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What were Chargaff’s rules
and why were they important?
- A=T and G=C (ALMOST)
- important: indicates double helix model
- important: confirms base pairing
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Describe two types of point
mutations and give examples of their effects.
- substitution- one base is changed to another
- deletion- one base is removed
ex: deletion or substitution of a stop term alters amino acid production
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Describe the Watson - Crick Model of DNA.
- double helix (two interwoven strands of nucleotides) (spiral staircase)
- displays base pairing- hydrogen bonds between a and t and gc, confirming chargaffs rules
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Explain the
Central Dogma of Molecular Biology
- the flow of genetic info can be moved from DNA to RNA to protein
- DNA--> transcription mRNA---> translation peptide
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Describe the Hershey and
Chase experiment and its results.
- bacteriophage (virus) with one DNA radioactive, another with a protein radioactive
- both reactive
- bacterium radioactive with DNA
- not radioactive with protein
shows DNA transfered genetic info, not the protein
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What is the complete
definition of the gene?
segment of DNA that contains all the info needed for protein of RNA synthesis
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Describe one
advantage and one disadvantage of transgenic plants.
higher crop yield/more food produces
1-Some changes in environmental cycles (for example, now our dear insect can not eat its food so needs to change his food source!)
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Describe
two differences between RNA and DNA.
RNA single strand, DNA double strand
RNA has U, DNA has T
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Compare the structure and
functions of the three types of RNA.
- mRNA: carries the message from dna in the nucleus to the cytoplasm during protein synthesis, one uncoiled strand
- tRNA: carries the amino acids to the mrna at the ribosome to make the polypeptides, clover shaped
- rRNA: is mostly just a structural one, it makes up the ribosome along with the proteins
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What is the role of base
pairing in replication, transcription and translation?
ensures each stage stays specified to the organism's unique genetic code
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