* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Cell Reproduction
Survey
Document related concepts
Hybrid (biology) wikipedia , lookup
Designer baby wikipedia , lookup
Polycomb Group Proteins and Cancer wikipedia , lookup
Y chromosome wikipedia , lookup
Site-specific recombinase technology wikipedia , lookup
Vectors in gene therapy wikipedia , lookup
Point mutation wikipedia , lookup
X-inactivation wikipedia , lookup
Microevolution wikipedia , lookup
Transcript
Cell Reproduction 3.02 Chromosomes • Rod shaped structures in the nucleus that only appear right before cell division Chromosomes Cont. • Types: – Autosomes • Not involved in sex determination – Sex Chromosomes • Determine sex – Female: XX – Male: XY • Numbers – Diploid: 2 of each • Body Cells • For humans 46 – Haploid: 1 of each • Gametes (sex cells) • For humans 23 Karyotype: chart of chromosome pairs used to detect abnormalities in chromosome number Cell Cycle • The regular cycle of grow, development, and reproduction. • Why? – To Grow – To Repair – To Replace Mitosis • A period of nuclear division in which 2 daughter cells are formed from 1 parent cell. – Each daughter cell contains a complete set of chromosomes – This produces more body cells Mitosis • Can you put these images in order? 4 1 1 2 3 Mitosis Cont. • Paired chromosomes are visible • Spindle fibers appear • Nucleolus and nuclear envelope breakdown Mitosis Cont. • Paired chromosomes line up along the cells middle Mitosis Cont. • Paired Chromosomes separate and move toward the opposite pole of the cell guided by the spindle fibers Mitosis cont. • Chromosomes reach opposite poles of the cell • Begin to uncoil into chromatin • Nuclear envelope and nucleolus begin to reform Asexual Reproduction • Some organisms use mitosis to reproduce. – All offspring are genetically identical to the parent. – Forms of asexual reproduction Budding Meiosis • The process of cell division in which haploid gametes are produced from diploid cells – Occurs in 2 stages 23 46 46 23 92 Meiosis I Meiosis II 23 – Allows for genetic recombination 46 23 Genetic Recombination: Shuffling genes from parents to get new combinations • Crossing Over – Exchanging equivalent information from homologous chromosomes • Random Assortment of Chromosomes – Independent Assortment – Chance distributes maternal and paternal chromosomes to gametes Fertilization • The fusion of 2 haploid gametes to produces a diploid zygote. • Fertilization is random. – Adds to genetic variation. Possible sperm Possible eggs How many different zygote combinations can these make? Other Sources of Variation • Gene Mutation – A change in the sequences – Types DNA • Point mutations • Frameshift mutations – Effects • Advantagous: produces a phenotype that is more suited to the environment • Neutral: does not help or hurt survival • Lethal: produces a phenotype that is less suited to the environment or causes a disease Mistakes in Meiosis • Nondisjunction: The failure of homologous chromosomes to separate properly. – Trisomy • Down’s Syndrome What gender is this person? Comparing Mitosis & Meiosis Mitosis Number of divisions? DNA replicated before each division? Homologous chromosomes separated? How many cells are produced? Cells all the same? Used for asexual or sexual reproduction? Meiosis Comparing Mitosis & Meiosis Mitosis Meiosis 1 2 DNA replicated before each division? Yes No Homologous chromosomes separated? No Yes 2 4 Yes No Asexual Sexual Number of divisions? How many cells are produced? Cells all the same? Used for asexual or sexual reproduction?