Back to AI Flashcard MakerBiology /LGS A-Level OCR Biology - Unit 6 - Genetics of living systems Part 3

LGS A-Level OCR Biology - Unit 6 - Genetics of living systems Part 3

Biology20 CardsCreated about 1 month ago

This deck Introns are non-coding DNA sequences that can regulate gene expression, act as mutation buffers, and are removed during mRNA processing.

Housekeeping genes

Genes that code for proteins which are necessary for reactions in metabolic pathways and are constantly required (enzymes)

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Key Terms

Term
Definition

Housekeeping genes

Genes that code for proteins which are necessary for reactions in metabolic pathways and are constantly required (enzymes)

Who has only exons

Prokaryotes and eukaryotes without jaw bones

| Jaw boned eukaryotes have introns and exons

Terminator region

Does not code for protein

Regulatory site

RNA polymerase is released to stop trancription

RNA-coding sequence

Genes turn into mRNA

| Has both introns and exons but introns are removed from premature mRNA during splicing to form mature mRNA

Methods to regulate gene expression at transcriptional level

Histone modification

| Transcription factors

Histone modification

Histones are +vely charged and DNA. -vely charged --> attraction

Modify charges to change degree of packaging

Acetylation and phosph...

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TermDefinition

Housekeeping genes

Genes that code for proteins which are necessary for reactions in metabolic pathways and are constantly required (enzymes)

Who has only exons

Prokaryotes and eukaryotes without jaw bones

| Jaw boned eukaryotes have introns and exons

Terminator region

Does not code for protein

Regulatory site

RNA polymerase is released to stop trancription

RNA-coding sequence

Genes turn into mRNA

| Has both introns and exons but introns are removed from premature mRNA during splicing to form mature mRNA

Methods to regulate gene expression at transcriptional level

Histone modification

| Transcription factors

Histone modification

Histones are +vely charged and DNA. -vely charged --> attraction

Modify charges to change degree of packaging

Acetylation and phosphorylation reduce +ve charge so transcription happens

Methylation increase +ve charge so transcription doesn't occur

Transcription factors as a method of gene expression

Control rate of transcription by binding to spp DNA sequences

Regulate genes to make sure they are expressed correctly

Work alone or w/ others as an activator or repressor of RNA polymerase

Regulating gene expression at the post transcriptional level

RNA processing

RNA editing

siRNA

Happens simultaneously

RNA processing

Pre-mRNA is modified --> mature-mRN A binds to ribosme and code for synthesis

Adenine cap is added at 5' and tail at 3'

Stabilises mRNA and delays degradation in cytoplasm, aids binding

Splicing and the addn. of adenine cap and tail occur in the nucleus

RNA editing

Some mRNA can be changed through base pair add., deln. or subn. Same effects as point mutations and results in synthesis of diff proteins w/ diff function s

Increases range of proteins that can be produced from one mRNA strand

Regulating gene expression at the translational level

Degradation of mRNA

Binding of inhibitory proteins

Protein kinases

Degradation of mRNA

More resilient the molecule, the longer it lasts in cytoplasm, more translation

Binding of inhibitory proteins

Occurs when protein is produced in wrong location or substrate is not available

Regulation of gene expression at the post translational level

Protein activation - allows protein to carry out its function

Protein activation

Occurs in Golgi

Adding non protein groups e.g. carbs, phosphates

Phosphorylation by protein kinases and ATP

Folding/ shortening proteins (2' structure)

Modification by cAMP

Control sites

Operator region and promoter region

Beta galactoside

An enzyme that catalyses the hydrolysis of lactose to glucose and galactose

Lactose permease

A protein that transports lactose into the cell

Lac i

Regulatory gene

Codes for repressor protein (transcription factor)

Always transcribed

Lac p

Promoter region

| Rna polymerase binds here