Unit 2, part 7 Flashcards
What is the first step in transcription?
Find the +1 base. This will be the start of the mRNA.
What are the two options for generating mRNA from the template DNA strand?
- Use base pairing rules (with U in place of T)
- Replace T’s with U’s in the coding DNA strand
What is the START codon in mRNA?
AUG
What is the Kozak sequence?
5’-ACC AUG G-3’
What is the significance of a STOP codon during translation?
Translation stops once a STOP codon is reached.
Identify the coding strand of the provided DNA sequence.
5’ TCT ATG GAC GTA CCA ACC ATG GCA AAA TTA CGG TAG AAA GCA AAT GAG 3’
What is the mRNA sequence derived from the coding strand?
5’ ACC AUG GCA AAA UUA CGG UAG AAA GCA AAU GAG 3’
What is the tRNA sequence corresponding to the mRNA?
3’ UAC-CGU-UUU-AAU-GCC
What is gene regulation?
The process that controls which genes are expressed in a cell.
List the 5 levels of gene regulation in eukaryotes.
- Epigenetic
- Transcriptional
- Post-transcriptional
- Translational
- Post-translational
What does ‘epigenetic’ refer to in gene expression?
Factors ‘above’ the genome that determine if a gene is accessible.
What is the role of transcription factors in transcriptional regulation?
They bind to the promoter and can increase or decrease transcription.
What is the significance of the poly A tail in mRNA?
Longer poly A tail = longer mRNA stability in the cytoplasm.
What is alternative splicing?
Joining different combinations of exons from the same gene to produce different mRNA transcripts.
Fill in the blank: The Central Dogma of Biology explains how a _______ is produced.
[protein]
What is the effect of histone deacetylation on chromatin structure?
Condensing: chromatin tightens and DNA is NOT accessible.
What does DNA methylation do?
Inhibits transcription by adding methyl groups to cytosine bases.
True/False: Gene expression is critical for embryonic development.
True
What are regulatory sequences in DNA?
Sequences that are NOT transcribed but are involved in gene regulation.
What is the role of RNA interference in translational regulation?
Interfering RNAs bind to target mRNA and prevent translation.
List two types of modifications that occur during post-translational regulation.
- Trimming amino acids
- Protein folding
What is a common effect of life experiences on DNA methylation patterns?
Patterns can change based on experiences (e.g., famine, pollution) and can be passed down.
What are the two examples of epigenetic factors mentioned?
- Histone modification
- DNA methylation
True/False: Regulatory genes are proteins that affect the expression of genes.
True
Fill in the blank: Regulatory elements provide places in the DNA where _______ can bind to upregulate or downregulate gene expression.
[regulatory proteins]
What does the term ‘translational machinery’ refer to?
Components needed for translation, such as ribosomes and charged tRNAs.
What is the function of ribonucleases in post-transcriptional regulation?
They degrade RNA and can identify mRNA via the 5’ cap & poly A tail.
