Genes & Chromosomes

Keywords

Genes, chromosomes, features, traits, generations, family, protein, DNA, deoxyribonucleic acid, structure, monosome.

Introduction

Our genes are important. They distinguish us from other people, by ways of hair colour, eye colour and height, plus other features we may have.

What are Genes?

Genes are functional units of heredity. To make this sound simpler, they are what is passed down to each new generation of family - this can be features like:

• Hair colour
• Eye colour
• Height
• Weight
• Metabolism
• Diseases

There are around 30,000 genes in each human body, all making us up with different features. They all form part of our DNA.

Scientists such as Gregor Mendel in the 1800s worked to find out how we change over generations, and this was found by three scientists in the 1900, who later found that their work wasn't new, and referred back to Mendel's work with pea plants.

What are Chromosomes?

A chromosome is a thread-like structure that is found in plants and animal cells. Each one (we have 46) is made of protein and a single molecule of DNA (Deoxyribonucleic Acid). Every cell of your body has these 46 chromosomes in them. Twenty-three from your mother, twenty-three from your father. Each gamete (the sexual reproduction cells - sperm and egg) each have 23 chromosomes.

Interesting fact: we inherit 23 chromosomes from our father, and we inherit 23 chromsomes from our mother. They are paired up to make 46 chromosomes.

What Do They Do?

A chromosome protects the DNA from falling apart, as they are structured with spool-like proteins called histones. Without this packaging, the molecules of DNA would be too long to fit inside cells.

If there are any changes in the number or structure of the chromosomes, this can lead to serious problems. If we look at the 21^st chromosome, and more specifically in people with Down's Syndrome, there is a third copy of it present, instead of the two copies found in others.

Monosomes

A Monosome is a single piece of RNA (specifically messenger RNA) that is not attached to a chromosome. Where a chromosome is a double up of genes and RNA forming the DNA, a monosome does not do this. It is simply an unpaired X chromosome.