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Lecture 14
Lecture 14

... o Independent assortment is violated when 2 genes are close together on the same chromosome ...
Chromosomes come in pairs
Chromosomes come in pairs

... diploid organisms: -Chromosomes come in pairs -One member of each pair comes from each parent - Cells that will turn into gametes are sequestered early in development - minimizing replication. -At sexual maturity, gamete production begins. -Gametes are haploid. Their union produces a new diploid org ...
Heredity – the passing of traits from parents to offspring
Heredity – the passing of traits from parents to offspring

... DNA – cellular material with all the information about what traits a living thing may have Chromosome – thread like structures that organize DNA, each chromosome is a long DNA molecule (about 1.5 meters!) Gene – part of the DNA molecule that carries a specific trait (composed of 2 alleles) (ex. flow ...
Name
Name

... 32. A ______________________ is the offspring of parents that have different alleles for a trait. 33. A punnett square shows all the possible combinations of _________________ resulting from a cross. 34. An organism’s _______________________________ is its allele combination. 35. Chromosomes carry _ ...
GENES AND CHROMOSOMES
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... mother and their Y chromosome from their father If the gene for white eyes is on the X chromosome it explains the fact that males carry only one copy of the gene that they got from their mother Calvin correlated an unusual pattern of inheritance, X linked, with an unusual pattern of chromosome segre ...
PPT 11-12
PPT 11-12

... • In metaphase II, the sister chromatids are arranged at the metaphase plate • Because of crossing over in meiosis I, the two sister chromatids of each chromosome are no longer genetically identical • The kinetochores of sister chromatids attach to microtubules extending from opposite poles ...
BIOL 101 Rev Oct 2015 - Glendale Community College
BIOL 101 Rev Oct 2015 - Glendale Community College

... Upon successful completion of the required coursework, the student will be able to:  describe and compare the structures of prokaryotic and eukaryotic cells;  describe, compare, and explain the differences between mitosis and meiosis, and identify cells in different stages of cell division;  defi ...
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Classical Papers
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... • “The association of paternal and maternal chromosomes in pairs and their subsequent separation during the reduction division…may constitute the physical basis of the Mendelian laws of heredity” ...
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The Chromosome Theory of Inheritance

... Humans & other mammals: X & Y = sex chromosomes ...
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Medaka Fish Haploid Embryonic Stem Cells

... Medaka fish is a small laboratory fish that is widely used as a model organism in biomedical research. Repeated attempts in Drosophila, frog, mice and even humans have failed to derive homologous haploid cell populations. For the first time, we have successfully established the culture conditions fo ...
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Mitosis - Walton High

... Duplicated chromosomes become fully visible. Organelles called centrioles move to opposite ends of the cell. The nucleolus and nuclear membrane ...
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Cell Division—Mitosis Notes

... • Why  do  cells  need  to  divide?   1. Living  things  grow  by   producing  more  cells,  NOT   because  each  cell  increases  in   size 2. Repair  of  damaged  Cssue 3. If  cell  gets  too  big,  it  cannot   get  enough  nutrients ...
Cell Division—Mitosis Notes EQ: How do cells divide? Cell Division cells
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... Fruit fly = 8 chromosomes Fruit fly skin cell = 8 chromosomes Fruit fly heart cell = 8 chromosomes Fruit fly muscle cell = 8 chromosomes ...
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... • During prophase, the spindle, or the fanlike microtubule structure that helps separate the chromosomes is formed. • The spindle connects the centrioles to the chromosomes. • During prophase, the nuclear membrane ...
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Mitosis Notes - Madeira City Schools

... assembling, microtubules of cytoskeleton disassemble providing material) ...
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Biology B Final Review ANSWERS

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Biology Notes: Seedless Nonvascular Plants (Moss Life Cycle)
Biology Notes: Seedless Nonvascular Plants (Moss Life Cycle)

... 2) Through _____________, sperm from the _____________ (male gametophyte) will _____________  to the ______________ (female gametophyte) to create a ______________   ______________  3) Diploid ______________ will ______________ from ______________  4) Sporophyte will ______________ haploid _________ ...
ch06 (1) - earthjay science
ch06 (1) - earthjay science

... Chromosomes kind and numbers are constant for a species Diploid cells – cells with paired homologous chromosomes Mitosis – regeneration of new cells in organisms Meiosis – occurs in sexual reproduction when gametes are formed Haploid cells – reproductive cells without paired chromosomes Variation in ...
Cell Cycle and Mitosis
Cell Cycle and Mitosis

... • Summarize the steps of mitosis/cytokinesis. • Prophase – chromatin condenses into chromosomes, the nuclear membrane breaks down, and the centrosomes move towards opposite sides of the cell. • Metaphase – chromosomes line up at the equator of the cell, with sister chromatids facing opposite sides o ...
File
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Ch 9 Mitosis
Ch 9 Mitosis

... cell 1n combine, the new cell will be diploid 2n]  These cells contain only 1 set of chromosomes  Haploid cells have half the number of chromosomes that are present in diploid cells  Human haploid cells have only 1 chromosome of each homologous pair & only 1 sex chromosomes ...
Sexual Reproduction in Plants
Sexual Reproduction in Plants

... For more awesome GCSE and A level resources, visit us at www.savemyexams.co.uk/ ...
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... 1. What are two ways that sexual reproduction helps create and maintain genetic diversity? ...
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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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