IGCSE Biology Paper-2: Specimen Questions with Answers 191 - 192 of 203

The given diagram is showing a cell organelle.

Which statement is Incorrect with respect to the organelle shown above?

Answer

a.

Explanation

Mitochondria are double membrane cell organelle.

Functions of Mitochondria

• Most of the ATP is produced by mitochondria during respiration. These ATP are required for performing various metabolic activities. Thus mitochondria is called powerhouse of cell.
• Enzymes of Krebs cycle, fatty acids synthesis, amino acids synthesis are found in matrix.
• The gene for male sterility in maize plants is found in mt DNA. Thus, it helps in cytoplasmic inheritance.
• Mitochondria help in Vitellogenesis in oocytes.
• Heme protein required for haemoglobin, cytochrome, and myoglobin is synthesized in mitochondria.

Transport in the body mainly occurs in the form of

Answer

c.

Explanation

Transport of: Occur in three forms:

As dissolve form: 7 % is transported as dissolved form in water of plasma.

As carbamino hemoglobin: Hb.

This percentage of combine with amino group of globin protein of haemoglobin to form carbamino haemoglobin

As bicarbonate compound (70 % CO₂)

• This percentage of diffuse in RBC and dissolve in water of cytoplasm to form carbonic acid.
• Formation of carbonic acid is occur in presence of carbonic anhydrase enzyme which increase rate of formation of carbonic acid 5000 times.
• Carbonic acid now dissociates into ions and Bicarbonate ions.
• To regulate pH of blood haemoglobin act as buffer and combine with H + ion to form Haemogloginic acid.
• Bicarbonate ions are highly diffusible ions. They diffuse in plasma from RBC and combine with ions to form Sodium Bicarbonate.
• To maintain ion equilibrium, in the same of ions ions also diffuse in RBC from plasma. It is called chloride shift or Hamburger phenomena.
• Ions combine with K + ion to form potassium chloride.