Lecture 24 Cryobiology
Lecture 24 Cryobiology
Final examination Time:2013-06-17第17周，星期一10：30一12：30 Address:东中院3-403
Final examination Time: 2013-06-17第17周, 星期一10:30－12:30 Address: 东中院3-403
Introduction to Cryobiology Study of living systems at any temperature below the standard physiological range and its application Above freezing temperature Below freezing temperature
Study of living systems at any temperature below the standard physiological range and its application Above freezing temperature Below freezing temperature Introduction to Cryobiology
What happens when temperature is lowered
What happens when temperature is lowered ?
Phase diagram of water p P点：固态的冰 PM段： 固态冰温度不断升高 D M点：冰，水两相平衡 MN段：液态水 N 点：汽，水两相平衡 NO段：水蒸气 6 M 0 S A g 0 2
T l g s D p A O M PM段：固态冰温度不断升高 N MN段：液态水 O NO段：水蒸气 M 点：冰，水两相平衡 N 点：汽，水两相平衡 P P 点：固态的冰 Phase diagram of water
Low temperature: 1999-06-03 ice formation 0151:28 1999-06-03 99906-03 015129 0151-327
Low temperature : ice formation
Supercooling and Ice Nucleation ●Supercooling the process of lowering the temperature of a liquid or a gas below its freezing point without it becoming a solid When two phases are in equilibrium: Chemical potentials of each component in two phases must be equal G(T)=G(T) Gibbs function,or the chemical potential
the process of lowering the temperature of a liquid or a gas below its freezing point without it becoming a solid Supercooling and Ice Nucleation Supercooling When two phases are in equilibrium:
Super cooling degree AT=TI-To At supercooling: G(T。)>G,(T。) △G(T。)=G(T。)-G,(T。) ≡△TAS(Tf) =Lr△T1Tf
T Tf To ( ) ( ) GL To Gs To f f f o L o s o L T T T S T G T G T G T / ( ) ( ) ( ) ( ) Super cooling degree At supercooling:
Ice Nucleation with different supercooling Cooling from 10C to -40C with Seed ice at-4C,hold at- cooling rate-20C/min,picture 40C/min for 2min,then cooling taken at-40C.(ice forms at to -400C at-20C/min.picture -10C) taken at-40C.(ice forms at -4C)
Cooling from 10oC to -40oC with cooling rate -20oC/min, picture taken at -40oC. (ice forms at -10oC) Seed ice at -4oC, hold at - 4oC/min for 2min, then cooling to -40oC at -20oC/min. picture taken at -40oC. (ice forms at -4oC) Ice Nucleation with different supercooling
When there are cells in the water solution Cross-Section of an Animal Cell Cell wall Cel Membrine Centrose开e mane Encoolasmc Ly多1B程号 Cytopiasm etculum 只t09me等 Rough ER Nuceus Nucleotus 5weo中ER Nucieclus Nuclear Me作由r法ne 风be4anet Cytcplasm Mtochoneron . PLANT CELL STRUCTURE