Biology AS Question Help

The generation time for a population of bacteria is the time taken for all the
bacteria to divide once by binary fission.
Use Figure 1 and the following equation to calculate the generation time
for this population of bacteria. Give your answer in hours.

This is the paper:

https://www.physicsandmathstutor.com/pdf-pages/?pdf=https%3A%2F%2Fpmt.physicsandmathstutor.com%2Fdownload%2FBiology%2FA-level%2FTopic-Qs%2FAQA%2F1-Biological-Molecules%2FSet-C%2F1.5%2520Nucleic%2520Acids%2520QP.pdf

It's question 2(b) for reference to the actual graph and equation. Thankss

Reply 1

Student2011584

-4 hours: 4x10^6
+4 hours: 3 x 10^9
log10(3x10^9/4x10^6)= 2.8750...
2.875/log(2) = 9.5507... This is for 8 hours so
8/9.5507... = 0.8376

Reply 2

preciouuss_

Original post by Student2011584

-4 hours: 4x10^6
+4 hours: 3 x 10^9
log10(3x10^9/4x10^6)= 2.8750...
2.875/log(2) = 9.5507... This is for 8 hours so
8/9.5507... = 0.8376

thanks so muchhh!

Reply 3

Bytwomuch

I have a question how is the 9.55... for 8hours?

(edited 11 months ago)

Reply 4

Jaakor48

Original post by Bytwomuch

I have a question how is the 9.55... for 8hours?

Because the 9.55 was for generations in 8 hours, we need to find the time for 1 generation as the question defined generation time as the time for all bacteria to divide once

So 8/9.55 gives you hour per 1 generation

Reply 5

ckx_x

Original post by Student2011584

-4 hours: 4x10^6
+4 hours: 3 x 10^9
log10(3x10^9/4x10^6)= 2.8750...
2.875/log(2) = 9.5507... This is for 8 hours so
8/9.5507... = 0.8376

Hey how did you find 3 and 4 for -4 and +4

Reply 6

Riema

Original post by Student2011584

-4 hours: 4x10^6
+4 hours: 3 x 10^9
log10(3x10^9/4x10^6)= 2.8750...
2.875/log(2) = 9.5507... This is for 8 hours so
8/9.5507... = 0.8376

how did you find those values?

Reply 7

Riema

Original post by ckx_x

Hey how did you find 3 and 4 for -4 and +4

instead of 10^9.x reading off the graph it would be xtimes10^9 so say reading off the graph we got 3 boxes above then it's 3x10^9 not 10^9.3? does that make sense?

Reply 8

Ewwe

Original post by Riema

instead of 10^9.x reading off the graph it would be xtimes10^9 so say reading off the graph we got 3 boxes above then it's 3x10^9 not 10^9.3? does that make sense?

No I'm sorry but the graph paper lines don't appear to be regularly spaced, they are much wider at the bottom. I can only count 3 x 10-6 and 2 x 10-9 - confused.com! How are you getting 4 and 3?

Reply 9

anonymous_001

Original post by Ewwe

No I'm sorry but the graph paper lines don't appear to be regularly spaced, they are much wider at the bottom. I can only count 3 x 10-6 and 2 x 10-9 - confused.com! How are you getting 4 and 3?

Hi! Had the same problem as you and I'm not really good at explaining so I'll put the link to the video which helped me. Skip to 41:34

https://www.youtube.com/watch?v=FE6AWWz5_j8

Hope it helps 😊