Cell Structure and Function - Curios from Curiosity

Criteria

Question/Task

3.2

Despite being limited in terms of genetic analysis (this was not possible on these samples) or biochemical analysis (Curiosity only has certain functions), scientists may be able to gain some knowledge of their closest relatives on earth. 

                Using your knowledge and understanding of how structure (both at cellular and whole organism level) can help classify organisms, and Illustrating your response with named examples from classified organisms on earth, suggest to what extent scientists could classify these Martian organisms.

1.2; 1.3

Some cells in the sample are isolated and scientists are looking at these in particular as the images are so clear.  Curiosity was able to stain these samples so that certain structures could be seen.  Here is an excerpt (analysis of cells B and D) from one team’s report:

“.. Stained images appear to show that cell B and D have structures common to both Prokaryotes and Eukaryotes.   If it were possible to analyse the functions of these structures, the classification of these cells could be determined.”

To what extent do you agree with the above excerpt? Suggest and explain any further evidence you would need (if the cells are brought to earth) to determine classification of these cells.

(Your response should fully discuss the distinguishing characteristics of Prokaryotes and Eukaryotes as well as clarify the ‘functions’ referred to in the excerpt)

2.3

Cell A seemed to have been preserved in a particularly good state.  Curiosity was able to carry out basic biochemical analyses.  One such analysis reveals that there is a surprisingly high concentration of Hydrogen ions inside the cell.  A team of cell biologists have agreed that the Hydrogen ions have probably entered the cell from the external environment; however, they disagree on the mode by which these ions have entered.  Factions within the teams support the following:

• Diffusion
• Facilitated Diffusion
• Active Transport
• Pinocytosis

Using your knowledge and understanding, and illustrated with named terrestrial examples, discuss the possibility of each of the above – how likely is each type of transport to be responsible for the Hydrogen ion content of the cell and what more evidence (to be collected if samples are brought to earth) would you need to support that mode of entry?

3.1

This is a diagram of Cell C from the Martian sample.  Scientists have suggested that it is part of a multicellular organism and is a specialised cell.  Bioteam 1 has suggested that it is a secretory cell like the beta cells in the pancreas because of the granules that appear to be vesicles.  However, Bioteam 2 has suggested that it is more like a neurone based on shape and that the vesicles may contain something similar to neurotransmitters. 

           Using your knowledge and understanding of the 2 terrestrial cell types above, to what extent do you agree with each team?  Suggest and explain what further evidence is needed for a reliable conclusion.