BIOL 3301 - Genetics Ch3A - Mitosis St
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Transcript of BIOL 3301 - Genetics Ch3A - Mitosis St
Main Principles
• Prokaryotes, eukaryotes• Each organism starts from one cell• All organisms are made of cells• Each cell of each organism has the same
number of chromosomes• Each species has a certain number of
chromosomes
Chromosome numbers in some plants Plant Species #Arabidopsis thaliana (diploid) 10Rye (diploid) 14Maize (diploid) 20Einkorn wheat (diploid) 14Durum wheat (tetraploid) 28Bread wheat(hexaploid) 42Potato (tetraploid) 48Cultivated tobacco (diploid) 48Adder's Tongue Fern (diploid) approx 1,440
Chromosome numbers (2n) in some animals Species # Species #Common fruit fly 8 Guinea Pig 64Dove 16 Garden snail 54Earthworm Octodrilus complanatus 36 Tibetan fox 36Domestic cat 38 Domestic pig 38Lab mouse 40 Lab rat 42Rabbit 44 Syrian hamster 44Hare 46 Human 46
Gorillas, Chimpanzees 48 Domestic sheep 54
Elephants 56 Cow 60Donkey 62 Horse 64Dog 78
Goldfish 100-104
Eukaryotic Chromosomes
• Haploid cell – n (number of chromosomes)• Diploid cell – 2n (number of chromosomes)• Genome• Homologous chromosomes• Autosomes, sex chromosomes• Karyotype
www.iknow.net/cell_div_education.html
sisterchromatids
duplicatedchromosome(2 DNA double helices)
Cell Cycle
• Stages of cell cycle• G1• G0• S• G2• All together -
interphase
• Stages of mitosis:• Prophase• Metaphase• Anaphase• Telophase• Cytokinesis
Mitosis
• Mitosis is a cellular division for _________________________________
• One cell after mitotic division produces ___________________________________
• The number of chromosomes is ___________________________________
Mitosis
• Chromosomes duplicate in interphase, forming sister chromatids
• Phases of mitosis:–
Interphase• S phase -chromosomes duplicate,
___________________________________• Microtubule organizing centers (MTOCs) –
_____________________________________• Centrosome –
_______________________________________________________________________________
G2 of Interphase
• - nucleus __________________________ - one or more nucleoli present - two pairs of centrioles ________________________________ - chromosomes have already duplicated __________________________________
Nucleolus
• ______________________________________________• Ribosomal or rDNA is a set of tandemly-repeated genes
coding for preribosomal RNA, serves as its foundation.• These segments of the chromosomes are called nucleolus
organizer regions or NORs.
Prophase
- chromatin coils & folds into _______________________________
- each chromosome consists of two identical __________________________________ - spindle forms consisting of microtubules - centrosomes ______________________
Prophase
• Fragmentation of many intracellular organelles except mitochondria and chloroplasts
• Nuclear membrane breaks into small vesicles• Microtubules formed in the cytoplasm invade the
nuclear space• Kinetochores – proteinaceous structures
associated with the centromeres
Prometaphase
• - nuclear membrane fragments - microtubules _________________________________ - spindle fibers extend from _______________________________ - bundles of microtubules (kinetochore microtubules) attach & put chromosomes in motion
Metaphase
• chromosomes move to ___________________________________
• identical chromatids are attached to kinetochore fibers radiating from opposite ends ______________________________
Anaphase
• - sister chromatids separate and are considered _________________________- spindle apparatus starts moving separate chromosomes to _____________________ - poles of cell move farther apart slightly elongating the cell
Telophase
• daughter nuclei begin to form __________________________________
• nuclear envelopes form• nucleoli reappear• chromatin uncoils and chromosomes
become ___________________________
http://www.bio.davidson.edu/misc/movies/CarMitosis.mov
http://www.bio.davidson.edu/misc/movies/mitosisnewt.mov – this one and nexthttp://www.bio.davidson.edu/misc/movies/mitosislily.mov
Vocabulary
• Prokaryotes, eukaryotes• Haploid, diploid• Chromosomes, chromosomal number• Karyotype• Homologous chromosomes• Sister chromatids
Vocabulary
• Locus (loci)• Gene, allele• Biparental inheritance – one from mom, one
from dad• Autosomes, sex-determining chromosomes• Somatic cells, germ cells, gametes, zygotes• Karyokinesis, cytokinesis