Cellular Control - 6 Flashcards
What is the reason that a brain cell differs from a muscle cell?
Different proteins are being made due to the activation and deactivation of different genes.
What happens to activated genes within a cell?
They are transcribed into mRNA, which is then translated into protein.
What is the process called that modifies a cell and leads to its specialization?
Differentiation.
What is a transcription factor (TF)?
Proteins that activate or deactivate genes.
What are the two types of transcription factors?
- Activators
- Repressors
What role do activators play in gene expression?
They bind to the promoter region and help RNA polymerase to bind and transcribe the gene.
What do repressors do in the context of gene expression?
They bind to the gene and block RNA polymerase from binding.
What is an operon?
A section of DNA that contains a cluster of genes controlled by a single promoter.
What are the components of an operon?
- Structural genes
- Control elements
- Regulatory gene
What is the function of the lac repressor in E. coli?
It binds to the operator region, blocking RNA polymerase from binding to the promoter region when lactose is absent.
What occurs when lactose is present in E. coli?
Lactose binds to the repressor, changing its shape and allowing RNA polymerase to transcribe the structural genes.
What does the lacZ gene code for?
An enzyme called beta-galactosidase.
What is splicing?
The process of removing introns from mRNA before translation.
In which type of organisms does splicing occur?
Eukaryotes.
What is cAMP?
A second messenger molecule that activates proteins by changing their 3D structure.
What role do Hox genes play in an organism?
They control the general organization of the organism’s body plan.
What is the importance of Hox genes in evolution?
They are highly conserved, indicating their crucial role in development.
What is apoptosis?
Controlled cell death where cells annihilate themselves without making a mess.
What is the function of mitosis in body plan development?
To create enough cells to fill the body.
What are the two types of stimuli that can activate apoptosis?
- Internal stimuli (e.g., DNA damage)
- External stimuli (e.g., pathogenic infection)
What is a mutation?
Any change to the base sequence of DNA.
What are the types of mutations?
- Substitution
- Insertion
- Deletion
- Inversion
What is a frameshift mutation?
A mutation that changes the codon and all following codons due to insertion or deletion.
What can lead to a neutral effect of a mutation on a protein’s function?
The mutation changes a base but the amino acid remains the same due to the degeneracy of the genetic code.
How can a mutation be beneficial or harmful?
It can produce a protein with an altered tertiary structure affecting the organism’s function.
