Lecture 7 Flashcards
Where is the mitochondria found?
In eukaryotic cells (plant/animal) in the cytoplasm
What is the function of mitochondria?
- 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
Are living mitochondria stationary?
No, they move around in the cytoplasm and congregate in areas of high metabolic activity
What does the shape of the mitochondria vary from?
Shape varies from rods to
spheres
What is the structure of the mitochondria?
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
Cristae structure?
- 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
Cristae function?
- Provide a large surface area for sequential chemical reactions to take place - Direct correlation between number of cristae and the activity of the cell
What is the structure and function of the matrix?
- 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.
Fo?
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
F1?
Located in the matrix and serves as the axil and catalytic parts of ATP synthase
What is cytosol?
The outer mitochondrial membrane
How does the reproduction of mitochondria work?
- 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
What 5 things does the Serial Endosymbiotic Theory provide evidence for?
- Mitochondria and chloroplasts have their own circular DNA
- Produce their own proteins
- They can replicate independently in the cell
- Their ribosomes are more like bacterial ribosomes
- Bacterial antibiotics, which do not affect eukaryotic cells can poison mitochondria and chloroplasts
Discuss the appearance of the endoplasmic reticulum in the cell.
- 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
What are the two types of ER?
Smooth and rough - Both are part of one interconnected system and are usually present in the same cell
What is the function of rough ER?
Protein synthesis and transport:
- The proteins are transported to various parts of the
cell and in particular to another organelle, the Golgi
Apparatus
What are the two types of proteins involved in the protein synthesis function of the rough ER?
- Water-soluble proteins, which cross the ER membrane and enter the lumen, for eventual release elsewhere
- Prospective Transmembrane proteins, which remain embedded in the ER membrane
What is the granulation which gives the rough ER its name is due to?
The attached ribosomes
