DNA 1 - Chromosomes, Genome & Migration

• What does DNA stand for?

  Deoxyribonucleic acid
• DNA has a double helix structure. How many strands is the helix made up of?

  2
• The DNA in typical human cell is found in tight coils known as chromosomes
• How many chromosomes are there in a typical human cell? 

  46
• Chromosomes exist in pairs. The chromosomes in the 23rd pair are known as the sex chromosomes 
• Do women have XX or XY sex chromosomes? 

  XX
• Remember that chromosomes only have an 'X' shape when the DNA has been duplicated ready for cell division. The rest of the time, they will look more like like an 'L'. 

  
• what is a gene?

  "A small section of DNA that codes for a specific protein"
• DNA can code for proteins by coding for the sequence in which amino acids are joined together. 
• What does the term 'genome' mean?

  The entire set of genetic material in an organism 
• Some genes can cause specific diseases. We call these inherited diseases. 
•  Understanding the genomes of different people around the world can tell us about the migration patterns of our ancestors.