Tag: structure of chloroplast

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

Which of the following processes forms chemical potential energy from electromagnetic energy?

  1. Respiration

  2. Photosynthesis

  3. Decomposition

  4. Nitrogen fixation

  5. Fermentation
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Electromagnetic energy is the same as radiation or light energy. This type of kinetic energy can take the form of visible light waves, like the light from a candle or a light bulb, or invisible waves, like radio waves, microwaves, x-rays and gamma rays. Further, irrespective of where radiation is coming from, it can travel in a vacuum. The electromagnetic energy in plants can be converted to stored chemical energy during photosynthesis. 

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

Which of the following is responsible for the red, orange and yellow colour of leaves?

  1. Carotenoids

  2. ATP

  3. Leaf decay

  4. Chlorophyll

  5. Over abundance of water
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Option 'A' is correct.

Carotenoids are responsible for the red, orange and yellow color of leaves. Carotenoids are present with chlorophyll, but in summer the leaves are green because of high levels of chlorophyll. Summer masks the color of carotenoids, During autumn, the color of carotenoids becomes more noticeable because of the degradation of chlorophyll. As the autumn progresses, carotenoids also degrade along with chlorophyll but at a much slower rate. Hence the yellow, orange, red colors become visible.   

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

The factory for synthesis of sugars in autotrophic eukaryotes is

  1. Chloroplast

  2. Mitochondrion

  3. Endoplasmic reticulum

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

Chloroplasts are the cell organelles where photosynthesis occurs. The light reactions occur in thylakoid membranes and dark reactions occur in stroma of chloroplasts. These reactions result in synthesis of sugars (glucose) in chloroplasts.

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

The light is trapped by photosynthetic pigments presents in the 

  1. Stroma

  2. Grana

  3. Quantosomes

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

The chloroplast is the cell organelles present in plant cells that are responsible for initiating the process of photosynthesis. Chloroplasts are double-membrane bound structures. The stroma of chloroplast is the jelly-fluid like structure in which another membrane system is presently called the thylakoids. These thylakoids are stacked upon each other to form the structure called grana. The grana are connected with each other by an extension of thylakoids called stroma lamellae. Thylakoid of grana has the photosynthetic pigments embedded in it that perform the trapping of sunlight and begin the light reaction of the photosynthesis.

A. Stroma is the region where the dark reaction of the photosynthesis occurs.
B. Grana is the region where the light reaction occurs through the trap of light by the photosynthetic pigment.
C. Quantasomes are the photosynthetic units made of pigments and are present in the grana.
D. Periplastidial space is the region between the inner membrane and the outer membrane of the plastids.
Hence, the correct answer is 'Grana'

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

Chloroplast stroma contains

  1. Chlorophyll

  2. Light dependent reaction enzymes

  3. Light independent reaction enzymes

  4. Ribosomes
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In photosynthesis, light-independent reactions are known as dark reactions. This process does not depend directly on the presence of light but is dependent on the products of light reaction i.e., ATP and NADPH. The dark reactions occur through Calvin cycle. They take place in the stromal matrix of the chloroplast. Chloroplast stroma contains light independent reaction enzymes which are required for the reaction. Thus, the correct answer is option C.

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

Where does the primary photochemical reaction occurs in chloroplast ? Where does the light reaction of photosynthesis taken place?

  1. Stroma

  2. Endoplasmic reticulum

  3. Quantasome or thylakoids (Grana)

  4. Inner membrane of chloroplast
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In the chloroplast, the primary photochemical reactions occur. During photosynthesis, primary reactions like the light-capturing and ATP-generating reactions occur on grana. Grana are stakes of thylakoids. Quantasomes are particles found in grana. During photosynthesis, the light-dependent reactions take place on the thylakoid membranes. The inside of the thylakoid membrane is called the lumen. Light-independent reactions take place in the stroma. 

Thus, the correct answer is 'Quantasome or thylakoids (Grana).'

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

Which of the following absorb light energy for photosynthesis : -

  1. Chlorophyll

  2. Water molecule
  3. O$ _{2}$

  4. RUBP
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
A pigment is a compound that absorbs a particular wavelength of visible light. Chlorophyll is a green pigment contained in thylakoid membranes of chloroplasts that are used in photosynthesis by plants. The process of photosynthesis occurs when green plants use the energy of light to convert carbon dioxide (CO2) and water (H2O) into carbohydrates. Light energy is absorbed by chlorophyll, a photosynthetic pigment of the plant, while air containing carbon dioxide and oxygen enters the plant through the leaf stomata.

So, the correct answer is 'Chlorophyll'.
Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

In which of the following parts of the plant cell does photosynthesis occur?

  1. The chloroplasts

  2. The mitochondria

  3. The nucleus

  4. The endoplasmic reticulum
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The green parts of the plants have the chlorophyll pigment containing chloroplasts. The chloroplast is a type of plastid which plays a major role in the photosynthesis process.

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

From the following, an organelle containing chlorophyll is

  1. Chloroplast

  2. Endoplasmic reticulum

  3. Nucleus

  4. Mitochondria
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
A. Chloroplasts are greenish plastids which possess photosynthetic pigments, chlorophylls and carotenoids and take part in the synthesis of food. Chlorophylls contain specialised light-absorbing green pigments, therefore help in photosynthesis.
B. Endoplasmic reticulum is a network of reticulum of tiny structures scattered in cytoplasm and composed of three structures- cisternae, tubules and vesicles.
C. Nucleus is a large organelle controlling all the activities of the eukaryotic cells and consists of nuclear envelope, nucleoplasm, nucleolus and chromatin.
D. Mitochondria are cylindrical double membrane organelles and composed of outer, inner membrane, crista and matrix.
So, the correct answer is 'Chloroplast'.
Multiple choice biology protectors of biosphere structure of chloroplast plastids photosynthetic pigments

Who gave chemical compositions of chlorophyll and carotenoids?

  1. Park and Biggins

  2. Meyer and French

  3. Willstatter and Stahl

  4. Arnon and Benson.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Chlorophyll which is an essential factor in photosynthesis was first isolated and namedby Joseph Bienaime Caventou and Peter Joseph Pelletier but the chemical composition of the same was first elucidated by the German chemist Richard Willstatter followed by Hans Fischer.  Carotenoids which are the organic pigments found in the chloroplasts and chromoplasts of plants and other photosynthetic organisms. These  are oil-soluble molecules comprising of 40 branched carbon units bonded together.