Tag: photosynthesis

Quizzes (18) Questions (162)

Questions Related to photosynthesis

Multiple choice biology photosynthesis site of photosynthesis chloroplast and pigments of photosynthesis pigments action spectrum and absorption spectrum spectrum of electromagnetic radiation

Why does the total amount of $CO _2$ in the atmosphere remains constant even though respiration liberates $CO _2$?

  1. $CO _2$ acts as a buffer
  2. $CO _2$ is converted to carbohydrates in photosynthesis
  3. $CO _2$ forms carbonic acid
  4. $CO _2$ undergoes cleavage during photosynthesis.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Most organisms release or exhale $CO _2$ during respiration. This $CO _2$  present in the environment is utilized by plants in the process of photosynthesis with the final product being a carbohydrate. This is how the amount of $CO _2$  in the atmosphere is kept under check.
So, the correct answer is '$CO _2$  is converted to carbohydrates in photosynthesis'.
Multiple choice botany photosynthesis historical events in photosynthesis history of photosynthesis introduction to photosynthesis

Who is called as 'father of plant physiology'?

  1. K. V Thimann

  2. Stephen Hales

  3. M. Calvin

  4. E. Rabinowitch
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Plant physiology is a subdiscipline of botany concerned with the functioning, or physiology, of plants. 

Stephen Hales is considered the 'father of plant physiology' for the many experiments he conducted in 1727; though Julius von Sachs unified the pieces of plant physiology and put them together as a discipline. 

Multiple choice botany photosynthesis modern concept of photosynthesis photosystems photosynthesis in higher plants

Oxygen released in photosynthesis is due to 

  1. Photophosphorylation.

  2. Photolysis of water.

  3. Photorespiration.

  4. Photons.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Photosynthesis is a process which occurs in two stages. The first is the light dependent reaction where the captured energy of light is used to make the ATP and NADPH. The second stage is where the reactions independent of light use these products to capture and reduce carbon dioxide. Photolysis is part of the light dependent reaction of the photosynthesis process.  
Photosynthesis photolysis can be represented as H$ _2$A + 2 photons --> 2 e$^-$ + 2H$^+$ + A, where the chemical nature of the 'A' depends on the organism. The experiments conducted by Samuel Ruben and Martin Kamen by using radioactive isotopes helped to prove that the oxygen liberated during photosynthesis came from photolysis the water.
Thus, the correct answer is option B.
Multiple choice botany photosynthesis modern concept of photosynthesis photosystems photosynthesis in higher plants

During photosynthesis, oxygen is evolved from

  1. $H _{2}S$.
  2. $H _{2}O$.
  3. $CO _{2}$.
  4. $HCO _{3}$.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Photosynthesis is a redox reaction in which carbon dioxide is reduced to sugars and water is oxidised to release oxygen.

Photolysis refers to light dependent split of water molecule, which occurs during photosynthesis. The process of photolysis provides electrons for non cyclic electron flow during non cyclic photophosphorylation. Mineral ions required for the process of photolysis are manganese, calcium and chlorine.

Multiple choice botany photosynthesis modern concept of photosynthesis photosystems photosynthesis in higher plants

In the process of photosynthesis, the water molecule is broken down in

  1. Red drop.

  2. Photolysis.

  3. Phoshorylation.

  4. Carbon assimilation.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Photosynthesis is chemically a redox reaction in which carbon dioxide is reduced and water is oxidised. During light reaction phase of photosynthesis, the electron that has been donated to the electron transport chain is replaced through photolysis (light dependent splitting) of water, a process that not only yields electrons but also is the source of almost all the oxygen in Earths atmosphere. 

Multiple choice botany photosynthesis modern concept of photosynthesis photosystems photosynthesis in higher plants

Photolysis of water releases ........... gas.

  1. ${ CO } _{ 2 }$
  2. ${ O } _{ 2 }$
  3. ${ NH } _{ 3 }$
  4. ${ CH } _{ 3 }$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Photolysis, the chemical process by which molecules are broken down into smaller units through the absorption of light.

Photolysis of water is the process by which water is split into H+, oxygen, and electrons in the presence of light.
So the answer is 'O2'.