HELP!!!

Cellular examination of a cyanobacterium and a diatom reveals that the diatom has (which structure?) that is absent in the cyanobacterium?
a. DNA
b. chloroplasts
c. plasma membrane
d. a cell wall with peptidoglycan
e. all of the above

Since this is not my area of expertise, I searched Google under the key words "cyanobacterium diatom anatomy" to get these possible sources:

http://www.mbari.org/staff/conn/botany/phytoplankton/phytoplankton_diatoms.htm
http://www.uic.edu/classes/bios/bios104/mike/bacteria01.htm
http://www.publish.csiro.au/?act=view_file&file_id=FPv29n3toc.pdf
http://stri.discoverlife.org/mp/20q?search=Algae
http://ebiomedia.com/prod/algaeguide1.html

I hope this helps. Thanks for asking.

Thank you!

You're welcome! I'm glad I could help. Now, let's break down the question and find the answer together.

The question asks which structure is present in a diatom but absent in a cyanobacterium. To determine the answer, we need to understand the characteristics and structures of both organisms.

A cyanobacterium is a type of bacteria that can perform photosynthesis. It is prokaryotic, meaning it lacks a nucleus and membrane-bound organelles. On the other hand, a diatom is a type of algae that is eukaryotic, meaning it has a nucleus and membrane-bound organelles.

Now, let's analyze the options:

a. DNA: Both cyanobacteria and diatoms have DNA, so this is not the correct answer.

b. Chloroplasts: Chloroplasts are responsible for photosynthesis and are present in diatoms. Cyanobacteria also carry out photosynthesis, but they do not have chloroplasts. So, this is the correct answer.

c. Plasma membrane: Both cyanobacteria and diatoms have a plasma membrane, so this is not the correct answer.

d. A cell wall with peptidoglycan: Peptidoglycan is a component of the cell wall in bacteria, including cyanobacteria. Diatoms have a cellulosic cell wall, so they do not have peptidoglycan. Therefore, this option is not the correct answer either.

e. All of the above: This option is not correct, as both cyanobacteria and diatoms do have DNA, plasma membrane, and a cell wall (although made of different materials).

Therefore, the correct answer to the question is b. chloroplasts.

I hope this explanation helps! Let me know if you have any more questions.