1. A chromosome contains one long DNA molecule.
DNA or deoxyribonucleic acid is a fundamental and essential macromolecule that is built from the chain of nucleotides. A nucleotide consists of one of four nitrogen-containing nucleobases (cytosine [C], guanine [G], adenine [A] or thymine [T]), a sugar called deoxyribose, and a phosphate group. DNA carries the genetic instructions used in the growth, development, functioning and reproduction of all known living organisms. It is organized (packed) into structures-chromosomes and during cell division, these chromosomes are duplicated in the process of DNA replication. The process of replication provides each cell with its own complete set of chromosomes.
2. Each gene in this molecule gives the instructions for making a PROTEIN.
The genetic information in a genome is held within genes. Genes are a sequence of DNA that codes for a molecule that has a function, and usually, it is a protein. During gene expression, the DNA is first copied into RNA in a process called transcription. Then, synthesized RNA can be directly functional or be the template for a protein that performs a function. Synthesis of protein from RNA is a process called translation.
3. Both chromosomes in a pair of HOMOLOGOUS chromosomes have the same GENE, but the two chromosomes may have different ALLELES.
Homologous chromosomes are a set of one maternal and one paternal chromosome. Those chromosomes pair up with each other inside a cell during meiosis. Homologs have the same genes in the same loci but the alleles may be different, resulting in different phenotypes of the same genes. During the meiosis, the process of crossing over occurs when homologous chromosome pair exchange parts of DNA with one another.
4. Chromosomes that are not homologous have different GENE which gives the instructions for making different kinds of proteins.
Non-homologous chromosomes differently from homologous consist of alleles of different types of genes. Non-homologous chromosomes do not pair during meiosis and the shape of the chromosome, the length of the arms and the position of the centromere, is different among those chromosomes.