A2.2.13 Cell differentiation (HL)

Define differentiation.

Differentiation is the process where pluripotent cells develop into specialized cells with unique structures and functions.

Why is differentiation important in multicellular organisms?

It is essential for forming tissues and organs.

Do all cells in an organism share the same DNA?

Yes, all cells share the same DNA, but differentiation ensures only specific genes are expressed in each cell type.

Give an example of cells with specialization potential.

Cells from the placenta or umbilical cord can specialize into nerve cells, muscle cells, or blood cells.

What is gene expression?

Gene expression is the process of using genetic information to produce functional products like proteins.

What are the two types of cues that influence gene expression?

Internal cues: Signals from within the cell.

External cues: Signals from the environment, such as hormones or growth factors.

Give an example of gene expression in muscle cells.

Muscle cells express genes for actin and myosin, which are proteins for contraction.

What are transcription factors?

Proteins that bind to specific DNA sequences near genes to regulate transcription.

What is the difference between activators and repressors in gene regulation?

Activators enhance gene expression by recruiting RNA polymerase, while repressors block RNA polymerase, preventing transcription.

What are epigenetic modifications?

Regulation of gene expression without altering the DNA sequence itself.

What is DNA methylation?

DNA methylation is the addition of methyl groups to DNA, often leading to gene silencing.

What is histone acetylation?

Histone acetylation is the addition of acetyl groups to histones, loosening DNA structure and making genes more accessible.

What is post-transcriptional control?

Regulation of gene expression after mRNA is produced, influencing mRNA stability and translation into proteins.

What are microRNAs (miRNAs)?

miRNAs bind to mRNA, blocking translation or marking it for degradation, acting as a fine-tuning mechanism for protein production.

What is post-translational modification?

Regulation of protein activity through chemical modifications after the protein is synthesized.

What is the role of phosphorylation in post-translational modification?

Phosphorylation adds phosphate groups to proteins, which can activate or deactivate them.

What are intrinsic factors in differentiation?

The cell's lineage and activation of specific transcription factors.

What are extrinsic factors in differentiation?

Signals from neighboring cells or the environment, such as growth factors.

What is hematopoiesis?

Hematopoiesis is the process by which stem cells in bone marrow differentiate into blood cells.

How do disruptions in differentiation affect cells?

Disruptions can cause serious issues, such as cancer, where cells lose specialization and proliferate uncontrollably.

Does differentiation challenge the idea of genetic determinism?

Yes, differentiation suggests that environmental factors can play a significant role in shaping an organism, beyond its genetic code.

What might a plant express in response to drought conditions?

A plant might express genes related to stress response, water conservation, and drought tolerance.