energy, etc Flashcards
Bioenergetics is the flow-
energy through living systems
Life requires energy
Energy is transferred in living organisms via metabolic reactions
Metabolism is the total-
of all chemical reactions of the life process
Controlled by enzymes
Chemical reactions include forming, breaking, and re-arranging chemical bonds
Metabolic pathways are the
making or breaking of bonds
Anabolic pathways create bonds and build polymers
Consumes energy
Catabolic pathways break bonds and breaks down polymers to monomers
Releases energy
Thermodynamics is the study
energy and energy transfer
First Law of Thermodynamics
Energy can neither be created nor destroyed
Second Law of Thermodynamics
Energy in a system becomes less organized over time (entropy)
Energy input is required to maintain organization
Electro-Magnetic Energy
Light (visible spectrum & Non-visible (microwaves, uV, and infra-red)
Heat energy: is in the infra-red spectrum
Kinetic energy
Energy associated with work and motion of a system: sound & waves in the ocean
Potential energy
Stored energy in the system: compressed springs
Chemical energy
Potential energy stored in the atoms because of their positions in relation to other atoms (bonds)
Cells must
capture, store, and use energy to counteract the effects of the second law of thermodynamics
The reactions to maintain organization are not 100% efficient
Energy lost as heat
enzymes can
Enzymes speed up the reaction times by reducing the energy of activation
Enzymes control the speed and direction of the reaction
enzymes also
Enzymes binds to chemical reactants called substrates
Enzymes have highly specific locations, called active sites where the substrate binds.
metabolism and enzymes
Quantity of enzymes in a cell
Amount of energy
Inhibitors (competitive or noncompetitive)
Activators
Competitive inhibition is
when similarly shaped substrates can block the intended substrate from a enzyme
Some drugs and neurotoxins work this way
Allosteric molecules are commonly
Cofactors – inorganic ions such as iron, magnesium, and zinc
Coenzymes – organic molecules such as vitamins
Statins can
reduce cholesterol by inhibiting the enzyme that makes cholesterol from lipids in the body
Acetaminophen (Tylenol
inhibits cyclooxygenase
Cox inhibitors – fever and selling reducers
Metabolic or Biochemical pathways are
orderly sequences of chemical reactions, mostly catalyzed by enzymes
Biochemical pathways are composed of
ezymes that are components in the cells plasma membranes. (remember the endomembrane system)
Negative Feedback System
As the concentration of product increases the metabolic pathway is turned off
Use inhibitor molecules
Most common feedback system
Positive Feedback System
As the concentration of product increases the metabolic pathway is turned on
Use activator molecules
Least common feedback system
ATP is the source of energy for most metabolic pathways
Composed of adenine and ribose (adenosine) and three phosphate groups
One phosphate group is cleaved off to release energy (ADP)
Phosphate can be added on to store energy (ATP)
Cyclic
Cellular respiration
a catabolic pathway, uses chemical energy from food molecules to turn ADP back into ATP.
ATP turning into ADP provides the energy to do work for the organism
C6H12O6 + 6O2 → 6CO2 + H2O + Energy
Glucose + oxygen → carbon dioxide + water + ATP*
Photosynthesis occurs in two main stages
Light dependent reactions
Generate energy carriers ATP and NADPH
Light independent reactions
Create sugars via the Calvin Cycle
Pigments transfer the energy from the visible light spectrum
into usable energy for metabolic processes
There are primary and secondary pigments
Secondary pigments include:
Chlorophyll b, c, d, and e
Carotene a and b
Xanthophylls
Phycoerythrins
Phycoblins
Inside the chloroplasts are the thylakoid discs that
“capture” the visible light
They are studded with antenna complexes that are a combination of proteins and pigments.
Each complex can have a different combination of pigments
Light is used to break
water (H2O) which releases electrons into the 2 electron transport chain (ETC)
Products of ETS
Oxygen, 1 ATP, & 1 NADPH
Carbon dioxide fixation
utilizes carbon dioxide to produce carbohydrates
Photosynthesis – Light Independent Step 1
Carbon fixation by the enzyme RuBisCO
CO2 is attached to organic molecules (RuBP)
Photosynthesis – Light Independent step 2
Energy from light dependent reaction is used to create G3P (Glucose-3-Phosphate)
A Reduction Reaction
G3P is a three-carbon sugar
Used to remake RuBP and glucose
Photosynthesis – Light Independent step 3
RuBP is regenerated
It requires 6 turns of the Calvin cycle to make 1 glucose
Requires 36 ATP and 24 NADPH total
Calvin-cycle only plants are called
C3 plants
First product is a 3-carbon sugar
C4 and CAM plants have evolved
alternative forms of photosynthesis that create a 4-carbon sugar and reduce loss to photorespiration
Catabolism are Energy Releasing Reactions
Cellular Respiration
1)Glycolysis
2) Oxidation of Pyruvate
(Actyl Co- enzyme A)
3) Kreb’s Cycle (Citric Acid Cycle)
4) Electron Transport (ETS)
Energy consuming reaction-
Oxidative Phosphorylation
Photosynthesis is the process by
which light energy is used to make sugars from carbon dioxide and water; it generates oxygen gas as a by-product
Cellular respiration is the process
of releasing energy from food molecules to fuel cellular activities; it generates carbon dioxide and water as by-products.
Four main reactions of cellular respiration
Glycolysis
Oxidation of pyruvate
Citric acid cycle
Electron transport (ETS)
Anaerobic
An Nucleic acid is the H+ & electron acceptor