Photo AI
(i) What is the chemical composition of a chromosome? (ii) What is meant by the term junk DNA? - Leaving Cert Biology - Question 7 - 2015
Question 7
(i) What is the chemical composition of a chromosome? (ii) What is meant by the term junk DNA?
Worked Solution & Example Answer:(i) What is the chemical composition of a chromosome? (ii) What is meant by the term junk DNA? - Leaving Cert Biology - Question 7 - 2015
Step 1
What is the chemical composition of a chromosome?
Answer
Chromosomes are primarily composed of two main types of molecules: DNA and proteins. The DNA serves as the genetic material, carrying the hereditary information necessary for the growth, development, and functioning of living organisms. The proteins, particularly histones, play a critical role by providing structural support; they help package the DNA into a compact form, allowing it to fit within the cell nucleus.
Step 2
What is meant by the term junk DNA?
Answer
The term 'junk DNA' refers to non-coding regions of DNA within a genome that do not contain instructions for making proteins. Historically, it was thought that these segments had no functional purpose. However, more recent research has suggested that some of this non-coding DNA may have regulatory roles, contribute to the structure of chromosomes, or play a part in gene expression.