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.
AI-generated explanation. Check against your textbook.
Explanation:
Option 3 is incorrect. In a woody stem, sapwood is the outer, younger part of secondary xylem that conducts water and minerals from roots to leaves. It is not the innermost part; the innermost secondary xylem is heartwood. Heartwood is darker due to deposits like tannins, resins, and essential oils and it provides mechanical support.
🧠 Did You Know?
In NCERT, sapwood is described as the conducting region for water, while heartwood is non-conducting but structurally important and often darker in color.
💡 NCERT Memory Line:
“Sapwood conducts water; heartwood is non-conducting and darker due to deposits.”
AI-generated explanation. Check against your textbook.
Explanation:
In NCERT, half-inferior (also called half-embedded) ovary means the ovary is partly below the point of attachment. Plum (Prunus) shows this condition, so the ovary is half-inferior. Thus option 4 is correct.
🧠 Did You Know?
Ovary position helps categorize flowers as superior, half-inferior, or inferior, affecting fruit development and floral structure.
💡 NCERT Memory Line:
Ovary position is a key feature in identifying different fruit types; plum is an example of half-inferior ovary as per NCERT explanations.
The body of the ovule is fused within the funicle
at:
AI-generated explanation. Check against your textbook.
Explanation:
The functional body of the ovule is attached within the funicle at the hilum. The hilum marks the point of attachment of the ovule to the ovary via the funicle, where the ovule body is fused. Thus, option 1 is correct. The micropyle is the opening in the integuments for pollen entry, not the attachment point. The nucellus is the tissue inside the integuments surrounding the embryo sac. The chalaza is the opposite end where integuments and nucellus are attached but not the attachment site for the funicle.
🧠 Did You Know?
In many angiosperms, the hilum is visible as a scar on the seed after fertilization, indicating where the funicle previously attached the ovule.
💡 NCERT Memory Line:
The hilum is the point of attachment of the ovule to the funicle; micropyle, nucellus, and chalaza describe other parts/endings of the ovule.
Large, empty colourless cells of the adaxial epidermis along the veins of grass leaves are:
AI-generated explanation. Check against your textbook.
Explanation:
Option 4 is correct. Bulliform cells are large, empty (colorless) epidermal cells found on the adaxial (upper) surface of grass leaves along the veins. They help in leaf folding and unfolding by changing turgor when the leaf loses or gains water, a characteristic described in NCERT for monocots like grasses.
🧠 Did You Know?
These cells cause the leaf to roll during drought, reducing transpiration and protecting the leaf.
💡 NCERT Memory Line:
“Bulliform cells are large, chloroplastless cells in the adaxial epidermis of grass leaves.”