Learning Materials
Features
Discover
All living cells within an organism contain the same genome, but why does each cell function differently from others? It is because the level of gene expression in different cells is controlled. Your skin cells are different from your hair cells, and your muscle cells are different from your cardiac cells because of the control of gene expression.
Millions of flashcards designed to help you ace your studies
Sign up for freeHow does increased DNA methylation affect gene transcription?
What is the correlation coefficient used for?
Which option shows the correct order of stem cells based on the types of cells they can specialize into?
How do stem cells divide?
True or False. Differentiated cells in the body have different genetic material.
True or False: Prokaryotic and eukaryotic cells contain introns and exons in their genomes.
True or False: Specialized cells can change their differentiation and turn into other cells.
What chemical modifications are part of epigenetic changes?
In which one of the cells below does mRNA splicing occur?
What type of stem cell is a zygote?
When does the control of gene expression being?
How does increased DNA methylation affect gene transcription?
What is the correlation coefficient used for?
Which option shows the correct order of stem cells based on the types of cells they can specialize into?
How do stem cells divide?
True or False. Differentiated cells in the body have different genetic material.
True or False: Prokaryotic and eukaryotic cells contain introns and exons in their genomes.
True or False: Specialized cells can change their differentiation and turn into other cells.
What chemical modifications are part of epigenetic changes?
In which one of the cells below does mRNA splicing occur?
What type of stem cell is a zygote?
When does the control of gene expression being?
Achieve better grades quicker with Premium
Geld-zurück-Garantie, wenn du durch die Prüfung fällst
Review generated flashcards
Start learning or create your own AI flashcards
Team Control of Gene Expression Teachers
By controlling what genes are expressed, we can regulate the metabolic activities of different cells. This is because genes encode for proteins which, in turn, determine the function of a cell. As a result, cells become specialized to perform specific functions. This is why regulating gene expression is highly important because, without it, we wouldn't have specialized cells.
But first off, we need to have cells that have the ability to specialize into a large range of cells. These are called stem cells.
Stem cells are defined as unspecialized cells that divide indefinitely by mitosis and differentiate into many cell types. There are three classes:
Totipotent stem cells
Pluripotent stem cells
Multipotent stem cells
Totipotent stem cells are present during the zygote stage and have the ability to differentiate into all cell types, including extra-embryonic cells (like the placenta). As you make your way down the list above, the range of differentiation decreases. When these cells become specialized, they can no longer become any other type of cell.
The fact that specialized cells no longer divide continuously is a good thing! It means they can efficiently perform their metabolic activities.
The regulation of gene expression begins before transcription, the first stage of protein synthesis. Regulatory proteins called transcription factors dictate which genes are expressed (turned 'on') and which genes are not expressed (turned 'off'). The diagram below illustrates the binding of a transcription factor to DNA. This process is tightly controlled so that specific messenger RNA (mRNA) molecules are produced, and therefore only specific proteins are produced.
Fig. 1 - The binding of a transcription factor to DNA
Another type of gene expression regulation that occurs at the transcriptional level includes the alteration of the DNA-histone complex. This type is especially fascinating because the base sequence of DNA is not changed, and yet it still has the ability to direct which genes are expressed. This is called epigenetics.
Epigenetics is the study of DNA and histone modifications to control gene expression. These modifications are heritable and are not caused by any changes to the base sequence of DNA. Modifications include DNA methylation and histone acetylation, illustrated in the diagram below. This has the effect of either condensing or loosening the DNA-histone complex. The pattern of modifications is called the epigenome.
Fig. 2 - DNA methylation and histone acetylation
Gene expression is tightly regulated, and for good reason. If the wrong genes are expressed or silenced, genetic diseases can arise. Cancer is a disease that is characterized by the uncontrollable proliferation of cells, and in some cases, the cause has an epigenetic origin.
Before translation occurs, additional changes to the mRNA molecule can occur. This can include mRNA splicing which is the removal of introns (non-coding DNA) from the molecule.
Even after translation, the polypeptide can be modified even further, such as the addition of chemical groups. A great example of this is the addition of a phosphate group to a polypeptide, catalysed by protein kinases. This addition can alter the folding of a protein and therefore change the protein function.
mRNA splicing occurs only in eukaryotic cells as their genome includes both introns and exons. Prokaryotic genomes contain only introns so mRNA splicing is unnecessary.
The sequencing of a genome maps out of the complete set of genetic information contained within an organism. For example, the Human Genome Project (1990-2003) was a collaborative effort to determine all the genes in our cells. But this was no easy endeavour. The project used technologies like whole-genome shotgun (WGS) sequencing, and from this came other advances. These include DNA hybridization, which is used to locate specific alleles of a gene and genetic fingerprinting. These technological advances have wide applications in disease treatment and forensic science.
Sign up for free to gain access to all our flashcards.
Why is the control of gene expression important?
The control of gene expression is important as it leads to the creation of specialised cells. Also, it determines what proteins are being produced in a cell.
What is the epigenetic control of gene expression?
Epigenetic control describes modifications to DNA and histones to regulate gene expression. These modifications are heritable and are therefore passed down generations and do not include changes to the base sequence of DNA.
How does the control of gene expression lead to differentiation?
Controlling the genes expressed in a cell means controlling what proteins are being synthesised. Proteins dictate the function of a cell, and therefore the expression of particular genes will result in a cell performing a particular function. This leads to a specialised cell.
What controls the timing of gene expression?
The timing of gene expression is controlled by proteins called transcription factors. These are regulatory proteins that bind to genes to activate their expression or silence their expression. They bind to genes to produce the required proteins when it is needed.
How do you control and regulate gene expression?
The control of gene expression can happen at a transcriptional and translational level. At a transcriptional level, transcription factors can activate or silence specific genes. DNA and histones can be modified to result in a tightly packed or loosely packed DNA-histone complex. At a translational level, chemical groups can be added to the polypeptide to affect the folding and function of a protein.
At StudySmarter, we have created a learning platform that serves millions of students. Meet the people who work hard to deliver fact based content as well as making sure it is verified.
Lily Hulatt is a Digital Content Specialist with over three years of experience in content strategy and curriculum design. She gained her PhD in English Literature from Durham University in 2022, taught in Durham University’s English Studies Department, and has contributed to a number of publications. Lily specialises in English Literature, English Language, History, and Philosophy.
Get to know Lily
Gabriel Freitas is an AI Engineer with a solid experience in software development, machine learning algorithms, and generative AI, including large language models’ (LLMs) applications. Graduated in Electrical Engineering at the University of São Paulo, he is currently pursuing an MSc in Computer Engineering at the University of Campinas, specializing in machine learning topics. Gabriel has a strong background in software engineering and has worked on projects involving computer vision, embedded AI, and LLM applications.
Get to know Gabriel
Explanations 
Flashcards 
StudySmarter AI 
Notes 
Study Plans 
Study Sets 
Exams 
Magazine 
Find a job 
Mobile App