Lab 6a - Cholorplasts and Mitochondria

Question 1

Summerize the reaction of photosynthesis

Answer 1

6CO2 + 12H2O –light E–> Glucose + 6O2 + 6H2O

Question 2

Summarize Cellular Respiration.

Answer 2

Glucose (C6H12O6) + 6O2 + 6H2O —> 6CO2 + 12H2O + ATP

Question 3

What does it mean when someone says chloroplasts have a double membrane system?

Answer 3

It means there is an outer membrane and an inner membrane

Question 4

What is the Stroma?

Answer 4

Fluid filled region that is enclosed by the inner membrane

Question 5

What is a thylakoid?

Answer 5

Interconnected set of flat disk like sacs

Question 6

What is the space inside the thylakoid (enclosed by the thylakoid membrane) called?

Answer 6

The thylakoid lumen

Question 7

What are stacks of thylakoid’s called?

Answer 7

Grana

Question 8

Where do the light reactions take place? Where do the dark reactions take place?

Answer 8

Light reactions: thylakoid membrane

Dark reactions: stroma

Question 9

Name the organisms that have this type of chloroplast and how many of that type of chloroplast it has.

Answer 9

Spiral shaped: Spirogyra - NA
C-shaped: Ulothrix - 1
Star shaped: Zygnema - 2
Circular/Oval: Elodea - Many! 50+
Ribbon: Mougeotia - 1

Question 10

Why might scientists believe that mitochondria evolved before chloroplasts?

Answer 10

Because if for example chloroplasts evolved before mitochondria, then there would be some cells that contain only chloroplasts, but on the contrary, we only see cells that have either both mitochondria and chloroplasts or only mitochondria.

Question 11

How does the symbiotic theory explain the double membrane system of the 2 organelles?

Answer 11

1. Cell that was engulfed was a prokaryotic aerobe (single membrane)
2. Cell that engulfed the aerobe did so by phagocytosis which added another layer of membrane (now double membraned)

Question 12

Discuss how G. nostochinearum and C. paradoxa are both eukaryotic cells that contain cyano bacterium, since this shows that it’s possible to for 2 organisms to co-exist, this supports symbiotic theory.

Answer 12

During the cauliflower assay, what is the main constituent of the first pellet?

Question 13

Nucleus

Answer 13

In the cauliflower assay, after the nucleus, what the other constituent?

Question 14

Sea sand

Answer 14

Where is the mitochondria located after the first centrifugation?

Question 15

In the supernatant

Answer 15

What is the main constituent of the second pellet (after second centrifugation)?

Question 16

What 4 things support symbiotic theory?

Answer 16

1. Double membrane system of chloroplast and mitochondria
2. No cholesterol on inner membrane
3. Independent genetic machinery + 1 long strand of genetic material like prokaryotes
4. Size of ribosomes and antibiotic sensitivity will be similar to prokaryotes

Question 17

What is symbiotic theory?

Answer 17

The theory that mitochondria and chloroplasts evolved by symbiotic relationships between ancient prokaryotes

Question 18

Function of the outer membrane in mitochondria?

Answer 18

1. Phospholipid synthesis

2. Fatty acid desaturation and elongation

Question 19

What is the function of the inner membrane of the mitochondria?

Answer 19

1. Electron transport chain
2. Oxidative phosphorylation
3. Metabolite transport

Question 20

What’s the difference between a chlamydomonas pyrenoid and and pilayella pyrenoid?

Answer 20

chlamydomonas pyrenoid is in the centre of the chloroplast and pilayella pyrenoid is burgeoning

Question 21

What does a pyrenoid do?

Answer 21

⬆️ local [CO2]
⬆️ [RubisCO]
Aids starch formation

Question 22

What do the ultra structures of chloroplasts in red algae, brown algae, and corn + oats, look like?

Answer 22

Red: thin grana
Brown: groups of 3s grana
Corn + oats: bundles of thick Grana