Biophysical CCM's carboxysomes

Question 1

first ps bac

Answer 1

300bya CO2 rich and O2 poor

Question 2

300mya what era?

Answer 2

300mya carboniferous era, lowest CO2 levels O2 highest

selection pressure for turbo charging CO2 around rubisco

Question 3

500 mya what happened

Answer 3

O2 levels started to increase CO2 fall

Question 4

over evolutionary time specificity factor for rubisco incresase

Answer 4

:)

Question 5

Thermophillic red algae specificty

Answer 5

150-238

Question 6

Cyanobac specificity

Answer 6

40-60

Question 7

problems for rubisco in aquatic environ

Answer 7

co2 limting
diffuses 10^4 times slower
present as bicarbonate
CO2 further reduced by phytoplankton, can even increase O2 levels 30%

bicarbonate in sea water 100x that of CO2

Question 8

cyanobacteria CCM

5 pumps take up bicarbonate

Answer 8

• StbA - inducible bicarbonate pump NA dependent
• bicA -low affinity high flux NA dependent pump
• BcT1 - 4 genes inducible HCO3 uptake
• 2 ATP dependent Co2 pumps thar upon uptake drive conversion to HCO3-

Question 9

ph is what in carboxysome

Answer 9

maintained the same as sea water in order to esure HCO3- stays as HCO3-, will diffuse out if not

Question 10

carboxysome is what shape

and has

Answer 10

icosahedron

prrof barrier to prevent escape of CO2

Question 11

carboxysome has CA , 3 types

Answer 11

carbonic anhydrase
CcmM
CcaA
Cso53

Question 12

CO2 is what of ambient?

Answer 12

10^3

Question 13

CCMs are …. and occur at ….

Answer 13

inducible

low CO2

Question 14

two types of carboxysomes

why

Answer 14

alpha and beta based on phylogeny of large subunit

beta- CO2 poor environments, alkaline esturie, show more inducible characteristics than a

alpha -nutrient deficient environments, sufficient CO2