Chapter 19 Part 1 Flashcards
What are two types of cell division?
Mitosis and meiosis
Zygote
Single cell after fertilization
Nuclear division occurring in somatic cell in which two identical daughter cells are generated
Mitosis
Nuclear division that results in gametes
Meiosis
Roles of mitosis
Growth and repair
Tightly coiled combination of a DNA molecule and specialized proteins called histones
Chromosome
Gene
Specific segment of DNA that directs the synthesis of a protein.
Somatic cells
All cells except egg or sperm
____ chromosomes in ____ pairs
46, 23
Homologous chromosome pair
2 chromosome (one from mother, one from father) with genes for the same traits
Sex chromosome
XX- female
XY- male
Autosome
All but the sex chromosomes.
Determine the expression of most of a person’s inherited characteristics
Two major phases of the cell cycle
Interphase and cell division
Accounts for most of the time that elapses during a cell cycle
Interphase
3 parts of interphase
G1
S
G2
G1
A time of major growth
S
DNA synthesis and growth
G2
Growth
Final preparations for cell division
Chromosomes consist of two chromatids
Centromere
The region of a replicated chromosome at which sister chromatids are held together
Sister chromatids
The two attached genetically identical chromatids
Stages of mitosis
Prophase
Metaphase
Anaphase
Telophase
When DNA is in a ___________ state it cannot be replicated and _____ activity is shut down
Condensed; gene
What changes occur during prophase
- chromosomes condense
- nuclear membrane begins to break down
- motoring spindle forms
- centrioles move away from each other
Metaphase
The chromosomes attach to the mitotic spindles forming a line at the center
Anaphase
• sister chromatids separate
The spindle fibers pull the chromosomes towards opposite poles of the cell
Telophase
Nuclear envelope forms around each group of chromosomes at each pole. Mitotic spindles disassembles
Cytokinesis
Division of the cytoplasm divides cell into two daughter cells
