Chapter 5 Flashcards
Collection of biochemical reactions, ultimate function is reproduction
Metabolism
Every cell ______ nutrients
Acquires
Metabolism requires energy from __________
light or nutrients
Energy is stored in ___________
Adenosine Triphosphate (ATP)
Cells _______ nutrients to form ________
Catabolize
Precursor metabolites
Precursor metabolites, energy from ATP, and enzymes are used in ____________
anabolic reactions
Enzymes plus ATP form
Macromolcules
Cells _______ once they have reached a critical mass
Reprodue
_______: exgeronic, break larger molecules into smaller products
Catabolic Pathways
________: endergonic, synthesize large molecules from thee smaller products of catabolism
Anabolic pathways
Oxidation and reduction (redox) reaction
- Transfer of electrons from an electron donor to an electron acceptor
- Reactions always occur simultaneously
Oxidation (3 Methods)
- Lose an electron
- Lose a hydrogen
- Gain an oxygen atom
Cells use electron carriers to carry electrons
Hydrogen often assists in the e- transfer
Nicotinamide adenine dinucleotide (NAD+ —–>
NADH
Nicotinamide adenine dinucleotide phosphate (NAD+) —>
NADPH
Flavine adenine dinucleotide (FAD) ——>
FADH2
Organisms release energy from nutrients, which is harnessed, and stored in high-energy phosphate bonds
ATP
__________: inorganic phosphate is added to substrate
phosphorylation
Cells phosphorylate ADP to ATP in 3 ways
- Substrate-level phosphorylation
- Oxidative phosporylation
- Photophosphorylation
The roles of Enzmes in metabolism
Enzymes are organic catalysts of chemical reactions
hydrolysis
Hydrolases
Rearrange atoms within a molecule
isomerases
anabolic (builds)
Ligases or polymerases
Spitting molecules without H2O
Lyases
Transfers e- or H to another molecule
Oxidoredyctases
Move a functional group to another molecule
Transferase
inactive proteins which require a cofactor to function (inorganic ions or coenzymes)
Apoenzymes
vitamins not synthesized by organism
Coenzymes
binding of apoenzyme and its cofactor yeild ________ an active enzymes
Holoenzymes
non protein enzymes some are RNA molecules called
Ribozymes
Activity of enzyme depends on closeness of fitt. upon activation, enzymes undergo an _______ for enzymes-substrate specificity
induce fit
The process of enzymatic activity
- Enzymes and substrate interact
- Enzymes substrate complex
- product released
- bonds are formed or broken
- enzymes reused
Enzymatic reaction influenced by
Temperature
pH
Enzyme and substrate concentration
Presense of inhibiotors
inhibitors
Substances that block an enzyme’s active site
do not denature enzymes
Molecules with a similar configuration can act as ______ which can outcompete for an enzymes active site
Inhibitors
________________ Binds at an allosteric site
Non-competive inhibitor
In excitatory allosteric control, an activator molecule bind to the allosteric site, causing the active site to change shape,____________________.
Activating an inactive enzymes
the end product of some metabolic pathways can result in
feedback inhibition
enzymes catabolize carbohydrates (ex Glucose) to harvest energy is 2 processes
- Cellular respiration
- Fermentation
Respiration includes gylcolysis , krebs cycle and electron transport to
oxidize pyruvic acid into CO2 and H20
Fermentation invovles gycolysis and pyruvic acid is
net completely oxidized
Glycolysis
occurs in cytoplasm of most cells
involves splitting of six carbon glucose into 2 pyruvic acids (3 carbon molecule) storing energry in ATP
3 stage of glycolysis involving 10 steps
Energy investment stage
lysis stage
energy conserving stage
Result of gylcolysis
Is net gain of 2 ATP molecules, 2 NADH and 2 Pyruvic acids molecules
Cellular respiration pyruvic acid products them completely oxidied to produce ATP by serier of redo reactions in cellular respiration or
in fermentation pyruvic acid incompletely oxidized
three stages of cellular respiration
- Synthesis of acetyl-CoA
- Krebs cycle
- Final series of redox reactions (electron transport chain)
Synthesis of acetyl-CoA
2- acetyl-CoA
2 CO2
2 NADH
up energy remains in bonds of acetyl CoA
energy form acetly-CoA transferred to coenzymes NAD+ and FAD
occurs in cytosol of prokaryotes and in matri of mitochondria in eukaryotes
The Krebs cycle
Kred cycle results in
2 ATP, 2 FADH2, 6 NADH, 4 CO2
MOst ATP is produced from serier of redox reactions known as an
Electron transport chain (ETC)
Energy from electrons used to pump protons (H+) across the membrane, ______________________.
establishing a prton gradient
Ectrochemical gradient to generat ATP
Chemiosmosis
Cells use __________ in redox reactions of ETC to creat proton gradient
Energy released
Protons flow down electrochemical gradient through ATP synthases that _____________________
Phospharylation ADP to ATP
total of - ____ ATP formed from one molecule of glucose
34
Integral membrane proteins which conatain flavin
Flavoprotein
Lipid soluble electron carriers
Ubiquinones
Intergral proteins w/ metal
Metal containing proteins
Intergral proteins associated w/ heme
Cytochromes
oxygen serves as fina electron accepto
Aerobic respiration
MOlecules other then oxygen serves as final electron acceptor
Anaerobic respiration
Alternatives to glycolysis
Yield fewer ATP than glyciysis
reduce coenzymes and yeild different metabolites needed in anabolic pathways
Uses pentse
Pentose phosphate pathways
Uses different enzymes than in glycolysis
Enter-doudoroff pathway
used if cells cannot completely oxidize glycose by cellular respiration
Fermentation
Cells require constant source of NAD+
connot be obtained usig glycolysis and kreb cycle
Ferminention provide cells with alternate source of NAD+
Partial oxidation of sugar to release energy using an organic molecule from witin the cell as final electron acceptor
