as starting substrates, most used for biosynthesis of amino acids
precursor metabolites
____________ is the key molecule to biosynthesis of monosaccharides and polysaccharides
glucose
synthesis of glucose from other molecules (can be from phosphenolpyruvate)
gluconeogenesis
energy storage polysaccharides and structural polysacs are synthesized from _____________
active glucose
CO2 to organic carbon
carbon fixation
Who does carbon fixation?
photoautotrophs and chemolithotrophs
calvin cycle, reductive TCA cycle, hydroxypropionate cycle, acetyl CoA pathway, 3 hydroxypropionate
cycles that do carbon fixation
used by most autotrophs to fix CO2, reductive pentose phosphate cycle, performed in stroma of chloroplasts (eukaryotes), inclusion bodies may be the site of CO2 fixation
calvin cycle
What are the 3 phases of the Calvin Cycle?
(1) carboxylation phase
(2) reduction phase
(3) regeneration phase
What is the enzyme that catalyzes the carboxylation phase of the calvin cycle?
ribulose 1.5 bisphosphate carboxylase (rubisco)
3 phosphoglycerate reduced to glyceraldehyde 3 phosphate (generated by RuBP)
reduction and regeneration phase of Calvin Cycle
performed by some chemolithotrophs, reverse direction of oxidative TCA cycle
reductive TCA cycle
CO2 fixation cycle performed by some archaea, green non sulfur bacteria and anoxygenic phototrophs
hydroxypropionate cycle
methanogens use portions for carbon fixation, unusual enzymes and coenymes
reductive acetyl CoA pathway
What are some gluconegenic intermediates?
glucose, fructose, mannose
galactose is made from ______________
nucleoside diphosphate derivatives
bacteria and algae synthesize glycogen and starch from ________
ADP
chemeoheterotrophs can use endogenous or exogeneous amino acids, chemolithotrohps and photoautotrophs use only ________ sources
endogeneous
all microbes synthesize their own _______ for safety reasons
nucleotides
carbon skeletons from intermediates of glycolysis or Citric acid cycle, amino group from inorganic nitrogen source from environment
amino acid biosynthesis
addition of nitrogen to carbon skeleton is important step, potential storage of nitrogen (ammonia, nitrate, nitrogen from the environment), ammonia nitrogen easily incorporated because it is highly reduced
nitrogen assimilation
how can ammonia be directly incorporated into the carbon skeleton?
(1) transaminase activity from one AA to another
(2) glutamate dehydrogenase
(3) glutamine synthetase
used by bacteria to reduce nitrate to ammonia and then incorporated it into organic form, nitrate reduction to nitrite catalyzed by nitrate reductase
assimilatory nitrate reduction
used in bio molecule
assimilatory
not in bio molecule
dissimilatory
reduction of atmospheric nitrogen to ammonia, catalyzed by nitrogenase, only archaea and bacteria
nitrogen fixation
3 steps to reduce N2 to 2 molecules of NH3, large ATP expenditure, NH3 can be incorporated into organic compounds after reduction
mechansim of nitrogenase activity
sulfate reduced to H2S and used to synthesize cysteine, cysteine can be used to form sulfur containing organic compounds
assimilatory sulfur reduction
adeninie and guanine, cyclic nitrogenous bases of 2 joined rings
purines
uracil, cytosine, and thymine, cyclic nitrogenous bases of single ring
pyrimidines
found in proteins, nucleic acids, ATP and some coenzymes, inorganic phosphate and organic phosphate esters
phosphorus assimilation
incorporated in ATP formation in photophosphorylation, oxidative phosphorylation, and SLP
inorganic phosphate
present in environment in dissolved or particulate form, hydrolyzed by phosphatases, release Pi
organic phosphate esters
complex, several different moleclues contribute to final purine skeleton, initial products are ribonucleotides, deoxyribonucleotides formed by reduction of nucleoside
purine biosynthesis
start with asparic acida and carbamoyl phosphate, ribonucleotide are initial products, deoxyribonucleotides formed of uracil and cytosine fromed by reduction of ribose to deoxyribose
pyrimidine biosynthesis
major requirement component in cell membrane, most bacterial and eukaryal lipids contain fatty acids
lipid synthesis
from acetyl CoA, malonyl CoA, NADPH from fatty acids synthase, intermediates attached to acyl carrier protein, different ways to double bond
fatty acid synthesis
made from fatty acids and glycerol phosphate, some gram + bacteria can store carbon and energy as triacylglycerol
triglycerols
phosphatidic acid and addition of amino acid
phopholipids
