Unit 2, part 4 Flashcards
What is the central dogma of biology?
DNA to RNA to Protein
This describes the flow of genetic information within a biological system.
What are the three main steps of transcription?
- Initiation
- Elongation
- Termination
Processing is also involved but is often considered separately.
Which direction does transcription occur?
5’ to 3’
This directionality is essential for RNA synthesis.
How does the RNA transcript relate to the DNA coding strand?
Identical (U in place of T)
The RNA transcript is complementary to the DNA template strand.
What is the sequence of the template DNA strand for the given coding strand: 5’ TCT AGG GAT GTA CCA ATA CGC GTG ACC ATG GCA AAA TTA CGG GCT ACG ATC CGA GTT TTA CCT CCG AAG TTG CCA CAA 3’?
3’ AGA TCC CTA CAT GGT TAT GCG CAC TGG TAC CGT TTT AAT GCC CGA TGC TAG GCT CAA AAT GGA GGC TTC AAC GGT GTT 5’
This sequence is complementary to the provided coding strand.
What is the sequence of the pre-mRNA transcribed from this DNA?
5’ AU GUA CCA AUA CGC GUG ACC AUG GCA AAA UUA CGG GCU ACG AUC CGA GUU UUA CCU CCG AAG UUG CCA CAA 3’
This sequence reflects the transcription process from the coding strand.
What is the role of RNA polymerase in transcription?
Adds ribonucleotides to the 3′ end of a growing RNA molecule
RNA polymerase initiates transcription by binding to the promoter.
What are the three main steps of mRNA processing?
- Add 5’ cap
- Add Poly(A) tail
- RNA splicing
These modifications enhance stability and facilitate translation.
What is the purpose of adding a 5’ cap to mRNA?
More stable and key for initiating translation
The 5’ cap protects RNA from degradation and assists in ribosome binding.
What is alternative splicing?
When exons from the same gene are joined together in different combinations
This leads to different mRNA transcripts and proteins from a single gene.
What is the difference between mRNA and DNA?
- mRNA has a 5’ cap
- mRNA has a Poly A tail
- DNA contains a promoter and introns
These differences are crucial for the function and processing of RNA.
What type of RNA is pre-mRNA?
The direct product of transcription in eukaryotes
It undergoes processing to become mature mRNA.
What is the function of tRNA in translation?
Brings an amino acid to the ribosome
tRNA helps connect amino acids to the growing polypeptide chain.
Fill in the blank: Transcription is the process of transferring information from a double-stranded DNA template to a single-stranded _______.
RNA
What occurs during the elongation phase of transcription?
Adding ribonucleotides to form a new RNA strand
RNA polymerase unwinds DNA and synthesizes RNA.
True or False: RNA polymerase reads the template strand of DNA in the 5′ to 3′ direction.
False
RNA polymerase reads the template strand in the 3′ to 5′ direction.
What is the role of spliceosomes during RNA processing?
Removes introns and joins exons together
This process allows for the formation of mature mRNA.
What is the input and output of the transcription process?
Input: DNA; Output: RNA
This reflects the central dogma of molecular biology.
