Redox Reactions Flashcards
What type of reaction allows for energy flow through living systems?
Redox reactions
Describe oxidation
Occurs when an atom or molecule loses and electron (hydrogen atom) (LEO)
Describe reduction
Occurs when an atom or molecule gains an electron (hydrogen atom) (GER)
Give two examples of redox reactions
In photosynthesis, carbon dioxide is reduced to glucose. In cellular respiration, glucose is oxidized to create ATP
Describe phototrophs
Green plants and algae can make glucose using light energy (“light-using self feeders). Also known as autotrophs
Describe heterotrophs
Organisms that feed on other organisms to obtain chemical energy (“other-feeders”)
Describe chemoautotrophs
Exceptions to phototrophs and heterotrophs. They can create food without using light. These “chemical self-feeders” are usually extremophiles
What do all organisms use as a primary source of energy?
Glucose
Give the equation for the oxidation of glucose
C6H12O6 + 6O2 —> 6CO2 + 6H2O + Energy
By what process do cells obtain chemical energy from food?
Aerobic cellular respiration through a series of enzyme-controlled redox reactions in which glucose is oxidized
Describe glucose oxidation
An exothermic reaction which allows cells to obtain energy from organic compounds. Covalent bonds in glucose are broken and rearranged into new and more stable configurations since they have less potential energy. Glucose is oxidized to CO2 and oxygen is reduced to water
Describe what happens to the free energy following glucose oxidation
Some of the free energy given off is trapped in the energy-carrying ATP molecules which can be used to power endothermic reactions that occur in the body. The rest is lost as heat to maintain body temperature
What enables glucose oxidation to occur quickly enough to meet the demands of the cell?
Enzymes
Describe NADH
Nicotinamide adenine dinucleotide. It is the primary coenzyme in the cell (without it the enzyme won’t work)
Describe how NAD+ is reduced
Two electrons and one proton (from the original glucose) attach to NAD+, reducing it to NADH, while the remaining proton dissolves into the surrounding solution as H+
What is the difference between NAD+ and NADH?
NAD+ is the oxidized form and is reduced to NADH + H+
What catalyzes the reduction of NAD+ to NADH?
Dehydrogenase
In which processes are NAD+ reduced?
Glycolysis, pyruvate oxidation, Kreb’s cycle
Where is NAD+ found?
In the cytoplasm and mitochondria
Give some facts about NAD+
Derivative of Vitamin B3 (cousin to niacin), antioxidant (kills free radicals that cause cancer), slows aging, has a positive effect on Alzheimer’s, Parkinson’s and depression
Draw a diagram of NAD+ and NADH
