CBSE 11TH BIOLOGY - Online Test
Q1. Male and female gametophytes do not have free independent existence in
Answer : Option A
Explaination / Solution:
Unlike bryophytes and pteridophytes , in gymnosperms ( Cedrus )the male and the female gametophytes do not have an independent free-living existence.
Q2. Which one is present nearest to plasmamembrane?
Answer : Option A
Explaination / Solution:
The cell wall of a young plant cell, the primary wallis capable of growth, which gradually diminishes as the cell matures and the secondary wall is formed on the inner (towards membrane) side of the cell.
Q3. Electrons from exited chlorophyll molecules of photosystem II are accepted first by
Answer : Option C
Explaination / Solution:
During potophosphorylation, electron released during photolysis of water passes through electron transport chain. The electron from exited chlorophyll molecules of Photosystem II are accepted first by quinine.
Q4. The regulatory centres for respiration are located in :
Answer : Option D
Explaination / Solution:
A specialised centre present in the medulla region of the brain called respiratory rhythm centre is primarily responsible for this regulation. In the pons region of the brain called pneumotaxic centre can moderate the functions of the respiratory rhythm centre.
Q5. Which of the following scientists won the nobel prize for discovering second messengers?
Answer : Option D
Explaination / Solution:
Second messengers are molecules that relay signals received at receptors on the cell surface to trigger physiological changes.
The Nobel Prize in Physiology or Medicine 1971 was awarded to Earl W. Sutherland, Jr. "for his discoveries concerning the mechanisms of the action of hormones".
Q6. A fish that has electric organ is
Answer : Option A
Explaination / Solution:
Torpedo fish has electric organ. They are known for being capable of producing an electric discharge ranging from 8 to 220 volts depending on species.
Q7. Identify the correct pairing between nitrogen bases in DNA.
Answer : Option C
Explaination / Solution:
There are two hydrogen bonds between A and T pairing. There are three hydrogen bonds between G andC pairing. Each strand appears like a helical staircase.
Q8.
When a person suffers from chest pain :
i. the reason for this suffering is decreased blood flow and simultaneously lowered oxygen supply to an area of the heart.
ii. deprived of oxygen, myocardium opts for alternative pathways i.e. anaerobic respiration and its byproduct ethanol causes the pain.
Answer : Option D
Explaination / Solution:
A symptom of acute chest pain appears when no enough oxygen is reaching the heart muscle.
Q9. Cellular respiration first takes place in
Answer : Option C
Explaination / Solution:
Cellular respiration takes place in two steps- Glycolysis and Kreb’s cycle. Glycolysis occurs in cytoplasm of cells and Kreb’s cycle in mitochondria. So, first step of respiration takes place in cytoplasm.
Q10.
Arrange the order of events taking place in anaphase II stage of meiosis:
a. Metaphase plate spilts
b. Each chromosome moves away from equatorial plane
c. Centromeres split and chromatids separate.
d. Chromatids move to opposite poles
Answer : Option B
Explaination / Solution:
During anaphase stage, metaphase plate splits and each chromosome moves away from equatorial plane splitting the centromere and separate chromatids which move to opposite poles.
