Genetics — Set 1
Biology · आनुवंशिकी · Questions 1–10 of 50
The genetic material of most living organisms is composed of which molecule?
Correct Answer: C. DNA
DNA serves as the primary hereditary material in humans and almost all other organisms. It contains the instructions necessary for an organism to develop, live, and reproduce. Most DNA is located in the cell nucleus, where it is called nuclear DNA.
Which of the following describes the 'Phenotype' of an organism?
Correct Answer: B. The physical appearance
The phenotype refers to the observable physical properties of an organism. This includes the organism's appearance, development, and behavior. It is determined by both the genetic makeup and environmental influences.
In a DNA molecule, Adenine always pairs with which nitrogenous base?
Correct Answer: C. Thymine
Adenine and Thymine form two hydrogen bonds to stay paired in the DNA double helix. This specific pairing is part of Chargaff's rules of base pairing. In RNA, however, Adenine pairs with Uracil instead of Thymine.
Which scientist is famously known as the 'Father of Genetics'?
Correct Answer: C. Gregor Mendel
Gregor Mendel established the fundamental laws of inheritance through his work with pea plants. He discovered that traits are passed down in discrete units which we now call genes. His findings laid the groundwork for the entire field of modern genetics.
What is the specific location of a gene on a chromosome called?
Correct Answer: D. Locus
A locus is the fixed position on a chromosome where a particular gene or genetic marker is located. The plural form of this term is known as loci. Knowing the locus is crucial for mapping the genome of any species.
Which of the following represents a 'Homozygous' condition?
Correct Answer: C. TT (variant)
The correct answer is 'TT (variant)'. Homozygous means having two identical alleles for a particular gene. If an organism has two dominant alleles like 'TT', it is called homozygous dominant. This state ensures that the specific trait will be consistently passed to offspring.
A sudden and permanent change in the DNA sequence of an organism is called a?
Correct Answer: D. Mutation
Mutations can result from DNA copying mistakes or exposure to environmental factors like radiation. While many mutations are neutral, some can lead to diseases or beneficial evolutionary changes. They are the primary source of genetic variation in all populations.
Which nitrogenous base is found in RNA but is absent in DNA?
Correct Answer: A. Uracil
Uracil replaces thymine in RNA molecules to pair with adenine. This chemical difference helps the cell distinguish between permanent DNA and temporary RNA messages. RNA is typically single-stranded, unlike the double-stranded DNA.
The process of copying a segment of DNA into RNA is known as?
Correct Answer: B. Transcription
Transcription is the first step of gene expression where a particular segment of DNA is copied into RNA. This process occurs within the nucleus of eukaryotic cells. The resulting mRNA carries the genetic code to the cytoplasm for protein synthesis.
How many autosomes are present in a normal human somatic cell?
Correct Answer: C. 44
A normal human cell contains 44 autosomes and 2 sex chromosomes. Autosomes are chromosomes that are not involved in determining the sex of an individual. They are arranged in 22 pairs in the human karyotype.