Tag: plastids

Questions Related to plastids

How many structures are of sporophytic origin?
Megasporocyte, Endothecium, Generative cell, Nucellus, Embryo sac, Sporogenous cell, Stigma. Integument

biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

  1. Six

  2. Five

  3. Four

  4. Seven

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Correct Option: A

Which one is not character of antennae?

biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

  1. To make photosynthesis more efficient

  2. To make wider range of absorption of incoming light

  3. Provide electron to primary electron acceptor of photosystem

  4. Reaction center is not part of it

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Correct Option: C
Explanation:

The light harvesting complexes are made up of hundreds of pigment molecules bound to proteins. Each photosystem has all the pigments (except one molecule of chlorophyll a) forming a  light harvesting system also called antennae. These pigments help to make photosynthesis more efficient by absorbing different wavelengths of light. The single chlorophyll a molecules form the reaction center. Therefore, the reaction center is not a part of antennae. 

So, the correct option is 'Provide electron to primary electron acceptor of photosystem'.

Read the given statements A & B and choose the correct option.
A. The ribosomes of the chloroplasts are smaller than the cytoplasmic ribosomes.
B. Chloroplasts can synthesise some of their proteins but they receive other proteins from cytoplasm.

biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

  1. Only statement A is correct.

  2. Only statement B is correct.

  3. Both statements are correct.

  4. Both statements are incorrect.

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Correct Option: A
Explanation:

A. Chloroplast ribosomes are similar to those found in the prokaryotes that is 70s type. Eukaryotic ribosomes which are found in the cytoplasm are of 80stype.

B. Most chloroplast and mitochondrial proteins, however, are synthesized outside the organelle on cytosolic ribosomes that are not bound to the rough endoplasmic reticulum.
So the correct option is 'Only statement A is correct'.

In a chlorophyll molecule, the magnesium is situated in the

biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

  1. corners of porphyrin

  2. centre of porphyrin

  3. isocyclic ring

  4. phytol chamber

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Correct Option: B
Explanation:

A chlorophyll molecule has a hydrophobic "tail" that embeds the molecule into the thylakoid membrane. The "head" of a chlorophyll molecule is a ring called a porphyrin. The porphyrin ring of chlorophyll, which has a magnesium atom at its centre, is the part of a chlorophyll molecule that absorbs light energy.

So, the correct option is 'Centre of porphyrin'.

Enzymes required for photophosphorylation are located in ............ of chloroplast.

biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

  1. Peristromium

  2. Plastidome

  3. Stroma

  4. Quantasome

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Correct Option: D
Explanation:

A) The peristomium is the first true body segment in an annelid worm's body in the anterior end.

B) Plastid or plastidome refers to the entire unit where photosynthesis takes place.
C) Enzymes that are responsible for photophosphorylation are not present in the stroma.
D) Quantasomes are particles found in the thylakoid membrane of chloroplasts in which photosynthesis takes place. They are embedded in the surface of thylakoid discs in chloroplasts. They are composed of lipids and proteins that include various photosynthetic pigments and redox carriers. For this reason, they are considered to be photosynthetic units. They occur in 2 sizes: the smaller quantasome is thought to represent the site of photosystem I, the larger to represent the site of photosystem II which are involved in photophosphorylation. 
So the correct answer is 'Quantasome'.

Quantasome is a unit related to

biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

  1. Respiration

  2. Ascent of sap

  3. Growth

  4. Photosynthesis

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Correct Option: D
Explanation:

A) Quantasomes are not involved in respiration.
B) Xylem is involved in the ascent of sap. Quantasomes do not play a part in the ascent of sap.

C) Quantasomes are involved in photosynthesis. They do not directly contribute to growth.
D) Quantasomes are particles found on the inner thylakoid membrane of chloroplasts in which photosynthesis takes place.
So the correct answer is 'Photosynthesis'.

On what basis, paper chromatography separates plant pigments?

biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

  1. The non - polarity of the solvents and pigments

  2. The polarity of the paper

  3. The polarity of the pigments

  4. All of the above

  5. None of the above

Show answer
Correct Option: D
Explanation:

Paper chromatography is a technique that is used in the laboratories to separate plant pigments. The concept used is that this helps to separate the mixture into its component molecules. The molecules migrate, or move up the paper, at different rates because of differences in solubility, molecular mass, and hydrogen bonding with the paper.