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23 Cards in this Set
- Front
- Back
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Hershey-Chase |
-Had trials to find out what made us, us -1st- used bacteriophage with sulfur in bacteria; nothing detected -2nd- used phosphorous in bacteria; DNA detected -Result: genetic material is DNA |
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Rosalind Franklin |
Took the first photo of DNA |
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Watson and Crick |
-Scientists working on the structure of DNA -When they saw Franklin's photo they knew how to build one -Made a model of DNA |
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DNA structure |
-Double helix (twists), double strands (connected like a latter by nucleotides) -Anti-parallel (5' to 3', 3' to 5') |
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DNA codes |
Genes (codes for proteins) Introns (do not code for genes) Exons (do code for genes, are expressed) |
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Chromosome |
tightly coiled DNA looks like an X Humans have 46, apes 48 |
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Chromatid |
one of a pair of sister chromatids (half of the X) |
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Telomere |
the end of the chromotids (acts as a protector) |
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Centromere |
the center of a chromosome (place where centrioles attach) |
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Plasmids |
-A circular strand of DNA that usually only contains 1 or 2 genes -can be taken up by bacteria and used -Ex. Insulin |
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DNA Components |
-Nucleotides (Deoxyribose, phosphate group, nitrogenous base) -4 Bases (A,G,C,T; T is replaced with U in RNA) ----Purines (2 rings; A and G) ----Pyrimidines (1 ring; C, T, & U) ----Complementary Pairs (A with T/U, G with C) |
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Replication |
-when cells divide they make another copy of DNA -Semi-conservative (conserve part of the original DNA and copy based on the pairings of the nucleotides) |
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Replication Process |
1. it untwists 2. enzymes (Helicase) unzip the nucleotides by braking Hydrogen bonds 3. free-floating nucleotides bond to the single strand 4. A different enzyme bonds together the newly formed pairs (DNA polymerase) ---Okazaki Fragments are the short parts of the replicated DNA |
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RNA |
-Phosphate group, ribose, Nitrogenous base (A,U,G,C) -single stranded -mRNA (messenger); rRNA (ribosomal); tRNA (transfer) |
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Steps of making a protein |
1. Transcription: DNA is copied, mRNA goes into cytoplasm 2. Editing: introns are cut out, exons are left and joined 3. Translation: mRNA attaches to a ribosom(rRNA), tRNA enters ribosome matching codons on mRNA 4. Completion: a STOP codon is read, the mRNA and newly formed protein is released |
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Mutations |
-any change in DNA sequence -may be spontaneous or caused by a mutagen (an agent that increases the frequency of mutation, chemical; UV light; radiation) -can be beneficial or deleterious -may have little or no effect -special enzymes proofread DNA and can fix errors |
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Types of Mutations |
-Point or substitution: causes the replacement of a single nucleotide with a different one -Frame Shift: a deletion or insertion -Chromosomal Inversions: an entire section of DNA is reversed (ex. hemophilia) |
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Technologies |
Recombinant DNA- genetically engineered DNA prepared by splicing genes from one species into the cells of a different species. DNA becomes part of the host's genetic makeup and replicates |
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Bacteriophage |
a virus that infects bacteria (only contains protein and DNA) |
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Radioactive Marker |
attaches an element that doesn't normally exist. When it decays it releases radiation, which can be detected |
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Codons |
3 nucleotides = 1 codon 1 codon = 1 amino acid lots of amino acids = protein (20 different amino acids) |
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Protein? |
-Polypeptide -chain of amino acids -DNA-> RNA = a code -3 nucleotides = 1 coden |
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Point Mutation |
Missense- code for different amino acid Nonsense-code for STOP Silent- code for same amino acid |
