Class 9

What explains the shape of a growth vs temperature curve for a bacterium (or Chlamy)

Increase in temp. increases the reaction rate

Peak = most ideal temp for functioning

When its too hot, enzyme denatures

In what ways is hexokinase different in a bacterium adapted to low temperature vs one adapted to high temperature. 

Hexokinase in cold temp:

• more flexible

Hexokinase in hot temp:

• rigid

Basics of measuring respiration in isolated mitochondria:  what do you need?

Need a oxygen electrode chamber

• purify mitochon. from a chlamy cell

• incubate mito in a buffer and put into electrode chamber

How can we measure rate of cellular respiration

By measuring change in O2 conc.

O2 conc. is always going down because it is the terminal e- acceptor

Change in respiration rate (oxygen consumption) in isolated mitochondria by addition of  NADH, ADP & Pi, uncoupler

NADH: O2 decreases cuz oxygen is being consumed by the electron transport (slight decrease)

ADP and Pi: steeper slope

Uncoupler: its the highest rate (ETC rate is increased) (steepest slope)

BUT

if ADP is added first, the line will be straight

For any slope to even happen, make sure NADH is added first

Rate of respiratory control

Rate of e- transport (O2 consumption) adjusts based on availability of ADP and Pi to make ATP

Autotrophic metabolism: Link(s) between photosynthesis and cellular respiration.

While photosynthesis builds up (anabolic) builds up glucose storing energy, cellular respiration (catabolic) breaks it down to release energy, creating a balanced flow

Photosynthesis uses light to combine O2 and H2O to produce glucose and O2.

Cellular respiration uses O2 to break down glucose, releasing energy and producing CO2 and water as waste

Two distinct roles served by G3P that is exported form the chloroplast into the cytosol: energy source and carbon source (why do we need both?)

1. Energy

2. Growth

Can Chlamy grow in the dark? Why acetate and not glucose?

YES it can

• heterotrophic growth

• Requires organic carbon source: acetate

• because it is a 2 carbon molecule which chlamy prefers and it can convert into acetyl coa which can be used in the citric acid cycle

The concept of Mixotrophic metabolism.

Can use light and CO2 to grow or use organic carbon molecules to grow

Can grow using only one method but thrives with both

Highest rate of growth