Calculating Clonal Cell Line Growth with Apoptosis
This solution outlines the steps to calculate the final cell count in a clonal mammalian cell line experiment, considering cell death due to apoptosis.
1. Define Parameters and Total Time
- Initial Cell Count ($N_0$): 1 cell
- Doubling Time ($T_d$): 24 hours
- Total Experiment Duration: 7 days
- Convert total duration to hours: $7 \text{ days} \times 24 \text{ hours/day} = 168 \text{ hours}$
2. Calculate Cell Growth Without Apoptosis
If no cells died, the total number of cells ($N$) after time ($t$) follows the formula $N = N_0 \times 2^{(t/T_d)}$.
- Number of doublings in 7 days: $168 \text{ hours} / 24 \text{ hours} = 7$ doublings
- Total cells without death: $1 \times 2^7 = 128$ cells
3. Account for Apoptosis
Apoptosis occurred after the first 48 hours.
- Calculate the number of cells present at 48 hours: $N_{48h} = 1 \times 2^{(48 \text{ hours} / 24 \text{ hours})} = 1 \times 2^2 = 4$ cells.
- One cell undergoes apoptosis. This leaves $4 - 1 = 3$ cells to continue proliferation from the 48-hour mark.
4. Calculate Final Cell Count
Calculate the growth for the remaining time period starting from the 3 surviving cells.
- Remaining time: $168 \text{ hours} - 48 \text{ hours} = 120 \text{ hours}$.
- Number of doublings in the remaining time: $120 \text{ hours} / 24 \text{ hours} = 5$ doublings.
- Final cell count = (Number of surviving cells at 48h) $\times 2^{\text{(Number of remaining doublings)}}$
- Final cell count = $3 \times 2^5 = 3 \times 32 = 96$ cells.
The total number of cells after 7 days is 96.
Important Questions from Kinetics of Cell Growth
- A synchronous culture containing $1.8 \times 10^5$ monkey kidney cells was seeded into three identical flasks. The doubling time of these cells is 24 h. After 24 h, the cells from all the three flasks were pooled and dispensed equally into each well of three 6-well plates. The number of cells in each well will be ________ $\times 10^4$.
- Maximum specific growth rate ($\mu_{max}$) of a microorganism is calculated by taking the (In=loge, X=biomass, t = time)
- Which one of the following is NOT used for the measurement of cell viability in animal cell culture?
- A T-flask is seeded with $10^5$ anchorage-dependent cells. The available area of the T-flask is $25 \text{ cm}^2$ and the volume of the medium is $25 \text{ ml}$. Assume that the cells are rectangles of size $5 \text{ µm} \times 2 \text{ µm}$. If the cells grow to monolayer confluence after $50 \text{ h}$, the growth rate in number of cells/($\text{cm}^2.\text{h}$) is _________ $ \times 10^5$.
- Determine the correctness or otherwise of the following Assertion (a) and the Reason (r) Assertion: In synchronous culture, majority of the cells move to next phase of the cell cycle simultaneously. Reason: Synchronous culture could be obtained by starving cells for essential nutrient components.
