Lecture Nineteen - Plant diversity I

Question 1

What are the three main tears of life?

Answer 1

Eukarya, Archea and Bacteria.

Question 2

Where did oxygenic photosynthesis evolve from?

Answer 2

Oxygenic photosynthesis evolved in cyanobacteria.

If not for photosynthetic organism, there would not be life as we know it on Earth, because oxygen (waste product of photosynthesis) was actually very rare, as it is very reactive, thus usually would not stay in the form O2 (oxidisation reactions).

Question 3

Is fungi more closely related to plants or animals?

Answer 3

Fungi is more closely related to animals.

Here are some of the similarities and differences between fungi, plants and animals.

Question 4

How did eukaryotes become photosythetic?

Answer 4

Chloroplasts (and mitochondria) originate through endosymbiosis.

The eukaryotic cell engulfed prokaryotes containing chloroplasts.

These chloroplasts eventually remained in their host cells, thus becomeing a part of them.

Question 5

What are some examples of cells that undergo temporary endosymbiosis?

Answer 5

Euplotes, a ciliate that engulds green algae in vacuoles and keeps them as photosynthetic endosymbionts for up to several weeks.

Up to 40% of ciliates in lakes and oceans feed on various algae and keep them as temporary endosymbionts.

Question 6

Explain primary and secondary endosymbiosis.

Answer 6

Occured in archaeplastoda lineage.

The initial cells engulfed cells containing chloroplasts = primary endosymbiosis.

These cells then were engulfed by other cells - secondary endosymbiosis.

Question 7

How can a cell contain two nuclei?

Answer 7

If a cell has engulfed another cell containing a chloroplast, then the chloroplast will have a remnent nucleus containing a small genome, which is essential for the function of the cell.

Question 8

What are the different parts of the plant diversity?

Answer 8