Cell Basics
What is cell division
The process by which one cell divides to form two or more new cells.
Which cells use binary fission?
Prokaryrotic Cells
What is the cell cycle?
The series of events a cell goes through as it grows, prepares, and divides.
What is mitosis?
Division of the nucleus that results in two identical nuclei.
Purpose of meiosis:
To produce haploid gametes for sexual reproduction.
What is a gene?
A segment of DNA that codes for a specific trait or protein.
What is binary fission?
A form of asexual reproduction where a prokaryotic cell copies its DNA and splits into two identical cells.
Cell cycle phases in order:
Interphase → Mitosis → Cytokinesis
Phases of mitosis in order:
Prophase → Metaphase → Anaphase → Telophase
How many cells are produced?
Four haploid cells.
What is a chromosome?
A tightly coiled structure of DNA and proteins that carries genetic information.
How is binary fission different from mitosis?
Binary fission does not involve a nucleus or mitotic phases; mitosis occurs in eukaryotes and includes PMAT.
What happens during interphase?
The cell grows, copies its DNA, and prepares for division.
What happens during metaphase?
Chromosomes line up at the metaphase plate in the center of the cell.
Difference between meiosis I and meiosis II:
Meiosis I separates homologous chromosomes; meiosis II separates sister chromatids.
What is the difference between chromatin and chromosomes?
Chromatin is loose, uncoiled DNA found in non-dividing cells; chromosomes are tightly condensed DNA found during cell division.
Why don’t prokaryotes need mitosis?
They lack a nucleus and membrane-bound organelles, so their DNA does not need complex organization to divide.
Why is interphase the longest phase?
Because cells spend most of their life growing and preparing rather than dividing.
Functions of centrioles and spindle fibers:
Centrioles help organize spindle fibers; spindle fibers attach to chromosomes and pull them apart.
Chromosome separation in meiosis I vs II:
In meiosis I, homologous chromosomes separate; in meiosis II, sister chromatids separate.
Why must DNA be organized into chromosomes before division?
To ensure DNA can be moved and separated accurately without becoming tangled or broken.
A cell divides and produces two identical cells. The process does not include a nucleus, mitotic spindle, or distinct phases like prophase or metaphase.
a) Is this cell prokaryotic or eukaryotic?
b) Name the process used.
c) Explain why this process works for this type of cell.
a) Prokaryotic
b) Binary fission
c) Prokaryotes lack a nucleus and membrane-bound organelles, so their DNA can replicate and separate without mitosis or a spindle apparatus.
What happens if the cell cycle isn’t regulated?
Uncontrolled cell division can occur, leading to cancer or abnormal cells.
Why is the metaphase plate important?
It ensures chromosomes are evenly divided; errors can result in cells with too many or too few chromosomes.
Why does meiosis create genetic variation?
Because of crossing over.