CBSE Questions for Class 11 Medical Biology Plant Kingdom Quiz 15 - MCQExams.com

Rhodophyta (red algae) has predominance of the red pigment, phycoerythrin along with chlorophyll a and chlorophyll d The red algae usually reproduce vegetatively by fragmentation, asexually by non-motile spores and sexually by non-motile gametes. The common members are Polysiphonia, Porphyra, Gracilaria and Gelidium.

So, the correct answer is 'Phycoerythrin'

Correct option: C

Explanation:

Red tide is caused by algal bloom. The algal blooms decrease the oxygen content of the water. It is caused by the algae Gonyaulax and can kill large numbers of fish and other sea life including dolphins and manatees and can make shellfish poisonous to humans. 
So, the correct answer is option C

• Fucus (rockweed), a brown alga, displays a diploid life history similar to the angiosperms.
• The zygote (2n) becomes an embryo (very young sporophyte) and develops into the mature Fucus with receptacles at the tip of the algae. 
• The receptacles are reproductive branches and contain many cavities with external pores, which contain antheridia (male) and oogonia (female), then through meiosis, sperm (n) and egg (n) are produced. 
• Syngamy occurs when the two fuse and become a zygote (2n).

Pyrenoids are commonly present in the chloroplasts of many algae and also in the bryophyte are associated with the operation of a carbon-concentrating mechanism (CCM). Pyrenoids are composed of a granular, homogeneous matrix around which are found starch deposits. A filamentous and fibrillar nature of the pyrenoid matrix are present in certain green algae.

Chlorophyceae make up an extremely large and important class of green algae. Members may be unicellular, colonial, or filamentous. Cells of unicellular and colonial chlorophyceans may have two or more flagella. There are about 2,650 living species of chlorophyceans. The main features of the class (and most plants) are the use of starch as the principal food reserve and the green chloroplasts with chlorophylls a and b. Inspite of plant characteristics, this algal group is not directly related to early land plants. The most complex of the class are the filamentous members, some of which exhibit features that are seen primarily in plants. Despite this similarity the class is not believed to have been the evolutionary source of plants.

Under certain conditions, Chlamydomonas changes from a motile organism to a non-motile form referred to as palmella stage. In this non-motile phase, vegetative divisions are prominent and motility is suppressed until special motile reproductive cells are formed. 

• Two branches of equal thickness are formed at every point of branching in the case of dichotomous branching.
• It is a distinctive feature of liverworts (division Bryophyta), e.g. Riccia and  Marchantia etc.
  
• As you can see in the above diagram, they do not have true roots, stems, or leaves. Instead, they have an above ground leaflike structure, known as a thallus that is dichotomously branched.