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AP Biology: Chapter 18

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Section 1

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DNA Packing

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Biology Science

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7 years ago

Date created

Mar 1, 2020

Cards (22)

Section 1

(22 cards)

DNA Packing

Front

- DNA coiling and folding - Degree of packing regulates transcription - No transcription, genes off - Wrapped histones - Double helix - Nucleosomes (beads on a string) - Chromatin fiber - Looped domains - Chromosome

Back

Control of Translation

Front

- Blocks initiation of translation stage - Regulatory protein attaches to the 5 end of mRNA - Prevents the attachment of ribosomal subunits and initiator tRNA - Blocks translation of mRNA protein

Back

The expression of genes can be controlled at all the following stages of protein synthesis EXCEPT:

Front

- protein folding

Back

Acetylation of Histones

Front

- Unwinds DNA - Loose histone enables transcription and genes to turn on - Attachment of COCH3 - Conformational change to histone proteins - Transcription factors have easier access to genes

Back

Post Transcriptional Control

Front

- Alternative RNA splicing - Variable processing of exons creates a family of proteins

Back

Operon

Front

- Genes grouped together with related functions

Back

RNA Interference siRNA

Front

- Short segments of RNA - Binds to mRNA - Creates sections of double stranded mRNA - Death tag for mRNA (Degration) - Causes gene silencing - Post transcriptional control - Turns off genes because no proteins are produced

Back

Gene Regulation

Front

- Don't block the enzyme's function, block transcription of genes for all enzymes in tryptophan pathway - Saves energy by not wasting it on unnecessary protein synthesis

Back

A mutation that makes the regulatory gene of an inducible operon nonfunctional would result in

Front

- continuous transcription of the operon's genes.

Back

DNA Methylation

Front

- Blocks transcription factors and genes turned off - Attachment of methyl groups to cytosine - Nearly permanent inactivation of genes - Ex: Barr body

Back

Feedback Inhibition

Front

- The product acts as an allosteric inhibitor of the 1st enzyme in tryptophan pathway but this is wasteful production of enzymes

Back

Transcription Initiation

Front

- Controls regions of DNA - Promoter closely controls DNA sequence and binding of RNA polymerase/ transcription factors (base rate) - Enhancer distantly controls DNA sequences and binds to activator proteins (high rate)

Back

Protein Processing and Degration

Front

- Folding, cleaving, adding sugar groups, and targets for transport - Ubiquitin tagging and proteasome degradation

Back

Ubiquitin

Front

- Death Tag - Marks unwanted proteins with a label - 76 amino acid polypeptide - Labeled proteins are broken down rapidly in waste disposers/proteasomes

Back

Operator

Front

- DNA binding site of repressor proteins

Back

All of the following are post-transcriptional modifications of eukaryotic mRNA EXCEPT:

Front

- Peptide bonds are formed

Back

Promoter

Front

- RNA polymerase binding site - Controls transcription of all genes in the operon - Transcribed as one unit and a single mRNA is made

Back

Regulation of mRNA Degradation

Front

- Life span of mRNA determines amount of protein synthesis

Back

Repressor Operon

Front

- Binds to DNA at the operator site - Blocking RNA polymerase - Blocks transcription - Similar to how a skateboard stops on a curb - ANABOLIC pathways (build) - Synthesizing end products - Cell allocates excess resources to other uses

Back

A mutation that inactivates the regulator gene of a repressible operon in an E. coli cell would result in

Front

- continuous transcription of the structural gene controlled by that regulator.

Back

Inducible Operon

Front

- CATABOLIC pathways (destroy) - Digesting nutrients to simpler molecules - Produce enzymes only when nutrients are available - Cell avoids making proteins that have nothing to do, allocates resources

Back

Proteasome

Front

- Protein Degrading Machine - Waste disposer - Breaks down any proteins into 7-9 amino acid fragments - Cellular recycling

Back