AI-generated explanation. Check against your textbook.
Explanation:
Phycoerythrin is a red pigment found predominantly in red algae (Rhodophyta). According to NCERT, red algae contain phycobiliproteins like phycoerythrin as major light-harvesting pigments, giving them their reddish color.
🧠 Did You Know?
Blue-green algae (cyanobacteria) mainly have phycocyanin and all have chlorophyll a; brown algae possess fucoxanthin, not phycoerythrin.
💡 NCERT Memory Line:
Red algae: major pigments include phycoerythrin (red pigment) along with other phycobiliproteins.
Which of the following statements is incorrect about gymnosperms?
AI-generated explanation. Check against your textbook.
Explanation:
Gymnosperms are heterosporous, producing microspores and megaspores. However, their gametophytes are not free-living; the male gametophyte (pollen grain) develops within the pollen grain and the female gametophyte develops inside the ovule on the sporophyte and remains dependent on it. Hence statement 2 is incorrect. The other statements are correct: many gymnosperms have needle-like leaves with a thick cuticle, and their seeds are naked (not enclosed in a fruit), i.e., not covered by ovary wall.
🧠 Did You Know?
In gymnosperms, fertilization leads to a seed that is exposed on the scale of a strobilus, not inside a fruit.
💡 NCERT Memory Line:
Gymnosperms are heterosporous; the male and female gametophytes are not free-living; seeds are naked.
Male and female gametophytes do not have an
independent free living existence in:
AI-generated explanation. Check against your textbook.
Explanation:
In angiosperms, the male and female gametophytes are microscopic and develop inside the sporophyte tissues (anther and ovule) and are dependent on the sporophyte for nutrition and development. Hence, they do not have an independent free-living existence.
🧠 Did You Know?
The pollen grain (male gametophyte) and the embryo sac (female gametophyte) are produced inside the parent plant, not free in the environment.
💡 NCERT Memory Line:
In angiosperms, the gametophytic phase is reduced and dependent on the sporophyte.
Which of the following pairs is of unicellular
algae?
AI-generated explanation. Check against your textbook.
Explanation:
Chlorella and Spirulina are considered unicellular organisms in NCERT. Chlorella is a simple, single-celled green alga. Spirulina is described as a blue-green alga (cyanobacterium) and, for the purposes of NCERT multiple-choice questions, treated as unicellular. Thus, this pair represents unicellular algae.
? Did You Know?
Other options include multicellular forms: Laminaria and Sargassum (brown algae), Gelidium and Gracilaria (red algae), and Anabaena (cyanobacterium) with Volvox (colonial green alga), not unicellular.
? NCERT Memory Line:
Unicellular green algae like Chlorella, and unicellular blue-green algae (spirulina) are examples used to illustrate single-celled photosynthetic organisms in NCERT discussions.
Read the following statements and choose the set of correct statements:
In the members of Phaeophyceae,
A. Asexual reproduction occurs usually by biflagellate zoospores.
B. Sexual reproduction is by oogamous method only.
C. Stored food is in the form of carbohydrates which is either mannitol or laminarin.
D. The major pigments found are chlorophyll a, c and carotenoids and xanthophyll.
E. Vegetative cells have a cellulosic wall, usually covered on the outside by gelatinous coating of algin.
Choose the correct answer from the options given below:
In which one of the following, the ovules are not enclosed by an ovary wall and remain exposed?
Gymnosperms such as Pinus bear naked ovules that are not enclosed within an ovary. Angiosperms have enclosed ovules, while bryophytes do not produce ovules.