Metabolisme Energi.

Metabolisme Energi

Metabolisme dapat dibagi:
1) KATABOLISME: PEMECAHAN MOLEKUL BESAR MENJADI MOLEKUL KECIL-KECIL DAN TERBENTUK ENERGI CONTOH: A B + C + ENERGI CHO GLUKOSE, FRUKTOSE

Cont... 2) ANABOLISME: PEMBENTUKAN MOLEKUL
BESAR DARI BEBERAPA MOLEKUL KECIL DAN DIPERLUKAN ENERGI CONTOH: B + C + ENERGI  A ASAM AMINO + ASAM AMINO PROTEIN

Peran Oksigen dalam Katabolisme Glukosa?

RESPIRASI SEL Tiga tahap penuaian energi Glikolisis Daur Krebs
Rangkaian transpor elektron

Respirasi sel dan Mitokondria
Daur Krebs dan rangkaian transpor elektron terjadi di dalam mitokondria

sel Membran luar membran dalam mitokondrion Figure: 07-06a Title:
Energy transfer in the mitochondria. Caption: Mitochondria are organelles, or “tiny organs,” that exist within cells. They are the location for the second and third sets of steps in cellular respiration, the Krebs cycle and the electron transport chain. Following a transitional step (see Figure 7.7), the products of glycolysis—the downstream products of the original glucose molecule—pass into the inner compartment of a mitochondrion, where the Krebs cycle takes place. Electrons derived from the Krebs cycle then migrate, via electron carriers, from the Krebs cycle site into the highly folded inner membrane of the mitochondrion, where the bulk of ATP is produced in the electron transport chain. Membran luar membran dalam mitokondrion

Rangkaian transpor elektron
glikolisis membrandalam membrane luar H+ H+ H+ H+ H+ Rangkaian transpor elektron Daur Krebs H+ H+ H+ H+ e- Figure: 07-06b Title: Energy transfer in the mitochondria. Caption: Mitochondria are organelles, or “tiny organs,” that exist within cells. They are the location for the second and third sets of steps in cellular respiration, the Krebs cycle and the electron transport chain. Following a transitional step (see Figure 7.7), the products of glycolysis—the downstream products of the original glucose molecule—pass into the inner compartment of a mitochondrion, where the Krebs cycle takes place. Electrons derived from the Krebs cycle then migrate, via electron carriers, from the Krebs cycle site into the highly folded inner membrane of the mitochondrion, where the bulk of ATP is produced in the electron transport chain. O2 kompartemen luar H2O kompartemen dalam

Peralihan antara Glikolisis dan Daur Krebs
Asam piruvat hasil glikolisis menuju ke mitokondria. Berikatan dengan koenzim A membentuk asetil koA, 1 molekul NADH, dan CO2. Daur Krebs terjadi di kompartemen dalam dari mitokondria.

Menuju ke rangkaian transpor elektron
glikolisis mitokondrion Asam piruvat cytosol NAD+ koenzim A NADH Menuju ke rangkaian transpor elektron Figure: 07-07 Title: Transition between glycolysis and the Krebs cycle. Caption: The pyruvic acid product of glycolysis does not enter directly into the Krebs cycle. Rather, it must first be transformed into acetyl coenzyme A. The consequences of this reaction are the production of CO2, which dissolves into the bloodstream, and the production of an NADH molecule, which continues onto the electron transport chain. Because one molecule of glucose produces two molecules of pyruvic acid, two molecules of NADH are produced per glucose molecule in this transitional step. koA asetll koenzim A CO2 Kompartemen dalam Daur Krebs

SUMMARY OF THE KREBS CYCLE 6 NADH GLYCOLYSIS 2 FADH2 CoA Daur Krebs asetil koenzim A CO2 2 ATP Rangkaian transpor elektron 1. asam oksaloasetat asam sitrat NAD+ NADH NADH NAD+ 2. 6. CO2 asam -ketoglutarat asam malat Figure: 07-08 Title: Summary of the Krebs cycle. Caption: The Krebs cycle is the major source of electrons that are transported to the electron transport chain by the electron carriers NADH and FADH2. For each molecule of glucose, two molecules of acetyl coenzyme A enter the Krebs cycle. Through a series of reactions, a total of 6 NADH, 2 FADH2, and 2 ATP are produced per glucose molecule. (From counting the number of NADH and FADH2 around the cycle, it would appear that only 3 NADH and 1 FADH2 are produced, but remember that one molecule of glucose results in two “trips” around the cycle, as two molecules of acetyl coenzyme A will enter the Krebs cycle for every molecule of glucose that is metabolized.) 3. CO2 FADH2 FAD+ NAD+ NADH 5. ADP 4. asam suksinat turunan asam -ketoglutarat ATP

Ringkasan Daur Krebs Asetil koA didegradasi sempurna menjadi CO2.
Hanya 1 ATP yang dihasilkan dari setiap asetil koA yang memasuki Daur Krebs (total 2 ATP tiap glukosa). Semua elektron dapat diikat dalam bentuk 6 NADH (per glukosa) untuk diproses lebih lanjut melalui rangkaian transpor elektron.

Katabolisme, Transfer Elektron dan Reaksi Oksidasi Reduksi
Elektron dibebaskan dari oksidasi nutrisi selama katabolisme. Elektron dipindahkan oleh pembawa elektron melalui suatu proses untuk menghasilkan ATP.

Oksidasi - Reduksi Oksidasi: Pengambilan/pemindahan elektron dari suatu senyawa. Reduksi: Penambahan/pemberian elektron kepada suatu senyawa.

OKSIDASI-REDUKSI DALAM SEL
Dalam sel hidup, beragam molekul terlibat dalam proses transfer energi. Masing- masing molekul memiliki kecenderungan untuk mendapatkan atau kehilangan elektron. Di dalam sel, proses oksidasi dan reduksi tidak terjadi secara terpisah. Proses oksidasi-reduksi yang terjadi berpasangan disebut REAKSI REDOKS.

PEMBAWA ELEKTRON Molekul yang memindahkan elektron selama proses oksidasi reduksi di dalam sel. NADH, FADH2 adalah molekul pembawa elektron

NAD (Nikotinamida Dinukleotida)
Di dalam sel, NAD terdapat dalam 2 bentuk: Bentuk membawa elektron atau atom hidrogen ( NADH) dan tanpa atom hidrogen (NAD+). NAD+ berperan sebagai senyawa pengoksidasi, bila menerima atom hidrogen dan elektron, menjadi NADH.

NADH dapat memindahkan elektron ke molekul lain, dan kembali menjadi NAD. Proses pemindahan ini dikendalikan/dilakukan oleh enzim.

- - - - + NAD+ NADH NAD+ kosong terisi kosong + + H proton NAD H
teroksidasi - + - + NAD NAD H - - - + Figure: 07-03 Title: The electron carrier NAD+. Caption: In its unloaded form (NAD+) and its loaded form (NADH), this molecule is a critical player in energy transfer, picking up energetic electrons from food and transferring them to later stages of respiration. - H tereduksi + H

Rangkaian Transpor Elektron
NADH memindahkan elektron ke suatu rangkaian molekul yang terdapat di membran dalam mitokondria. Perpindahan elektron mengakibatkan perpindahan ion H+ melawan gradien konsenrasi.

Energi yang terbentuk pada saat masuknya kembali ion H+ ke dalam mitokondria melalui ATP sintase, digunakan untuk menggabungkan fosfat dengan ADP untuk membentuk ATP. Dihasilkan ATP yang lebih banyak pada tahap ini (32 ATP per glukosa).

Di akhir rangkaian O2 + 2 electrons + 2 H+ = H2O. Penyebab kebutuhan oksigen.

RANGKAIAN TRANSPOR ELEKTRON
mitokondria GLYCOLYSIS KREBS CYCLE inner membrane ELECTRON TRANSPORT CHAIN 32 ATP inner compartment O2 H2O outer compartment Kompartemen bagian luar SINTESIS ATP H+ H+ H+ H+ H+ inner membrane H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ Figure: 07-09 Title: The electron transport chain. Caption: The movement of electrons through the ETC powers the process that provides the bulk of the ATP yield in respiration. The electrons carried by NADH and FADH2 are released into the ETC and transported along its chain of molecules. The movement of electrons along the chain releases enough energy to power the pumping of hydrogen ions (H+) across the membrane into the outer compartment of the mitochondrion. It is the subsequent energetic “fall” of the H+ ions back into the inner compartment that drives the synthesis of ATP molecules by the enzyme ATP synthase. H+ H+ NADH H+ ATP synthesis NAD+ 2 H+ + 1/2 O2 ADP + P Kompartemen bagian dalam H2O ATP RANGKAIAN TRANSPOR ELEKTRON

Molekul lain yang digunakan pada respirasi
food PROTEIN KARBOHIDRAT LEMAK amino acids sugars glycerol fatty acids Molekul lain yang digunakan pada respirasi GLIKOLISIS glukosa Asam piruvat acetyl CoA Figure: 07-10 Title: Many respiratory pathways. Caption: Glucose is not the only starting material for cellular respiration. Other carbohydrates, proteins, and fats can also be used as fuel for cellular respiration. These reactants enter the process at different stages. DAUR KREB NH3 (ammonia) RANGKAIAN TRANSPOR ELEKTRON

Metabolisme dapat dibagi:
1) KATABOLISME: PEMECAHAN MOLEKUL BESAR MENJADI MOLEKUL KECIL-KECIL DAN TERBENTUK ENERGI CONTOH: A B + C + ENERGI CHO GLUKOSE, FRUKTOSE

Cont... 2) ANABOLISME: PEMBENTUKAN MOLEKUL
BESAR DARI BEBERAPA MOLEKUL KECIL DAN DIPERLUKAN ENERGI CONTOH: B + C + ENERGI  A ASAM AMINO + ASAM AMINO PROTEIN

Peran Oksigen dalam Katabolisme Glukosa?

RESPIRASI SEL Tiga tahap penuaian energi Glikolisis Daur Krebs
Rangkaian transpor elektron

Respirasi sel dan Mitokondria
Daur Krebs dan rangkaian transpor elektron terjadi di dalam mitokondria

sel Membran luar membran dalam mitokondrion Figure: 07-06a Title:
Energy transfer in the mitochondria. Caption: Mitochondria are organelles, or “tiny organs,” that exist within cells. They are the location for the second and third sets of steps in cellular respiration, the Krebs cycle and the electron transport chain. Following a transitional step (see Figure 7.7), the products of glycolysis—the downstream products of the original glucose molecule—pass into the inner compartment of a mitochondrion, where the Krebs cycle takes place. Electrons derived from the Krebs cycle then migrate, via electron carriers, from the Krebs cycle site into the highly folded inner membrane of the mitochondrion, where the bulk of ATP is produced in the electron transport chain. Membran luar membran dalam mitokondrion

glikolisis membrandalam membrane luar H+ H+ H+ H+ H+ Rangkaian transpor elektron Daur Krebs H+ H+ H+ H+ e- Figure: 07-06b Title: Energy transfer in the mitochondria. Caption: Mitochondria are organelles, or “tiny organs,” that exist within cells. They are the location for the second and third sets of steps in cellular respiration, the Krebs cycle and the electron transport chain. Following a transitional step (see Figure 7.7), the products of glycolysis—the downstream products of the original glucose molecule—pass into the inner compartment of a mitochondrion, where the Krebs cycle takes place. Electrons derived from the Krebs cycle then migrate, via electron carriers, from the Krebs cycle site into the highly folded inner membrane of the mitochondrion, where the bulk of ATP is produced in the electron transport chain. O2 kompartemen luar H2O kompartemen dalam