MCB 2050 Lecture Notes #1 2025/2026
(Flash Cards) 100% Verified.
Eukaryotes are multicellular. What does this compartmentalization achieve?
Compartmentalization allows for complex eukaryotic gene regulation.
What does complexity achieve?
Multiple levels of gene control.
Therefore, what do both compartmentalization and complexity facilitate in eukaryotes?
Complex gene regulation.
Eukaryotes are differentiated and grow at different rates. How is complex gene regulation
advantageous? 2 types of control
Spatial control. Only expresses a specific subset of the genome. Think of tissues and cell types.
Temporal control. Accounts for different developmental stages and processes. Therefore, their
genes must be switched on or off.
Where are the two locations(steps) of gene site regulation?
The sites of regulation are at transcription and protein modification.
Why is gene regulation sourced at these two points?
@ transcription, this is the most economical in terms of resource and energy use. @ protein
modification, it is a fast response reaction. This occurs in the cytoplasm where the protein can
modify. An example is heat shock protein.
What are the two factors that induct gene expression?
By biological factors and environmental factors. Examples include steroid and peptide hormones
considering biological factors.
Why is transcription more difficultly controlled in eukaryotes vs prokaryotes? Key word
Eukaryotic genes are sequestered in the nucleus
What does "sequestered" mean?
Since eukaryotes are membrane bound organelles, environmental factors must be transmitted and
received from the extracellular membrane all the way into the nucleus onto the chromosome.
How else do eukaryotes have more obstacles when facing gene regulation?
Many eukaryotes are multicellular and environmental cues have to pass inter cellularly for
regulation.
Otherwise, consider protein-DNA interaction on gene regulation. Is it different from prokaryotes?
No, it is still positively and negatively regulated, and transcription factors remain the same.
, Consider the induction of gene expression. Give examples?
Biological factors and Environmental factors. Specifically with biological factors, steroid and peptide
hormones. Heat Shock is an example of an environmental factor.
How is gene expression regulated by steroid hormone?
Steroid hormone, a lipid-soluble molecule derived from cholesterol, is able to permeate the cell
membrane.
1. The steroid hormone combines with the receptor protein.
2. The hormone/receptor complex binds to hormone response element in the DNA.
3. Stimulates transcription.
How is gene expression regulated by peptide hormone?
Peptide hormone, a linear chain of amino acid, is unable to permeate the cell membrane.
1. The peptide hormone attaches to membrane-bound receptor proteins and activates.
2. Hormone/receptor complex activates a cytoplasmic protein signal.
3. Cytoplasmic protein transducts a signal to the nucleus.
4. Signal induces a transcription factor.
5. Bound transcription factor stimulates transcription.
When a hormone transmits a signal to a cell, what is this called?
Signal transduction.
What is significant about the heat-shock protein in its evolutionary history?
It is a highly conserved polypeptide found in both eukaryotes and prokaryotes.
What types of interactions regulate transcription?
Protein-protein and protein-DNA interaction.
What gene transcribes for heat shock protein? Under what environmental condition?
In Drosophila, HSP70 gene encodes for the heat-shock protein. In order to induce transcription, the
temperature must exceed 33 degrees celsius.
But how is this gene induced?
By HSTF (protein), a mediating polypeptide which will undergo phosphorylation when heat stressed
found in the nuclei. It will bind specifically to the Heat-Shock Response Elements (HSE/DNA or RNA)
upstream which will activate transcription.
Note HSTF! Where is it found? When it binds to HSE, what is this binding called?
Remember that HSTF exists in the cytoplasm in an inactivated form until it is phosphorylated. It is
activated once it binds with HSE, transported by a chaperone into the nucleus. This overall process is
called Induction.
Gene regulation at the transcriptional level is the most important step of gene regulation. How is
DNA regulated?
By promoters and enhancers.
How is DNA protein regulated?
(Flash Cards) 100% Verified.
Eukaryotes are multicellular. What does this compartmentalization achieve?
Compartmentalization allows for complex eukaryotic gene regulation.
What does complexity achieve?
Multiple levels of gene control.
Therefore, what do both compartmentalization and complexity facilitate in eukaryotes?
Complex gene regulation.
Eukaryotes are differentiated and grow at different rates. How is complex gene regulation
advantageous? 2 types of control
Spatial control. Only expresses a specific subset of the genome. Think of tissues and cell types.
Temporal control. Accounts for different developmental stages and processes. Therefore, their
genes must be switched on or off.
Where are the two locations(steps) of gene site regulation?
The sites of regulation are at transcription and protein modification.
Why is gene regulation sourced at these two points?
@ transcription, this is the most economical in terms of resource and energy use. @ protein
modification, it is a fast response reaction. This occurs in the cytoplasm where the protein can
modify. An example is heat shock protein.
What are the two factors that induct gene expression?
By biological factors and environmental factors. Examples include steroid and peptide hormones
considering biological factors.
Why is transcription more difficultly controlled in eukaryotes vs prokaryotes? Key word
Eukaryotic genes are sequestered in the nucleus
What does "sequestered" mean?
Since eukaryotes are membrane bound organelles, environmental factors must be transmitted and
received from the extracellular membrane all the way into the nucleus onto the chromosome.
How else do eukaryotes have more obstacles when facing gene regulation?
Many eukaryotes are multicellular and environmental cues have to pass inter cellularly for
regulation.
Otherwise, consider protein-DNA interaction on gene regulation. Is it different from prokaryotes?
No, it is still positively and negatively regulated, and transcription factors remain the same.
, Consider the induction of gene expression. Give examples?
Biological factors and Environmental factors. Specifically with biological factors, steroid and peptide
hormones. Heat Shock is an example of an environmental factor.
How is gene expression regulated by steroid hormone?
Steroid hormone, a lipid-soluble molecule derived from cholesterol, is able to permeate the cell
membrane.
1. The steroid hormone combines with the receptor protein.
2. The hormone/receptor complex binds to hormone response element in the DNA.
3. Stimulates transcription.
How is gene expression regulated by peptide hormone?
Peptide hormone, a linear chain of amino acid, is unable to permeate the cell membrane.
1. The peptide hormone attaches to membrane-bound receptor proteins and activates.
2. Hormone/receptor complex activates a cytoplasmic protein signal.
3. Cytoplasmic protein transducts a signal to the nucleus.
4. Signal induces a transcription factor.
5. Bound transcription factor stimulates transcription.
When a hormone transmits a signal to a cell, what is this called?
Signal transduction.
What is significant about the heat-shock protein in its evolutionary history?
It is a highly conserved polypeptide found in both eukaryotes and prokaryotes.
What types of interactions regulate transcription?
Protein-protein and protein-DNA interaction.
What gene transcribes for heat shock protein? Under what environmental condition?
In Drosophila, HSP70 gene encodes for the heat-shock protein. In order to induce transcription, the
temperature must exceed 33 degrees celsius.
But how is this gene induced?
By HSTF (protein), a mediating polypeptide which will undergo phosphorylation when heat stressed
found in the nuclei. It will bind specifically to the Heat-Shock Response Elements (HSE/DNA or RNA)
upstream which will activate transcription.
Note HSTF! Where is it found? When it binds to HSE, what is this binding called?
Remember that HSTF exists in the cytoplasm in an inactivated form until it is phosphorylated. It is
activated once it binds with HSE, transported by a chaperone into the nucleus. This overall process is
called Induction.
Gene regulation at the transcriptional level is the most important step of gene regulation. How is
DNA regulated?
By promoters and enhancers.
How is DNA protein regulated?
