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Slide 1
Slide 1

... divide into 2 new cells. – Centromere connects the chromatids or double rods of chromosomes. – Centrioles are organelles used to separate & pull chromosomes into new nuclei. » Spindle fibers are bands that extend from the centriole & attach to the chromosome & pull it into separate nuclei. ...
DNAandGeneticsEducDept
DNAandGeneticsEducDept

... chromosomes by half • One cell divides into four cells with each the haploid (n) number of chromosomes • The first meiotic division reduces the number of chromosomes • The second meiotic division is actually mitosis which increases the number of cells • Meiosis is the process through which gametes a ...
The Cell Cycle - cloudfront.net
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... Horse 30 pair or 60 chromosomes Each chromosome is made of genes. The combinations of genes is what express Itself in the individual. The genes are made up of individual DNA. When the nucleus replicates it copies The DNA. Sometimes the replication process makes mistakes. That is how Mutations happen ...
3 Meiosis - Lab RatKOS
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... Sex cells are made during meiosis. Meiosis is a copying process that produces cells with half the usual number of chromosomes. Meiosis keeps the total number of chromosomes the same from one generation to the next. In meiosis, each sex cell that is made gets only one chromosome from each homologous ...
Chapter 6.1 Chromosomes and Cell Reproduction
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... Let’s make a triploid sea urchin embryo by fertilizing an egg with two sperm. The resulting zygote does divide, but the mitotic spindles are multicentric. Sometimes, this triploid entity even produced a 4-cell embryo. The resulting blastomeres, when separated, invariably failed to develop further. I ...
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... Human somatic cells (__body____cells) are ___diploid___ or 2n. Each human somatic cell has __46__chromosomes, or 23 pairs of chromosomes. Of these 23 pairs, 22 pairs are called __homologous__pairs, meaning they contain the same genes in the same order. The 44 chromosomes that make up the 22 homologo ...
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... (3) It removes waste products that are produced in the cells of the fetus. (4) It synthesizes food for the embryo. 2. All cells in an embryo have the same DNA. However, the embryonic cells form organs, such as the brain and the kidneys, which have very different structures and functions. These diffe ...
Unit IX Teacher Notes 2017
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... Human somatic cells (__body____cells) are ___diploid___ or 2n. Each human somatic cell has __46__chromosomes, or 23 pairs of chromosomes. Of these 23 pairs, 22 pairs are called __homologous__pairs, meaning they contain the same genes in the same order. The 44 chromosomes that make up the 22 homologo ...
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... the nucleus, the spindle starts to form Centromere: area where DNA molecules are attached Sister Chromatids: identical chromosomes Centrioles: organelle that creates spindle fibers ...
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... surface area to volume becomes too small – they must divide into two cells. Cell division a part of the cell cycle is essential for the growth and development of an organism. However, no cell lives forever. In prokaryotic cells, cell division is called binary fission, and is accomplished in two fair ...
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... A person that has ONE copy of an AUTOSOMAL RECESSIVE allele and does not express the trait, but can pass it along to his/her offspring is called a __________________. A. mutant B. carrier C. gene marker The failure of homologous chromosomes to separate during meiosis is called ____________________ A ...
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... Most cells spend about 90% of their time in interphase. Cells actively synthesize materials they need to grow. Chromosomes are duplicated. Interphase can be divided into three stages: 1. G1 phase: Just after cell division. Cell grows in size, increases number of organelles, and ...
Chapter 8: Mitosis - Cell Division and Reproduction
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... 1. Prophase: Cell prepares for division. 2. Metaphase: Chromosomes line up in “middle” of cell. 3. Anaphase: Sister chromatids split and migrate to opposite sides of the cell. 4. Telophase: DNA is equally divided into two new daughter cells. Cytokinesis usually occurs. ...
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Meiosis



Meiosis /maɪˈoʊsɨs/ is a specialized type of cell division which reduces the chromosome number by half. This process occurs in all sexually reproducing single-celled and multi-celled eukaryotes, including animals, plants, and fungi. Errors in meiosis resulting in aneuploidy are the leading known cause of miscarriage and the most frequent genetic cause of developmental disabilities. In meiosis, DNA replication is followed by two rounds of cell division to produce four daughter cells each with half the number of chromosomes as the original parent cell. The two meiotic divisions are known as meiosis I and meiosis II. Before meiosis begins, during S phase of the cell cycle, the DNA of each chromosome is replicated so that it consists of two identical sister chromatids. In meiosis I, homologous chromosomes pair with each other and can exchange genetic material in a process called chromosomal crossover. The homologous chromosomes are then segregated into two new daughter cells, each containing half the number of chromosomes as the parent cell. At the end of meiosis I, sister chromatids remain attached and may differ from one another if crossing-over occurred. In meiosis II, the two cells produced during meiosis I divide again. Sister chromatids segregate from one another to produce four total daughter cells. These cells can mature into various types of gametes such as ova, sperm, spores, or pollen.Because the number of chromosomes is halved during meiosis, gametes can fuse (i.e. fertilization) to form a zygote with a complete chromosome count containing a combination of paternal and maternal chromosomes. Thus, meiosis and fertilization facilitate sexual reproduction with successive generations maintaining the same number of chromosomes. For example, a typical diploid human cell contains 23 pairs of chromosomes (46 total, half of maternal origin and half of paternal origin). Meiosis produces haploid gametes with one set of 23 chromosomes. When two gametes (an egg and a sperm) fuse, the resulting zygote is once again diploid, with the mother and father each contributing 23 chromosomes. This same pattern, but not the same number of chromosomes, occurs in all organisms that utilize meiosis. Thus, if a species has 30 chromosomes in its somatic cells, it will produce gametes with 15 chromosomes.
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