Bio

• DNA is a large molecule called 'deoxyribose nucleic acid'
• DNA is found in the nucleus of all eukaryotic cells
• All living things have DNA
• One DNA molecule is called a 'chromosome'
• Chromosomes and their genes are made of a molecule called DNA
• DNA molecules carry the code that controls what your cells are made of and what they do
• DNA stands for deoxyribonucleic acid
• Each chromosome is a very long molecule of tightly coiled DNA
• DNA controls all the chemical changes that take place in the cell
• DNA controls what kind of cell is formed and what kind of organism is produced
• DNA is a fundamental molecule of life
• DNA is Universal, meaning a bit of DNA will produce the same protein in all organisms
• DNA is extremely large → a single strand of DNA from one cell can stretch out to 2 -3 m long
• You have 10 trillion cells in your body, so your total DNA would actually reach the Sun and back – 4 times!
• DNA is a chain of sub-units called nucleotides
• Nucleotide


  Made up of a pentagon shaped sugar called deoxyribose, a phosphate group, and a nitrogen containing base
• DNA is a double helix spiral

  
• Nitrogenous bases in DNA

  • Adenine (A)
  • Thymine (T)
  • Guanine (G)
  • Cytosine (C)
• Adenine always pairs up with Thymine, and Cytosine always pairs up with Guanine
• A sample of DNA was sequenced and was found to contain 30% Guanine. The percentage of each other nitrogen base would be 30% Cytosine, 20% Adenine, and 20% Thymine
• DNA is described using the letters of the nitrogenous bases on one strand
• Different sequences of nitrogenous bases control what you look like, how your heart beats, allergic reactions and how quickly you build muscle
• The code in your DNA is used to create proteins
• Gene


  The section of a DNA molecule which makes a protein
• There are many genes on a chromosome
• DNA is wrapped around special proteins called histones, which condenses DNA until it forms coils. These coils form chromosomes

  
• You have 46 chromosomes in the human body → 23 from your mother and 23 from your father
• Chromosome groups


  • Autosomes (22)
  • Sex chromosomes (X and Y)
• Chromosomes from your mother and father pair up
• Homologous chromosomes


  Paired chromosomes
• Non-homologous chromosomes


  Non-paired chromosomes
• DNA is essentially a long recipe book for various proteins, which are the building blocks of life
• Gene regulation helps ensure cells will produce functional proteins for that cell type → turns genes 'on' and 'off'
• Chromosomes


  Structures that contain DNA and genes
• Genes


  Sections of DNA that hold the code to make different things in the cell
• DNA is a long recipe book for various proteins, which are the building blocks of life
• Each gene is a single recipe in the book, giving you the instructions to make one protein
• Genes


  • Help cells become specialised
  • Not all cells 'express' the entire genetic code
  • Gene regulation turns genes 'on' and 'off'
• Skin cells will only produce proteins needed in the skin, not those found in your digestive system
• DNA


  A code for proteins