Ifoocytes are already at metaphase 2 during ovulation and atfertilization meiosis 2 completes with help from the sperm, thenhow does the paternal DNA from the sperm âmixâ with the maternalDNA if crossing over occurs during meiosis 1?
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Related questions
Which statements pertaining to genetic variability are correct? Check all that apply (note that wrong answers will be deducted from right answers)!
Crossing over is defined by the exchange of chromosome pieces during metaphase one of meiosis. |
If a germ cell (i.e. parent cell before meiosis) had only two pairs of homologous chromosomes (i.e. 4 chromosomes total) there are 2 possible combinations of maternal and paternal chromosomes in gametes. |
Siblings produced by sexual reproduction are different because sperms are different from one another and eggs are different from one another, and the combination of an egg and sperm is basically unique. |
Random fertilization means that all possible combinations of eggs and sperm are equally likely, i.e. it is pure chance which sperm fuses with which egg. |
Individual chromosomes contain thousands of genes. This means that during each crossing over event, more than one gene is exchanged between paternal and maternal chromosomes. |
Title: Meiosis Lab
Part 1: Modeling Meiosis Without Crossing Over (reformat as needed)
Take photos of the following stages of your meiosis bead simulation. Insert and label the following images:
Meiosis 1: Prophase I and Metaphase I
Meiosis 2: Metaphase II and Telophase II
Part 2: Modeling Meiosis With Crossing Over (reformat as needed)
Take photos of the following stages of your meiosis bead simulation. Insert and label the following images:
Meiosis with Crossing Over: Metaphase I and Telophase II
Questions â use the lab Introduction, your textbook and other sources to answer the following.
What is the state of DNA at the end of meiosis I? Are the chromosomes replicated or unreplicated? Diploid or haploid?
Why are chromosomes important?
How are Meiosis I and Meiosis II different?
Name two ways meiosis contribute to genetic recombination or genetic variety.
Why do you use non-sister chromatids to demonstrate crossing over? What would happen if you crossed over sister chromatids?
How many chromosomes were present in your simulation when meiosis I started?
Why is it necessary to reduce the chromosome number in gametes, but not in other cells of an organism?
If humans have 46 chromosomes in each of their body cells, determine how many chromosomes you would expect to find in the following:
Sperm | Egg | Daughter cell after mitosis | Daughter cell after meiosis |
Investigate a disease that is caused by a chromosomal mutation due to nondisjunction. When does the mutation occur? What chromosome is affected? What are the consequences?