Unit 3 Flashcards
Chapters 8-10
Bioluminescence
Process in which some organisms convert energy to light
Metabolism
The totality of an organism’s chemical reactions that allow for work and functionality
Catabolism
Metabolic pathways that release energy by disassembling complex molecules and breaking bonds
Anabolism
Metabolic pathways that consume energy from the environment so they can build complex molecules from smaller ones
Bioenergetics
The study of how energy flows through living organisms
Energy
The capacity to cause change and perform work
Chemical Energy
The energy available for release from a chemical reaction
Thermodynamics
The study of energy transformation
Kinetic Energy
The energy associated with motion
Thermal Energy
The random movement of atoms/molecules as a type of kinetic energy
Potential Energy
The energy matter possesses because of location and structure
Spontaneous Processes
Reactions that occur without energy input and naturally increase the disorder of the universe
Entropy
Disorder
The First Law of Thermodynamics
Energy can be transferred and transformed, but it cannot be created nor destroyed
The Second Law of Thermodynamics
Every energy transfer increases the entropy of the universe
Enthalpy
The total energy of a system (often heat)
Free Energy
The measure of a system’s instability and the likelihood of atomic motion and interaction. Reactions occur in order to reach a more stable state
Equilibrium
The state of maximum systematic stability. Once equilibrium is reached, no more work can occur
Exergonic Reactions
Reactions that proceed with a net release of free energy, spontaneous, negative delta G
Endergonic Reactions
Reactions that absorb free energy from their surroundings, nonspontaneous, positive delta G
Energy Coupling
The cells’ use of exergonic processes to drive endergonic ones and conserve energy
Phosphorylation
The transfer of a phosphate group to another molecule which changes the shape and function as well as releases energy when the phosphate group “pops” off
Phosphorylated Intermediate
The bound inorganic phosphate to its recipient molecule during phosphorylation
Catalyst
A chemical agent that speeds up a reaction without being consumed, and instead can be used multiple times
Activation Energy
The initial energy needed to start a chemical reaction often supplied as thermal energy (heat)
Substrate
The reactant(s) that an enzyme interacts/binds with
Enzyme-Substrate Complex
The bound substrate to its enzyme at the beginning of the reaction
Active Site
The region on an enzyme where the substrate binds to, it usually has an induced fit which orients the substrate in a way that enhances the enzyme’s ability to catalyze the reaction
Enzyme
A type of protein that lowers the activation energy for a reaction by orienting substrates correction, placing stress on substrate bonds, providing a closed microenvironment for the reaction to take place, and covalently binding to the substrate causing orbitals to hybridize.
Cofactor
A nonprotein enzyme that helps catalyze the reaction such as metals and vitamins
Coenzyme
An organic protein that assists the enzyme during catalysis
Competitive Inhibitors
When another molecule directly binds to the active site in place of the intended substrate
Noncompetitive Inhibitors
When another molecule binds to another part of the enzyme, changing its shape to where the substrate can no longer fit in the new shape of the active site
Allosteric Regulation
When a regulatory molecule binds to a protein and affects the protein’s shape and function at a different site. This is done controllably so through gene regulation
Cooperativity
When one substrate molecule’s binding primes the enzyme to act on additional substrate molecules which catalyze the substrates at a different site more effectively
Feedback Inhibition
When the end product of a metabolic pathway shuts down/ends further use of the pathway/enzyme for the time being. This prevents the cell from wasting resources since it only produces what is needed by the cell at that specific time
Aerobic Respiration
The consumption of organic molecules and oxygen to yield ATP for the cell
Anaerobic Respiration
The breakdown of large organic compounds ending with a final electron acceptor other than oxygen and producing water
Fermentation
The partial degradation of sugars that occurs without the presence of oxygen. Only glycolysis can occur, and it yields different products: ethanol and lactic acid
Cellular Respiration
The process by which cells break down large molecules into glucose and use those molecules of glucose to emit ATP, carbon dioxide, and water
Redox Reactions
The transfer of electrons during chemical reactions which releases stored energy
Oxidation
When a substance loses electrons
Reduction
When a substance gains electrons, its charge is being reduced (more negative)
Reducing Agent
The electron donor/molecule that is being oxidized
Oxidizing Agent
The electron acceptor/molecule that is being reduced
Electron Transport Chain
The passage of electrons through a series of steps which ultimately powers ATP synthesis
Substrate-Level Phosphorylation
Minor ATP production via a phosphorylated intermediate rather than inorganic phosphate (glycolysis and Krebs cycle)
Glycolysis
The splitting of glucose into 2 molecules of pyruvate which occurs in the cytoplasm and yields 2 ATP. This stage does not require O2
Krebs (Citric Acid) Cycle
The process in which pyruvate molecules are oxidized and large amounts of CO2 are emitted. 2 ATP are also yielded from the cycle and it requires O2 to regenerate NAD+ and occurs in the mitochondrial matrix
Pyruvate Oxidation
This step allows for pyruvate to cross into the mitochondria by being converted to acetyl coenzyme A
Oxidative Phosphorylation
The process in which most of the ATP is produced (26-28) via the electron transport chain. This step occurs within the mitochondrial cristae
Electron Carriers
Small organic molecules that alternate from reduced and oxidized states as they accept and donate electrons (NAD+ and FAD 2+)
Cytochromes
Proteins that include iron atoms and play an important role in electron transport because they act as a cofactor
Chemiosmosis
The use of energy from the H+ gradient to drive cellular work
ATP Synthase
The enzyme that acts as a hydraulic pump funneling electrons as they travel down the ETC and are received by oxygen, forming water which indirectly causes ADP to interact with inorganic phosphate and form large amounts of ATP
Proton-Motive Force
The H+ gradient’s ability to do work for the cell
Kinases
Enzymes involved with ATP/ADP phosphorylation
Isomerase
An enzyme that catalyzes reactions that create isomers
Photosynthesis
Process used by autotrophs to convert solar energy into chemical energy (ATP and sugars)
Autotrophs
Organisms that sustain themselves without eating other organisms by producing their own fuel/food
Heterotrophs
Organisms that obtain their energy from other organisms through consumption
Chloroplasts
The cellular organelle that organisms possess if they carry out photosynthesis (ex. plants and some prokaryotes)
Mesophyll Cells
The cells that make up the interior tissue of leaves
Stomata
Microscopic plant pores that can be opened or closed
Stroma
The “cytoplasm” of the chloroplast, dense fluid that is found between the thylakoids and the chloroplast’s double membrane
Thylakoids
The connected sacs found in the chloroplast that create a 3rd membrane system for photosynthesis to take place. Chlorophyll pigments are contained here
Grana/Granum
Stack/column of thylakoids
Chlorophyll
The pigment that gives leaves their green color by reflecting green light and absorbing other wavelengths in the form of photons
Light Reactions
Takes place in the thylakoids, splits water and releases oxygen, hydrogen ions from water reduce the NADP+ electron acceptor and ATP
Photophosphorylation
Process of using light (absorbed in the form of photons) to bounce chlorophyll electrons to an excited state and when they fall back down to stabilize the molecule, energy is released which drives the production of ATP via ATP synthase
Calvin Cycle
Occurs in the stroma, uses the ATP and NADPH formed in light reactions, incorporates CO2 into organic molecules (sugar) by process of carbon fixation
Photosystem
A biochemical mechanism that allows for the chlorophyll to absorb light for photosynthesis at different wavelengths
Reaction-Center Complex
Protein where chlorophyll is located and releases its excited electron to the primary electron acceptor (NADP+) within the membrane of the thylakoid
Light-Harvesting Complexes
Pigment molecules that transfer the energy of photons to the reaction-center complex
G3P
Glyceraldehyde-3phosphate; the product of carbon fixation which can be classified as a type of sugar molecule (stored energy)
Rubisco
The enzyme that catalyzes the Calvin cycle, must be regenerated
Photorespiration
A metabolic process in which rubisco adds oxygen instead of carbon dioxide to the Calvin cycle which wastes energy in the long run and produces a 2-C sugar instead
C4 Plants
Variety of plants that minimize photorespiration by incorporating CO2 into 4-C compounds (ex. maize, sugar cane)
Bundle-Sheath Cells
The tightly packed cells that surround the veins of the leaf
