Gene Regulation

use "answer with terms"

No

Does each somatic cell express the same genes even having the same genetic information?

Different types of cells are made (liver, muscle, nerve, etc)

What does difference in expression lead to?

Prokaryotes

Prokaryotes or Eukaryotes: gene expression is regulated primarily during transcription

Eukaryotes

Prokaryotes or Eukaryotes: gene expression is regulated at multiple levels

The type and amount of protein produced in the cell

What does 2 things does regulation determine?

gene expression

Process of “turning on” a gene to produce RNA & protein

Mechanism that REGULATES when a gene is expressed to make RNA and protein, how much should be made, and when it’s time to stop making it

Gene Regulation

Differential gene expression

What causes somatic cells to differentiate from one another because of what genes are expressed (bone cells look different than fat cells)

false

True or false: cells express all the genes in their genome all the time

Regulatory molecules

Bacteria have specific __________ ________ that control whether a particular gene will be transcribed into mRNA. They bind DNA near the gene.

RNA polymerase

Regulatory molecules help or block this builder

Operons

Related genes in bacteria that are often found in groups , transcribed from one promoter, function in the same process

Uptake, metabolism

Lac operon contains genes that encode proteins involved in the _______ and _______ of lactose

It will turn on

When glucose is not available but lactose is what will the E. Coli bacteria do?

Glucose and Galactose

What is lactose broken down into?

LacY, LacZ, LacA

Lac operon contains what genes?

They are transcribed using one promoter

How are these genes made into a single mRNA?

inducible system

when glucose is unavailable but lactose is and the lac operon can be induced and activated, what kind of system is this?

Regulatory DNA sequences

Regions of DNA on the lac operon where regulatory proteins can bind

Regulatory proteins

These proteins bind and control whether or not transcription occurs

Promoter

DNA sequence where RNA polymerase binds and example of a regulatory DNA sequence

Operator

Another regulatory DNA sequence that determines if transcription will be blocked or induced

negative regulatory protein

Causes transcription to be blocked when attached to the operator

Activator, cAMP-CAP

______ also known as ______-____ protein complex binds to the operator and induces transcription

Epigenetics

Regulating gene expression at multiple levels, beginning with control to access to DNA

Methylation

Causes DNA to wrap tightly around histones and pack tightly together preventing transcription factors from binding to the DNA (resulting in genes being silenced)

Acetylation

DNA wrapped loosely around histones allowing transcription factors to bind to the DNA and be expressed

True

True or False: Methylation and Acetylation are temporary and reversible and don’t alter the nucleotide sequence

Bind to the promoter

What must transcription factors do first before RNA can bind for transcription?

Promoter

Transcription factors that are specific to a gene must bind to the ______

Activators and repressors

2 types of transcription factors

Binding sites

Often close to the promoter but can also be far away

True

True or False: Some gene are expressed in more than one body part or type of cell

Enhancers

Far way clusters of binding sites for activators and activates the gene in a certain cell type or body part

Tissue specific enhancer

control a gene’s expression in a certain part of the body (ex: Tbx4 in mice)

Coordinately Regulated Genes

group of genes may be regulated by the same transcription factors and co-expressed, can be on different chromosomes, but they are all controlled by the same transcription factors

Eukaryotic or Prokaryotic: not organized into operons

Prokaryotic

Coordinately Regulated Expression: copies of the activators recognize specific control elements and ______________ transcribe the genes

simultaneously

RNA processing

(splicing, adding cap & tail) can be regulated, and alternative splicing produces different mRNAs

Translation

may be increased or inhibited by regulators

Chemical modifications

response to external stimuli such as stress, lack of nutrients, heat, or UV light exposure, which can alter epigenetic accessibility, transcription, mRNA stability, or translation—all resulting in changes in expression of various genes

RNA decay rate/RNA Stability

Can influence how much protein is made in the call, increase results in less protein

Small RNA/ miRNA

can bind to mRNA and degrade them or block its translation

small interfering RNAs (siRNAs)

inhibits gene expression

Environmental factors

can affect gene expression, and therefore the phenotype of an organism

Examples:

change in the fur color gene in Himalayan rabbits expressing different colors

Soil pH affects the gene expression of flower color in Hydrangeas