INTRODUCTION TO GENETICS AND EVOLUTION 🔬

A double-helix
 strand of DNA

During the first four weeks of Year 10, 10Sp has been working on Genetics and Evolution in Science - a subject I was quite looking forward to last year, simply based on the fact I knew what a mitochondria is. But going into this I've learnt that there is a lot more to cells, genetics, genes, DNA, and reproduction than what I thought.

What are genes, and what is DNA? Did you know that DNA stands for deoxynucleic acid? I didn't. You may be familiar with the 'double-helix' shaped strand of DNA, those tiny little strands that contain genetic instructions, for the development, and furthermore, the function, of living things. A DNA strand that contains instructions for /control a specific feature such as eye colour is called a gene. Genes are responsible for telling the human body how to make proteins, which determine the function and structure of cells. They are inherited from your parents. 

DNA and it's location
DNA is located inside the nucleus of the cell - the nucleus is known as the 'boss' as it coordinates the activities of the cell. Chromosomes, for which you inherit 23 from each parent (making 46 in total) are made from DNA strands. They look a bit like this > 

Chromosones, Pair 23, and Karyotypes
Focusing a bit more on chromosones, we did an activity based on Karyotypes. Karyotypes is basically a picture of the chromosomes a cell hosts, used to look for abnormalities. For example, a result of a condition caused by chromosome abnormality is down's syndrome. This condition is caused by an extra '21' chromosome. 

For the task we had to match each side of the chromosome to another by matching their banding, size, shape, etc. Chromosomes aren't exactly identical but they look very similar to not only its second half of the pair, but the other chromosomes, making this task pretty difficult. 

If you know anything about chromosomes you must know about pair 23. Pair 23 is your sex chromosome - the pair of chromosomes that determine your gender. For males, the pair is made up of an x and y chromosome. For females, both sides of the pair are x chromosomes.

Answers to the questions listed:

1. There are 46 chromosomes found in the typical human cell. 

2. 23 chromosomes are inherited from your mother, and 23 chromosomes are inherited from your father.