5b slides Flashcards
why are inducible operons associated with catabolic pathways
only need to be induced when molecules that gets brokwn down is actually present, otherwisw it would not be energetically effieicent
lactose metabolism
breaking down lactose into simple sugars
why is gene reglation important in multicellular organisms
respond to environmental and cellular signals
what is essential for cellular differentiation
different tissues
tissues
groups of similar cells that act as a functional unit
what do all the cells within an orgabism contain
identical genomes
what do diffrences between cell types result from
differential gene expression
differential gene expression
expression of different sets of genes by cells with the same genome
if you were to extract DNA, mRNA expression (transcripts) and proteins from multiple cell types, how would they differ
DNA EXTRACTION WOULD BE IDENTICAL BETWEEN CELL TYPES, BUT PROTEIN EXTRACTION AND RNA EXPRESSION WOULD BE DIFFERENT
in all organisms, gene expression is commony controlled at
trancription
during which steps can gene expression be regulated in eukartotes
chromatin modification and transcription
what are the stages of gene expression
- chromatin modification
- transcription
- RNA processing
- transport to cytoplasm
- translation
- prtein processing
- transport to cellular destination
- degradation of protein
chromatin modication
DNA unpacking/packing can make the DNA available/unavailable to be bound by RNA polymerase and transcription factors
transcription step in gene expression stage
signals that upregulate/downregulate transcription
RNA processing step in gene expression stage
steps of processing can be regulated
transport to cytoplasm step in gene expression stage
mRNA must exit nucelar membrane to each ribosome, this extiing can be regulated
translation step in gene expression stage
where protein is synthesized
protein processing step in gene expression stage
post translational protein modiciation is the final step in making a fully functional protein
transport to cellular destination step in gene expression stage
extracellular, transmembrane, intracellular
final step in gene expression stage
degradation of protein and mRNA in cytoplasm
How does chromatin modification regulate gene expression?
Gene regulation controls when and how much a gene is expressed. Chromatin regulation and DNA methylation are two ways to regulate genes. Chromatin regulation involves histone modifications, while DNA methylation adds methyl groups. Both are examples of epigenetic regulation and are crucial for proper cell function.
how are genes with highly packed heterochromatin usually expressed
they are not usually expressed
heterochromatin
eularyotic chromatin that remains highly compacted during interphase and is generally not transcribed
euchromatin
less condensed form of eukaryotic chromatin that is available for transcription
what do chemical modifications to histones and DNA chromatin influence
both chromatin strucre and gene expression
histone acetylation
addition of an acetyl group to histone tail amino acids opens up chromatin and promotes transcription
what do addition of methyl groups condensing chromatin inhibit
transcription
what can methylation of DNA lead to
gene silencing
gene silencing
(turning off a gene) regulation of gene expression in a cell to prevent the expression of a certain gene
how does regulating transcription affect gene expression
as in bacteria the regaultion of transcription initiation in eukaryotes involves prteins thta bind to DNA and either faciliatte or inhibit binding of RNA polymerase
control elements
egements of non coding DNA that serves as binding sites for transcription factors
distal control elements are further from the
promoter and include enhancers
proximal contorl elements are closer to the
promoter
exons
expressed sequences that encode a protein
introns
intervening sequences that get removed and do not encode a proteintr
transcription factors
proteins that promote transcription
what is the purpose of intrond
introns are used to be considered as junk but new research show sthet have roles in evolution and gene regulation. they contain regulatort elements that infleunce gene expressions such as enhancers and silencers
poly a tail
added to the 3’ end of the transcript
GTP cap added to the
5’ end of transcript
