STD 11 - 3. Plant kingdom — NEET STD 11 Science — Question

Assertion: The members of phacophyceae vary in colour from olive green to various shades of brown.
Reason: Colour depending upon the amount of laminarin or mannitol present in it.

Gymnosperms produce neither flower nor fruit because they do not possess

What is true about packaging of DNA Helix in eukaryotes ?
(i) Negatively charged DNA is wrapped around the positively charged basic histone proteins octamer to form a structure called nucleosome.
(ii) A typical nucleosome contains 200 bp of DNA helix.
(iii) Nucleosomes constitute the repeating unit of a structure in nucleus called chromatin.
(iv) The nucleosomes in chromatin are seen as 'beads-on-string' structure when viewed under electron microscope (EM).
(v) Chromatin fibres are further coiled and condensed at metaphase stage of cell division to form chromosomes.
(vi) The packaging of chromatin at higher level requires additional set of proteins that collectively are referred to as Non-Histone Chromosomal (NHC) proteins.

Delete odd one (factors affecting enzyme activity).

Vessels are mainly found in

Exarch xylem is found in

Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A):
During pregnancy in human female some hormones are secreted by more than one tissue/organ.
Reason (R):
In human female the relaxin hormone are secreted from placenta as well as mammary gland.
In the light of the above statements, choose the most appropriate answer from the options given below:

Respiration is seen in

Oogamous means