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DNA

Definitions
1. DNA – Deoxyribonucleic Acid A nucleic acid that consists of a nucleotides made up of the sugar deoxyribose, phosphate group and one of four nitrogenous bases (adenine, thymine, guanine, cytosine) Genetic information is encoded in the sequence of three bases
2. RNA-Ribonucleic acid that consists of a single strange of nuceotides, each consisting of a sugar ribose, a phosphate group and one of four nitrogenous bases (adenine, uracil, guanine, cytosine) Three form exsist – Mrna (messenger), Rna (ribosomal), Trna (transfer)
3. Nucleotide-A molecule formed of a sugar, a nitrogenous base and an inorganic phosphate group. Nucleotides are the component molecules of nucleic acid – Polynucleotid – a chain of nucleotides
4. Chromatin-The thread like mass of DNA and is associated with proteins found within the nucleus of a cell
5. Mitosis –Cell division characterised by the formation of two daughter cells, each of which possesses the diploid number of chromosomes
6. DNA replication-The process in which a double helix DNA strand is copied to produce two identical DNA molecules – two daughter cells contain the exact DNA information as parent.
7. Amino acid – The component molecules of proteins - a simple organic compound containing both a carboxyl (—COOH) and an amino (—NH2) group.
8. Codon is a sequence of three DNA or RNA nucleotides that corresponds with a specific amino acid or stop signal during protein synthesis. DNA and RNA molecules are written in a language of four nucleotides; meanwhile, the language of proteins includes 20 amino acids - Three base sequence in DNA (triplet) goes to - -- Three base sequence in mRNA (codon) codes which for an amino acid
9. Peptide bond -A bond formed between the amino group of one amino acid and the carboxyl group of a second amino acid - broken with water
10. Protein synthesis – the process whereby biological cells generate new proteins;
11. Transcription –The genetic code is transcribe (copied) from DNA to mRNA. Transcription takes place in the nucleus
12. Translation –The genetic code carried by mRNA is translated into the sequence of amino acids in protein
13. Ribosome –Organelle that is the site for protein synthesis
14. Polymerase- A enzyme that assembles new DNA by copying existing strand
15. tRna - Transfer RNA - Brings matching amino acids rRna - Ribosomal RNA -decodes the Mrna Mrna - Messenger RNA to copy DNA
Difference between DNA and Rna
DNA Replication
1. 1. An enzyme, DNA gyrase, separates each side of the double helix.
  1. 2. Enzyme helicase, unwinds the double helix. Several small proteins temporarily bind to each side and keep the sides separated.
    1. 3. An enzyme complex, DNA polymerase, walks down the DNA strands and adds new nucleotides to each strand. The nucleotides pair up: adenine (A) with thymine (T) and guanine (G) with cytosine (C). A subunit of the DNA polymerase proofreads the new DNA..
      1. 4. An enzyme, DNA ligase, seals up the fragments into long continuous strands. The new copies automatically wind up again
Why are protein important
1. Structural e.g. collagen; keratin
2. Enzymes e.g. digestive; metabolic pathways..
3. Hormones e.g. insulin, thyroid hormones
4. Neuropeptides e.g. endorphins
5. Transport e.g. haemoglobin (o2 ); albumin
6. Receptors e.g. neurotransmitter and hormonal
7. Antibodies e.g. Immunoglobulins • Ion Channels e.g. sodium channels
8. What destroys Protein?
  1. Temperature/PH
DNA to GENE
1. Amino acid
  1. All amino acids have a Amine -NH2 and CooH group
  2. Polypeptide bond
    1. A chain of amino acids
    2. Is dehydrated so always loses the aminos OH and H (H20) - to break replace H20
2. STEP 1 ****TRANSCRIPTION*****: The first step in transcription is the partial unwinding of the DNA molecule so that the portion of DNA that codes for the needed protein can be transcribed. Once the DNA molecule is unwound at the correct location, an enzyme called RNA polymerase helps line up nucleotides to create a complementary strand of mRNA.
  1. STEP 2: *****TRANSLATION***** In translation, mRNA is sent to the cytoplasm, where it bonds with ribosomes (rRNA), the sites of protein synthesis. Once the mRNA is in place, tRNA molecules, each associated with specific amino acids, bind to the ribosome in a sequence defined by the mRNA code. - this creates an anti codon.
    1. IN translation they create a peptide bond - this MUST ALWAYS START WITH AUG and finish with UAA UGA UAG
    2. MRNA CODON IS THE SAME AS THE DNA EXCEPT U IS USED
3. Key Points
  1. Transcription factor -Transcription factors are proteins involved in the process of converting, or transcribing, DNA into RNA - RNA Polymerse
  2. Tata box- where DNA can be read from
  3. Promoter- is a region of DNA that initiates transcription of a particular gene
  4. RNA polymerase - Produces a new nullities for Mrna to transcribe on.
  5. Termination signal - End part of the chromosome being transcriped
  6. Polyribosome - Allows many copies of the same protein to be produced

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DNA

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	Created by Clarissa Mackay over 9 years ago