Metabolism in cells involves three main phases:
1. Digestion breaks down large molecules into smaller subunits that can enter cells.
2. Glycolysis and oxidation in the cytoplasm further breaks down sugars into pyruvate and acetyl CoA, producing a net of two ATP per glucose.
3. The citric acid cycle and oxidative phosphorylation are the major phases of ATP generation, where acetyl CoA enters the citric acid cycle in mitochondria producing NADH and FADH2 to drive oxidative phosphorylation and generate most of the cell's ATP through electron transport.
2. Metabolisme
• Semua reaksi kimia yang bertujuan untuk mempertahankan fungsi sel
disebut dengan metabolism sel.
• Metabolisme sel bertujuan menghasilkan energi untuk menjalankan fungsi
struktur sel.
3. Metabolisme
• Anabolisme : The energy-using
process of metabolism is called
anabolism (ana = upward)
(menggunakan)
• Katabolisme :The energy releasing
process is known as catabolism (cata
= downward) (Melepaskan)
Metabolisme
4. Metabolisme
• Metabolism provides the cell with the energy it needs to synthesize (produce)
cellular structures.
• Dietary proteins, fats, and starches are hydrolyzed in the intestinal tract into amino
acids, fatty acids, and glucose, respectively.
• These constituents are then absorbed, circulated, and taken up by the cell, where
they may be used for various vital cellular processes, including the production of
ATP.
• the process by which ATP is produced is one example of a series of reactions called
a metabolic pathway.
5. Kata kunci biochemical reactions
Catalisis oleh
enzim
Enzim +
Substrat
Specicific
substance
Product/hasil
6. Role of AdenosineTriphosphate
• Best known about ATP is its role as a universal “fuel” inside living cells.
• ATP is used by the cell for muscle contraction and active transport of
molecules across cellular membranes.
• The function ofATP is not only to store energy but also to transfer it from
one molecule to another.
• Energy is stored by molecules of carbohydrate, lipid, and protein, which,
when catabolized, transfer energy to ATP.
9. Phase 1: Digestion
• Large molecules are broken down into their smaller subunits—proteins into
amino acids, polysaccharides into simple sugars, and fats into fatty acids
and glycerol.These processes occur outside the cell by the action of
secreted enzymes.
10. Phase 2: Glycolysis and oxidation
• The small molecules enter cells and are further broken down in the
cytoplasm. Most of the sugars are converted into pyruvate. Pyruvate then
enters mitochondria and is converted to the acetyl groups of acetyl
coenzymeA (acetyl CoA). Acetyl CoA, like ATP, releases energy when it is
hydrolyzed.
• Glycolysis produces a net of two molecules ofATP per glucose molecule
through the process of oxidation, or the removal and transfer of a pair of
electrons.
11. Phase 2: Glycolysis and oxidation
• This process, often called oxidative cellular metabolism, involves 10 biochemical
reactions. In reactions 1 through 5, glucose is converted to two, three-carbon
aldehyde compounds (glyceraldehyde-3phosphate [G3P]), which Require energy in
the form ofATP.The next Five reactionsConvert G3P molecules into pyruvate
molecules And generate four molecules of ATP for eachTwo molecules of G3P. In
addition, two molecules of nicotinamide adenine dinucleotide (NAD) are further
oxidized to produce four more molecules of ATP.
• After subtracting two molecules of ATP to drive the reactions, the net yield is six
ATP molecules for each molecule of glucose.
12.
13. Phase 3: Citric acid cycle (Krebs cycle, tricarboxylic
acid cycle).
• Most of the ATP is generated during this final phase. It begins with the citric
acid cycle and ends with oxidative phosphorylation.About two thirds of the
total oxidation of carbon compounds in most cells is accomplished during
this phase.The major end products are carbon dioxide (CO2) and two
dinucleotides—reduced nicotinamide adenine dinucleotide (NADH) and the
reduced form of flavin adenine dinucleotide (FADH2)—which transfer their
electrons into the electron-transport chain.
