Bài giảng Sinh lý thực vật - Bài 17: Pha tối

QUANG HÔÏP<br /> <br /> PHA TOÁI<br /> Pha thu nhaän saûn phaåm pha saùng (ATP +<br /> NADPH) ñeå toång hôïp höõu cô (Carbohydrate)<br /> [khoâng phuï thuoäc vaøo aùnh saùng]<br /> <br /> Photosynthesis<br /> Photosynthesis: h<br /> 6CO2 + 6H2O Chlorophyll C6H12O6 + 6O2<br /> <br /> Calvin cycle<br /> <br /> Quang hôïp<br /> nhoùm thöïc vaät C3<br /> <br /> The first product of CO2 fixation is 3-phosphoglycerate<br /> 3-<br /> <br /> 14CO<br /> <br /> 2<br /> <br /> M. Calvin & A. Benson exposed<br /> green algae to 14CO2 for short<br /> periods of time in the presence of<br /> light. They separated and<br /> identified the labeled products by<br /> paper chromatography.<br /> <br /> pump<br /> <br /> boiling<br /> methanol<br /> <br /> algae<br /> light<br /> 14 C<br /> <br /> appeared first in<br /> the carboxyl carbon of<br /> 3-phosphoglycerate.<br /> <br /> 14CO 2<br /> <br /> H-C-OH<br /> CH 2-O- P<br /> <br /> 1<br /> <br /> CHUOÃI CAÙC PHAÛN ÖÙNG ÑOÀNG HOÙA CARBON C3<br /> <br /> Light-dependent reactions<br /> <br /> Carbon fixation reactions<br /> Chloroplast<br /> <br /> Lig ht<br /> reacti o ns<br /> <br /> 6CO2 + 6H2O<br /> (6C)<br /> 6 CO<br /> <br /> Calvi n<br /> cycl e<br /> <br /> 6 molecules of<br /> 2<br /> CO2<br /> <br /> 6 x 5C = 30C<br /> <br /> 6 molecules of<br /> ribulose bisphosphate<br /> (RuBP)<br /> <br /> C6H12O6 + 6O2<br /> CO 2 molecules are captured by<br /> RuBP1 resulting in an unstable<br /> intermediate that is immediately<br /> broken apart into 2 PGA<br /> <br /> 36C<br /> <br /> CO2 uptake<br /> phase<br /> <br /> 30C<br /> <br /> 12 molecules of<br /> Phosphoglycerate (PGA)<br /> <br /> 12 ATPs<br /> <br /> 6 molecules of ribose<br /> phosphate (RP)<br /> RuBP<br /> regeneration<br /> phase<br /> <br /> CALVIN<br /> CYCLE<br /> Carbon<br /> reduction<br /> phase<br /> <br /> 6C<br /> Glucose and other<br /> carbohydrate synthesis<br /> <br /> 12 ADPs<br /> 12 NADPH,H+<br /> 12 NADP<br /> <br /> 12 molecules<br /> of glyceraldehyde-3phosphate (G3P)<br /> 12 molecules<br /> of glyceraldehyde-3phosphate (G3P)<br /> <br /> PGA is phosphorylated<br /> by ATP and reduced by<br /> NADPH.<br /> <br /> 36C<br /> <br /> 2<br /> <br /> The Benson-Calvin cycle<br /> An antiporter exchanges Pi with triose phosphates<br /> <br /> 3 RuBP<br /> 3 x C5<br /> <br /> 3ATP<br /> <br /> 3CO2<br /> carboxylation<br /> <br /> regeneration<br /> <br /> 5 x C3<br /> <br /> 6 glycerate 3-P<br /> (6 x C3)<br /> 6ATP + 6 NADPH<br /> reduction<br /> <br /> 1 x C3 product<br /> <br /> 6 triose-P<br /> (6 x C3)<br /> <br /> Ribulose 1,5 Bisphosphate Carboxylase/Oxidase<br /> <br /> Caùùc enzyme ñoùng vai troøø quan troïïng trong<br /> Ca<br /> ng<br /> tro<br /> trong<br /> chu trình Calvin ñöôïc ñieààu hoøøa bôûûi aùnh saùùng:<br /> trì<br /> ñöô ie ho bô nh sang:<br /> <br /> RUBISCO:<br /> <br /> Rubisco<br /> NADP: Glyceraldehyde 3-phosphate dehydrogenase<br /> Fructose 1,6-bisphosphatase<br /> 1,6 Sedoheptulose 1,7 bisphosphatase<br />  Ribulose 5-phosphate kinase<br /> Cô cheáá ñieààu hoøøa thöôøng thoâng qua vieääc hình thaøønh hay phaùù boûû<br /> che ie ho thö ng<br /> vie<br /> tha nh<br /> pha bo<br /> caùùc lieân keáát disulfide<br /> ca<br /> ke<br /> <br /> <br /> <br /> <br />  Nhạy<br /> Nhạy<br /> <br /> cảm với ánh sáng mạnh<br /> cả vớ<br /> sá mạ<br /> lực với CO2 thấp<br /> ự vớ<br /> ấ<br /> l<br /> th<br />  Không chịu nhiệt độ cao<br /> chị nhiệ độ<br />  Tính 2 mặt:<br /> Tính<br />  Ái<br /> <br /> Rubisco gaén vaøo cô chaát<br /> <br /> • CO2<br /> • O2<br /> >>> Quang hô hấp >>> không những không tạo<br /> Quang<br /> hấ >>> không nhữ<br /> tạ<br /> đường mà còn phân hủy đường đã tích lũy<br /> ường mà còn<br /> hủ đường đã tích lũ<br /> <br /> 3<br /> <br /> HIEÄN TÖÔÏNG QUANG HOÂ HAÁP<br /> <br /> Enzyme<br /> RUBISCO xuùc<br /> taùc phaûn öùng vôùi<br /> oxygen gaây ra<br /> hieän töôïng<br /> quang hoâ haáp<br /> <br /> Ribulose 1,5-bisphosphate carboxylase-oxygenase (Rubisco)<br /> ibu<br /> 1,5- bisphosphate arboxylaseRubisco)<br /> <br /> C5 + C1<br /> RuBP + CO2 + H2O<br /> <br /> 2 x C3<br /> carboxylase<br /> <br /> 2 (glycerate 3-P)<br /> <br /> C3 + C2<br /> <br /> C5<br /> RuBP + O2<br /> oxygenase<br /> <br /> glycerate 3-P +<br /> glycollate 2-P<br /> <br /> 4<br /> <br /> Photorespiratory pathway/Quang hoâ haáp<br /> <br /> Photorespiratory pathway<br /> 2 x C2<br /> <br /> 2 glycollate-2-P<br /> <br /> 1 x C3 + CO2<br /> 2 glycollate<br /> <br /> 2 x C2<br /> <br /> 2 glycine (C2)<br /> <br /> 2 glycollate-2-P<br /> <br /> 2 glycollate<br /> <br /> glycine<br /> decarboxylase<br /> <br /> Rubisco<br /> glycine<br /> decarboxylase<br /> mitochondrion<br /> <br /> chloroplast<br /> <br /> 2 glycine (C2)<br /> <br /> peroxisome<br /> <br /> peroxisome<br /> Rubisco<br /> CO2<br /> NH 3<br /> NADH<br /> <br /> mitochondrion<br /> <br /> chloroplast<br /> <br /> CO2<br /> NH 3<br /> NADH<br /> <br /> peroxisome<br /> <br /> peroxisome<br /> glycerate-3-P<br /> <br /> 1 x C3 + CO2<br /> <br /> serine (C3)<br /> <br /> glycerate-3-P<br /> <br /> serine (C3)<br /> <br /> 5<br /> <br />