Lecture 7

Question 1

Where is the mitochondria found?

Answer 1

In eukaryotic cells (plant/animal) in the cytoplasm

Question 2

What is the function of mitochondria?

Answer 2

• The powerhouse of the cell
• Role in Adenosine Triphosphate (ATP) production
• They contain the enzymes used in oxidative phosphorylation, which is used to convert ADP to ATP
• Synthesis of ATP by oxidative phosphorylation

Question 3

Are living mitochondria stationary?

Answer 3

No, they move around in the cytoplasm and congregate in areas of high metabolic activity

Question 4

What does the shape of the mitochondria vary from?

Answer 4

Shape varies from rods to

spheres

Question 5

What is the structure of the mitochondria?

Answer 5

Each mitochondrion is
bounded by two membranes:
– A smooth outer membrane
– An inner membrane, folded into thin plates called cristae
- The interior of the mitochondrion is called the matrix

Question 6

Cristae structure?

Answer 6

• Infolds of the inner plasma membrane
• May extend from wall to wall or only part of the way
• Occasionally the cristae may
  be tubular or some other
  shape

Question 7

Cristae function?

Answer 7

- Provide a large surface area
for sequential chemical
reactions to take place
- Direct correlation between
number of cristae and the
activity of the cell

Question 8

What is the structure and function of the matrix?

Answer 8

• The interior of the mitochondrion
• Contains ribosomes and non-chromosomal DNA
• Manufactures its own proteins with mtDNA
• Contains Kreb’s or citric acid cycle enzymes, which convert chemical energy in our food into ATP energy.

Question 9

Fo?

Answer 9

Located within the inner membrane and serves as a router like motor and channel for the transport of H+ ions from the intermediate space into the matrix

Question 10

F1?

Answer 10

Located in the matrix and serves as the axil and catalytic parts of ATP synthase

Question 11

What is cytosol?

Answer 11

The outer mitochondrial membrane

Question 12

How does the reproduction of mitochondria work?

Answer 12

- When a cell divides
mitochondria are distributed
equally to the two daughter
cells
- Thereafter mitochondria
increase in numbers to bring
them up to the levels required
for efficient cell function
- They arise from pre-existing
mitochondria by division

Question 13

What 5 things does the Serial Endosymbiotic Theory provide evidence for?

Answer 13

1. Mitochondria and chloroplasts have their own circular DNA
2. Produce their own proteins
3. They can replicate independently in the cell
4. Their ribosomes are more like bacterial ribosomes
5. Bacterial antibiotics, which do not affect eukaryotic cells can poison mitochondria and chloroplasts

Question 14

Discuss the appearance of the endoplasmic reticulum in the cell.

Answer 14

• It extends from the nuclear
  envelope almost (but not quite) to the plasma membrane
• The interconnecting channels
  or tubules may expand in
  places to form flattened discs
  called cisternae
• These may localize the ER into certain cytoplasmic areas

Question 15

What are the two types of ER?

Answer 15

Smooth and rough
- Both are part of one
interconnected system and
are usually present in the
same cell

Question 16

What is the function of rough ER?

Answer 16

Protein synthesis and transport:
- The proteins are transported to various parts of the
cell and in particular to another organelle, the Golgi
Apparatus

Question 17

What are the two types of proteins involved in the protein synthesis function of the rough ER?

Answer 17

1. Water-soluble proteins, which cross the ER membrane and enter the lumen, for eventual release elsewhere
2. Prospective Transmembrane proteins, which remain embedded in the ER membrane

Question 18

What is the granulation which gives the rough ER its name is due to?

Answer 18

The attached ribosomes