Tag: plastids

Quizzes (2) Questions (67)

Questions Related to plastids

Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

Cytochrome is a :

  1. Mg containing pyrrole rings

  2. Fe containing porphyrin ring

  3. Nucleotide

  4. Alloy of inchrome.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

(B) Fe containing Porphyrin ring 


Cytochromes are heme proteins that undergo oxidation Reduction reaction and differentiated on the Basis of 

their apoprotein structure, heme structures, and optical absorption in the visible spectrum.

As cytochromes are heme proteins which contain Iron compound in the Tetrapyrrole/Porphyrin structure.

Option B is correct.

Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

If 24 G-3-P molecule are formed in $C _3$ plants. Calculate 
a) the number of $CO _2$ used and 
b) the number of $G3P$ used for regeneration $RuBP$ molecule.

  1. a=12, b=20

  2. a=24, b=48

  3. a=12, b=24

  4. a=20, b=12
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
All together for one G3P to leave the cycle (and go towards glucose blend), three CO2 particles must enter the cycle, giving three new molecules of settled carbon. At the point when three CO2 particles enter the cycle, six G3P atoms are made. One leaves the cycle and is utilized to make glucose, while the other five must be reused to recover three atoms of the RuBP acceptor. 
3 CO2 joins with 3 RuBP acceptors, making 6 atoms of (G3P). 
1 G3P particle leaves the cycle and goes towards making glucose. 
5 G3P particles are reused, recovering 3 RuBP acceptor atoms.
So, the correct option is 'a=12, b=24'.
Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

What percentage of water, proteins, lipids and pigments are present in chloroplasts respectively?

  1. 50, 25, 15 and 10

  2. 90, 5, 2 and 3

  3. 95, 2, 1 and 2

  4. 85, 10, 3 and 2
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The chloroplasts are composed of the carbohydrates, lipids, proteins, chlorophyll, carotenoids (carotene and xanthophylls), DNA, RNA and certain enzymes and co-enzymes. The chloroplasts also contain some metallic atoms as Fe, Cu, Mn and Zn. By chemical analysis, these consist of lipids and proteins basically. Lipids are mainly phospholipid components of the membranes and lamellae. Proteins also contain enzymes, which are fully present in mature plastids. By the chemical analysis, it is observed that chloroplastids contain 90% of water, 5% of proteins, 2% of lipids and 3% of pigments.

Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

Thylakoids possess photosynthetic units called

  1. Photosystem.

  2. Electron transport system.

  3. Photolysis complex.

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

Thylakoid is a sheet-like membrane-bound structure which is the site of the light-dependent photosynthesis reactions within the chloroplasts and cyanobacteria. Photosystems are then functional and structural units of protein complexes involved in photosynthesis.

The electron transport chain is a series of the proteins and organic molecules which are found in the inner membrane of the mitochondria. Photolysis is the chemical process by which molecules are broken down into smaller units through the absorption of light.

The synthesis of ATP in chloroplasts, promoted by light, is termed as photophosphorylation

So the correct option is A.

Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

Which pigment absorbs the red and far-red light?

  1. Cytochrome

  2. Phytochrome

  3. Carotenoids

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

Phytochrome is a light sensitive pigment in plants and some bacteria and fungi. It exists in two interconvertible forms- Pr and Pfr. Pfr absorbs far red light of 730 nm wavelength. When it absorbs far red light, it converts to its original form, Pr. Thus Pfr is the active form of phytochrome which inhibits flowering.

Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

Solarisation is a process in which

  1. Sugars are formed with the help of solar energy

  2. Chlorophyll is formed

  3. Destrution of chlorophyll and ultimate death of protoplasmic compounds occurs

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Chlorophyll pigments trap sunlight during the process of photosynthesis but get destroyed on exposure to light of higher intensity. An exposure to high light intensity for even a small duration can be harmful. The destruction of chlorophyll when exposed to light of high intensity is called as solarization. It occurs due to irreversible chemical changes in the structure of chlorophyll molecule.

Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

If a tree flowers thrice in a year, in the months of October, January and July in northern India the plant is

  1. Photo and thermo-sensitive.

  2. Photo and thermo-insensitive.

  3. Photosensitive but thermo-insensitive.

  4. Thermo-sensitive but photo-insensitive.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Plants are able to detect and respond to light, gravity, changes in temperature and chemicals. Plants respond to the changing seasons to initiate their development and flowering. The photoperiodic stimulus is found to be responsible for flowering, light quality, vernalization, autonomous and GA pathways are also responsible for regulating the flowering time in plants. While vernalization and photoperiodic pathways are environmental dependents, the autonomous pathway promotes flowering in all conditions. Hence for a tree that flowers thrice a year, the plant has to be both photo and thermo-insensitive.

Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

Photosynthetic units are referred as

  1. Quantasomes

  2. Oxysomes

  3. Phycobilisomes
  4. $F _{1}$ particles
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Photosynthetic units are referred as quantasomes. Quantasomes are particles found in the thylakoid membrane of chloroplasts in which photosynthesis takes place.

Oxysomes are the structures which are present on the surface of the folded inner membrane of the mitochondria. They are also called as f$ _0$-f$ _1$ particles or ATP synthase. They play an important role in the formation of energy for the functioning of the cell.
The protein complexes attached to thylakoid membranes are known as phycobilisomes. They are made up of phycobiliproteins and help in the transfer of light energy to chlorophyll-a molecule of photosystem-II.
Thus, the correct answer is option A. 

Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

Isotopes employed to study the process of photosynthesis reaction are

  1. $S^{68}\, and\, P^{32}$
  2. $C^{14}\, and\, O^{18}$
  3. $N^{14}\, and\, Co^{60}$
  4. $N^{14}\, and\, O^{18}$
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 in dark reaction and water is oxidised to release oxygen in light reaction of photosynthesis. $C^{14}$ label was used to trace the path of carbon in the dark reaction in $C _3$ plants by Calvin, Benson and Basham. The $O^{18}$ label was used by Rumen and Kamen to experimentally prove that the source of oxygen released during light reaction of photosynthesis is water.