BSC 1010C Lecture Notes - Lecture 11: Synaptonemal Complex, Meiosis, Fertilisation

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lavenderpig501

1 Oct 2016

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Gametes(egg and sperm) are haploid cells, which contains 1 set of all chromosomes. Somatic cells: non-reproductive cells that contain 4 chromosomes. Sexual life cycles have both haploid and diploid stages. Two sets of chromosomes are present in somatic cells(diploid) One set of chromosomes is present in gametes(haploid) Germ-line cells are set aside early in animal development. Germ-line cells: cells that eventually will form haploid gametes by meiosis. Meiosis in a diploid organism consists of 2 rounds of division: meiosis i, and meiosis ii, with each round containing prophase, metaphase, anaphase, and telophase stages. Meiosis ii is like mitosis without the replication of dna. Aneuploid gametes: one gamete with no chromosome and another gamete with two copies of a chromosome. Centromeres of sister chromatids remain connected through meiosis i. Sister kinetochores are attached to the same pole during meiosis i. Meiosis: form of cell division that leads to the production of gametes. Homologous chromosomes: pairs of chromosomes in diploid organisms.

Related Questions

Which of the following statements is NOT TRUE about chromosomes?

Prokaryotes have a singel, circular chromosome

Eukaryotes have multiple, linear chromosomes.

Human cells normally 23 pairs of chromosomes.

Eukaryote chromosomes are composed of only DNA

Which of the following is NOT TRUE about reproduction?

Eukaryotes life cycles include a haploid and diploid phase.

Prokaryotes reproduce asexually.

Eukaryotes can propagate by asexual or sexual reproduction.

Prokaryotes typically reproduce slower than eukaryotes.

Which of the folllowing animal cells is most likely haploid?

nerve cell

muscle cell

sperm cell

liver cell

When human gametes fuse, they form a _____.

		Haploid egg
		Diploid zygote
		Haploid zygote
		Triploid egg

13. Meiosis differs from mitosis in that:
a. meiosis results in the production of two new cells, whilemitosis results in the production for four new
cells., b. meiosis is used for growth and repair, while mitosis isused for production of eggs and sperm., c.
cytokinesis can be unequal following meiosis, but is approximatelyequal following mitosis., d. meiosis
involves one cell division, while mitosis involves two celldivisions., e. meiosis results in the production of
diploid cells, while mitosis results in the production of haploidcells.
14. Bits of maternal and paternal chromosomes are exchanged betweenhomologous chromosomes during
synapsis of meiosis I. This process is called:
a. crossing over., b. random mating., c. random fertilization., d.random shuffling of parental
chromosomes.,
e. mutation.
15. The advantage of sexual reproduction over asexual reproductionis that:
a. all young are genetically identical to the parent., b. malesmust evolve a copulatory organ., c. genetic
variability in the population is increased., d. females must evolvea vagina., e. mates are not needed.
16. Many different types of information are used to constructphylogenetic trees. Which of the following types
of information is the most direct measure of evolutionaryrelatedness?
a. physiology, b. gene sequence data, c. the fossil record, d.information about the structure of ribosomes.,
e. information about the structure of enzymes
17. A species is:
a. a group of individuals that can interbreed under naturalconditions and produce fertile offspring., b.
denoted by both a genus and a species name., c. the onlybiologically defined taxon., d. a group of
organisms with a large number of traits in common., e. all of theabove.
18. The process of spermatogenesis results in:
A. 4 diploid sperm; B. 1 diploid sperm and 3 haploid polar bodies;C. 1 haploid sperm and 3 haploid
polar bodies; D. 4 haploid sperm
19. Which cell division process results in an unequal division ofthe cytoplasm?
A. Spermatogenesis; B. Testiculargenesis; C. Oogenesis; D. None ofthe above
20. Meiosis is the process by which:
A. 1 diploid cell becomes 4 haploid cells; B. 1 diploid cellbecomes 1 haploid cell and 3 haploid polar
bodies; C. 1 haploid cell becomes 4 diploid cells; D. Both A andB
21. The phase of mitosis where chromosomes line up at the equator(middle) of the cell is called:
A. Anaphase; B. Telophase; C. Interphase; D. Metaphase
22. Chromosome #6 from Mom and Chromosome #6 from Dad form achromosome pair called:
A. Sister Chromatids; B. Centromeres; C. Homologous Chromosomes; D.Spindle Apparatus

scarlethare433

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?

BSC 1010C Lecture Notes - Lecture 11: Synaptonemal Complex, Meiosis, Fertilisation

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