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When one mother cell becomes two identical daughter cells:
What are some examples of organisms that utilize asexual reproduction?
Prokaryotic cells, some sea stars and eukaryotic yeast cells
What type of cells utilize mitosis and which cells use meiosis?
Sperm and egg cells use meiosis (sexual reproduction) and somatic cells utilize mitosis (asexual reproduction).
Single-celled bacteria and archaea reproduce by a type of cell division called ___________
Binary fission ("dividing in half")
Why is binary fussion classified as asexual reproduction?
Because it divides into two genetically identical daughter cells
What is the most different about sexual reproduction from asexual reproduction?
Asexual reproduction creates two genetically identical offspring, sexual reproduction creates genetically different hapliod cells
How many chromosomes do haploid cells have? What about diploid cells?
What is chromatin composed of?
DNA and protein
What are chromosomes composed of?
Coiled up chromotin (DNA and protein)
What are sister chromatids?
Prior to cell division in eukaryotic cells, chromosomes replicate creating sister chromatids.
What attaches sister chromatids together?
What is the first phase of eukaryotic cell division? What occurs during this phase?
- During this time, a cell has very high metabolic activity and the cell performs normal functions. Interphase is made of three subphases: G1 ("first gap") phase, S ("synthesis") phase, G2 ("gap 2") phase.
- During S phase the DNA chromosomes are replicated
What is the second phase of eukaryotic cell division (mitosis)?
- The second phase of mitosis is the mitotic phase, consisting of mitosis and cytokinesis.
- During this phase the cell's contents (chromosomes and cell contents) divide evenly. The division creates two genetically equal daughter cells.
What is cytokinesis?
Cytokinesis occurs in mitosis just before the mitotic phase ends. During this phase the cytoplasm divides into two cells.
What are the five distinguishable phases that occur in mitosis?
*prior to mitosis, interphase occurs*
- 1- prophase (chromosomes become coiled)
- 2- prometaphase (nuclear envelope breaks, spindles attach to kinetochores starting movement, spindles begin movement toward poles)
- 3- metaphase- (all chromosomes line up in center w/ fully formed mitotic spindle)
- 4- anaphase- (chromosomes separate, moving towards poles and non-attached spindles lengthen)
- 5- telophase and cytokineis- (cell elongation, chromatin uncoils, division of cytoplasm)
What occurs in prophase of mitosis?
Chromatin becomes coiled into chromosomes and mitotic spindles begin form
What is anchorage dependence?
Most animal cells must be in contact with a smooth surface to divide.
What is difference between plant and animal cell cytokinesis?
Animal cells separate via cleavage furrow, where a ring of microfilaments contract. Plant cells utilize cell plates where vesicles form a membranous disk and create two cells.
What occurs during telophase and cytokinesis in mitosis?
This process is the reverse of prophase.
During telophase, chromatin fibers uncoil from structured chromosomes and genetically identical nuclei is created.
Cytokinesis is the division of cytoplasm via cleavage furrow.
What happens during anaphase in mitosis?
Sister chromatids (lined up in the center) are pulled apart via spindles towards the poles. Spindles not connected to chromatids lengthen towards towards the center.
What occurs during metaphase during mitosis?
Chromosomes are lined up into the middle of the cell, equidistant from each pole.
What occurs during prometaphase during mitosis?
The nuclear envelope opens as mitotic spindles attach to kinetochores. Chromosomes begin to move toward the center of the cell.
What is density-dependent inhibition?
Phenomenon in which crowded cells stop dividing. For example, animal cells on a dish surface multiply to a single layer and stop once the cells start touching one another. If cells are removed, they divide again to fill the empty space.
What type of protein is secreted by certain body cells that stimulate other cells to divide?
During what phase of mitosis does chromatin become coiled into chromosomes and mitotic spindles begin to form?
During what phase of mitosis does the nuclear envelope open and mitotic spindles attach to kinetochores, causing the chromosomes to begin to move toward the center o the cells?
During what phase of mitosis does the mitotic spindle become fully formed, with poles on each end of the cell, and the chromosomes line up in the middle of the cell on the metaphase plate?
During what phase of mitosis do the spindles and kinetochores move the chromosomes towards the poles of the cell, separating the sister chromatids. During this time, unconnected spindles move toward the center of the cell, lengthening. What phase is this?
During what phase of mitosis does the cleavage furrow form, chromatin fibers uncoil, mitotic spindles disappear, and the cytoplasm divides into two?
Telophase and cytokinesis.
Which cell control checkpoint seems to be the most important one?
The G1 checkpoint, which determines whether a cell with progress to the S phase where DNA division occurs. IF a cell never gets cleared for the checkpoint, it stays in the G0 phase (like many mature nerve cells).
What occurs if a cell does not have normal cell cycle control singles or cycles? What is it called if these cells invade other areas?
Tumors; cancer cells.
What is a tumor? What is the difference between a benign tumor and a malignant tumor?
A tumor is a mass of abnormally growing cells that have otherwise normal tissue.
A benign tumor is when the abnormal mass of growing cells remain in their original site (these can usually be easily removed surgically or left alone).
A malignant tumor occurs when the growing mass of cells invades into other parts of the body, interupting normal organ function. A malignant tumor is a cancerous one.
What are a few differences about cancer cells from normal cells?
- - They are not controlled via normal cell cycle control systems
- - They produce their own growth hormone
- - They do not exhibit density-dependent inhibition (they just keep growing).
What is an example of a gamete? How many chromosomes do they poccess?
An egg or sperm cell; 22 plus a sex chromosome!
What is the difference between diploid and haploid cells?
Diploid cells contain the full 46 chromosomes. Haploid cells only contain half the normal amount of chromosomes (23).
What is the biggest difference between mitosis and meiosis?
Mitosis produces genetically identical offspring, where meiosis creates genetically different offspring.
Give a brief overview of meiosis
- 1. Interphase (homologous chromosomes duplicate into two sets of sister chromosomes)
- 2. Meiosis I (homologous chromosomes separate. Each set of sister chromosomes move apart, going from one to two cells).
- 3. Meiosis II (sister chromosomes separate, creating four diploid cells)
**ADD SLIDES FOR SECTION 8.13***
What occurs during prophase I of meiosis?
Chromosomes duplicate into sister chromosomes and remain pared together (four sets of two). Crossing over occurs between non-sister chromatids.
What occurs during metaphase I of meiosis?
Pairs of homologous chromosomes line up on the metaphase plate in the center of the cell.
What occurs during anaphase I and telophase I in meiosis?
Homologous chromosomes separate during anaphase I and the cell divides (two pairs - four chromosomes- per cell)
What occurs during meosis II of meiosis?
Sister chromosomes progress through prophase II, metaphase II, anaphase II and telophase II and cytokinesis. This results in four two-chromosome genetically different cells.
What is the difference between prophase I and prophase II of meiosis?
Prophase I begins with a diploid cell (full set of chromosomes) and prophase II begins with a haploid cell.
What is a chiasma?
The site where chromosomes cross over.
What occurs with nondisjunction?
Members of a chromosome fail to separate, creating an uneven distribution of chromosomes.
Explain trisomy 21.
Instead of just two chromosome 21's, there are three. This is what causes Down syndrome.
What is the difference between deletion, duplication, inversion and translocation?
- Deletion- Fragment of chromosome disappears
- Duplication- Fragment of chromosome becomes attached as extra segment to sister chromatid or homologous chromosome
- Inversion- Fragment attaches to original chromosome in reverse orientation
- Translocation- Chromosomal fragment joins a nonhomologous chromosome.