Spooling refers to gathering or collecting the isolated DNA strands after extraction, i.e., the DNA that has been purified is spooled around a rod or stick. This is the collection step of DNA isolation. Hence, option 4 is correct.
🧠Did You Know?
In labs, DNA can appear as a white, cottony mass that can be wound or spooled on a glass rod when it precipitates out of solution.
💡 NCERT Memory Line:
Spooling = collection of isolated DNA during isolation procedures.
Consider following features:
(A) Organ system level of organisation
(B) Bilateral symmetry
(C) True coelomates with segmentation of body
Select the correct option of animal groups which
possess all the above characteristics.
Explanation:
The correct option is 2: Annelida, Arthropoda and Chordata. All three groups show organ system level of organisation and bilateral symmetry. They are true coelomates and exhibit body segmentation (Annelida and Arthropoda are clearly segmented;Chordata shows segmentation in its body plan, such as somites in many groups). Thus they possess all the features listed: organ-system level, bilateral symmetry, and true coelomate with segmentation.
🧠Did You Know?
While Mollusca are bilaterally symmetrical and coelomate with organ systems, they are not typically described as having true body segmentation like Annelids or Arthropods in the NCERT context.
💡 NCERT Memory Line:
Organ system level, bilateral symmetry, and true coelom with segmentation are characteristic of Annelida and Arthropoda; Chordata also shows segmentation in its body plan.
The ciliated epithelial cells are required to move
particles or mucus in a specific direction. In humans, these cells are mainly present in:
Explanation:
Ciliated epithelial cells help move mucus or particles in a fixed direction. In humans, these ciliated cells line the bronchioles, helping clear inhaled dust, and the Fallopian tubes, helping move the egg towards the uterus. Thus, option 1 (Bronchioles and Fallopian tubes) is correct according to NCERT concepts about ciliated lining in these organs.
🧠Did You Know?
In the respiratory tract, cilia beat together to push mucus upward toward the throat, a process called mucociliary clearance.
💡 NCERT Memory Line:
Ciliated epithelium is present in the Fallopian tubes and in the bronchi/bronchioles, aiding movement of cells or mucus in a specific direction.
Tidal Volume and Expiratory Reserve Volume of an
athlete is 500 mL and 1000 mL respectively. What
will be his Expiratory Capacity if the Residual
Volume is 1200 mL?
