Chapter 8 Flashcards
Why can a eukaryotic cells not simply split into two?
Because then only one daughter cell would inherit the nucleus and the DNA. A cell’s cytoplasm only splits after its DNA has been copied and packaged into more than one nucleus.
What is Mitosis?
Mitosis is a nuclear division mechanism that occurs in somatic (body) cells of multicelled organisms.
What is Meiosis?
The basis of sexual reproduction, in humans and mammals gametes (sperm and eggs) develop from immature reproductive cells.
Functions of Mitosis cytoplasm division (4).
In all multicelled eukaryotes, the basis of three processes:1. Increases in body size during growth2. Replacement of dead or worn-out cells3. Repair of damaged tissuesIn single-celled and many multicelled species, also thebasis of asexual reproduction
Function of Meiosis cytoplasm division.
In single-celled and multicelled eukaryotes, the basis of sexual reproduction; precedes gamete formation or spore formation.
Function of Prokaryotic fission.
In bacteria and archaeans alone, the basis of sexual reproduction.
What are Sister Chromatids?
Two attached molecules of DNA (attached as one chromosome)
What are Histones?
“Spools” of proteins. Under a microscope appears as beads on a string.
What are Nucleosomes?
A “bead” of a histone, the smallest unit of structural organization in eukaryotic chromosomes.
What is a Centromere?
The constricted region of a sister chromatid.
What are Kinetochores?
Binding sites for microtubules that tether the chromatids.
What is a Cell Cycle?
A series of events from one cell division to the next. Consists of: mitosis, cytoplasmic division, and interphase.
What is Interphase?
Interphase consists of three stages that increases the mass, doubles the cytoplasmic components, and duplicates the DNA of a cell.
What are the three stages of Interphase?
- G1 - Interval (Gap) of cell growth and activity before the onset of DNA replication.2. Time of “Synthesis” (DNA replication).3. G2 - Second interval (Gap) after DNA replication where the cell prepares for division.
What is the Chromosome Number?
The sum of all chromosomes in a cell of a given type.