Tag: bio-chemistry

Questions Related to bio-chemistry

Which one of these is not correct regarding peroxisomes?

bio-chemistry structure and function of cell organelles microbodies living organisms and energy production single membrane bound organelles

  1. Single membrane bound organelles

  2. Perform photorespiration in $C _{3}$ plants

  3. Take part in synthesis and storage of lipids

  4. Protect a cell from the toxic effects of $H _{2}O _{2}$

Show answer
Correct Option: C
Explanation:
SER takes part in synthesis and storage of lipids. Peroxisomes are the single membrane bound cell organelles, which perform photorespiration in association with chloroplasts and mitochondria. They protect the cell from the toxic effects of $H _{2}O _{2}$.
So, the correct answer is 'Take part in synthesis and storage of lipids'.

Which of the following statements regarding spherosomes is not correct?

bio-chemistry structure and function of cell organelles microbodies living organisms and energy production single membrane bound organelles

  1. Abundant in the endosperm cells of oil seeds

  2. Bounded by a single membrane

  3. Take part in synthesis and storage of lipids

  4. Take part in photorespiration

Show answer
Correct Option: D
Explanation:
Sphaerosomes are small cell organelles bounded by single membrane which take part in storage and synthesis of lipids. Sphaerosomes occur abundantly in the endosperm cells of oil seeds. Sphaerosomes of some tissues (e.g., tobacco endosperm, maize root tip) contain hydrolytic enzymes. Therefore, they are considered to have lysosomic activity. They donot take part in photorespiration.
So, the correct answer is 'Take part in photorespiration'.

Cell organelle extracted from endosperm of germinating castor beans are

bio-chemistry structure and function of cell organelles microbodies living organisms and energy production single membrane bound organelles

  1. Glyoxysomes

  2. Vacuoles

  3. Mitochondria

  4. None of the above

Show answer
Correct Option: A
Explanation:
Glyoxysomes are microbodies which contain enzymes for $\beta - oxidation$ of fatty acids and glyoxylate pathway. They are considered to be special peroxisomes. They occur abundantly in germinating endosperm cells of oil seeds.
So, the correct answer is 'Glyoxysomes'.

All the following statements are correct, except

bio-chemistry structure and function of cell organelles microbodies living organisms and energy production single membrane bound organelles

  1. Peroxisomes are quite common in the photosynthetic cells. Their number can be 70-100 per mesophyll cell, wherein they interact with mitochondria and chloroplasts to take part in photorespiration

  2. Glyoxysomes are numerous in the the endosperm of wheat.

  3. The ER-bound ribosomes synthesise secretory membrane and lysosomal protein

  4. Ribosomes when associated with ET are attached with their 60S sub-unit

Show answer
Correct Option: A
Explanation:

Peroxisomes are cytoplasmic organelles that play a central role in break down of fatty acids and other oxidation reactions in the cell.

So, the correct option is 'Peroxisomes are quite common in the photosynthetic cells. Their number can be 70-100 per mesophyll cell, wherein they interact with mitochondria and chloroplasts to take part in photorespiration'.

Which of the following organelle is associated with triglyceride metabolism?

bio-chemistry structure and function of cell organelles microbodies living organisms and energy production single membrane bound organelles

  1. Peroxisome

  2. Glyxosome

  3. Sphaerosome

  4. Transosome

Show answer
Correct Option: A
Explanation:

 Peroxisomes are cell organelles that are involved in lipid or triglyceride metabolism. They are bound by a single membrane and are present in the cytosol.

So, the correct answer is 'Peroxisome'.

The function of glyoxysome is

bio-chemistry structure and function of cell organelles microbodies living organisms and energy production single membrane bound organelles

  1. Protein metabolism

  2. Carbohydrate metabolism

  3. Fat metabolism

  4. Protein synthesis

Show answer
Correct Option: C

Which of the following statements regarding sphaerosomes is not correct?

bio-chemistry structure and function of cell organelles microbodies living organisms and energy production single membrane bound organelles

  1. Abundant in the endosperm cells of oil seeds

  2. Bounded by a single membrane

  3. Take part in synthesis and storage of lipids

  4. Take part in photorespiration

Show answer
Correct Option: D
Explanation:

Sphaerosomes are small cell organelles bounded by single membrane which take part in storage and synthesis of lipids. Sphaerosomes occur abundantly in the endosperm cells of oil seeds. Sphaerosomes of some tissues (e.g., tobacco endosperm, maize root tip) contain hydrolytic enzymes. Therefore, they are considered to have lysosomic activity. They donot take part in photorespiration.
So, the correct answer is 'Take part in photorespiration'.

Cell organelles taking part in photorespiration are ____________.

bio-chemistry structure and function of cell organelles microbodies living organisms and energy production single membrane bound organelles

  1. Peroxisomes

  2. Glyoxisomes

  3. Dictysomes

  4. Endoplasmic reticulum

Show answer
Correct Option: A
Explanation:

Peroxisomes are membrane-bound organelles in eukaryotes. Photorespiration is a light-dependent process that takes place in mitochondria in which oxygen is absorbed and carbon dioxide is released. It is counter-productive to photosynthetic carbon dioxide fixation and decreases plant productivity. But it also provides protection against conditions caused by high light intensity, drought, and salinity.  Thus the correct answer is option A.

Read the given statements and select the correct option.


Statement 1: Peroxisomes are involved in photorespiration of the plant cells and help in the lipid metabolism of animal cells.
Statement 2: They are the cell's garbage disposal system.

bio-chemistry structure and function of cell organelles microbodies living organisms and energy production single membrane bound organelles

  1. Both statements 1 and 2 are correct

  2. Statement 1 is correct but statement 2 is incorrect

  3. Statement 2 is correct but statement 2 is incorrect

  4. Both statements 1 and 2 are incorrect

Show answer
Correct Option: B
Explanation:

Peroxisomes are found in photosynthetic cells and perform photorespiration. They also take part in lipid metabolism. Lysosomes are the cell's garbage disposal system and not the peroxisomes.

So, Statement 1 is correct and statement 2 is incorrect.

Glycolate cycle occurs in?

bio-chemistry structure and function of cell organelles microbodies living organisms and energy production single membrane bound organelles

  1. Lysosomes

  2. Ribosomes

  3. Glyoxysomes

  4. Peroxisomes

Show answer
Correct Option: C
Explanation:
In plants, the glyoxylate cycle occurs in specialized cells called glyoxysomes. During germination, the seeds used lipids as the energy source to form the shoot. Acetyl CoA proceeds through glyoxylate cycle and released succinate as the end product. This cycle occurs only in glyoxysomes, which are lying in the fat storage tissues of germinating seeds. 

Hence, the correct answer is option C.