Question

chloroplast:
1) describe 2 examples of how form is linked to function.
2) what Is the name of the electron donor and final electron acceptor for light dependent reactions (overall photosystem 1 and 2)
3) similarities and differences in ATP production between mitochondria and chloroplast

Answer 1

Answer-:

1) Describe 2 examples of how form is linked to function.

Explanation-

a-The photosysnthesis are follow for food formation like sugar (carbohydrate) and biomaas (carbon)storage for plant life spun.

b-In this process oxygen is most important product that is the base of life of our biotic system.

2) What is the name of the electron doner and final electron acceptor for light dependent reactions (overall photosystem 1 and 2) ?

Explanation-

Process of light dependent reaction-:

1- Light energy splits water and extracts electron in photosystem II (PS II) ;then electron are moved from PS-II to cytochrome b6f to photosysem I (PS-I) and reduse energy.

2-Electron are re energized in PS-I and those high energy electrons reduce NADP+ to NADPH.

3-In non cyclic photophosphorylation cytochrome b6f uses the energy of electrons from PS-II to pump hydrogen ion from  the lumen to the stroma ;this energy allows ATP synthase to attach a third phosphate group to ADP,which from ATP.

4-In cyclic photophosphorylation ,cytochrome b6f uses the energy of electrons from both PS-II to PS-I to create more ATPand to stop the production of NADPH ,maintaining the right proportions of NADPH and ATP.

KEY TERMS-:

1-PHOTOSYSTEM- Either of two biochemical system active in chloroplast that are part of photosynthesis .

2-Photophosphorylation-The addition of a phosphate(PO43-) group to a protein or other organic molecule by photosynthesis.

3-Chemiosmosis-The movement of ion across a selectively permeable   membrane down their electrochemical gradient.

3)Similarities and differences in ATP production between mitochondria and chloroplast.

Explanation-

Similarities

Mitochondria and chloroplast both have:

• A double membrane surrounding the organelles.
• Purportedly prokaryotic origins according to the endosymbiotic theory which suggests that mitochondria and chloroplast were once prokaryotic bacteria engulfed by endocytosis in early eukaryotes.
• Their own circular DNA which codes for certain enzymes required for the chemical reactions that take place in these organelles.
• Their own 70S ribosomes made up of 50S and 30S subunits to translate proteins
• The enzyme ATP synthase which utilizes the energy released from the movement of protons across it (proton-motive force) to phosphorylate ADP to ATP. (Thus, another similarity would be that they both produce ATP)
• Electron transport chains, which are embedded in the inner mitochondrial membrane and thylakoid membrane in mitochondria and chloroplasts respectively.
• Both organelles have chemical cycles in which the initial acceptor is regenerated at the end of the cycle. In mitochondria, the Krebs cycle occurs after which oxaloacetate is regenerated at the end of the reaction. In chloroplasts, the Calvin cycle occurs in which ribulose bisphosphate (RuBP) is regenerated at the end of the reaction.

Differences

• Obvious structural and naming differences that you should be able to figure out from the diagram above.
• Mitochondria are involved in cellular respiration whereas chloroplasts are involved in photosynthesis. Thus, the overall chemical reactions for the processes occurring in them are different and reversed.

• - Respiration: C6H12O6+6O2 ---> 6CO2+6H2O+ATP

  - Photosynthesis: 6CO2+6H2O --->C6H12O6+6O2

• Mitochondria are found in all animal and plant cells. Chloroplasts, however, are found in only specific types of plant cells, such as the palisade mesophyll and spongy mesophyll cells of leaves. These cells are the ones involved in carrying out photosynthesis. Other types of plant cells, such as root cells do not contain chloroplasts.
• Chloroplasts contain pigments such as chlorophyll a, chlorophyll b and carotenoids. Mitochondria do not contain any such pigments.
• The ATP synthase in mitochondria and chloroplast are orientated differently. ATP synthase in mitochondria points into the matrix, with protons flowing from the intermembrane space to the matrix. In chloroplasts however, ATP synthase points towards the stroma, and protons flow from the thylakoid space into the stroma.
• The types of electron acceptors present in mitochondria and chloroplast vary. While mitochondria contain NAD and FAD, chloroplasts contain NADP.
• The sources of energy used to synthesize ATP in mitochondria and chloroplasts are different. In mitochondria, this energy comes from the oxidation of glucose, and is hence termed oxidative phosphorylation. In chloroplast, this energy comes from light, so it is called photophosphorylation.
• Mitochondria function under both light and dark conditions. Chloroplasts, on the other hand, do need light to function.
• Electron transport chains: The final electron acceptor in mitochondria is oxygen, whereas the final electron acceptor in chloroplasts is NADP.
• In mitochondria, the root source of electrons is generally glucose (it could be other substrates depending on what was utilized). In chloroplasts, however, the root source of electrons is the photolysis of water occurring at photosystem II. Water (H2O) is broken down to release 2 protons, 2 electrons and a molecule of oxygen.
• Mitochondria give out carbon dioxide from the decarboxylation (removal of carbon)reactions that occur during the link reaction and Krebs cycle but chloroplasts give out oxygen due to photolysis as explained above.

Reference-: LUMEN boundless biology.

Quora (A level biology... by -Rozalin Mohanty).