Cell Cycle Control

The video explains the cell cycle control system, highlighting the role of external signals like growth factors and internal molecules such as protein kinases and cyclins. It describes how these elements regulate cell division, ensuring proper growth and maintenance in eukaryotic organisms. The video also covers the signal transduction cascade and the formation of cyclin-CDK complexes, which are crucial for cell cycle progression.

What is the primary reason for the variation in cell division rates among different cell types?

• The size of the cell

• The temperature of the environment

• The age of the organism

• The regulation of the cell cycle at the molecular level

What are growth factors primarily responsible for in the context of cell proliferation?

• Increasing cell size

• Changing cell shape

• Regulating and coordinating cell proliferation

• Decreasing cell lifespan

How do growth factors typically communicate with nearby cells?

• Through long-range signaling

• Through paracrine signaling

• By altering the cell's DNA

• Via direct contact

What is the role of transcription factors in the cell cycle?

• They destroy unnecessary proteins

• They control the rate of transcription of genetic information

• They provide energy for cell division

• They transport nutrients into the cell

Which molecules are responsible for guiding a cell from one phase of the cell cycle to the next?

• Ribosomes

• Cyclins and cyclin-dependent kinases

• Mitochondria

• DNA polymerases

What is the function of protein kinases in the cell cycle?

• They activate or inactivate other proteins through phosphorylation

• They transport oxygen

• They synthesize DNA

• They break down glucose

What happens when a cyclin binds to a cyclin-dependent kinase (CDK)?

• The cell stops dividing

• The cyclin is destroyed

• The CDK is activated and can phosphorylate target proteins

• The CDK is deactivated

What is the result of a cyclin-CDK complex phosphorylating a target protein?

• The target protein can be either activated or inactivated

• The target protein is always inactivated

• The target protein is always activated

• The target protein is destroyed

What is the role of cyclin-dependent kinases (CDKs) in the cell cycle?

• They provide structural support to the cell

• They transport genetic material

• They produce energy for the cell

• They regulate the transition between different phases of the cell cycle

How do external and internal signals work together in the cell cycle control system?

• They both contribute to the formation and activation of cyclin-CDK complexes

• They only affect the cell during cell division

• They operate independently of each other

• They cancel each other out