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34 terms

Biology chapter 4 - Chemical energy and ATP

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ATP
1) molecule that transfers energy from the breakdown of food molecules to cell processes.
2) carries chemical energy that cells can use.
3) energy carried by _____ is released when a phosphate group is removed
ADP
1) Lower energy molecule that can be converted into ATP by the addition of a phosphate group.
2) when a phosphate group is removed, energy is released and ATP becomes_______
chemosynthesis
Process by which some organisms use chemical energy instead of light energy to make energy storing carbon based molecules. __________organisms make their own food
Photosynthesis
a process that captures energy from sunlight to make sugars that store chemical energy
chlorophyll
a molecule in chloroplasts, that absorbs some of the energy in visible light. Plants have two types of these (a & b)
chloroplasts
membrane bound organelles where photosynthesis takes place in plants
grana & stroma
two main parts of chloroplasts needed for photosynthesis
thylakoids
stacks of coin shaped membrane enclosed compartments. membrane contains chlorophyll, or other light absorbing molecules, and proteins
stroma
the fluid that surrounds the grana inside a chloroplast
light dependent reactions
capture energy from the sunlight
1) chlorophyll absorbs energy from the sunlight. Energy is transferred along the thylakoid membrane. H2O molecules are broken down. Oxygen molecules are released
2) Energy carried along the thylakoid membrane
light independent reactions
use energy from light dependent reactions to make sugars. Main function is to capture and transfer energy
1) CO2 is added to a cycle of chemical reactions to build larger molecules.Energy from light dependent reactions is used in the reactions
2) A molecule of simple sugar is formed. The sugar (glucose) stores some of the energy that was captured from sunlight
equations for photosynthesis
6CO2 + 6H2O >>>>>>>>>>>C6H12O6 + 6O2
Carbon dioxide + water >>>light, enzymes >>a sugar + oxygen
Photosystems
Series of light absorbing pigments and proteins that capture and transfer energy in the thykaloid membrane
two photosystems
photosystems 1 & 2
Photosystem 2 & electron transport
1) energy absorbed from sunlight
2) Water molecules split
3) Hydrogen ions transported
Photosystem 1 & Energy carrying molecules
4) Energy is absorbed from sunlight
5) NADPH is produced when electrons is added to NADP
ATP production
6) Hydrogen ions diffuse through a protein channel
7) ATP produced. ADP is changed into ATP when hydrogen ions flow through ATP synthase
Summary of light dependent reactions
1) Energy is captured from sunlight by light absorbing molecules. Energy is transferred to electrons that enter an electron transport chain
2) water molecules are broken down into H+ ions, electrons, and oxygen molecules.
3) Energized electrons have 2 functions. They provide energy for H+ ion transport, they are added to NADP+ to form NADPH.
4) the flow of H+ ions through ATP synthase makes ATP
5) The products are oxygen, NADPH,a nd ATP. Oxygen is given off as a waste product. Energy from ATP & NADPH is used later to make sugars
The Calvin Cycle
Use carbon dioxide gas from the atmosphere and the energy carried by ATP and NADPH to make simple sugars
1) CARBON DIOXIDE IS ADDED - CO2 molecules are added to five-carbon molecules. Six-carbon molecules are formed
2) THREE-CARBON MOLECULES FORMED - Energy (ATP & NADPH) from the light dependent reactions is used by enzymes to split the six carbon molecules. Three-carbon molecules are formed and rearranged.
3) THREE-CARBON MOLECULES EXIT - most three-carbon molecules stays but one high energy three-carbon molecule leaves the cycle. After 2 three-carbon molecules have left the cycle, they are bonded together to build a six-carbon sugar molecule such as glucose.
4) THREE-CARBON MOLECULE RECYCLED - Energy from ATP molecule is used to change the three-carbon molecules back into the five-carbon molecules. The five-carbon molecules stays in the cycle. These molecules are added to the new CO2 molecules that enter the cycle
Summary of light independent Reactions
1) Carbon dioxide enters the Calvin cycle
2) ATP and NADPH from the light dependent reactions transfers energy to the Calvin cycle and keep the cycle going
3) One high-energy three-carbon molecule is made for every three molecules of carbon dioxide that enter the cycle
4) two high energy three-carbon molecules are bonded together to make sugar. Therefore, six molecules of carbon dioxide must be added to to the Calvin cycle to make one six-carbon sugar
5) the products are six-carbon sugar such as glucose, NADP+, and ADP. The NADP+ and ADP molecules return to the light dependent reactions.
Cellular respiration
Releases chemical energy from sugars and other carbon-based molecules to make ATP when oxygen is present
aerobic
Cellular respiration is an ______process. It needs oxygen to take place. Cellular respiration takes place in the mitochondria because they make the most of a cell's ATP
glycolysis
splits glucose into into two three-carbon molecules and make two molecules of ATP
anaerobic
process that does not require oxygen to occur
Krebs cycle
produces molecules that carry energy to the second part of cellular respiration. Takes place int eh interior space (matrix) of mitochondrion
Stage 1 :Krebs cycle & Stage 2 :Electron transport
KREBS CYCLE (STAGE 1)
1) three-carbon molecules from glycolysis are broken down in a cycle of chemical reactions. a small number of ATP molecules are made. Other types of energy-carrying molecules are also made. Carbon dioxide is given off as a waste product
2) Energy-carrying molecules transfer energy to stage 2
ELECTRON TRANSPORT (STAGE 2)
3) Energy is transferred to a chain of proteins in the inner membrane of the mitochondrion
4) ATP molecules are produced. heat and water are released as waste products.
up to 38 ATP molecules are made. 2 from glycolysis and 34 or 36 from cellular respiration
process of Glycolysis
1) 2 ATP molecules are used to energize a glucose molecule. the Glucose is split into two three-carbon molecules. A series of enzymes and chemical reactions rearranges the three-carbon molecules
2) Energized electrons from the three-carbon molecules are transferred to molecules of NAD+. Molecules of NADH are formed. A series of reactions converts the three-carbon molecules to pyruvate which enters cellular respiration. Four ATP molecules are made.

*glycolysis makes 4 ATP molecules from two ATP molecules used to first split the glucose molecule
The Krebs cycle (first main part of cellular respiration)
1) Pyruvate broken down
2) Coenzyme A bonds to the two-carbon molecule. This intermediate molecule enters the the Krebs cycle
3) Citric acid is formed
4) Citric acid is broken down and NADH is made
5)The five carbon molecule is broken down. NADH and ATP is made
6) The four-carbon molecule is rearranged. NADH and FADH are formed
glycolysis produces two pyruvate molecules
totals are - 6 carbon dioxide, 2 ATP, 8 NADH, 2 FADH2 molecules
Electron transport chain (second main part of cellular respiration)
1) electrons removed
2) Hydrogen ions transported
3) ATP produced
4) WAter formed
Products of cellular respiration are
1) carbon dioxide from the Krebs cycle and from the breakdown of pyruvate before the Krebs cycle
2) WAter from the electron transport chain
3) a net gain of 38 ATP molecules for every glucose molecule - 2 from glycolysis, 2 from the Krebs cycle, and up to 34 from the electron transport chain
Fermentation
is an aenerobic process. Does not make ATP but it allows glycolysis to continue. Removes electrons from NADH molecules and recycles NAD+ molecules for Glycolysis.
Lactid acid
product of fermentation in many types of cells, including human muscle cells. anaerobic process
examples of fermentation in food
pizza crust, cheese, bread, yogurt