PPT KULIAH respirasi

BOTANIBOTANI FARMASIFARMASI

RESPIRASI PADA TUMBUHAN

RESPIRASI RESPIRASI PROSES PEMBENTUKAN DAN PROSES PEMBENTUKAN DAN PELEPASAN ENERGI YANG SIAP DIGUNAKAN UNTUK PELEPASAN ENERGI YANG SIAP DIGUNAKAN UNTUK PROSE PERTUMBUHAN DAN HIDUP TUMBUHAN.PROSE PERTUMBUHAN DAN HIDUP TUMBUHAN.

RESPIRASIRESPIRASITERJADI DENGAN CARA OKSIDASI PADA TEMPERATUR RENDAH DARI

KARBOHIDRAT DENGAN BANTUAN ENZIM DAN SISTEM KEHIDUPAN PADA TUMBUHAN.

MERUPAKAN REAKSI KEBALIKAN DARI FOTOSINTESIS :1. TERJADI SECARA SPESIFIK DENGAN HASIL YANG BERBEDA.

2. TERJADI PADA ORGANELA YANG BERBEDA.

RESPIRASIRESPIRASI

REAKSI KIMIA YANG TERJADI SELAMA RESPIRASI

C6H12O6 + 6O2 + 40 ADP + 40 Phosphates → 6 CO2 + 6 H2O + 40 ATP

RESPIRASI

PROSES DIMANA TERJADI PENGUBAHAN KARBOHIDRAT MENJADI ENERGI YANG SIAP DIGUNAKAN (ATP) PADA TUMBUHAN HIDUP DAN HEWAN.

1. TERJADI BERSAMAAN DENGAN FOTOSINTESIS

2. TERJADI PADA MALAM HARI3. PADA BUAH YANG TUMBUH DAN MATANG4. PADA BIJI YANG SUDAH TUA (DORMANT

SEEDS)

KAPAN RESPIRASI TERJADI ???

DIMANAKAH RESPIRASI TERJADI?DIMANAKAH RESPIRASI TERJADI?RESPIRASI TERJADI DI MITOKONDRIAMITOKONDRIA MERUPAKAN ORGANELLA YANG DITUTUP OLEH MEMBRAN YANG TERDISTRIBUSI PADA SITOSOL PADA ORGANISME EUKARIOT.FUNGSI UTAMA DARI MITOKONDRIA ADALAH UNTUK MENGUBAH MAKANAN MENJADI ENRGI YANG POTENSIAL (ATP)

KOMPENSASI CAHAYA PADA RESPIRASIKOMPENSASI CAHAYA PADA RESPIRASITINGKAT INTENSITAS CAHAYA MENENTUKAN KECEPATAN RESPIRASI

(PEMBENTUKAN CO2) DIMANA AKAN SEBANDING DENGAN KECEPATAN FOTOSINTESIS (PENGGUNAAN CO2).

TERJADI PADA TUMBUHAN YANG HIDUP DI LUAR RUNGAN.

RESPIRASI AEROB (AEROB RESPIRATION)RESPIRASI AEROB (AEROB RESPIRATION)

3 TAHAP RESPIRASI3 TAHAP RESPIRASI1. GLIKOLISIS (TERJADI DI SITOSOL)

TAHAP – TAHAP PADA LIGHT REACTIONTAHAP – TAHAP PADA LIGHT REACTION4. REDUKSI NADP MENJADI NADPH2

SIKLUS KREBS (TCA CYCLE)/SIKLUS ASAM SIKLUS KREBS (TCA CYCLE)/SIKLUS ASAM SITRATSITRAT1.TERJADI DI MATRIX MITOKONDRIA

2. SERANGKAIAN SIKLUS YANG MEMECAH PYRUVAT MENJADI C02 DAN KERANGKA KARBON YANG LAIN.

3. KERANGKA KARBON TERSEBUT DIPAKAI SEBAGAI PEMBENTUKAN PROTEIN, LEMAK, DINDING SEL, HORMON, PIGMEN,DAN MATRIX BIOLOGIS LAINNYA.

3. DIHASILKAN CO2 DAN DIHASILKAN 10 NADH

TRANSPOR ELEKTRONTRANSPOR ELEKTRON◦ ‘Oxidative Phosphorylation’◦ Series of Proteins in the Mitochondria Helps

Transfer Electrons (e-) from NADH to Oxygen Releases a Lot of Energy

◦ Occurs on Mitochondrial Inner Membrane (Proteins Bound to Membrane)

Respiration StepsRespiration Steps◦ Released Energy

Is Used to Drive the Reaction ADP + P → ATP Many ATP Are

Made◦ Oxygen Is

Required for this Step

◦ Water Is Produced

http://www.uccs.edu/~rmelamed/MicroFall2002/Chapter%205/ch05.htm

Anaerobic RespirationAnaerobic RespirationOnly 2 ATP Are Formed instead of 40

from Aerobic Respiration◦Plant Soon Runs out of Energy◦Can Begin to Suffer from Toxic Levels of

Ethanol and Related CompoundsExtended Periods of Anaerobic

Respiration will Seriously Reduced Plant Growth and Yields

Anaerobic:C6H12O6 + O2 → 2 CH2O5 + 2 H2O + 2 ATPAerobic:C6H12O6 + 6O2 + 40 ADP + 40 Phosphates → 6 CO2 + 6 H2O + 40 ATP

PhotorespirationPhotorespiration In the "normal" reaction, CO2 is

joined with RUBP to form 2 molecules of 3PGA

In the process called photorespiration, O2 replaces CO2 in a non-productive, wasteful reaction

It is believed that photorespiration in plants has increased over geologic time and is the result of increasing levels of O2 in the atmosphere--the byproduct of photosynthetic organisms themselves

The appearance of C4-type plants appears to be an evolutionary mechanism by which photorespiration is suppressed

It has long been the dream of biologists to increase the production of certain crop plants, such as wheat, that carry on C3 PS by genetically re-engineer them to perform C4 PS

It seems unlikely that this goal will be accomplished in the near future due to the complex anatomical and metabolic differences that exist between C3- and C4-type plants

PhotorespirationPhotorespirationRespiration Driven by Light EnergyDiscovered when Scientists Realized that

some Plants Have Faster Respiration Rate in Light than in Dark

Occurs in Chloroplasts and other Structures in a Photosynthetic Cell

Rubisco can React with Oxygen to Start a slightly Different Series of Rxs◦ Result in a Loss or no Net Gain of Dry Matter for

the Plant◦ Less ATP Is Produced from the Photorespiration

http://www.botany.hawaii.edu/faculty/webb/BOT311/BOT311-00/PSyn/Image81.gif

Factors Influencing Factors Influencing PhotorespirationPhotorespirationO2 : CO2 RatioIf Cells Have Low O2 but Higher CO2,

Normal PS Calvin Cycle DominatesC4 Plants Have Little Photorespiration

because They Carry the CO2 to the bundle Sheath Cells and can Build up High [CO2]◦Calvin Cycle Rxs always Favored over

PhotorespirationIf Cells Have Higher O2 and Lower CO2,

Photorespiration Dominateshttp://www.botany.hawaii.edu/faculty/webb/BOT311/BOT311-00/PSyn/Image81.gif

Factors Influencing Factors Influencing PhotorespirationPhotorespirationLight Intensity

◦Increasing Light Intensity will Increase Energy for the Photorespiration Process and for PS

◦C3 Plants Light-Saturate at Lower Light Intensities than C4 Plants Reach Their ‘Break-Even Point’ at much Lower

Light Levels due to Increasing Photorespiration


Factors Influencing Factors Influencing PhotorespirationPhotorespiration

Temperature◦Aerobic

Respiration and Photorespiration Increase with Temp

◦Plants Have Optimum, Minimum and Maximum Temp Ranges



Net Photosynthesis or Net Assimilation Rate◦C4 Plants generally Have Net Assimilation

Rates about 2 to 3 Times that of C3 Plants◦C4 Plants Are often Called Efficient Plants

and C3 Plants Called Non-Efficient Plants◦A Few C3 Plants Have Low Respiration and

Similar Assimilation Rates as C4 Plants Sunflower Peanut



Net Photosynthesis or Net Assimilation Rate◦Cooler Temps Are the only Time when C3

Plants Have Higher Net Assimilation Rates than C4 Plants PEP Carboxylase Needed to Incorporate CO2

into the 4-Carbon Structure no Longer Functions

C4 PS Rates Drop Dramatically or Stophttp://www.botany.hawaii.edu/faculty/webb/BOT311/BOT311-00/PSyn/Image81.gif

Factors Affecting Factors Affecting RespirationRespiration

Kind of Cell or Tissue◦Young and Developing Cells

(Meristematic Areas) usually Have Higher Respiration Rates

◦Developing and Ripening Fruit and Seeds, too

◦Older Cells and Structural Cells Respire at Lower Rates


Temperature◦Respiration generally Has Higher

Optimum and Maximum Temps than PS Rxs

◦Can Have Net Dry Matter Loss at High Temps where Respiration Exceeds PS

◦Temp Refers to Temp Inside Plant or Animal Cell, not Air Temp Using Irrigation to Help Cool the Plant Can

Keep the Plant in Net Gain Range


Oxygen◦Low O2 Can Reduce Aerobic Respiration

and Increase Anaerobic Respiration◦Low O2 Can Reduce Photorespiration


Light◦Can Enhance Rate of Photorespiration◦Does not Directly Affect other Forms of

Respiration


[Glucose]◦Adequate Glucose Needed to Carry out

Respiration◦Reductions can Occur

Reduced PS Reduced Flow of Carbohydrates in Plant

Insect Feeding Phloem Blockages


[CO2]◦Higher CO2 Levels Reduce Rate of

Respiration Feedback Inhibition

◦Seldom Occurs except when O2 Levels Are Limited Flooded, Compacted Soils


[ATP]◦Higher [ATP] Reduces Rate of Respiration

Feedback Inhibition◦Usually Occurs when other Metabolic

Processes Have Slowed or Stopped


Plant Injury◦ Injury will Increase Respiration◦ Plant’s Growth Rate Increases in Attempt to

Recover Mechanical Damage Hail Mowing, Grazing, Cultivation, Wind

◦ Plant Synthesizes Compounds to Fight Pests Insect Feeding Diseases

◦ Some Herbicides Kill Plants by Disrupting or Affecting Respiration Generally an Indirect Effect Herbicide Disrupts Enzyme Activity or some other

Metabolic Process that will Affect Respiration

Plant Mitochondria and Plant Mitochondria and Chloroplasts May Have Evolved Chloroplasts May Have Evolved from Bacteriafrom Bacteria

Many of the features of the mitochondrial genetic system resemble those found in prokaryotes like bacteria. This has strengthened the theory that mitochondria are the evolutionary descendants of a prokaryote that established an endosymbiotic relationship with the ancestors of eukaryotic cells early in the history of life on earth. However, many of the genes needed for mitochondrial function have since moved to the nuclear genome.

PPT KULIAH respirasi

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