This is our learning resource on Mitochondria, in the form of a quiz. There may be more than one correct answer for each question, or equally just one. It is advised that this quiz is used as a consolidation resource, and that lectures have been revised, as well as the content of "Karp, G. C. (2014). Cell Biology. 7th ed. New Jersey: John Wiley." is covered (or any other molecular cell biology text book.
Here is a practice at answering:
Mitochondria are an organelle within the cell. True or False?
What does the outer boundary of a mitochondria contain?
What is the inner membrane subdivided into?
Inner boundary membrane
ATP synthesising membrane
Approximately what length is a mitochondrion?
According to one of the structural models, what structure joins the major domains of the inner membrane?
What characteristic makes the outer membrane permeable?
Why is the mitochondria termed as 'semi-autonomous'?
It has it's own DNA and therefore replication is not controlled by cell division but most of the proteins it requires are encoded for by the nucleus and without them, the mitochondrion would not be functional.
It can only partially carry out its function on its own without the intervention of other organelles to complete a task.
It has it's own DNA and ribosomes within the matrix but requires substrates from the cytosol such as pyruvate to carry out its function as it doesn't contain the right enzymes to make the substrates itself.
How do mitochondria normally exist in cells?
In a syncytium
What does fusion of mitochondria result in the mixing of?
The outer membranes only
The inner membranes only
The outer membranes and contents of the matrix only
The outer membranes, inner membranes and the contents of the matrix
What are 2 important roles of mitochondrial fusion?
For transport of mitochondria
To allow communication between organelles
For distribution of mitochondria
To buffer defects that arise in the mitochondria
What does mitochondrial division facilitate?
Distribution and transport of mitochondria
Communication between organelles
The buffering defects that arise in mitochondria
Division does not facilitate any processes
What are the only outer membrane proteins essential for fusion of mitochondria?
Dynamin-related proteins (DRPs)
No outer membrane proteins are essential for fusion
What mediate the division events of mitochondria?
Dynamin-related proteins (DRPs)
The electron transport chain
There are no specific proteins
The placement of the mitochondrial division site is dependent on an interaction with which other organelle?
Mitochondria will elongate and form net-like structures due to?
Loss of mitochondrial division
Loss of mitochondrial fusion
Loss of mitochondrial division and fusion
Too much mitochondrial division
Which of these is NOT a result of loss of mitochondrial fusion?
Facilitation of cell death in response to apoptotic signals
Formation of well-connected networks
Slow cell growth
Reduced activity of all respiratory complexes
Loss of control of mitochondrial shape
Mitochondria are continually fusing and dividing, they are likely to contain...
Wild-type DNA only
Both mutant and wild-type DNA
Mutant DNA only
ATP synthase is embedded into the plasma membrane of the inner membrane of the mitochondria, but which part is this?
The generation of ATP via the use of a proton gradient is used by which ATP associated complex?
F – Type
V – Type
C – Type
The C – subunits are used by protons as a transporter to ‘pass’ through the a – subunit. How many C – subunits are found in the bacterial/plastid ATP synthase complex?
10 – 15 subunits
8 – 10 subunits
5 – 8 subunits
True or false: the addition of a proton to the COOH group found on a C – subunit causes the neutralisation of the group which in turn generates the rotation seen in an active complex?
The use of opposite charges are used to generate the motion of the C – subunit which drives the rotation of the stalk. The attraction between the COO- group and which amino acid on the Stator causes the motion?
How many α and β subunits are there on the head of each ATP synthase?
What causes the α and β subunits to change from an open to a loose to a tight formation to generate ATP?
Orientation of the α and β subunits
Orientation of the Stator
Orientation of the ϒ stalk
True or false: ATP synthase can associate together, with their stalk regions back to back to form a dimer?
The Respirasome is a complex of multiple complexes which are used in the electron transport chain. Which of the following is the make-up of the Respirasome?
Complex I, Complex II and Complex IV
Complex I, Complex III and Complex VI
Complex I, Complex III and Complex IV
The action of Complex I, allows for the translocation of four protons into the intermembrane space, this action is also coupled with which other process?
The reduction of NADH
The reduction of Ubiquinone
The addition of sugars
Which of the following is NOT another name for Complex II?
Succinate Coenzyme Q reductase
Succinate Fumarate reductase
Complex III contains cytochrome b, cytochrome c, and Fe-S Reiske protein. Which of these structures is encoded for by a mitochondrial gene?
Fe-S Reiske protein
Complex IV makes use of atmospheric oxygen to generate water. This process is achieved via the creation of what, between haem groups CuB and a3, causing the reduction of oxygen?
An oxide bridge.
A peroxide bridge.
A Severn Bridge.
What role does Mitochondria have in regulating the levels of calcium in the cell?
Mitochondria acts as an intracellular buffer of calcium.
The majority of the calcium absorbed by the cell is then absorbed by the mitochondria to avoid precipitation when in contact with phosphate groups.
Mitochondria does not play any role in regulating levels of calcium.
Mitochondria has various functions in the cell apart from oxidative phosphorylation. Which of these is also a mitochondrial function?
Detoxification of toxic respiratory products
Read this paper:
Xu, Y., Peng, L. and Li, Y. (2005). Impaired development of mitochondria plays a role in the central nervous system defects of fetal alcohol syndrome. Birth Defects Research 73: 83-91.
According to the paper, why is full mitochondrial development important within mammals (3 marks):
It can lead to poorly formed organs and central nervous system.
It leads to abnormal cellular metabolism.
It is important in homeostasis
None of the above