Cell Genetics & Division Flashcards
(27 cards)
Where is the prokaryotic genome located?
In the nucleoid region, not enclosed by a membrane.
What is the shape of prokaryotic DNA?
Circular.
What are plasmids in prokaryotic cells?
Small, circular DNA molecules that may carry genes advantageous for survival, such as antibiotic resistance.
Where is the eukaryotic genome housed?
In the nucleus, protected by the nuclear envelope.
How is eukaryotic DNA organized?
Into linear DNA molecules that wrap around histone proteins to form nucleosomes, which further coil into chromatin.
What are homologous pairs of chromosomes?
Chromosomes that occur in pairs in diploid organisms (e.g., humans have 23 pairs).
What are alleles?
Variants of genes that contribute to genetic diversity.
What happens during the G1 Phase of interphase?
The cell grows, producing necessary proteins and organelles, and accumulates materials for DNA synthesis.
What happens during the S Phase of interphase?
DNA replication occurs, producing two identical sister chromatids for each chromosome, and centrosomes replicate.
What happens during the G2 Phase of interphase?
The cell undergoes final preparations for mitosis, such as synthesizing proteins for spindle formation, and organelles may increase in number.
What is the main outcome of mitosis?
A precise process ensuring that each daughter cell receives a complete set of chromosomes.
What happens during prophase of mitosis?
Chromosomes condense and spindle fibers form.
What happens during metaphase of mitosis?
Chromosomes align at the metaphase plate.
What happens during anaphase of mitosis?
Sister chromatids are pulled apart to opposite poles.
What happens during telophase of mitosis?
Chromosomes decondense, and nuclear envelopes reform.
How does cytokinesis differ in animal and plant cells?
Animal cells form a cleavage furrow via a contractile ring, while plant cells form a cell plate.
What are the key components involved in cleavage furrow formation in animal cells?
Actin filaments forming the contractile ring and myosin motor proteins interacting with actin to generate contractile force.
What materials are transported to the center of the cell plate formation in plant cells?
Golgi vesicles filled with cell wall materials like cellulose.
What is the G0 phase?
A resting stage where the cell is not actively dividing.
Give an example of cells that remain in G0 permanently.
Neurons.
What does the G1 Checkpoint ensure?
That the cell is large enough, has sufficient resources, and that DNA is undamaged before proceeding to S phase.
What does the G2 Checkpoint confirm?
That DNA replication is complete and accurate, preventing progression to mitosis if errors are detected.
What does the M (Spindle) Checkpoint ensure?
That all chromosomes are properly attached to spindle fibers before anaphase, preventing uneven segregation.
What causes uncontrolled cell division leading to cancer?
Mutations in genes regulating the cell cycle.
