LIFE 102 Exam 4 Flashcards
DNA base pairing rules
Adenine (A) pairs with Thymine (T) forming 2 hydrogen bonds
Cytosine (C) pairs with Guanine (G) forming 3 hydrogen bonds
Transcription Factors
Proteins that regulate gene expression by assisting or blocking transcription
Where are transcription factors made
The cytoplasm and move to nucleus to act on specific genes
What do transcription factors do
They either activate or repress the transcription of specific genes to specific DNA sequences near the gene like enhancers or promoters
DNA Methylation
The addition of methyl group (-CH3) to the DNA molecule usually at cytosine bases
Effect on gene expression
Silences genes by preventing the binding of transcription factors
Gene regulation
Happens at multiple levels
- during transcription
- RNA processing
- translation
Purpose of gene regulation
Ensure that correct genes are expressed at the right time and in the right cell
Location of gene regulation
Eukaryotes: nucleus
Prokaryotes: cytoplasm
RNA Polymerase
The enzyme that synthesizes RNA from the DNA template
Promoter
A DNA sequence where RNA polymerase binds to begin transcription
Template Strand
The strand of DNA that is read by RNA polymerase to create the complementary RNA strand
Ribonucelotides
RNA building blocks (A, U, T, C, G)
Transcription factors
Proteins that help polymerase bind to the promoter
Location of transcription
The nucleus of eukaryotes and cytoplasm of prokaryotes
Step 1 of transcription: Initiation
RNA polymerase binds to the promoter with the help of transcription factors.
Step 2 of transcription: Elongation
RNA polymerase moves along the DNA, synthesizing the RNA transcript.
Step 3 of transcription: Termination
RNA polymerase reaches the terminator sequence, and the newly synthesized RNA is released.
Translation location
The cytoplasm for both prokaryotes and eukaryotes
mRNA processing
Does not happen in prokaryotes and happens before going to cytoplasm in eukaryotes
