Mention the exact location of the following:
Genes:
Topic: Location of genes
Try it
Pick an option and check your answer. The full worked answer is below either way.
Answer
(c) Present on chromosomes.
GENES are segments of DNA located on the CHROMOSOMES, which lie in the nucleus. A single chromosome carries hundreds or thousands of genes.
The hierarchy worth holding, from smallest to largest: DNA → GENE → CHROMOSOME → NUCLEUS. Think of the chromosome as the book and the gene as one sentence in it.
The wrong options are all real structures with no hereditary role: the CELL WALL gives rigidity to a plant cell; the CHLOROPLAST carries out photosynthesis; the CENTROSOME organises the spindle.
Genes occupy a fixed position on the chromosome called the LOCUS, and the alternative forms of a gene at the same locus on homologous chromosomes are the ALLELES — which is what Question 1(iv) of this paper is about.
Present on chromosomes.