Anatomy of the cell & cell cycle Flashcards
What is the cell cycle?
The cell cycle is the period between the birth of a cell and its division into two daughter cells, including interphase and mitosis.
What are the main phases of the cell cycle?
G1 phase, S phase, G2 phase (interphase), and M phase (mitosis).
What happens during the G1 phase?
Cell grows, prepares for DNA replication, and responds to growth factors. Molecular machinery needed for the cycle is produced.
What happens during the S phase?
DNA is replicated to ensure each daughter cell receives a full set of chromosomes. Cyclin A and CDKs regulate this phase.
What happens during the G2 phase?
The cell prepares for division, nuclear membrane begins to break down, and chromosomes condense.
What is the role of cyclins in the cell cycle?
Cyclins activate CDKs, which regulate the progression through the cycle. Cyclins are degraded after completing their role.
What are some disorders caused by defective DNA repair during replication?
Examples include:
- Xeroderma Pigmentosum: Sensitivity to UV light and risk of skin cancer.
- HNPCC (Lynch syndrome): Caused by mismatch repair defects.
What are the phases of mitosis?
Prophase, metaphase, anaphase, and telophase.
What is colchicine’s role in studying mitosis?
Colchicine inhibits spindle fiber formation, arresting cells in metaphase, used in karyotyping and cancer therapy research.
What is the difference between G0 and G1 phases?
G0 is a resting phase where cells no longer divide, while G1 is active preparation for DNA replication.
What are the main components of the plasma membrane?
A bilayer of amphipathic phospholipids with hydrophilic heads and hydrophobic tails, containing integral proteins like receptors and channels.
What is the function of mitochondria?
Mitochondria generate ATP through oxidative phosphorylation and synthesize some lipids and proteins. They contain their own DNA.
What are the two types of endoplasmic reticulum and their functions?
Rough ER: Protein synthesis and glycoprotein formation.
Smooth ER: Lipid synthesis and detoxification.
What is the role of the Golgi apparatus?
Modifies, sorts, and packages macromolecules from the ER for secretion or use in the cell.
What are the three types of cytoskeletal filaments and their functions?
Microfilaments: Made of actin, maintain cell shape, and assist in movement.
Intermediate filaments: Provide mechanical strength.
Microtubules: Act as ‘motorways’ for organelle transport and form the mitotic spindle.
What are intercellular junctions and their types?
Specialized structures connecting cells:
- Occluding (tight junctions): Form diffusion barriers.
- Anchoring (desmosomes, adherens): Provide mechanical strength.
- Communicating (gap junctions): Allow molecular signaling between cells.
What is the nucleolus and its function?
A dense region in the nucleus responsible for ribosome production.
How do microtubules facilitate intracellular transport?
They serve as tracks for motor proteins (dynein and kinesin) that transport organelles and vesicles.
What are cell inclusions?
Non-essential structures like lipid droplets, glycogen stores, or pigments, which may be temporary or permanent.
How does the structure of DNA relate to its function in replication?
DNA’s double helix allows each strand to serve as a template for replication. Complementary base pairing ensures accurate copying.
