Tag: mechanism of photosynthesis

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Questions Related to mechanism of photosynthesis

Multiple choice bio-chemistry biological oxidation chemiosmotic hypothesis living organisms and energy production mechanism of photosynthesis

Who am I?

  1. I am ATP producing factory

  2. I am single layered, but maintain cellular osmotic pressure

  3. I support the cell, but I am not cell wall I have a body resembling net

  4. I am chemical factory of the cell

  5. Leaves are green because of me
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Mitochondria are the primary sites of aerobic respiration and are famously referred to as the powerhouses of the cell because they produce the majority of ATP.

Multiple choice bio-chemistry biological oxidation chemiosmotic hypothesis living organisms and energy production mechanism of photosynthesis

How many ATP molecules will be produced when one molecule of 3-phosphosphoglyceric acid is completely oxidised : 

  1. 16

  2. 32

  3. 64

  4. 48
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

One molecule of 3-phosphoglyceric acid enters the glycolytic pathway after the initial steps. Its complete oxidation through glycolysis and the Krebs cycle yields 16 ATP molecules.

Multiple choice bio-chemistry biological oxidation chemiosmotic hypothesis living organisms and energy production mechanism of photosynthesis

How many ATP molecules are produced after complete oxidation of one molecule of fructose-1, 6-bis-phosphate ?

  1. 40

  2. 32

  3. 38

  4. 44
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Fructose-1,6-bisphosphate is already phosphorylated. It bypasses the initial investment phase of glycolysis, resulting in a net gain of 40 ATP molecules upon complete oxidation.

Multiple choice bio-chemistry biological oxidation chemiosmotic hypothesis living organisms and energy production mechanism of photosynthesis

During photosynthesis 

  1. $O _{2}$ evolved comes from $CO _{2}$

  2. ATP is formed

  3. ATP is not formed

  4. Water is required as medium but it does not take part in photosynthesis
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Photosynthesis is an anabolic process, which helps in forming ATP, where it is called as energy currency. During the light reaction photophosphorylation takes place producing ATP and $NADPH _2$ which is used as energy source for dark reaction.

Multiple choice bio-chemistry biological oxidation chemiosmotic hypothesis living organisms and energy production mechanism of photosynthesis

ATP synthesis proposed by Peter Mitchell is 

  1. Phosphorylation

  2. Photophosphorylation

  3. Oxidative phosphorylation

  4. Chemiosmotic synthesis
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Peter Mitchell proposed a theory to explain the production of ATP which is 'Mitchell's chemiosmotic coupling hypothesis'. According to this theory:

  1. Inner membrane of mitochondria acts as a transducer of energy and converts energy to chemical energy of ATP along the electrochemical gradient.
  2. Inner mitochondrial membrane is impermeable to NADH, ATP, H+, OH-.
  3. ATP synthesis and electron transport are coupled with proton gradient.
So the answer is 'Chemiosmotic synthesis'.

Multiple choice bio-chemistry biological oxidation chemiosmotic hypothesis living organisms and energy production mechanism of photosynthesis

ATP is injected in cyanide poisoning because it is

  1. Necessary for cellular functions
  2. Necessary for $Na^+$ - $K^+$ pump
  3. $Na^+$ - $K^+$ pump operates at the cell membranes

  4. ATP breaks down cyanide
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Cyanide inhibits cytochrome c oxidase, blocking the electron transport chain and halting ATP production. Injecting ATP provides the necessary energy for vital cellular functions that would otherwise fail.

Multiple choice bio-chemistry biological oxidation chemiosmotic hypothesis living organisms and energy production mechanism of photosynthesis

Chemiosmotic hypothesis given by Peter Mitchell proposes the mechanism of

  1. Synthesis of ATP.
  2. Synthesis of FADH$ _2$.

  3. Synthesis of NADH.

  4. Synthesis of NADPH.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Peter Mitchell proposed a hypothesis known as the chemiosmotic hypothesis that an electrochemical concentration gradient of protons across a membrane could be utilized to make ATP. He linked this process to osmosis, the diffusion of water across a membrane, this is the reason it is called chemiosmosis.

So the correct option is 'Synthesis of ATP'.

Multiple choice bio-chemistry biological oxidation chemiosmotic hypothesis living organisms and energy production mechanism of photosynthesis

Light reaction in stroma lamellae of chloroplast results in the production of

  1. ATP
  2. NADPH$ _2$
  3. ATP + NADPH$ _2$
  4. O$ _2$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A) Along with ATP, ${ NADPH } _{ 2 }$ is also produced.
B) Along with ${ NADPH } _{ 2 }$, ATP is also produced.

C) The light reaction that takes place in the stroma lamellae is the non-cyclic phosphorylation and ATP and ${ NADPH } _{ 2 }$ are the products.
D) Oxygen is also liberated during the light reaction but is not the main product.
So the correct answer is 'ATP + ${ NADPH } _{ 2 }$'.

Multiple choice bio-chemistry biological oxidation chemiosmotic hypothesis living organisms and energy production mechanism of photosynthesis

ATP does not provide phosphate in the reaction

  1. Glucose Glucose 6-P

  2. Fructose Fructose 6-P

  3. PGAL 1 : 3-diPGA

  4. PEPA Pyruvic acid
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In the conversion of PGAL to 1,3-bisphosphoglycerate, the phosphate group is added via inorganic phosphate (Pi) and oxidation, not by transferring a phosphate from ATP.