46 terms

Cell Cycle Test

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Growth factors
Factors that stimulate the cell to divide:
- as growth occurs more demands on DNA
- as growth occurs it becomes less efficient in moving nutrients and waste across the cell membrane
Importance of cell division
Growth development, tissue renewal, reproduction
Asexual reproduction
Process by which a single parent reproduces by itself
Sexual Reproduction
A reproductive process that involves two parents that combine their genetic material to produce a new organism, which differs from both parents
Chromosomes
Genetic information bundled into packages of DNA
Chromatin
Clusters of DNA, RNA, and proteins in the nucleus of a cell make up chromosomes
Cell division
Process by which a cell divides into two new daughter cells
Cell Cycle
Series of events that cells go through as they grow and divide
Interphase (Mitosis/Meiosis)
Cell grows, performs its normal functions, and prepares for division; consists of G1, S, and G2 phases
Sister chromatids
Identical copies of a chromosome; full sets of these are created during the S sub-phase of interphase
Mitosis
The first stage of the cell division cycle, division of the cell nucleus
Prophase (mitosis)
1. Chromatin condenses into chromosomes
2. Centriole pairs separate, move toward opposite sides of the cell, and form spindle fibers made of microtubules
3. The fibers radiate outward from the centrioles
nuclear membrane dissolves which allows spindle fibers to contact chromosomes
Metaphase (mitosis)
1. Chromosomes line up in the middle of the cell
2. Spindle fibers connect the centromere of each chromosome to the two poles of the spindle
Anaphase (mitosis)
1. Sister chromatids separate
2. Move to opposite ends of the cell
Telophase (mitosis)
1. Chromosomes begin to spread apart
2. Spindles break down
3. New nuclear membrane forms around each cluster of chromosomes
Cytokinesis (Mitosis/Meiosis)
Division of the cytoplasm

Animal- cell membrane is drawn inward until split into two equal parts

Plant- a cell plate forms, gradually develops into cell membranes that split equally
Centromere
The region of the chromosome that holds the two sister chromatids together during mitosis
Spindle fibers
Protein structures which move the chromosomes during cell division
Centrioles
Cell organelle that helps organize cell division in animal cells only
Metaphase plate
An imaginary structure between the two poles of the cell where chromosomes line up during metaphase
Karyotype
A picture of all the chromosomes in a cell arranged in pairs
Cyclins
Proteins that regulate the timing of the cell cycle in eukaryotic cells
Apoptosis
Process of programmed cell death
What is cancer?
Uncontrolled growth of abnormal cells in the body. ... Old cells do not die and instead grow out of control, forming new, abnormal cells. These extra cells may form a mass of tissue, called a tumor

Lost the ability to stop growing
Why is cancer considered a disease of the cell cycle?
Cancer breaks down the cell cycle and cells fail to grow properly with the right DNA because it was produced to quickly and can not die
Diploid cell
A cell containing two sets of chromosomes (2n), one set inherited from each parent
Haploid cell
A cell containing only a single set of chromosomes (n), a single set of genes, "one pair"
Homologous chromosomes
Two different chromosomes with different forms of information (not identical; contain different information for the same trait, from male and female parents)
Meiosis I
The first division of a two-stage process of cell division in sexually reproducing organisms that results in cells with half the number of chromosome sets as the original cell
Prophase I (Meiosis)
1. Each replicated chromosome pairs with its corresponding homologous chromosome
2. Crossing over - chromatids cross over one another, the crossed sections of the chromatids are exchanged, produces new alleles
Alleles
Different versions of a gene
Metaphase I (Meiosis)
Prepared homologous chromosomes line up across center of cell
Anaphase I (Meiosis)
Spindle fibers split and move homologous chromosomes to opposite sides
Telophase I (Meiosis)
Nuclear envelopes form around the pairs of chromatids and the cell starts to pinch in the middle
Meiosis II
The two cells produced by Meiosis I have sets of chromosomes + alleles that are different from each other and form the diploid cell that enters meiosis II

Two cells enter a second meiosis division non replication
Prophase II (Meiosis)
Chromosomes become visible
Metaphase II , Anaphase II, Telophase II, Cytokinesis (Meiosis)
Final four phases are similar to meiosis, however the result is 4 haploid daughter cells
Gametes
Reproductive cells (sperm and egg)
Fertilization
Process in sexual reproduction in which male and female reproductive cells join to form a new cell
Zygote
Fertilized egg
Autosomes
Chromosomes that are not directly involved in determining the sex of an individual

- Females have 44 (22 pairs)
- Males have 44 (22 pairs)
Sex chromosomes
Chromosomes that determine the sex of an individual

- Females have 2 (x,x)
- Males have 2 (x,y)
Total number of chromosomes (Humans)
Males and Females both have 46 (23 pairs) chromosomes
Similarities of Mitosis and Meiosis:
- copying of genetic material of chromosomes
Differences of Mitosis and Meiosis:
Mitosis:
- When two sets of genetic material separate each daughter cell receives one complete set of chromosomes
- Doesn't change the chromosome # of the original cell
- Creates two genetically identical diploid cells

Meiosis:
- Homologous chromosomes line up and then move to separate daughter cells
- Reduces the chromosome # by half
- Creates four genetically different haploid cells
Tetrad
Structure containing 4 chromatids that forms during meiosis