Kinetics of substrate uptake in cell kinetics

Question 1

Cells consume substrate from the external environment and channel it into different metabolic
pathways. What kind of uses is the substrate

Answer 1

Some substrates may be directed into growth and product synthesis; another fraction is used to generate energy for maintenance activities.

Question 2

Give the equation for the rate of substrate uptake during cell culture, as a function of biomass concentration.

Answer 2

Question 3

In the absence of extracellular product synthesis, we assume that all substrates entering the cell is
used for growth and maintenance functions. Give the equation for the rates of these cell activities

Answer 3

Question 4

What’s the problem with this equation?

Answer 4

When s is zero, the above equation predicts that substrate consumption will proceed at a rate equal to msx.
Substrate uptake in the absence of substrate is impossible.

This equation is a realistic description of substrate uptake when there is external substrate available.

Question 5

In cultures where product synthesis is only indirectly coupled to energy metabolism, what 3 things are the rate of substrate consumption a function of? Give this equation

Answer 5

The growth rate, the rate of product formation, and the rate of substrate uptake for maintenance

Question 6

What happens when the products are directly linked to energy generation?

Answer 6

substrate requirements for product
formation are already accounted for in terms representing growth- and maintenance-associated substrate uptake. So equation is the same as for substrate requirements for in the absence of extracellular product synthesis