Chapter 7 Flashcards
What is the One Gene-One Enzyme Hypothesis?
A hypothesis proposed by Beadle and Tatum that states that each gene is unique and codes for the synthesis of a single enzyme
What is the One Gene-One Polypeptide Hypothesis?
A hypothesis that says that a gene is unique and codes for the synthesis of a single polypeptide; restated version of One Gene-One Enzyme hypothesis
Define Central Dogma
The transfer of info from DNA to RNA to proteins
What are the 2 steps involved in the process of transferring info from DNA to RNA to proteins?
- Transcription
- Translation
What is Transcription?
Info encoded in DNA is transcribed onto a complementary RNA strand. This occurs in the nucleus of a eukaryotic cell. This is done because unlike DNA, RNA can exit the nucleus and enter the cytosol. The info encoded in DNA is simply rewritten in RNA in the same language (of bases)
What is translation?
Translation is the assembly of amino acids into polypeptides following the instructions coded in RNA. “Translation” literally refers to translating the language of RNA (in bases) into the language of amino acids in order to assemble the polypeptides. This takes place in ribosomes in cytosol.
Compare and Contrast RNA & DNA
RNA:
- Single stranded
- Guanine pairs with Cytosine (Same)
- Adenine pairs with Uracil (No Thymine)
- Ribose sugar
DNA:
- Double stranded
- Guanine pairs with Cytosine (Same)
- Adenine pairs with Thymine (No Uracil)
- Deoxyribose sugar
What are the 3 types of RNA involved in protein synthesis?
- mRNA
- tRNA
- rRNA
State properties of mRNA
- Length varies depending on length of gene copied
- Acts as intermediary between DNA and ribosomes
- Ribosomes translate mRNA into proteins
- RNA version of encoded DNA
State properties of tRNA
- Acts as the delivery system of amino acids to ribosomes as they synthesize proteins
- Very short, only 70 to 90 base pairs
