11. The messages received by and transmitted from the brain to the various parts of the body take the form of which of the following impulses? (UPSC Prelims 1983)
[A] Nervous impulses
[B] Chemical impulses
[C] Mechanical impulses
[D] Automatic impulses
Show Answer
Correct Answer: A [Nervous impulses]
Notes:
The message to the brain form any body part takes the form of nervous impulses. Nerve impulses are mostly electrical signals along the dendrites to produce a nerve impulse or action potential. The action potential is the result of ions moving in and out of the cell.
12. Which of the following clearly define Lineage? (UPSC Prelims 1986)
[A] A straight line joining any two points on the globe
[B] The line of descendants of a particular ancestor
[C] The paleolithic age
[D] The linking of genes
Show Answer
Correct Answer: B [The line of descendants of a particular ancestor]
Notes:
A lineage is a single line of descent or linear chain within the tree while a clade is a monophyletic group, containing a single ancestor and all its descendants. Phylogenetic trees are typically created from DNA, RNA or protein sequence data.
13. Which of the following features of the human immunodeficiency virus (HIV) makes it a living entity? (UPSC Prelims 1990)
[A] Excrete in human serum
[B] Disturb host cell respiration
[C] Undergo auto-reproduction
[D] Move from one cell to another
Show Answer
Correct Answer: C [Undergo auto-reproduction]
Notes:
The human immunodeficiency virus is a type of virus called a retrovirus. Like all viruses, human immunodeficiency virus reproduces using the genetic machinery of the cell it infects. With the help of an enzyme called integrase (also produced by HIV), the viral DNA becomes integrated with the cell’s DNA.
14. Which among the following genus is known as the ‘handy man’?
[A] Homo sapiens sapiens
[B] Homo habilis
[C] Homo sapiens neanderthelensis
[D] Homo erectus
Show Answer
Correct Answer: B [Homo habilis]
Notes:
Homo habilis– He had a face similar to his ancestors. The skull and brain size indicate that he may have been able to speak. The earliest tools made were from this era. Homo habilis is known as the ‘handy man’ because he was the first to make and use tools.
15. Which branch of biology is known for the study of fruits?
[A] Pomology
[B] Agronomy
[C] Floriculture
[D] None of these
Show Answer
Correct Answer: A [Pomology]
Notes:
Pomology is a branch of botany that studies fruit and its cultivation.
16. Who among the following is considered to be the father of DNA?
[A] James Watson
[B] Hargobind Khurana
[C] Alec Jeffereys
[D] Leslie Orgel
Show Answer
Correct Answer: A [James Watson]
Notes:
James Dewey Watson is an American molecular biologist, geneticist, and zoologist. In 1953, he co-authored with Francis Crick the academic paper proposing the double helix structure of the DNA molecule.
17. 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.
18. Which is known as mitoplast?
[A] another name for mitochondria
[B] mitochondria without outer membrane
[C] mitochondria without inner membrane
[D] mitochondria without membranes
Show Answer
Correct Answer: B [mitochondria without outer membrane]
Notes:
Mitochondria without an outer membrane are called mitoplasts. Mitoplasts are useful for electrophysiological analysis of mitochondrial function.
19. Which sugar is present in DNA?
[A] Heptose
[B] Hexone
[C] Tetrose
[D] Pentose
Show Answer
Correct Answer: D [Pentose]
Notes:
Deoxyribose is present in DNA. It is also known as pentose sugar, consisting of 5 carbon atoms. The chemical formula of deoxyribose is C5H10O4. DNA is the genetic carrier in all living organisms. The full form of DNA is Deoxyribonucleic Acid.
20. 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.
