CBSE 11TH BIOLOGY - Online Test
Q1. Exarch xylem is present in
Answer : Option C
Explaination / Solution:
The xylem in which protoxylemis outside and metaxylem is inside is called exarch xylem. This kind of xylem is found in roots of dicots.
Q2. Which pair of enzyme promotes femaleness in flowers?
Answer : Option D
Explaination / Solution:
Flower Sex Conversions :
- Gibberellins (GA3) promote maleness
- Ethylene and auxins promote femaleness
Q3. Which plant shows valvate aestivation?
Answer : Option B
Explaination / Solution:
When sepals or petals in a whorl just touch one another at the margin, without overlapping, as in Calotropis, it is said to be valvate.
Q4. Blood consists of
Answer : Option B
Explaination / Solution:
Blood is a fluid connective tissue containing plasma. It contains red blood cells (RBC), white blood cells (WBC) and platelets suspended in the plasma.
Q5. Which is NOT the characteristic of viroids?
Answer : Option A
Explaination / Solution:
Viroids are smaller than viruses and caused potato spindle tuber disease. It was found to be a free RNA; it lacked the protein coat that is found in viruses, hence the name viroid. The RNA of the viroid was of low molecular weight.
Q6. In wall of guard cell, cellulose microfibrils are arranged
Answer : Option B
Explaination / Solution:
The cells surrounding the stomata pore is called guard cell. It is bean shaped in dicots and dumbbell shape in monocots. Cellulose microfibrils are arranged radially in guard cell.
Q7. Plant with zinc deficiency show reduced biosynthesis of
Answer : Option B
Explaination / Solution:
Plants obtain zinc as Zn2+ ions. It activates various enzymes,especially carboxylases. It is also needed in the synthesis of auxin.If there is deficiency in zinc to plants then it leads to reduced synthesis of auxin.
Q8. Malnutrition covers :
Answer : Option C
Explaination / Solution:
Malnutrition is the condition of having less than required amount of food or more than required amount of food. Both condition is harmful to health. So, malnutrition covers both undernutrition and overnutrition.
Q9. Cell organelles with single membrane is
Answer : Option C
Explaination / Solution:
Lysosomes are single membrane structures containing enzymes for digestion of all types of macromolecules.
Q10. Who proved that oxygen evolved in photosynthesis comes from water?
Answer : Option C
Explaination / Solution:
Ruben, Hassid and Kamen proved that Oxygen evolved during photosynthesis comes from water and not from carbon dioxide. For this, they used water with heavy isotope of oxygen, 18O.
