Question

A - If 15 cell culture flasks contain 6 x 10⁵ cells per ml and each flask holds 25 mls, how many cells are there in total (in scientific notation)?

B - Given the following equation, C1V1 = C2V2: Calculate the volume of stock solution and the volume of water required to make 500 mL with a 400 mg/mL concentration from a stock containing 1600 mg/mL.

C - Given that 2n = 20 , fill in both the number of chromosomes and chromatids at each of the following stages during the cell cycle:

Interphase: in G1 and G2

Mitosis:    in Metaphase and Anaphase

Post-Mitosis: in each Daughter Cell (assume directly after Cytokinesis)

(straight forward answer with no long explanation would be fine! will rate - thank you) :)

Answer 1

A. We have 15 cell culture flasks contain 6 x 105 cells per ml and each flask holds 25 mls, Then-

Total volume of all the flask would be = 25 × 15

                                                                                                                                                                                                                        = 375 ml

No of cells per ml = 6 x 105

Total number of cells would be= 2.25 x 108

There are 2.25 x 108 cells in total.

B. We need to know what volume (V1) of the stock to use as part of the 500 ml total volume needed.

V1= The volume of stock to start with (to be calculated)

C1= 1600 mg/ml in stock solution

V2= total volume needed at the new concentration (500 ml)

C2= the new concentration (400mg/ml)

Given C1V1=C2V2

1600mg/ml x V1 = 400 mg/ml x 500 ml

After cancelling the units,

125 ml

So, 125 ml of stock solution would be taken and to make it 500 ml 375 ml of water to be added.

C.         Given that 2n = 20, then both the number of chromosomes and chromatids at each of the following stages during the cell cycle:

Interphase: in G1 and G2= in interphase G1 stage the other cell contents are duplicated not chromosome so no of chromosome= 20

In G2 no of chromosomes = 20

No of chromatids= 40

Mitosis:    in Metaphase , No of chromosomes= 20 and No of chromatids= 40

and Anaphase, No of chromosomes=20

Post-Mitosis: in each Daughter Cell contains identical genetic information that is the same number of chromosomes= 20