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Mitochondria: Structure, function and development

Frage 1 von 33

1

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?

Wähle eins der folgenden:

  • WAHR
  • FALSCH

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Frage 2 von 33

2

What does the outer boundary of a mitochondria contain?

Wähle eine oder mehr der folgenden:

  • Cristae

  • Outer membrane

  • Inner membrane

  • Cytosol

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Frage 3 von 33

2

What is the inner membrane subdivided into?

Wähle eine oder mehr der folgenden:

  • Inner boundary membrane

  • Thylakoid membrane

  • Cristae

  • ATP synthesising membrane

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Frage 4 von 33

1

Approximately what length is a mitochondrion?

Wähle eine der folgenden:

  • 1-2μm

  • 0.1- 05μm

  • 3- 5μm

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Frage 5 von 33

1

According to one of the structural models, what structure joins the major domains of the inner membrane?

Wähle eine der folgenden:

  • Cristae junction

  • Interlinking-tubular connection

  • Connexins

  • Domain-binding protein

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Frage 6 von 33

1

What characteristic makes the outer membrane permeable?

Wähle eine oder mehr der folgenden:

  • Voltage-gated channels

  • Porins

  • Ligand-gated channels

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Frage 7 von 33

2

Why is the mitochondria termed as 'semi-autonomous'?

Wähle eine oder mehr der folgenden:

  • 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.

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Frage 8 von 33

2

How do mitochondria normally exist in cells?

Wähle eine oder mehr der folgenden:

  • Individually

  • In a syncytium

  • In pairs

  • Separated

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Frage 9 von 33

1

What does fusion of mitochondria result in the mixing of?

Wähle eine oder mehr der folgenden:

  • 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

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Frage 10 von 33

2

What are 2 important roles of mitochondrial fusion?

Wähle eine oder mehr der folgenden:

  • For transport of mitochondria

  • To allow communication between organelles

  • For distribution of mitochondria

  • To buffer defects that arise in the mitochondria

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Frage 11 von 33

1

What does mitochondrial division facilitate?

Wähle eine oder mehr der folgenden:

  • Distribution and transport of mitochondria

  • Communication between organelles

  • The buffering defects that arise in mitochondria

  • Division does not facilitate any processes

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Frage 12 von 33

1

What are the only outer membrane proteins essential for fusion of mitochondria?

Wähle eine oder mehr der folgenden:

  • Dynamin-related proteins (DRPs)

  • Sodium-potassium pumps

  • Mitofusins

  • No outer membrane proteins are essential for fusion

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Frage 13 von 33

1

What mediate the division events of mitochondria?

Wähle eine oder mehr der folgenden:

  • Mitofusins

  • Dynamin-related proteins (DRPs)

  • The electron transport chain

  • There are no specific proteins

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Frage 14 von 33

1

The placement of the mitochondrial division site is dependent on an interaction with which other organelle?

Wähle eine oder mehr der folgenden:

  • Peroxisome

  • ER

  • Nucleus

  • Lysosome

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Frage 15 von 33

1

Mitochondria will elongate and form net-like structures due to?

Wähle eine oder mehr der folgenden:

  • Loss of mitochondrial division

  • Loss of mitochondrial fusion

  • Loss of mitochondrial division and fusion

  • Too much mitochondrial division

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Frage 16 von 33

1

Which of these is NOT a result of loss of mitochondrial fusion?

Wähle eine oder mehr der folgenden:

  • 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

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Frage 17 von 33

1

Mitochondria are continually fusing and dividing, they are likely to contain...

Wähle eine oder mehr der folgenden:

  • Wild-type DNA only

  • Both mutant and wild-type DNA

  • Mutant DNA only

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Frage 18 von 33

1

ATP synthase is embedded into the plasma membrane of the inner membrane of the mitochondria, but which part is this?

Wähle eine oder mehr der folgenden:

  • Stalk

  • Base

  • Head

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Frage 19 von 33

1

The generation of ATP via the use of a proton gradient is used by which ATP associated complex?

Wähle eine oder mehr der folgenden:

  • F – Type

  • V – Type

  • C – Type

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Frage 20 von 33

1

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?

Wähle eine oder mehr der folgenden:

  • 10 – 15 subunits

  • 8 – 10 subunits

  • 5 – 8 subunits

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Frage 21 von 33

2

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?

Wähle eins der folgenden:

  • WAHR
  • FALSCH

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Frage 22 von 33

1

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?

Wähle eine der folgenden:

  • Lysine

  • Arginine

  • Histidine

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Frage 23 von 33

1

How many α and β subunits are there on the head of each ATP synthase?

Wähle eine der folgenden:

  • 3 each

  • 4 each

  • 6 each

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Frage 24 von 33

1

What causes the α and β subunits to change from an open to a loose to a tight formation to generate ATP?

Wähle eine der folgenden:

  • Orientation of the α and β subunits

  • Orientation of the Stator

  • Orientation of the ϒ stalk

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Frage 25 von 33

1

True or false: ATP synthase can associate together, with their stalk regions back to back to form a dimer?

Wähle eins der folgenden:

  • WAHR
  • FALSCH

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Frage 26 von 33

3

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?

Wähle eine der folgenden:

  • Complex I, Complex II and Complex IV

  • Complex I, Complex III and Complex VI

  • Complex I, Complex III and Complex IV

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Frage 27 von 33

1

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?

Wähle eine der folgenden:

  • The reduction of NADH

  • The reduction of Ubiquinone

  • The addition of sugars

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Frage 28 von 33

1

Which of the following is NOT another name for Complex II?

Wähle eine der folgenden:

  • Succinate Coenzyme Q reductase

  • Succinate Dehydrogenase

  • Succinate Fumarate reductase

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Frage 29 von 33

1

Complex III contains cytochrome b, cytochrome c, and Fe-S Reiske protein. Which of these structures is encoded for by a mitochondrial gene?

Wähle eine der folgenden:

  • Cytochrome b

  • Cytochrome c

  • Fe-S Reiske protein

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Frage 30 von 33

1

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?

Wähle eine oder mehr der folgenden:

  • An oxide bridge.

  • A peroxide bridge.

  • A Severn Bridge.

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Frage 31 von 33

1

What role does Mitochondria have in regulating the levels of calcium in the cell?

Wähle eine der folgenden:

  • 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.

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Frage 32 von 33

2

Mitochondria has various functions in the cell apart from oxidative phosphorylation. Which of these is also a mitochondrial function?

Wähle eine der folgenden:

  • Apoptosis

  • Detoxification of toxic respiratory products

  • Glucose metabolism

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Frage 33 von 33

3

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.
http://onlinelibrary.wiley.com/doi/10.1002/bdra.20110/full

According to the paper, why is full mitochondrial development important within mammals (3 marks):

Wähle eine oder mehr der folgenden:

  • 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

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