Created by Chelsi Souch
over 8 years ago
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Question | Answer |
CELLS CONTAIN THOUSANDS OF DIFFERENT PROTEINS | unique AA sequence unique 3-D structure a specific function CELLS ALSO CONTAIN MEMBRANE SYSTEMS AND ORGANELLES etc. CELL MUST HAVE INFORMATION TO ORGANIZE ITSELF IN THIS WAY AND, WHEN A CELL DIVIDES, THIS INFORMATION MUST BE PASSED TO THE NEXT GENERATION |
THE SEARCH FOR THE GENETIC MATERIAL | The DNA molecule contains instructions for the development and functioning of all living organisms |
FREDERICK GRIFFITHS | MOVEMENT OF A SUBSTANCE FROM ONE STRAIN OF BACTERIA TO ANOTHER TRANSFORMS HARMLESS STRAINS INTO PATHOGENIC (disease causing) STRAINS |
OSWALD AVERY | REMOVED ALL PROTEIN FROM R BACTERIA BUT TRANSFORMING ACTIVITY NOT REDUCED DETAILED CHEMICAL AND BIOCHEMICAL TESTS SHOWED THAT THE “TRANSFORMING PRINCIPLE” PASSED FROM DEAD TO LIVING BACTERIA WAS DNA! DNA is the HEREDITARY MATERIAL! |
THE GENTIC INSTRUCTION OF VIRUSES ARE CONTAINED IN DNA | BACTERIOPHAGE (bacteria infecting viruses) INFECTING BACTERIAL CELL |
ROSALIND FRANKLIN | X-RAY CRYSTALLOGRAPHIC STRUCTURE OF DNA |
WATSON AND CRICK (1953) | PROPOSED THE STRUCTURE OF DNA: * That there were two strands of nucleotides in DNA * That ONLY certain combinations of bases could pair with each other NOBEL PRIZE IN 1962 |
DNA POLYNUCLEOTIDE | |
CHEMICAL PROPERTIES OF THE THREE CHEMICAL COMPOUNDS IN NUCLEOTIDES | • Phosphate group: Acidic and negatively charged in basic pH • Sugar : Pentose (5C) Ribose in RNA and Deoxyribose in DNA • Nitrogenous bases: A, T, G, C, U (Adenine, Thymine, Guanine,Cytosine, Uracil) A, G have two ring structure: Purines G, C, U have one ring structure: Pyrimidines |
DNA vs RNA | DNA has deoxyribose pentose sugar RNA has Ribose pentose sugar • DNA double stranded RNA single stranded • DNA has Pyrimidine: Thymine, Cytosine RNA has pyrimidine: Uracil, Cytocine Both have the purines: Adenine and Guanine |
DNA REPLICATION Making more DNA in a cell | Occurs in S phase of cell cycle ٭ Depends on specific base pairing ٭ Requires complete and faithful copies of DNA be produced ٭ Each half of the double helix can act as a template upon which, a new missing half is built ٭ Each new double helix consists of one old and one new strand (semi-conservative ) |
How does information in DNA is given to make proteins? | Takes place via TWO processes: 1. Information in DNA is first TRANSCRIBED INTO THAT OF RNA 2. Information in RNA is then TRANSLATED INTO PROTEINS (Nucleic acid language to Protein language) – In eukaryotic cells, • Transcription occurs in the nucleus. • Translation occurs in the cytoplasm |
FLOW OF GENETIC INFORMATION | |
Translation is divided into three phases: | •Initiation • Elongation • Termination |
MUTATIONS: 2 Types | 1. Base substitutions Point mutation 2. Base insertions or Deletions Frame shift mutations Mutations may result from • errors in DNA replication transcription or recombination (crossing over) or • physical or chemical agents e.g., UV irradiation and chemicals called mutagens. – Mutations are often harmful but are also useful in nature and the laboratory as a source of genetic diversity, which makes evolution by natural selection possible |
There are many ways chromosomes may rearrange: Chromosomes break naturally or due to exposure to radiation | 1. Duplication 2. Translocation 3. Inversion 4. Deletions |
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