1. Describe the processes of synapsis and crossing-over and explain when these processes occur within meiosis....

1. Describe the processes of synapsis and crossing-over and explain when these processes occur within meiosis.

2. Describe how chromosomal variation is an advantage to sexually reproducing organisms.

Expert Solution

1:Synapsis (also called syndesis) is the pairing of two homologous chromosomes that occurs during meiosis. It allows matching-up of homologous pairs prior to their segregation, and possible chromosomal crossover between them. Synapsis takes place during prophase I of meiosis.

Crossing over is the exchange of genes between two chromosomes, resulting in non-identical chromatids that comprise the genetic material of gametes. This process occurs during Prophase I of Meiosis, just prior to chromosome alignment and splitting of the cell.

2:In many animals, it is actually the only mode of reproduction. The genetic diversity of sexually-produced offspring is thought to give species a better chance of surviving in an unpredictable or changing environment. Scientists recognize some real disadvantages to sexual reproduction.

gladiator answered 2 years ago

Comparing nuclear and chromosomal activities in mitosis and meiosis Mitosis Meiosis Synapsis Crossing over When centromeres...

Comparing nuclear and chromosomal activities in mitosis and meiosis Mitosis Meiosis Synapsis Crossing over When centromeres separate Chromosome structure and movement during anaphase Number of divisions Number of chromosomes in daughter cells Genetic similarity of daughter cells to parent cells

To simulate Prophase of Meiosis I - Synapsis and Crossing Over: 1. Homologous chromosomes come together...

To simulate Prophase of Meiosis I - Synapsis and Crossing Over: 1. Homologous chromosomes come together and synapse along their entire length. This pairing (synapsis) of homologous chromosomes represents the first big difference between mitosis and meiosis. This pairing will produce two tetrads, each consisting of four chromatids. Entwine the two chromosomes to simulate synapsis. 2. To simulate crossing over, start with your long tetrad and transfer the circles on the red chromatid at the fourth bead or “gene” to...

6. At which stage(s) of meiosis does the following occur? 1. Replication? ______________________________________ 2. Crossing over?...

6. At which stage(s) of meiosis does the following occur? 1. Replication? ______________________________________ 2. Crossing over? ______________________________________ 3. Random assortment? ______________________________________ 4. Separation of bivalents? ______________________________________ 5. Separation of sister chromatids? ______________________________________ 6. Transition from diploid to haploid? ______________________________________

What is the significance of crossing over and when does it occur??

4. During what phase of meiosis does crossing-over occur? Give a reason why it cannot occur...

4. During what phase of meiosis does crossing-over occur? Give a reason why it cannot occur during the following phase (the phase immediately after the phase you chose for the first part of your answer).

Explain in detail the process of meiosis including the significance of tetrad formation, crossing over, and...

Explain in detail the process of meiosis including the significance of tetrad formation, crossing over, and the Law of Independent Assortment in maintaining chromosome number and genetic variability. Explain the key features that make it different from mitosis.

What is crossing over? How is meiosis related to this phenomenon?

1. Name five differences between mitosis and meiosis. 2. During meiosis, which two processes occur that...

1. Name five differences between mitosis and meiosis. 2. During meiosis, which two processes occur that can increase genetic variation in the gametes? A. independent assortment and crossing over B. crossing over and cytokinesis C. separation of the sister chromatids in Anaphase I and cytokinesis D. independent assortment and cytokinesis E. cytokinesis and sexual reproduction

What are the stages of Meiosis, synaptonemal complex and crossing over in Prophase, chromosome number in...

What are the stages of Meiosis, synaptonemal complex and crossing over in Prophase, chromosome number in each stage for mitosis and meiosis

1) Explain how this cellular mechanism affects variation: Crossing over Briefly explain how the mechanism (crossing...

1) Explain how this cellular mechanism affects variation: Crossing over Briefly explain how the mechanism (crossing over) could contribute to genetic variation in offspring. Be specific how this mechanism gives this result, when it occurs during the cell cycle, and be specific as to the type of genetic variation produced (from base-pair sequences to whole genomes).

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