AOS1 Cell Cycle and Cell Growth, Death and Differentiation Flashcards
What is binary fission?
Binary fission is the process by which prokaryotic cells divide to reproduce asexually.
In which type of cells does binary fission occur?
Binary fission occurs in prokaryotic cells, such as bacteria and archaea.
What is the first step of binary fission?
The first step is the replication of the cell’s DNA.
How does DNA replication occur in prokaryotic cells during binary fission?
The circular DNA molecule is copied, starting at the origin of replication, resulting in two identical DNA molecules.
What happens after DNA replication in binary fission?
The two DNA molecules move to opposite ends of the cell.
What structure forms to divide the prokaryotic cell during binary fission?
A septum (a new cell wall) forms between the two DNA molecules.
What is the final step of binary fission?
The cell splits into two daughter cells, each with an identical copy of the original DNA.
How do the daughter cells compare to the parent cell after binary fission?
The daughter cells are genetically identical to the parent cell.
Why is binary fission considered an asexual reproduction method?
Because it involves only one parent cell and produces genetically identical offspring without the involvement of sexual gametes.
What is the role of the origin of replication in binary fission?
It is the specific location on the circular DNA where replication begins.
How does binary fission contribute to the rapid growth of bacterial populations?
It allows for quick and efficient reproduction, often resulting in exponential population growth under favorable conditions.
What factors can influence the rate of binary fission in prokaryotic cells?
Environmental conditions such as nutrient availability, temperature, and pH can affect the rate of binary fission.
How does binary fission ensure genetic consistency?
The DNA is replicated accurately, and each daughter cell receives an identical copy of the DNA, maintaining genetic consistency.
Can binary fission lead to genetic variation? If so, how?
While binary fission itself does not create genetic variation, mutations during DNA replication can introduce genetic changes.
What is the significance of the septum formation during binary fission?
The septum ensures that the cell divides into two separate entities, each with its own complete set of DNA.
How does the size of prokaryotic cells change during binary fission?
The cell grows to roughly double its original size before dividing into two smaller daughter cells.
Why is binary fission efficient for prokaryotic organisms?
It is a simple and quick process that allows for rapid population increase, essential for survival and adaptation in changing environments.
What role do cell membrane and cell wall play in binary fission?
The cell membrane and cell wall grow inward at the septum to separate the two new cells.
How often can binary fission occur under optimal conditions?
Some bacteria can undergo binary fission every 20 minutes under optimal conditions.
What is the primary benefit of binary fission for prokaryotic cells?
It enables rapid and efficient reproduction, allowing prokaryotic populations to quickly adapt to their environments.
What are the main phases of the eukaryotic cell cycle?
Interphase and the mitotic (M) phase.
What are the sub-phases of interphase?
G1 phase, S phase, and G2 phase.
What occurs during the G1 phase of interphase?
The cell grows and carries out normal functions, while also preparing for DNA replication.
What happens during the S phase of interphase?
DNA replication occurs, resulting in the duplication of chromosomes.
What takes place during the G2 phase of interphase?
The cell continues to grow and prepares for mitosis by producing the proteins and organelles needed for cell division.
What are the sub-phases of mitosis?
Prophase, metaphase, anaphase, and telophase.
What happens during prophase?
Chromatins condense into visible chromosomes, the nuclear envelope begins to disintegrate, and the mitotic spindle starts to form.
What occurs during metaphase?
Chromosomes align at the metaphase plate (the cell’s equatorial plane) (down the middle).
What occurs during anaphase?
Sister chromatids are pulled apart to opposite poles of the cell by the spindle fibers.
What takes place during telophase?
Chromosomes de-condense back into chromatin, the nuclear envelope re-forms around each set of chromosomes, and the spindle apparatus disassembles.
What is cytokinesis?
Cytokinesis is the process of dividing the cytoplasm to form two distinct daughter cells.
How does cytokinesis differ in animal cells and plant cells?
In animal cells, cytokinesis occurs through the formation of a cleavage furrow. In plant cells, a cell plate forms to divide the cells.
What is the cleavage furrow?
The cleavage furrow is an indentation that appears in the cell membrane during cytokinesis in animal cells, eventually leading to the cell splitting into two.
What is the cell plate, and how is it formed?
The cell plate is a structure that forms in plant cells during cytokinesis, created by vesicles from the Golgi apparatus coalescing at the center of the cell to form a new cell wall.
What is the significance of the mitotic spindle?
The mitotic spindle, made of microtubules, is crucial for separating chromosomes during mitosis.
How do centrioles function in animal cell mitosis?
Centrioles help organize the mitotic spindle and ensure proper distribution of chromosomes.
What role does the nuclear envelope play during mitosis?
The nuclear envelope breaks down in prophase and re-forms around the separated chromosomes in telophase.
What ensures that each daughter cell receives an identical set of chromosomes?
The precise alignment and separation of chromosomes during metaphase and anaphase.
Why is the eukaryotic cell cycle tightly regulated?
To ensure accurate DNA replication and division, preventing mutations and maintaining cellular health.