Tag: photosynthesis

Questions Related to photosynthesis

Which of the following can be measured by UV spectroscopy?

botany photosynthesis action spectrum and absorption spectrum spectrum of electromagnetic radiation chloroplast and pigments of photosynthesis site of photosynthesis

  1. Turbidity

  2. Bacterial growth

  3. Cell count

  4. All of the above

Show answer
Correct Option: D
Explanation:
UV spectroscopy (400-700nm) is a type of absorption spectroscopy in which light of ultra-violet region is absorbed by the molecule resulting in the excitation of the electrons from the ground state to higher energy state. It obeys the Beer-Lambert law that states that when a beam of monochromatic light passes through a solution of an absorbing substance, the rate of decrease of intensity of radiation with the thickness of the absorbing solution is directly proportional to the incident radiation as well as the concentration of the solution. Hence it is used to determine turbidity, bacterial growth and cell count. Thus, the correct answer is option D.

The special features of spectrophotometer includes

botany photosynthesis action spectrum and absorption spectrum spectrum of electromagnetic radiation chloroplast and pigments of photosynthesis site of photosynthesis

  1. Spectral bandwidth

  2. Percentage of sample-transmission

  3. Logarithmic range of sample absorption

  4. All of the above

Show answer
Correct Option: D
Explanation:

In a spectrophotometer, the spectrometer produces the desired range of wavelength of light from a wide range of wavelengths. Transmittance (T) is the percentage of sample transmission and is defined as the fraction of light that passes through the sample. It is related to absorption by the expression 

Absorbance(A)= --logT=--logIt/Io, where It is the amount of light transmitted and Io is the amount of light incident on the cuvette solution. 
So, the correct answer is 'All of the above'

Which of the following parts of spectrophotometer allows to incident mechanically selected bandwidth for spectroscopy?

botany photosynthesis action spectrum and absorption spectrum spectrum of electromagnetic radiation chloroplast and pigments of photosynthesis site of photosynthesis

  1. Monochromator

  2. Amplifier

  3. Photoresistor

  4. All of the above

Show answer
Correct Option: A
Explanation:

Monochromator filters/allows only a single/particular wavelength of light to pass through the solution.

So, the correct answer is 'Monochromator'

Which of the following is mainly used to the light intensity and optical properties in a UV spectrophotometer?

botany photosynthesis action spectrum and absorption spectrum spectrum of electromagnetic radiation chloroplast and pigments of photosynthesis site of photosynthesis

  1. Photometer

  2. Monochromator

  3. Diode

  4. All of the above

Show answer
Correct Option: A
Explanation:

UV spectroscopy is a type of absorption spectroscopy in which light of ultra-violet region is absorbed by the molecule resulting in the excitation of the electrons from the ground state to higher energy state. A photometer is a part of a UV spectrophotometer and measures light intensity or the optical properties of solutions. Thus the correct answer is option A.

Which of the following can be measured by photometer?

botany photosynthesis action spectrum and absorption spectrum spectrum of electromagnetic radiation chloroplast and pigments of photosynthesis site of photosynthesis

  1. Illuminance

  2. Irradiance

  3. Fluorescence

  4. All of the above

Show answer
Correct Option: D
Explanation:

A photometer is an instrument that measures the strength of electromagnetic radiations in the ultraviolet, visible and the infrared spectrum. Most of the photometers convert light into electric current with the help of a photoresistor. photodiode or a photomultiplier. 

So, the correct answer is 'All of the above'

Which of the following statement can be related to UV spectroscopy?

botany photosynthesis action spectrum and absorption spectrum spectrum of electromagnetic radiation chloroplast and pigments of photosynthesis site of photosynthesis

  1. The comparative study of absorbance and transmittance of reference and sample is done.

  2. It follows lambert beer law.

  3. It cannot be used for cell count.

  4. Both A and B.

Show answer
Correct Option: D
Explanation:
The Beer-Lambert law states that the quantity of light absorbed by a sample is directly proportional to its concentration and the path length of light that passes through the sample. This law forms the basis of UV spectroscopy. Transmittance (T) is defined as the fraction of light that passes through the sample. It is related to absorption by the expression 
Absorbance(A)= --logT=--logIt/Io, where It is the amount of light transmitted and Io is the amount of light incident on the cuvette sample. Hence it can be used for cell counting in a sample by determining the transmittance. 
So, the correct answer is 'Both A and B.'

Amount of $ C{ O} _{ 2 } $ mixed  annually is about 

botany photosynthesis action spectrum and absorption spectrum spectrum of electromagnetic radiation chloroplast and pigments of photosynthesis site of photosynthesis

  1. $70\times 1{ 0 }^{10 } Kg $

  2. $ 70\times 1{ 0 }^{11 } Kg$

  3. $ 70\times 1{ 0 }^{13 } Kg $

  4. $ 70\times 1{ 0 }^{13 } g $

Show answer
Correct Option: A
Explanation:

David Keeling started measuring the annual CO2 production from an observatory in Hawaii. He found the amount to be $70\times 1 { 0 } ^ { 10 } Kg$.
So, the correct option is '$70\times 1 { 0 } ^ { 10 } Kg$'

In PS I, the reaction centre Chl a has absorption maxima at ________; whereas in PS II, the reaction centre Chl a has absorption maxima at _________. 
botany photosynthesis action spectrum and absorption spectrum spectrum of electromagnetic radiation chloroplast and pigments of photosynthesis site of photosynthesis

  1. 700 nm, 680nm

  2. 680 nm, 700nm

  3. 400 nm, 500 nm

  4. 700 nm, 800 nm

Show answer
Correct Option: A
Explanation:

The reaction center of photosystem I (PSI) is referred to as $ P _{700}$ where "P" stands for "Pigment" and "700" stands for the wavelength of light that this particular chlorophyll molecule absorbs most strongly. The reaction center of photosystem II (PS II) is referred to as $ P _{680}$ for comparable reasons. 

For NADPH + $ H^{+}$ formation 
botany photosynthesis action spectrum and absorption spectrum spectrum of electromagnetic radiation chloroplast and pigments of photosynthesis site of photosynthesis

  1. only PS I is required

  2. only PS II is required

  3. both PS I and PS II are required

  4. only stroma is required

Show answer
Correct Option: C
Explanation:
NADPH is formed during non-cyclic photophosphorylation wherein both PSI and PS II are involved. 
So, the correct answer is 'both PS I and PS II are required'

The empirical formula of a hydrocarbon is $CH _{3}.$ It's molecular weight is $30$, What is molecular formula of the compound.

botany photosynthesis action spectrum and absorption spectrum spectrum of electromagnetic radiation chloroplast and pigments of photosynthesis site of photosynthesis

  1. $CH _4$

  2. $C _2H _6$

  3. $C _3H _8$

  4. $C _4H _{10}$

Show answer
Correct Option: B
Explanation:

  • Formula for finding molecular formula is
  • Molecular formula= n x Empirical formula
  • Now n = molecular weight /  empirical weight
  • therefore n = 30/15
        Where 15 is the weight of the empirical formula CH3
        n=2
Now the molecular formula = 2 x CH3
                                               = C2H6
Therefore the answer option B is correct.