Structure of a mitochondrion

Assignment

1) Structure of a mitochondrion.

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A- Outer membrane

B- Inner membrane

D- Cristae

E- Intermembrane space

C- Matrix

2) Why hydrogen and electron carriers are embedded in the inner mitochondrial membranes.

Hydrogen and electron carriers are embedded in the inner mitochondrial membranes to decrease the distance that they travel when going to matrix. The inner mitochondrial membrane contains Cristae that are highly folded and many in numb3r to increase the surface area for the reactions.

3) Protein composition of complex 1 -4.

Complex 1

The following are the proteins that are involved 4in the first complex.

Lethal syndrome; C8orf38

Lethal neonatal; C20orf7

Encephalopathy; C60RF66

Encephalopathy; NDUFAF4

Cardiomyopathy plus Encephalomolopathy; NDUFAF1

Childhood encephalopathy; NDUFAF2

Lethal neonatal encephalopathy; NDUFAF3

Ecsit and Ind1

Complex 2 contains;

Iron- Sulphur protein SDHB

Complex 3 contains; Ubiquinol-cytochrome core proteins 1 and 2

Core1 contains; QCR, UQCRC1

Core 2 contains; QCR2, UQCRC2

Complex 4 contains; Contains; Iron proteins like, Rieske (FeS)

Cytochrome

(b) Alternative name for complex V is ATP synthase.

4) The inhibitory sites of;

(a) Cyanide- chloroplast

(b) Malonate- matrix

(d) Antimycin A. – matrix

(e) Rotenone- matrix

(f) Carbon monoxide- grana

5) structure of subunit of the F0F1 ATP synthase.

F0F1 ATP synthase structure.1

b c

2581275200660 k

3933825-19050 r

Hydrogen ions in

Hydrogen ions out

6) The mechanism through which ATP is synthesised

ATP is synthesised in Mitochondria. It takes two steps in its synthesis. The first step takes place during the light reaction of photosynthesis. The electrons move through cytochrome from a region called grana.

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1 The diagram was obtained from Otheo, L. (2007) ‘Understanding the cell’ Topholo publishers.

In the light energy stage, the energy (light) is used to produce chemical free energy and this energy is then stored in form of glucose. All the reactions in this stage take place in thylakoid membrane. The reaction mainly involves the combination of carbon dioxide with water to produce energy and glucose and oxygen gas. The product is NADP+ which combines later in the light independent stage to produce ATP. ATP is not produced at this stage but if it is produced then it goes to the second stage.

Water oxygen

1304925121920The first stage. Involves light

Light stage

The first stage. Involves light

Light stage

Light

ATP NADP ADP NADP+

130492562230Second does not need light

Dark stage

Second does not need light

Dark stage

Carbon dioxide

Glucose

The second is the dark at times called the Calvin Cycle, carbon (IV) oxide is changed into glucose. It takes place in the stroma of mitochondrion. The purpose is to reduce glucose from carbon dioxide. This is done through a sequence of reactions. There are numerous products and by products that are formed in the process.

References;

Otheo, L. (2007), ‘Understanding the cell’, Topholo publishers.

Raghavendra, A. (2000) ‘Photosynthesis: a comprehensive treatise’, Publisher Cambridge University Press,