8. Redox Reactions
â˘Removal of an electron from a molecule, results in
decreased potential energy, and its addition increases the
potential energy of the other.
â˘Most of the energy stored in atoms and used to fuel cell
function is in the form of high-energy electrons.
â˘The transfer of energy in the form of electrons allows the
cell to transfer and use energy in an incremental fashion.
9. ELECTRON CARRIERS
â˘In living systems, a small class of compounds
functions as electrons.
â˘They bind and carry high-energy electrons
between compounds in pathways.
â˘They are derived from the B vitamin group and
are derivatives of nucleotide.
15. â˘A living cell cannot store significant amounts of energy
â˘Excess energy would result in an excessive thermal
condition that could damage and destroy the cell.
â˘A cell must be able to handle that energy in a way that
enables the cell to store energy and release it for use
only as needed.
16.
17. â˘When ATP is broken down, usually by removal of its
terminal phosphate group, energy is releasedâwhich
energy is used by our cells to do work. Usually by the
released phosphate binds to another molecule,
activating it.
â˘Phosphoanhydride bonds â between phosphate
groups of ATP.
20. â˘Hydrolysis â water is split, resulting hydrogen atom
and hydroxyl group.
â˘The hydrolysis of ATP produces ADP (Adenosine
diphosphate), with an inorganic phosphate ion (Pi)
and the release of free energy. Hydrolysis is
reversible!
21. â˘To carry out life processes, ATP is continuously
broken down into ADP.
â˘ADP is continuously regenerated into ATP by the
reattachment of a third phosphate group.
ENERGY FROM ATP
22. Where does this energy come from?
â˘In nearly every living thing on earth, the energy
comes from the metabolism of glucose.
â˘ATP is a direct link between the limited set of
exergonic pathways of glucose catabolism and the
multitude of endergonic pathways that power living
cells.
24. Catabolism
â˘Larger molecules broken down into smaller ones
--Stages 1-4 (Digestion; Formation of Acetyl CoA;
Citric Acid Cycle; Electron Transport Chain &
Oxidative Phosphorylation)
â˘Releases energy (may be stored temporarily as ATP)
â˘Ex. CELLULAR RESPIRATION
25. â˘Acetyl-CoA (acetyl coenzyme A) is a molecule that
participates in many biochemical reactions in
carbohydrate and lipid metabolism.
â˘Its main function is to deliver the acetyl group to the
citric acid cycle (Krebs cycle) to be oxidized for
production.
28. Introduction
â˘From the GreekâŚ
PHOTO = produced by light
SYNTHESIS = a whole made of parts put together.
Definition: PHOTOSYNTHESIS is the process whereby plants, algae,
some bacteria, use the energy of the sun to synthesize organic
compounds (sugars) from inorganic compounds (CO2 and water).
29. Importance
PHOTOSYNTHESIS is one of the most important
biological process on earth!
⢠Provides the oxygen we breathe
⢠Consumes much of the CO2
⢠Food
⢠Energy
30. 2 Processes of Photosynthesis
⢠Light-dependent Reaction
-Energy from sunlight is absorbed by chlorophyll and that energy is
converted into stored chemical energy.
-Occurs in the thylakoid lumen.
⢠Light-independent Reactions (Calvin Cycle)
- Chemical energy harvested during the light-dependent reactions drive
the assembly of sugar molecules from carbon dioxide.
- Occurs in the chloroplast stroma.
38. 3 STAGES:
â˘GLYCOLYSIS â breaking down of glucose
â˘THE KREBâS CYCLE - produces NADH and
FADH2 for ETC and fuels production of ATP.
â˘ELECTRON TRANSPORT CHAIN
39.
40. GLYCOLYSIS (Summary)
⢠Anaerobic process (requires NO OXYGEN)
⢠Occurs in the cellâs cytoplasm.
⢠Invests 2 molecules of ATP in order to work (split glucose into half).
⢠Energy return of 4 ATP molecules.
⢠But the ATP Net Yield is only 2 since the process invests 2 ATP
molecules at the beginning of glycolysis.
⢠Produces 2 NADH molecules (which will enter ETC).
⢠Also produces 2 pyruvate molecules/pyruvic acid (which will enter The
Krebâs Cycle).
41.
42. THE KREBâS CYCLE (Summary)
⢠Aerobic process (Requires Oxygen)
⢠Occurs in the mitochondrial matrix of the cell.
⢠Needs the pyruvate from glycolysis to start the process, together with
Acetyl Co-enzyme A.
⢠Two CO2 and 2 NADH will be released âprep stage.
⢠Acetyl Co-A combines with Oxaloacetate to make citrate/citric acid.
⢠Uses FAD+ electron carrier which is reduced to FADH+
⢠Produce 4 CO2, 6 NADH, 2 FADH2, 2 ATP
43.
44. ELECTRON TRANSPORT CHAIN
⢠Aerobic process (Requires Oxygen!)
⢠Occurs in the mitochondrial inner folding (cristae).
⢠Uses four complexes to transport electrons creating proton
gradient (H+) to generate the function of ATP Synthase.
⢠Requires NADH and FADH2 molecules to generate 34 ATPs.
45.
46. Don't let your teacher affect your love for science. You
can be a scientist outside of the classroom too. Be
your own teacher. Keep your love of learning and you
will do just fine.ďťż
ENJOY THE VIDEOS! ď
Hinweis der Redaktion
This involves cellular processes such as the building and breaking down of complex molecules occur through stepwise chemical reactions. Some of these chemical reactions are spontaneous and release energy, whereas other requires energy to proceed.
We use great deal of energy while thinking and even during sleeping. In fact, the living cells constantly use energy.
Energy production within a cell involves many coordinated chemical pathways and most of these pathways are combinations of OXIDATION and REDUCTION.
Since they occur together, these pairs of electrons are called Redox Reactions.
There are eight types of vitamin B: thiamin (B1), riboflavin, niacin, pantothenic acid, biotin, vitamin B6 (pyridoxine), folate (called folic acid when included in supplements), vitamin B12 (cyanocobalamin).
Get all eight B vitamins âfrom a variety of foods: Whole grains (brown rice, barley, millet), Meat (red meat, poultry, fish), Eggs and dairy products (milk, cheese), Legumes (beans, lentils), Seeds and nuts (sunflower seeds, almonds), Dark, leafy vegetables (broccoli, spinach, kai lan)
These are the compounds that can be easily reduced (they accept electrons) or oxidized (they lose electrons).
NAD (Nicotinamide Adenine Dinucleotide) â derived from vitamin B, Niacin (lowers cholesterol, ease arthritis and boost brain function)
NAD+ (Oxidized from) â can accept electrons from an organic molecule; NADH (Reduced form)
Another variation of NAD, NADP, contains an extra phosphate group.
Similarly, FAD is derived from vitamin B2. Reduced form is FADH2.
NAD+ (Oxidized from) â can accept electrons from an organic molecule; NADH (Reduced form)
Both of NAD+ and FAD+ are extensively used in energy extraction from sugars (Cellular Respiration). And NADP plays an important role in anabolic reactions and photosynthesis.
ATP is often called the energy currency of the cell.
An ATP functions like that of a rechargeable battery.
ATP alters the structure of integral proteins, changing its affinity for sodium and potassium. In this way, the cell performs work, pumping ions against their electrochemical gradients.
Oxygen on earth allowed for the evolution of aerobic respiration and higher life-forms.