Mitosis Flashcards
What is mitosis?
Mitosis is a type of cell division where one cell divides to form two genetically identical cells, each containing the same number of chromosomes as the parent cell.
Why is maintaining the species’ chromosome number important?
It ensures that all body cells have the correct genetic information for normal development, growth, and reproduction.
Where does mitosis occur?
Mitosis occurs in all body cells except for gametes (egg and sperm cells).
What happens during interphase before mitosis?
The cell grows, carries out normal functions, and replicates its chromosomes to prepare for division.
What happens during prophase?
Chromosomes become visible, the nucleolus disappears, centrioles move apart, spindle fibers form, and the nuclear envelope breaks down.
What are the four stages of mitosis?
Prophase, Metaphase, Anaphase, Telophase.
What happens during metaphase?
Chromosomes line up at the center (equator) of the cell, still connected by their centromeres.
What happens during anaphase?
Chromatids separate and move to opposite poles of the cell.
What happens during telophase?
Chromosomes unwind, nuclear envelopes reform around each group, forming two nuclei.
What is cytokinesis?
The final division of the cytoplasm, resulting in two separate but identical cells.
What is the chromosome number in humans?
46 chromosomes in body cells (diploid number 2n).
What is meant by diploid and haploid numbers?
Diploid (2n) is the full set (46 in humans); haploid (n) is half (23 in humans, found in gametes).
What is DNA?
Deoxyribonucleic acid, the molecule that holds all genetic information in genes.
What is a gene?
A unit of heredity controlling characteristics like hair color and eye color.
What is replication?
The copying of DNA during interphase to ensure each new cell has identical genetic material.
How does mitosis contribute to growth?
By producing more identical cells, allowing organisms to grow from a single zygote into a multicellular body.
How does mitosis support asexual reproduction?
It produces offspring genetically identical to the parent by copying all genetic material without variation (except for mutations).
What is binary fission?
A form of asexual reproduction in unicellular organisms where the organism divides into two identical parts.
What is vegetative propagation?
A type of asexual reproduction where parts of plants like tubers, runners, or leaves develop into new plants.
Give an example of a plant that reproduces by runners.
Strawberry plants.
What is artificial propagation?
Human techniques like cutting, grafting, cloning, and tissue culture to create new plants.
What is grafting?
Attaching a scion (desired plant piece) to a stock (rooted plant) to grow a new plant.
What is tissue culture?
Growing plant tissues in an artificial medium to quickly produce many identical plants.
What is a clone?
An exact genetic copy of an organism.
How was Dolly the sheep cloned?
By transferring a nucleus from a body cell into an egg cell without a nucleus, and then implanting it into a surrogate mother.
What is a major disadvantage of cloning animals?
It may introduce problems from using “old” nuclei, and ethical concerns arise with cloning, especially in humans.
What is the advantage of animal cloning?
Superior traits can be preserved without the risk of genetic variation during reproduction.
What happens if mutation occurs during mitosis?
Faulty copying of genes can cause major changes, such as diseases like sickle cell anemia.
Why are identical twins considered clones?
They come from the same zygote that splits, resulting in two genetically identical individuals.
What are homologous chromosomes?
Chromosome pairs, one from each parent, that are similar in structure and gene content.
