BIOL 1010U Lecture Notes - Lecture 15: Sarcoma, Platelet-Derived Growth Factor, Cytokinesis

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salmoncrab283

8 Nov 2017

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Bio 1010u: lecture 15: cell division and cell cycle (part 2) Includes two rounds of nuclear division: meiosis i and meiosis ii. Each daughter cells contains half of the number of chromosomes as the parent. Each daughter cell is genetically unique (different from mitosis) Synapsis: homologous chromosomes pair with each other side by side, gene for gene (unique to meiosis: result: a four stranded structure called a bivalent. Chiasmata within bivalents are visible crossovers between non-sister chromatids. Non-sister chromosomes are chromatids from the paternal and the maternal chromosomes. Crossing over is important because there is no nucleotides lost or gained, no cell is the same, enzymes activate and cut the dna and reattached, chiasmata represent the swapping of the dna: genetic variation. Maternal and paternal homologues are randomly distributed: allows for increases in genetic variation. Reductional division: from a diploid cell, to two haploid cells. There is no dna synthesis between meiosis i and meiosis ii.

Related Questions

Determine whether the following applies to mitosis, meiosis, orboth; also identify the specific stage of cell division thatapplies (e.g. mitosis prophase, meiosis anaphase II, etc)

1) chromosomes pairs line up across the center of the cell

2) sister chromatids seperate

3) spindle fibers separate homologous chromosomes

4) 4 haploid daughter cells are produced

5) a cell 1st undergoes DNA replication

6) chromosomes line up single file across the middle of thecell

7) sister chromatids separate from each other

8) 2 haploid daughter cells form

9) the nuclear membrane re forms

10) spindle fibers attach to pairs of homologous chromosomes

11) the nuclear membrane begins to dissolve

12) centrosomes duplicate

13) synapsis and crossing over occurs

14) 2 diploid daughter cells form

turquoiseporpoise808

-Complete the following sentences: metaphase of mitosis, prophase II of meiosis, crossing over, anaphase I of meiosis, variable, random fertilization, identical, random orientation, metaphase I of meiosis, prophase I of meiosis, metaphase II of meiosis, reduction division

Two processes that occur during meiosis produce genetically ____________ cells.

In a process called ____________ , paired homologous chromosomes align randomly at the cell equator. This occurs during this stage of cell division: ____________ .

In a process called ____________ , genetic material is exchanged between homologous chromosomes. This occurs during this stage of cell division: ____________ .

-Complete the following paragraph to describe nondisjunction and the resulting effects on chromosome number.

words: euploidy, primary nondisjunction, nomal, nondisjunction, secondary nondisjunction, homologous chromosomes, abnormal, trisomy, monosomy, sister chromatids, aneuploid

1.During meiosis I, ____________ separate and move towards opposite ends of the poles.

2.During meiosis II, ____________ separate and move towards opposite ends of the poles.

3.During meiosis I, if both members of a homologous pair go into the same daughter cell, ____________ is said to occur and no normal gametes are produced.

4.During meiosis II, if the sister chromatids fail to separate and both daughter chromosomes go into the same gamete, ____________ is said to occur. Half the gametes are aneuploid while the other half are euploid.

5.If an egg that contains 24 chromosomes instead of 23 chromosomes is fertilized by a normal sperm, ____________ is said to have occurred.

6.If an egg that contains 22 chromosomes instead of 23 chromosomes is fertilized by a normal sperm, ____________ is said to have occurred.

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?

BIOL 1010U Lecture Notes - Lecture 15: Sarcoma, Platelet-Derived Growth Factor, Cytokinesis

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