This question is about stem cells - AQA - GCSE Biology Combined Science - Question 6 - 2018 - Paper 1

The economic use of plant stem cells is to produce large numbers of identical plants.

To convert picograms to grams, we can use the conversion:

6 ext{ picograms} = 6 imes 10^{-12} ext{ grams}.

Hence, the mass is: $6 imes 10^{-12} ext{ grams}$.

The total cell cycle time is 15 hours. From the cell cycle diagram (not shown here, but assuming typical proportions in cell cycles), if approximately 28% of the time is spent in mitosis, we can calculate:

$\text{Time in mitosis} = 15 \text{ hours} \times \frac{28}{100} = 4.2 \text{ hours}.$

Therefore, time spent in mitosis = 4.20 hours.

1. Stage 1 (Interphase): The cell grows and increases the number of organelles, including DNA replication where the cell duplicates its genetic information.
2. Stage 2 (Mitosis): Chromosomes align and separate into two identical sets, and the nucleus divides. The cytoplasm divides into two genetically identical daughter cells.
3. Stage 3 (Cytokinesis): This final phase involves the division of the cytoplasm, leading to the formation of two distinct, genetically identical cells.

Advantages:

1. May be used to cure or treat current/future diseases, such as diabetes or paralysis.
2. Can produce replacement cells, tissues, or organs, which could replace those lost to damage.

Disadvantages:

1. The potential destruction of the embryo raises ethical concerns.
2. There is a risk of the body rejecting the transplanted cells, leading to complications.