Cellular Metabolism Flashcards
What is the first law of thermodynamics?
Energy can’t be created nor destroyed and can only be transformed form one form to another
What is the second law of thermodynamics?
Closed system moves towards increased disorder (entropy)
Why do living systems defy the second law of thermodynamics?
open systems maintain and increase their organization
what is the energy in a system available for dong work and is equal to energy in chemical bonds minus unusable energy?
Free energy
What reaction release free energy, is spontaneous and slow, and the system loses free energy (downhill)
Exergonic reactions
What reaction needs free energy to be added to the system, is uphill, and products have more energy than reactants and is powered by ATP in organisms?
Endergonic reactions
What is the energy needed to break chemical bonds and form reaction products?
Activation energy
True or False:
ALL reactions need activation energy to proceed
True
True or False:
Can increasing temperature provide activation energy?
True
What do organisms use that are chemical substances that accelerate reaction rates without being changed by the reaction and without affecting the products?
Catalysts
What are biological catalysts that reduce required activation energy for a reaction, does not supply activation energy and lower the activation energy barrier?
Enzyme
Most enzyme are?
Proteins
What suffix do enzyme names use?
-ase
What do some enzymes require to function?
Cofactors
What are cofactors?
small, non-protein groups and can be metallic ions or coenzymes
True or False:
RNA can have enzymatic activity
True
What RNA provides activation energy needed for translation?
Ribosomal RNA (rRNA)
True or False:
Small RNA fragments in bacteria can recognize and digest viral DNA
True
How does an enzyme function?
associating with its substrate
What is formed when a substrate binds with an enzyme?
Enzyme-substrate complex
True or False:
enzymes that are involved in energy-providing cellular reactions are CONSTANTLY active and operate in sets
True
Enzymes have a a high…
High specifity
True or False:
enzyme catalyzed reactions are reversible
True
True or False:
Reactions tend to go predominantly in one direction
True
What does the net direction depend on?
The energy content of the substances involved
Enzymes can be regulated in terms of?
Quantity and activity
True or False:
Genes related to enzyme synthesis can be switched on or off
True
True or False:
enzymes may be activated or inhibited by the presence or concentration of certain molecules
True
What is the final product of a metabolic pathway that inhibits the first enzyme in said pathway?
Feedback inhibition
True or False:
Many enzymes have active and inactive forms
True
What is the energy currency of all organisms?
Adenosine Triphosphate (ATP)
ATP provides free energy to enzymes requiring reactions by serving as?
An intermediate in coupled reactions
ATP components:
adenine and ribose sugar
Adenosine
ATP components:
consists of 3 phosphate groups connected by high energy phosphoanhydride bonds
Triphosphate group
Is ATP an energy-coupling agent or a fuel?
Energy-coupling agent
All cells obtain their energy from?
Oxidation-reduction reactions (redox)
What is redox?
transfer of electrons from electron donor (reducing agent) to electron acceptor (oxidizing agent)
What happens to the electron donor when it LOSES electrons?
becomes oxidized
What happens to the electron acceptor when it GAINS electrons?
becomes reduced
What does the flow of electrons through a series of carrier molecules produce?
ATP
What is the last molecule to be reduced in the chain that also determines the efficiency of cellular metabolism?
Final electron acceptor
What are heterotrophs?
organisms that can’t synthesize their own food and must obtain from external sources
What heterotroph uses molecular oxygen as its final electron acceptor?
Aerobes
What heterotroph use a different molecule as the final electron acceptor?
Anaerobes
True or False:
aerobic metabolism is more efficient than anaerobic metabolism
true
How much more energy is recovered when oxygen is used as the final acceptor (aerobic)
20x
What stage of cellular respiration has the food in the intestines broken down into small molecules that can be absorbed into the blood stream but has no useful energy yield?
Stage I - Digestion
What stage of cellular respiration occurs in the cytoplasm (glycolysis) and mitochondria (pyruvic acid conversion) and where most of the glucose is converted into 3-carbon units (pyruvic acid) in the cytoplasm, Acetyl-CoA is formed, and a small amount of ATP is produced?
Stage II - Small molecules to Acetyl-CoA
What stage of cellular respiration occurs entirely in the mitochondria and the acetyl-CoA is channeled into the krebs cycle, the acetyl group is completely oxidized to CO2, the electrons released from the acetyl groups travel to carriers that pass them along ETC and the accepted electrons are accepted by oxygen at the end of the chain forms H2O?
Stage III - Final oxidation of fuel molecules
What is the overall reaction of cellular respiration?
Glucose + 2 ATP + 36 ADP + 36 P + 6 O2 > 6CO2 + 2 ADP + 36 ATP + 6 H2O
