DNA
what happens if the amino acids are in a different order?
Different combinations of amino acids make different proteins
Why is the order of the base pairs critical in DNA?
Because it is this that determines the order of AMINO ACIDS in a PROTEIN which is vital for our called to function
How are the bases always paired?
Adenine is always paired with Thymine Cytosine is always paired with Guanine
Summary points
1. A molecule of DNA is shaped like a twisted ladder called a DOUBLE HELIX 2. The "rungs" of the ladder are made of pairs of BASES 3. ADENINE pairs with THYNINE- AT 4. CYTOSINE PAIRS WITH GUANINE- CG 5, DNA carries the genetic code which tells the cells to make proteins 6. The DNA strand that can do this is called a TRIPLET 7. Each TRIPLET is a code for one AMINO ACID in the PROTEIN 8. PROTEINS are long chains of AMINO ACIDS and are important components in every cell and needed for essential cell functions
How does DNA control the cell?
1. DNA controls the joining together of amnio acids to make a specific protein in a call. The order of BASES in a section of DNA decides the order of AMINO ACIDS in the protein. 2. A sequence of three bases is called a TRIPLET or a CODON 3. Each CODON codes for a certain amino acid e.g. CGA- code for arginine ATA- codes for Tyrosine TAC- codes for methionine CAA codes for proline 4. Therefore certain lengths of DNA molecule codes for different proteins 5. Some certain amino acids have more than one code e.g. argine = GCA & AGT
What is meant by DNA bases?
1. Each DNA forms 4 bases A- Adenine T- Thymine C- Cytosine G- Guanine
what are proteins so important ?
1. Our bodies use proteins all the time 2. They are an important component in every cell 3. Proteins are used for almost all functions of the cell 4. eg proteins are used for - making haemoglobin molecules (red blood cells) - building and repairing tissues (e.g. connective tissue/muscle tissue/nervous tissue/epithelial (skin) tissue
What are proteins?
1. Proteins are long chains of amino acids 2. There are 20 different types of amino acid from which to make proteins
what is the structure of DNA
1. The DNA molecule is like a twisted ladder (double helix) 2. Two strands on the sides (the "rails") are made of sugar and phosphate 3. the rungs are made up of bases which link the strands together
where is DNA
1. found in nucleus of cell 2. Although a human cell is only a few 1ooths of a millimetre in diameter, each one contains more than a metre of DNA 3. DNA is twisted into a spiral called double helix which is tightly coiled up to form chromosomes. 4. Genes are packed along the length of the chromosomes which are stored in the nucleus
what does DNA stand for ?
DNA stands for deoxyribonucleic acid, DE OXY RIBO NUCLEIC ACID which is the molecule that carries genetic information in humans and all other living organisms
