Chapter 8 Cell Reproduction
Terms in this set (55)
rod-shaped structures made of DNA and proteins
the DNA in eukaryotic cells wraps tightly around proteins called histones
Chromosomes consist of two identical halves: each half of the chromosome is a chromatid
The two chromatids of a chromosome are attached at a point called a centromere
the less tightly coiled DNA-protein complex is called chromatin
chromosomes that determine the sex of an organism, and they may also carry genes for otehr charactersitics
All of the other chromosomes in an organism are called autosomes
the two copies of each autosome. Homologous chromosomes are the same size and shape and carry genes for the same traits.
a photomicrograph of the chromosomes in a normal dividing cell found in a human
cells having two sets of chromosomes are diploid. Have two autosomes for each homologous pair.
sperm cells and egg cells are haploid cells, containing onyl one set of chromosomes
the division of a prokaryotic cell into two offspring cells
results in new cells with genetic material that is identical to the genetic material of the original cell. Occurs in organisms undergoing growth, development, repair, or asexual reproduction
the production of offspring from one parent
occurs during the formation of gametes
haploid reproductive cells
the time between the cell divisions is called interphase. Interphase is divided into three phases, and cell division is divided into two phases.
During mitosis, the nucleus of a cell divides. Cytokinesis is the division of the cell's cytoplasm.
the first phase of mitosis. During prophase, the copied DNA coils into chromosomes.
contain centrioles, two pairs of dark spots called centrosomes appear next to the disappearing nucleus
in animal cells, each centrosome contains a pair of small, cylindrical bodies called centrioles.
Mitotic apparatus (Spindle fibers)
made of microtubules radiate/emerge from the centrosomes in preparation for metaphase
attach to a disk-shaped protein- called a kinetochore- that is found in the centromere region of each chromosome.
disk-shaped protein where kinetochore fibers attach to
extend across the dividing cell from centrosome to centrosome but do not attach to the chromosomes.
the second phase of mitosis. During metaphase, the chromosomes line up along the midline of the dividing cell.
the third phase of mitosis. During anaphase, the chromatids of each chromosome begin moving toward opposite poles of the cell.
the fourth phase of mitosis. During telophase, the chromosomes reach opposite poles of the cell, and a cleavage furrow is formed. Cytokinesis follows.
(literal cell cleavage) the area of the cell membrane that pinches in and eventually separates the dividing cell into two cells
In plant cells, vesicles from the Golgi apparatus join together at the midline of the dividing cell to form a cell plate. A cell wall eventually forms from the cell plate at the midline, dividing the cell into two cells
stem cells are unspecialized cells that give rise to the different types of cells that make up the human body
cellular structure shaped like a star, formed around each centrosome during mitosis in an animal cell.
the Cell Cyle
repeating events in a life cycle
What is the difference between
What is a karyotype?
picture of all 46 of a person's chromosomes
What is the cell cycle? What are the subphases of this cycle?
Cell cycle: repeating events in life of cell
Divided into two phases
-Interphase: time between divisions (3 phases)
~G1 phase: growth and maturation
Gets too big, begin preparation for division
~S phase: DNA synthesis
~G2 phase: division prep
~Mitosis: division of nucleus
G0 phase: cell exits cell cycle; does not divide in this phase (nerve cells) after maturity after G1
Not ready does not have any resources
What is mitosis?
Occurs during growth, repair, development or asexual reproduction
Produces 2 genetically identical daughter cells
What are the different phases of mitosis?
What happens in prophase?
- DNA coils around the histones to form into chromosomes
- Nucleolus and nuclear membrane disappear
- Centrosomes which contain centrioles appear near the nucleus; begin moving toward opposite poles
- Spindle fibers emerge out from the centrosomes (2 types of fibers: kinetochore fibers attach to chromatids at the centromere/kinetochore and polar fibers which extend across cell)
What happens in metaphase?
- Chromosomes line up along center of cell
- Metaphase/cell plate: one chromatid, one chromatid is on the other. Ropes called kinetochore fibers, and will get yanked apart.
What happens in anaphase?
- Chromatids move centromere first towards poles
- Polar fibers elongate the cell
What happens in telophase?
- Chromatids begin to unravel
- Spindle disassembles
- Nucleolus and nucleus reform
What is cytokinesis? How does it occur in animal cells vs plant cells?
During telophase, the cytoplasm begins dividing by the process of cytokinesis. In animal cell, binary fission, and in plant cell, cell wall.
What is the end result of mitosis?
Each offspring receives an identical copy of the original cell's chromosomes and approximately one-half of the original cell's cytoplasm and organelles
How is mitosis controlled?
What happens if mutation occurs that affects the cell cycle?
What is a cancer cell?
What is meiosis?
What happens during Meiosis 1? Meiosis 2?
What is a synapsis? What is a tetrad?
What happens during crossing over? When does it occur?
What is independent assortment? When does it occur?
What is spermatogenesis? What is the end result?
What is oogenesis? What is the end result?
What are the sources of genetic variation in eukaryotic organisms?