Biology Flashcards
What is an operon?
An operon is a unit of genetic function found in bacteria consisting of a promoter and an operator and a cluster of genes
Differenciate a repressible and inducible operon
> repressible operon are usually on and can be deactivated
inducible operon are usually of and can be activated
Sort the stage form precursor to essential product
- increase tryptophan
- trp repressor activated
- transcription by polymerase II
- tryptophan pathway enzyme
- tryptophan synthesis
This process is anabolic
Sort the stage from nutrient to simpler molecule
- high lactose
- high allolactose
- active lac repressor
- transcription by polymerase II
- lactose pathway
- hydrolysis
Contrast positive and negative regulation
positive regulation enable gene expression while negative regulation prevent it
Explain the negative regulation of the trp operon
The presence of tryptophan acts as a co-repressor, leading to repression of the trp operon. (ensure that tryptophan is only produce when needed)
Explain the negative regulation of the lac operon
the presence of lactose alleviates the repression of the lac operon. enabling the bacterium to use lactose as a carbon source.
Explain the positive regulation of the lac operon
-cAMP bind allosterically to a regulatory protein
- CRP binds to promoter
- This binding facilitate the binding of RNA polymerase
-This stimulate the transcription of the lac operon gene
List the stages in which gene expression can be regulated.
Transcription, RNA processing, translation, degradation and protein modification
Define epigenetic inheritance
Trait transmitted by mechanism not linked to the nucleotide sequence
Differentiate the role of general transcription and specific transcription
General transcription initiate transcription by binding a component protein to the TATA box while specific transcription initiates gene expression by acting as a promoter or enhancer
Describe the role of control elements
They serves as a binding site for transcription factor and help recruit transcription initiators.
provide example of post-transcriptional factor
Ex. alternative RNA splicing, reversible phosphorylation, protein modified post-translation,
Sort genetic material from lower to higher level
DNA < histone < nucleosome < chromatin < Chromosome
Why do thermophilic organisms have a higher GC content?
Because GC are more thermally stable, so they act better in high temp
Define semi-conservative DNA replication.
Each new DNA molecules conserve half of the origin molecule
Differentiate lagging strand synthesis from leading strands synthesis
Leading strand- same direction as replication fork, use 1 RNA primer, continuous
Lagging strand- away from replication fork direction, use multiple primer, discontinuous
List the step of PCR
- Denaturation of parental DNA
- Annealing of DNA primer
- elongation
Define telomere
sequence of dna that can be repeated over 1000 time. (protect the organism from being eroded during successive round of replication
Provide counter example of gene hypothesis
One gene = one enzyme- tubulin, insulin ( not all genes code for enzyme)
One gene = one protein- hemoglobin (many protein are made of multiple subunit)
One gene = one polypeptide- mRNA, tRNA
contrast transcription and translation in eukaryotes and prokaryotes
in prokaryotes, transcription occur immediately and in cytoplasm while transcription occurs in nucleus, in eukaryotes. Translation occurs in cytoplasm in eukaryotes.
Contrast to two types of mutation
Synonymous: change codon but doesn’t affect amino acids
Non-Synonymous: change codon and amino acids
explain effects of mutation
> Missense: affect the primary, secondary and tertiary structure of protein
Non-conservative missense: lead to amino acid with very different chemical properties
Point-mutation: change in a single base pair within the dna molecule
indels: cause loss of protein function
differentiate between anabolic and catabolic pathway
Catabolic pathway breakdown complex molecule to smaller molecule while anabolic builds complex molecule
