11. In which of the following weeks the heart of human embryo starts beating?
[A] in the first week of its development
[B] in the third week of its development
[C] in the fourth week of its development
[D] in the sixth week of its development
Show Answer
Correct Answer: D [in the sixth week of its development]
Notes:
By 6 weeks, baby’s heart starts beating 110 times a minute. It has four hollow chambers, each with an entrance and an exit to allow blood to flow in and out of each chamber. In just two more weeks, that number will rise to 150-170 beats a minute.
12. Which one of the following is a useful functional association between fungi and the roots of higher plants?
[A] Biofertilizer
[B] Coralloid root
[C] Lichen
[D] Mycorrhiza
Show Answer
Correct Answer: D [Mycorrhiza]
Notes:
A mycorrhiza is a symbiotic association between a fungus and a plant. The term mycorrhiza refers to the role of the fungus in the plant’s rhizosphere, its root system. Mycorrhizae play important roles in plant nutrition, soil biology and soil chemistry.
13. With reference to the blood in a normal person, which one of the following statements is correct?
[A] Compared to arteries, veins are less numerous and hold less of the body’s blood at any given time
[B] Blood cells constitute about 70 per cent of the total volume of the blood
[C] White Blood Cells (WBC) are made by lymph nodes only
[D] The blood has more platelets than WBC
Show Answer
Correct Answer: D [The blood has more platelets than WBC]
Notes:
Blood has more platelets than corpuscles. A microlitre of blood contains 5,000-10,000 of White blood cells (WBC) and 150,000-500,000 platelets.
14. What is the name of the vessel that delivers the nutrient rich blood from the stomach and small intestine to the liver?
[A] Left hepatic artery
[B] Hepatic vein
[C] Right hepatic artery
[D] Hepatic portal vein
Show Answer
Correct Answer: D [Hepatic portal vein]
Notes:
The portal vein or hepatic portal vein is a blood vessel that carries blood from the gastrointestinal tract, gallbladder, pancreas and spleen to the liver. This blood contains nutrients and toxins extracted from digested contents.
15. Which phylum does the salamander belong to?
[A] Mollusca
[B] Amphibians
[C] Reptiles
[D] Mammals
Show Answer
Correct Answer: B [Amphibians]
Notes:
Those organisms which can live on both land and water are called amphibians. Some examples of amphibians are frogs and toads, newts, salamanders and caecilians.
16. Which of the following are blue-green algae?
[A] Prokaryotes
[B] Eukaryotes
[C] Both 1 and 2
[D] Neither 1 nor 2
Show Answer
Correct Answer: A [Prokaryotes]
Notes:
Blue-green algae or cyanobacteria are prokaryotes. They lack membrane bound organelles and a nucleus.
17. Which of the following is hemoglobin?
[A] Primary structure
[B] Secondary structure
[C] Tertiary structure
[D] Quaternary structure
Show Answer
Correct Answer: D [Quaternary structure]
Notes:
Hemoglobin has a quaternary structure. It consists of two pairs of separate proteins, designated α and β chains.
18. Which of the following virus has its envelope from the host cell nucleus?
[A] Paramyxoviruses
[B] Retroviruses
[C] Orthomyxoviruses
[D] Herpesviruses
Show Answer
Correct Answer: D [Herpesviruses]
Notes:
The Herpesviridae are a large family of DNA viruses. It causes infections and some diseases in animals, including humans. Herpes viruses are divided into three groups: α herpesviruses, herpes simplex virus types 1 and 2.
19. Which one of the following plants has seeds but no flowers and fruits?
[A] Bryophytes
[B] Gymnosperms
[C] Mosses
[D] Pteridophytes
Show Answer
Correct Answer: B [Gymnosperms]
Notes:
Gymnosperms are a group of seed-producing plants. These include conifers, cycads, ginkgo and gnatophytes, which make up the clade gymnosperms. These living members are also known as acrogynosperms.
20. Green algae, red algae and brown algae are common examples of__?
[A] Thallophyta
[B] Bryophyta
[C] Pteridophyta
[D] Gymnosperms
Show Answer
Correct Answer: A [Thallophyta]
Notes:
Green algae, red algae and brown algae are common examples of Thallophyta.
