DNA is composed of nucleotides, which are composed of three parts:
1. A five carbon carbohydrate (pentose)
Pentose is classified as a monosaccharide (simple carbohydrate), and its molecular formula is represented by 
. They are water soluble molecules with sweet taste. Monosaccharides may have from three carbon atoms (trioses) to six (hexoses). In DNA is present pentose (5 carbon atoms)
2. A nitrogenous base
Nitrogenous bases are ring-shaped compounds that contain nitrogen in their molecular structure. They are classified into two groups: purines and pyrimidines
The purine bases are adenine (A) and guanine (G). They are larger and contain more than one ring in their structure,.
The pyrimidines, cytosine (C), uracil (U) and thymine (T), are smaller and composed of a single ring.
3. One or more phosphate groups
A phosphate consists of a trivalent anion that contains one phosphorus atom and four oxygen atoms. Its molecular formula is expressed by 
.
Answer choices:
- A frame shift mutation in the X chromosome of a cheek cell
- A chromosomal mutation in the Y chromosome of a kidney cell
- A point mutation in the first chromosome of a sperm cell
- A substitution mutation in the third chromosome of a uterus cell
Answers:
A point mutation in the first chromosome of a sperm cell
Explanation:
Only mutations that affect the germ line are passed on to the next generation. Therefore, only mutations in the egg and sperm of an individual have the potential to affect the next generation.
Mutations in cheek cells, kidney cells, and uterus cells might cause cell death or cancer. This genetic material is not passed on to the next generation, only the egg and sperm contribute this material. Therefore, only mutations here will affect the generation.
Organs or skeletal elements of animals and organisms
