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29 Cards in this Set
- Front
- Back
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DNA
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written instructions for all proteins
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What 4 people discovered the structure of DNA?
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- James Watson and Francis Crick (Built a double helix)
-Rosalind Franklin and Maurice Wilkins (Took X-ray pictures of DNA) |
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What is DNA’s 4 bases?
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adenine A) - a purine
guanine G) - a purine thymine (T) - a pyrimidine cytosine (C) - a pyrimidine |
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Structure of DNA: complimentary base pairing
(purine + pyrimidine) |
Adenine (A) <-> Thymine (T)
Guanine (G) <-> Cytosine (C) |
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Semi-conservative replication
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- DNA (Double Helix) splits in half (zips open)
- each half is template to replace the missing half - resulting DNA is 1/2 old and 1/2 new |
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Replication of DNA
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- DNA helicase unwinds and unzips
- DNA polymerase adds complementary nucleotides resulting in complementary base pairing - DNA Ligase repairs backbone - Results in two matching double helix molecules |
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RNA
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single strand of nucleotide basis (half DNA)
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Gene
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A segment of DNA that specifies that amino acid sequence of a protein.
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What shape is DNA?
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Double Helix
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RNA’s 4 bases
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Adenine, Guanine, Uracil, Cytosine,
A G U C |
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DNA replication
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- DNA Helicase unwinds and unzips
- DNA Polymerase adds complementary nucleotides - DNA Ligase repairs backbone - Resulting in two matching double helix molecules. |
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Semiconservative
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Each half template is to replace the missing half. Half old and half new.
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Gene expression
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Making a protein from a gene.
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Transcription
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When RNA is created, Making a readable copy of a gene from DNA, happens inside the Nucleus
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mRNA
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Takes a message from DNA to the ribosomes
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Exons
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Are joined together (expressed segments)
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Introns
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Sections are cut out (Intragene Segments)
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rRNA
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Makes up ribosomes along with proteins
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tRNA
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Transfers amino acids to ribosomes
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Ribosome
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protein factory in cytoplasm or on ER
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Codons
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3 nucleotide unit of mRNA
What are they? Provide some protection against mutation How many total codons? 64 different mRNA How many “stop” codons?- 3 (Punction) |
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How does a ribosome build a protein?
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Initiation- starts the peptide chain
Elongation- adds amino acids in order Termination- ends peptide chain |
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Gene mutations
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A change in the sequence of bases within a gene. Errors in replication.
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Point mutations
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Nucleotide substitution
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Silent
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Codon for same amino acid
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Nonsense
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Changes in amino acid codon (stop codon)
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Missense
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Codon for different amino acid
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Frameshift mutations
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Insertion or deletion shifts nucleotides, one or more are inserted or deleted.
What causes mutations? |
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What causes mutations?
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1. DNA damage from environmental agents such as ultraviolet light (sunshine), nuclear radiation or certain chemicals
1. Mistakes that occur when a cell copies its DNA in preparation for cell division. |
