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G6PD deficiency. Glucose-6-phosphate dehydrogenase ( G6PD ) ( 葡萄糖 -6- 磷酸脫氫酶 ) is an enzyme produced in immature red blood cells. G6PD deficiency. It protects the red blood cells from being oxidized and destroyed. G6PD deficiency.
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G6PD deficiency Glucose-6-phosphate dehydrogenase (G6PD) (葡萄糖-6-磷酸脫氫酶) is an enzyme produced in immature red blood cells.
G6PD deficiency It protects the red blood cells from being oxidized and destroyed.
G6PD deficiency About 5% of the HK population have G6PD deficiency (葡萄糖-6-磷酸脫氫酶缺乏症/蠶豆症).
G6PD deficiency If they are exposed to substances with oxidizing properties, their red blood cells will break down rapidly.
How does a mutation in the gene for G6PD cause the enzyme deficiency
Organism estimated size estimated gene number average gene density chromosome # Homo sapiens (human) 2900 million bases ~30,000 1 gene per 100,000 bases 46 Rattus norvegicus (rat) 2,750 million bases ~30,000 1 gene per 100,000 bases 42 Mus musculus (mouse) 2500 million bases ~30,000 1 gene per 100,000 bases 40 Drosophila melanogaster 180 million bases 13,600 1 gene per 9,000 bases 8 (fruit fly) Arabidopsis thaliana 125 million bases 25,500 1 gene per 4000 bases 5 (plant) Zea mays (corn) 5000 million bases ~25,000 1 gene per 200,000 bases 10 Oryza sativa (rice) 565 ~25,000 1 gene per 23000 bases 12 Caenorhabditis elegans 97 million bases 19,100 1 gene per 5000 bases 6 (roundworm) Saccharomyces cerevisiae 12 million bases 6300 1 gene per 2000 bases 16 (yeast) Escherichia coli 4.7 million bases 3200 1 gene per 1400 bases 1 (bacteria) H. influenzae (bacteria) 1.8 million bases 1700 1 gene per 1000 bases 1
DNA – Organic Bases Pyrimidine Purines
DNA - The molecule of life Each cell: • 46 chromosomes • 2 meters of DNA • 3 billion DNA bases • Approximately 30,000 genes
28.1 From DNA to proteins The genetic code • the way in which the base sequence in a DNA strand determines the amino acid sequence in a polypeptide
28.1 From DNA to proteins The genetic code Gln Ala Leu Ser Glu Arg Lys Thr How? Gly Asn Met Trp His Asp Phe Tyr Ile Cys Pro Val 4 bases 20 amino acids
28.1 From DNA to proteins The genetic code • three bases code for one amino acid triplet code (三聯體密碼) DNA strand amino acids
28.1 From DNA to proteins The genetic code • 43 = 64 triplet codes More than enough!
28.1 From DNA to proteins The genetic code • degenerate code (簡併密碼) Cys Cys
28.1 From DNA to proteins The genetic code • some are start signals and stop signals • no gaps, read in a non-overlapping manner
28.1 From DNA to proteins The genetic code • universal Cys
28.1 From DNA to proteins Animation Protein synthesis • two stages: nucleus transcription(轉錄) 1 • DNA RNA translation(轉譯) 2 • RNA polypeptide cytoplasm
28.1 From DNA to proteins … … … … … … … … … … 1 Transcription a The two DNA strands are held together by weak hydrogen bonds.
28.1 From DNA to proteins … … … … … … … … … … … 1 Transcription b The hydrogen bonds break and the two DNA strands separate.
28.1 From DNA to proteins … … … … … … … … … … 1 Transcription c Under the action of RNA polymerase, free nucleotides are added against a template. template strand free nucleotides
28.1 From DNA to proteins … … … … … … … … … … 1 Transcription c A messenger RNA is synthesized. template strand triplet code mRNA codon (密碼子)
28.1 From DNA to proteins … … … … … … … … … … 1 Transcription d The messenger RNA leaves the nucleus. template strand mRNA to cytoplasm