Question

Select all that apply chromosomes____. always occur in pairs are tight coils of DNA can be analyzed in a karyotype carry thousands of genes are carried on genes

Answer 1

Answer:

The correct answers are:

1. Are tight coils of DNA
2. Can be analysed in a karyotype.
3. Carry thousand of genes.

Explanation:

• Chromosome occur:

1. In pairs only in diploid organisms, who have two sets of genes, one obtained from the father and other from the mother.
2. But circular chromosomes in single form can be found in haploid organisms, like prokaryotes, which have a single copy of the genome.
3. Polyploid organisms carry multiple copies of a chromosome. This is observed mostly in plants like rice or wheat.

• Chromosomes are formed by the compaction of the double-stranded DNA with the help of proteins. The DNA coils sequentially into the nucleosome, 10 nano-meter fibre, 30 nano-meter and then into the metaphase chromosome.
• DNA is analysed by the method of karyotyping in which the chromosomes are observed, counted and checked for abnormality in the cells, in metaphase stage of cell-division ( when the chromosomes can be distinctly identified).
• Each chromosome carries multiple genes as the chromosome is formed by the coiling up of the long DNA carrying genes.
• Chromosome carry genes, chromosomes are not carried on genes.