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224 Cards in this Set
- Front
- Back
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Integral protein
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Spans the membrane from one side to the other.
One end must be hydrophilic on outside (polar amino acid) and hydrophilic inside lipid portion of membrane (non-polar amino acid). |
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Is the amino acid side of the membrane polar or nonpolar?
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Polar (hydrophilic)
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Six major functions of membrane proteins
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Transport
Enzymatic activity Signal transduction Cell-cell recognition Intercellular Joining Attachment to the cytoskeleton and extracellular matrix (ECM) |
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What plays the main role in cell to cell recognition?
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Carbohydrates
Cells recognize each other by binding to surface molecules, often containing carbohydrates, on the extracellular surface of the plasma membrane Membrane carbohydrates may be covalently bonded to lipids (forming glycolipids) or more commonly to proteins (forming glycoproteins) Carbohydrates on the external side of the plasma membrane vary among species, individuals, and even cell types in an individual |
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The cell membrane is made where?
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Golgi Apparatus
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What happens when more cell membrane is produced but the cell is not growing?
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The cell will maintain homeostasis, excreting cell membrane at same rate of creation of cell membrane
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What makes a molecule hydrophobic?
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It being non-polar (and reverse, hydrophilic = polar)
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What molecules can pass easily through the plasma membrane?
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Hydrophobic (nonpolar) molecules, such as hydrocarbons, can dissolve in the lipid bilayer and pass through the membrane rapidly
• Polar molecules, such as sugars, do not cross the membrane easily |
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Are hydrocarbons polar or non-polar?
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Non-polar
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Are sugars polar or non-polar?
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Polar
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How do selected polar molecules pass through the membrane?
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• Transport proteins allow passage of hydrophilic substances across the membrane
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Channel proteins
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Some transport proteins, called channel proteins, have a hydrophilic channel that certain molecules or ions can use as a tunnel
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What are the channel proteins that allow water to pass through the membrane?
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• Aquaporins
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How do carrier proteins take molecules across the membrane?
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• They bind to molecules and change shape to shuttle them across the membrane
• A transport protein is specific for the substance it moves |
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What is Diffusion?
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the tendency for molecules to spread out evenly into the available space
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How do substances diffuse?
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• Substances diffuse down their concentration gradient, the region along which the density of a chemical substance increases or decreases
• No work must be done to move substances down the concentration gradient • The diffusion of a substance across a biological membrane is passive transport because no energy is expended by the cell to make it happen |
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What is Tonicity?
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The ability of a surrounding solution to cause a cell to gain or lose water
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What is the lysing of red blood cells called?
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Hemolysis (do to increased volume and bursting of cell)
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What is the difference between plant and animal cells with hypo and hypertonic solution?
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Hypertonic: Animal cell will eventually lyse.....plant cell will become turgid (due to cell wall expansion until pressure gradient)
Isotonic: Animal cell = normal ........plant cell = flaccid Hypotonic: Animal cell = shriveled ......... Plant cell = plasmolyzed |
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Why does a plant cell not lyse when the cell wall can no longer expand?
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An equilibrium is created by the cell wall due to pressure (not tonicity), once the cell wall expansion is reached (like a balloon) the pressure gradient causes equilibrium even when the tonicity is still unequal
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With carrier proteins, is the concentration gradient required?
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Yes, the carrier proteins are necessary to pass, but the flow is still with the concentration gradient.
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Plasmodesmata
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Microscopic channels which traverse the cell walls of plant cells and some algal cells, enabling transport and communication between them
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Active transport requires?
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Energy (Na / K exchange pump of animals is good example)......movement of molecules against the gradient
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Where do the Na and K go in the exchange pump?
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Na out of cell / K into cell
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Which of the following require energy: Diffusion, facilitated diffusion, active-transport?
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Only active transport
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What do Na/K exchange pump maintain?
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The membrane potential
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What is Membrane potential?
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the voltage difference across a membrane
• Voltage is created by differences in the distribution of positive and negative ions across a membrane |
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What is the electrochemical gradient?
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• Two combined forces, collectively called the electrochemical gradient, drive the diffusion of ions across a membrane
1. A chemical force (the ion’s concentration gradient) 2. An electrical force (the effect of the membrane potential on the ion’s movement) |
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What is a electrogenic pump?
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A transport protein that generates voltage across a membrane
• Electrogenic pumps help store energy that can be used for cellular work |
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What is a major animal Electrogenic pump?
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sodium-potassium pump
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What is a main electrogenic pump of plants, fungi, and bacteria?
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Proton pump (transporting protons....Hydrogen)
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What is Cotransport?
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Occurs when active transport of a solute indirectly drives transport of other solutes
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What is an example in plants of Cotransport?
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Plants commonly use the gradient of hydrogen ions generated by proton pumps to drive active transport of nutrients into the cell (eg. Sucrose)
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What is bulk transport?
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transport across the plasma membrane by exocytosis and endocytosis
• Large molecules, such as polysaccharides and proteins, cross the membrane in bulk via vesicles • Bulk transport requires energy • Small molecules and water enter or leave the cell through the lipid bilayer or via transport proteins |
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What is exocytosis?
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transport vesicles migrate to the membrane, fuse with it, and release their contents
Many secretory cells use exocytosis to export their products |
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What is endocytosis?
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transport vesicles migrate to the membrane, fuse with it, and release their contents
Many secretory cells use exocytosis to export their products |
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What is receptor-mediated endocytosis?
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Binding of ligands to receptors triggers vesicle formation
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What is a ligand?
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Any molecule that binds specifically to a receptor site of another molecule
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What are the three types of endocytosis?
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1. Phagocytosis (“cellular eating”) – large particles (“food” or other particle into a vacuole)
2. Pinocytosis (“cellular drinking”) – small intake into a vesicle 3. Receptor-mediated endocytosis – ligands/receptors into coated vesicle internalizing of the molecule received |
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What is phagocytosis?
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When a cell engulfs a particle in a vacuole
The vacuole fuses with a LYSOSOME to digest the particle |
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What is Metabolism?
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The totality of an organism’s chemical reactions (both building up and tearing down)
• Metabolism is an emergent property of life that arises from interactions between molecules within the cell |
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What are Catabolic pathways?
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The release of energy by breaking down complex molecules into simpler compounds
• Cellular respiration, the breakdown of glucose in the presence of oxygen, is an example of a pathway of catabolism |
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What are Anabolic pathways?
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The consuming of energy to build complex molecules from simpler ones
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What is an example of anabolic pathways?
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The synthesis of protein from amino acids is an example of anabolism
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What is Bioenergetics
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the study of how organisms manage their energy resources
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Define Energy
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the capacity to cause change
(Energy exists in various forms, some of which can perform work) |
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What is Kinetic energy?
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energy associated with motion
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What is thermal energy?
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Heat....which is kinetic energy associated with random movement of atoms or molecules
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What is Potential energy?
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energy that matter possesses because of its location or structure (eg. Ball on hill)
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What is Chemical energy?
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Potential energy available for release in a chemical reaction
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What is Thermodynamics?
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The study of energy transformations
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Are Organisms open systems or isolated systems?
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Open systems
• isolated system, such as that approximated by liquid in a thermos, is isolated from its surroundings • In an open system, energy and matter can be transferred between the system and its surroundings |
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First law of thermodynamics
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Energy can be transferred and transformed, but it cannot be created or destroyed
(also called the principle of conservation of energy) |
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Is ALL the energy transferred in energy transfer?
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No, some energy is unusable, and is often lost as heat
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What is entropy?
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Disorder
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Second law of thermodynamics
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Every energy transfer or transformation increases the entropy (disorder) of the universe
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What tells us whether or not the reaction occurs spontaneously?
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The free-energy change of a reaction
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What is free energy?
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(ΔG ) Energy that can do work when temperature and pressure are uniform, as in a living cell
Measure of a system’s instability, its tendency to change to a more stable state |
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What change in free energy (∆G) is spontaneous?
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Only processes with a negative ∆G are spontaneous
Spontaneous processes can be harnessed to perform work • During a spontaneous change, free energy decreases and the stability of a system increases • A process is spontaneous and can perform work only when it is moving toward equilibrium |
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Exergonic reaction
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proceeds with a net release of free energy and is spontaneous (- ∆G)
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Endergonic reaction
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absorbs free energy from its surroundings and is nonspontaneous (+∆G)
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How does ATP power cellular work?
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Coupling exergonic reactions to endergonic reactions
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What three main kinds of work does a cell do?
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– Chemical
– Transport – Mechanical |
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ATP components
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Sugar, phosphate, nitrogenous base........ = nucleotide
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What is energy coupling?
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the use of an exergonic process to drive an endergonic one
To do work, cells manage energy resources by energy coupling • Most energy coupling in cells is mediated by ATP |
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How is energy made with ATP?
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• ATP drives endergonic reactions by phosphorylation; transferring a phosphate group to some other molecule, such as a reactant
The bonds between the phosphate groups of ATP’s tail can be broken by hydrolysis • Energy is released from ATP when the terminal phosphate bond is broken |
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Does the release in energy come from the phosphate bonds themselves?
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No, from the chemical change to a state of lower free energy
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What is the recipient molecule of the phosphate group called?
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Phosphorylated intermediate
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What types of work are involved with ATP?
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• The three types of cellular work (mechanical, transport, and chemical) are powered by the hydrolysis of ATP
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How does the Hydrolysis of ATP Perform Work?
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• In the cell, the energy from the exergonic reaction of ATP hydrolysis can be used to drive an endergonic reaction
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Overall, are the coupled reactions of ATP endergonic or exergonic?
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Exergonic
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Where does energy to phosphorylate ADP comes from?
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Catabolic reactions in the cell
• The ATP cycle is a revolving door through which energy passes during its transfer from catabolic to anabolic pathways |
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Describe ATP as a renewable resource.....
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Regenerated by addition of a phosphate group to adenosine diphosphate (ADP)
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In the ATP cycle, energy for making ATP from ADP is ____ from ____ while energy for cellular work is _____?
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Exergonic (energy-creating), catabolism ........endergonic (energy-consuming)
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Describe the example of enzymatic breakdown of Sucrose?
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Sucrose + H2O → Sucrase → Glucose and Fructose
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Hydrolysis of Sucrose by enzyme Sucrase is an example of an ___?
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Enzyme catalyzed reaction
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Every chemical reaction between molecules involves ____ and ____.
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bond breaking and bond forming
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Do Enzymes affect the change in free energy (∆G)?
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No, instead, they hasten reactions that would occur eventually (not a change in product)
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What is activation energy?
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The initial energy needed to start a chemical reaction is called the free energy of activation, or activation energy (EA)
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Activation energy is often supplied in the form ____.
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Thermal energy that the reactant molecules absorb from their surroundings
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How do Enzymes catalyze reactions?
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By lowering the EA barrier
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What is enzyme’s substrate?
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The reactant that an enzyme acts on
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Enzyme-substrate complex
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What is formed when the enzyme binds to its substrate.
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What is the active site?
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The region on the enzyme where the substrate binds
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What is induced fit?
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The fit of a substrate brings chemical groups of the active site into positions that enhance their ability to catalyze the reaction
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What binds to what in an enzymatic reaction?
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The substrate binds to the active site of the enzyme
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The active site can lower an EA barrier by?
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– Orienting substrates correctly
– Straining substrate bonds – Providing a favorable microenvironment – Covalently bonding to the substrate |
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An enzyme’s activity can be affected by?
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– General environmental factors, such as temperature and pH
– Chemicals that specifically influence the enzyme |
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What is important about the optimal conditions of an enzyme?
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• Each enzyme has an optimal temperature in which it can function
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Optimal conditions (pH and Temp) of enzyme favor the most ____.
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Active shape for the enzyme molecule
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What are enzyme Cofactors?
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NONPROTEIN enzyme helpers (normally non-organic (metal ion) but can be organic)
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An organic cofactor is called a ____?
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Coenzyme (include vitamins)
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Cofactor and Coenzyme
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Coenzyme is a cofactor.
Cofactor = any Nonprotein enzyme helper Coenzyme = organic cofactor |
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What are Competitive inhibitors?
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Inhibitors that bind to the active site of an enzyme, competing with the substrate
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What are Noncompetitive inhibitors?
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Inhibitors that bind to another part of an enzyme, causing the enzyme to change shape and making the active site less effective
(Examples of inhibitors include toxins, poisons, pesticides, and antibiotics) |
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What is the Vmax?
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The point at which a protein cannot act any faster (every time a reaction is finished, another substrate is available to be reacted with, and the protein is in use again....represented by the flat lie after the curve)
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What is the Km?
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The half way point to the Vmax
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Evolution of enzymes (relation to genes)
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• Enzymes are proteins encoded by genes
• Changes (mutations) in genes lead to changes in amino acid composition of an enzyme • Altered amino acids in enzymes may alter their substrate specificity • Under new environmental conditions a novel form of an enzyme might be favored |
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What is a way to control the enzyme?
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• A cell switching on or off the genes that encode specific enzymes or by regulating the activity of enzymes
• Chemical chaos would result if a cell’s metabolic pathways were not tightly regulated |
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How are substrates held in active site of enzyme?
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By weak interactions
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Allosteric regulation
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-Occurs when a regulatory molecule binds to a protein at one site and affects the protein’s function at another site
-Either inhibit or stimulate an enzyme’s activity |
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What are most allosterically regulated enzymes made from?
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polypeptide subunits
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Each enzyme has ___ and ___ forms.
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Active and inactive
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What does the binding of an activator do?
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Stabilizes the active form of the enzyme
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What does the binding of an inhibitor do?
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Stabilizes the inactive form of the enzyme
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Where does the activator fit into?
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The regulatory site
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What is Cooperativity?
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A form of allosteric regulation that can amplify enzyme activity
• One substrate molecule primes an enzyme to act on additional substrate molecules more readily |
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Why is Cooperativity considered allosteric?
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Because binding by a substrate to one active site affects catalysis in a different active site
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Why are allosteric regulators attractive drug candidates for enzyme regulation?
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Because of their specificity
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What are caspases?
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proteolytic enzymes (protein –breakdown-ers ......polypeptides to peptides)
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What can inhibiting caspases do?
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It may help management of inappropriate inflammatory responses
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What is feedback inhibition?
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The end product of a metabolic pathway shuts down the pathway
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How does feedback inhibition prevent a cell from wasting chemical resources?
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Keeps it from synthesizing more product than is needed
The final product binds to the allosteric site (back) of the enzyme, inhibiting it from reacting with more substrate |
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How do structures within the cell help bring order to metabolic pathways?
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• Some enzymes act as structural components of membranes
• In eukaryotic cells, some enzymes reside in specific organelles; for example, enzymes for cellular respiration are located in mitochondria |
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Model of Ecosystem circle.
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Light energy → Photosynthesis → produce organic molecules and O2 → Cellular Resp. in Mitochondria (make ATP for work) → byproduct = CO2 and H2O → combines with light energy back to Photosynthesis
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How do Catabolic pathways yield energy?
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By oxidizing organic fuels
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Some redox reactions do not transfer electrons but ____.
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Change the electron sharing in covalent bonds
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What is an example of redox reactions not transferring e- but sharing in covalent bonds?
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Methane (CH4 and O2)
CH4 + 2O2 → CO2 + energy + 2 H2O |
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During cellular respiration, the fuel (such as glucose) is ____, and O2 is _____.
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Oxidized (to CO2)......reduced (to H2O)
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Electrons from organic compounds are usually first transferred to ___.
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NAD+, a coenzyme
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As an electron acceptor, NAD+ functions as an _____ during cellular respiration.
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oxidizing agent
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Each NADH (the reduced form of NAD+) represents ____.
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stored energy that is tapped to synthesize ATP
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What enzyme is used to help reduce NAD+?
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Dehydrogenase (take away hydrogen)
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Stages of Cellular Respiration?
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Glycolysis (breaks down glucose into two molecules of pyruvate)
-The citric acid cycle [Krebs] (completes the breakdown of glucose) -Oxidative phosphorylation [e- transport chain] (accounts for most of the ATP synthesis) |
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What does Glycolysis due?
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breaks down glucose into two molecules of pyruvate
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What does the citric acid cycle [Krebs] do?
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Completes the breakdown of glucose
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What do the first two stages of cellular respiration end in?
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substrate level phosphorylation
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What does oxidative phosphorylation [e- transport chain] do?
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Accounts for most of the ATP synthesis
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Which of the 3 stages of cellular respiration occur inside the mitochondria?
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2) citric acid cycle [Krebs] and (3) Oxidative phosphorylation [e- transport chain]
(1) Glycolysis occurs in cytoplasm |
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What stage is the only stage that ends in oxidative phosphorylation?
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The e- transport chain (the others are substrate level phosphorylation)
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Why is oxidative phosphorylation called “oxidative?”
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Because it is powered by redox reactions
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What process accounts for almost 90% of the ATP generated by cellular respiration
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Oxidative phosphorylation
• A smaller amount of ATP is formed in glycolysis and the citric acid cycle by substrate-level phosphorylation |
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For each molecule of glucose degraded to CO2 and water by respiration, the cell makes up to ____ molecules of ATP.
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32
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What does Glycolysis mean?
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“splitting of sugar” -- breaks down glucose into two molecules of pyruvate
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How many steps in Glycolysis?
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10
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What are the two major phases of Glycolysis?
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1. Energy investment phase (steps 1-5)
2. Energy payoff phase (steps 6-10) |
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Is Glycolysis anaerobic or aerobic?
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anaerobic
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After pyruvate is oxidized, the ____ completes the energy-yielding oxidation of organic molecules.
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Citric acid cycle (Krebs Cycle)
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Before the citric acid cycle can begin, ___ must be converted to ___, which links glycolysis to the citric acid cycle. (Intermediate step)
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Pyruvate........acetyl Coenzyme A (acetyl CoA)
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What catalyzes the three reactions that carry out the oxidation of Pyruvate to Acetyl CoA?
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A multi-enzyme complex
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What completes the break down of pyruvate to CO2?
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The citric acid cycle (Krebs cycle)
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What does the last seven (7/8) steps of the Krebs Cycle do?
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Decompose the citrate back to oxaloacetate (making the process a cycle)
Citrate → Oxalo-acetate |
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The ___ and ___ produced by the cycle relay electrons extracted from food to the electron transport chain.
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NADH and FADH2
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What does the Krebs cycle generate per turn?
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1 ATP
3 NADH 1 FADH2 (by oxidizes organic fuel derived from pyruvate) |
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How many steps does the Citric Acid Cycle have?
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Eight steps
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How many enzymes are used in the Krebs Cycle?
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8; one specific enzyme for step
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How is citrate formed in the cycle?
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The acetyl-group of acetyl CoA joins the cycle by combining with oxalo-acetate.
Citrate = acetyl (of acetyl CoA) + Oxylo-acetate |
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During oxidative phosphorylation, ____ couples ____ to ____.
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Chemiosmosis couples electron transport (Exergonic) to ATP synthesis (endergonic)
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Following glycolysis and the citric acid cycle, what accounts for most of the energy extracted from food?
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NADH and FADH2
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What are NADH and FADH2?
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Electron carriers
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What do NADH and FADH2 do?
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These two electron carriers donate electrons to the electron transport chain, which powers ATP synthesis via oxidative phosphorylation
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Where is the electron transport chain located?
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In the inner membrane (cristae) of the mitochondrion
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How is oxidative phosphorylation powered?
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Via ATP synthesis
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What is most abundant enzyme on the planet?
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Rubisco
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What composes most of the chain’s components?
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Proteins, which exist in multiprotein complexes
• (The carriers alternate reduced and oxidized states as they accept and donate electrons) |
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Does free energy go up or down as you go down the transport chain?
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DOWN (it is exergonic)
Electrons drop in free energy, finally passed to O2, forming H2O |
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What is the last place the e- is transferred to before oxidation?
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Cytochrome oxidase
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What is Chemiosmosis?
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The Energy-Coupling Mechanism
• the use of energy in a H+ gradient to drive cellular work |
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What is caused when Electrons are transferred in the electron transport chain?
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Proteins to pump H+ from the mitochondrial matrix to the inter-membrane space
• H+ then moves back across the membrane, passing through the proton, ATP synthase (enzyme) |
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How does ATP synthase uses drive phosphorylation of ATP?
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Uses the exergonic flow of H+
• This is an example of chemiosmosis, the use of energy in a H+ gradient to drive cellular work |
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What happens if an FADH2 comes in at a wrong place (a second step instead of the first)?
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Less ATP is produced (it missed the opportunity for H+ ions).
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The energy stored in a H+ gradient across a membrane couples ___ to ____.
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The redox reactions of the electron transport chain to ATP synthesis
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What is the H+ gradient is referred to as ___?
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A proton-motive force, emphasizing its capacity to do work
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What is the general flow of energy during cellular respiration?
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glucose → NADH → electron transport chain → proton-motive force → ATP
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How much the energy in a glucose molecule is transferred to ATP during cellular respiration? How effective is Cellular Respiration? %
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About 34%, making about 32 ATP (like an engine, only 25% of energy is effective)
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Is the number of ATP is known exactly?
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No
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Brown fat
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Hibernating animals have it
Babies have it (to keep them warm) but loose it when the get older Some think that adults still have some Produces heat instead of ATP through “uncoupling,” uncoupling H+ LESS ATP is produced, but the animal does not need it as its metabolism is low |
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What happens when no O2 is available?
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In that case, glycolysis couples with fermentation or anaerobic respiration to produce ATP
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What are 2 common types of fermentation?
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• Two common types are alcohol fermentation and lactic acid fermentation
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What does the process of Fermentation consist of?
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Fermentation consists of:
glycolysis + reactions that regenerate NAD+, which can be reused by glycolysis |
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Why does glycolysis need NAD+?
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It needs a place to put the electron to continue the chain
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What is the oxidizing agent in Fermentation, aerobic and anaerobic metabolism?
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NAD+ (it accepts the e-)
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Is Glycolysis used in all 3: Fermentation, aerobic and anaerobic metabolism?
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Yes, glycolysis (net ATP =2) to oxidize glucose and harvest chemical energy of food
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Is the final e- acceptor the same in fermentation and cellular respiration?
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No.
Fermentation = An organic molecule (such as pyruvate or acetaldehyde). Cellular respiration = O2. |
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What is the difference in ATP production in Cellular respiration vs Fermentation?
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Cell. Resp. = 32 ATP per glucose molecule.
Fermentation = 2 ATP per glucose molecule. |
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Relationship between obligate anaerobes and O2.
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Obligate anaerobes carry out fermentation or anaerobic respiration and cannot survive in the presence of O2
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What are facultative anaerobes?
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They can survive using either fermentation or cellular respiration (like yeast and many bacteria).
In a facultative anaerobe, pyruvate is a fork in the metabolic road that leads to two alternative catabolic routes |
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What is the evolutionary significance of Glycolysis?
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Prokaryotes are thought to have used glycolysis long before there was oxygen in the atmosphere (Very little O2 was available in the atmosphere until about 2.7 billion years ago, so early prokaryotes likely used only glycolysis to generate ATP) - Glycolysis is a very ancient process
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Why are glycolysis and the citric acid cycle important to other metabolic pathways?
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Gycolysis and the citric acid cycle are major intersections to various catabolic and anabolic pathways
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How many calories do fats produce per gram?
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9
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How many calories do carbs produce per gram?
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4
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Diamination means?
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The removal of Nitrogen before metabolism (entrance into the citric acid cycle)
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Key enzyme to feedback inhibition?
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Phosphate Fructokinase (inhibited by ATP)
• Control of catabolism is based mainly on regulating the activity of enzymes at strategic points in the catabolic pathway |
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What is the most common mechanism for control?
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Feedback inhibition
• If ATP concentration begins to drop, respiration speeds up; when there is plenty of ATP, respiration slows down |
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What is Photosynthesis? (generally)
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the process that converts solar energy into chemical energy
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Explain what Autotrophs do?
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“self feeding”
They sustain themselves without eating anything derived from other organisms • Autotrophs are the producers of the biosphere, producing organic molecules from CO2 and other inorganic molecules • Almost all plants are photoautotrophs, using the energy of sunlight to make organic molecules |
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What is an Autotroph?
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An organism that can make nutritive organic molecules from inorganic sources via photosynthesis.
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in what organisms does Photosynthesis occur?
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In plants, algae, certain other protists, and some prokaryotes
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What is the opposite of autotrophs?
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Heterotrophs
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What are Heterotrophs?
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Heterotrophs obtain their organic material from other organisms
• Heterotrophs are the consumers of the biosphere • Almost all heterotrophs, including humans, depend on photoautotrophs for food and O2 |
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From where are Chloroplasts likely evolved?
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Photosynthetic bacteria (structurally similar to them)
• The structural organization of these cells allows for the chemical reactions of photosynthesis – they do photosynthesis exactly the same |
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What are the major locations of photosynthesis?
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Leaves (some plants have green stems as well...cacti use this model)
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Where does the green color come from?
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Chlorophyll
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What is Chlorophyll?
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The green pigment within chloroplasts (double membrane)
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Where are Chloroplasts mainly found?
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In cells of the mesophyll, the interior tissue of the leaf
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How many chloroplasts are contained in each mesophyll cell?
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c. 30–40
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Define stomata.
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Microscopic pores through which CO2 enters and O2 exits the leaf.
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What are Thylakoids
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connected sacs in the chloroplast
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Where is the chlorophyll found
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on the membranes of thylakoids.
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Thylakoids may be stacked in columns called ___.
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grana
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What are stroma?
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the connective, functionally supportive framework of a biological cell, tissue, or organ
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What do Stroma contain?
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DNA and rhibosomes
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Do Chloroplasts contain stroma?
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yes, a dense interior fluid
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What is the reaction of photosynthesis?
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6 CO2 + 12 H2O + Light energy → C6H12O6 + 6 O2 + 6 H2O
(the reverse is cellular respiration) |
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What is the reverse of the photosynthesis reaction?
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Cellular respiration
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What is Photolysis?
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Chloroplasts split H2O into H and O, incorporating the electrons of H into sugar molecules and releasing oxygen as a by-product (to produce ATP)
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Where does the atmospheric O2 come from?
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H2O (photolysis by the chloroplasts)
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Where does the carbon and oxygen of the sugar+water of photosynthesis come from?
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CO2
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Photosynthesis _____ the direction of electron flow compared to respiration?
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reverses
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Photosynthesis is a redox process in which H2O is ___ and CO2 is _____.
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Oxidized , reduced
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Photosynthesis is an endergonic or exergonic process?
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Endergonic........the energy boost is provided by light
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Photosynthesis consists of what 2 parts: the ___ (the photo part) and _____ (the synthesis part).
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light reactions, Calvin cycle
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Where do the light reaction occur?
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In the thylakoids
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What are the 4 photosynthesis light reactions?
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–Split H2O
–Release O2 –Reduce NADP+ to NADPH –Generate ATP from ADP by photophosphorylation |
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Main purpose of Light Reactions?
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Make ATP to power Calvin Cycle
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What is the final e- acceptor in the light reaction?
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NADP+
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What is the wavelength of light for Photosystem II (PS-II ...the 1st one)?
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680
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What is the wavelength of light for Photosystem I (PS-I...the 2nd one)?
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700
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Where does the Calvin Cycle happen?
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In the Stroma
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The Calvin cycle forms what using what?
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Makes: G3P --- Sugar (eventually)
From: CO2 (using ATP and NADPH) |
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How does the Calvin cycle begin?
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With CARBON FIXATION, incorporating CO2 into organic molecules
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Purpose of Calvin Cycle?
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G3P production [aka GADP] (which makes carbs.....eg. glucose, cellulose, starch)
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What is G3P
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Glyceraldehyde 3-phosphate (GADP) - a chemical compound that occurs as an intermediate
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5. Every type of chemical bond contains a certain amount of energy. The total bond energy, which is essentially equivalent to the total potential energy of the system, is a quantity known as:
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enthalpy
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