BIOL 1090 Lecture Notes - Lecture 3: Synaptonemal Complex, Synapsis, Meiosis

22 views5 pages

sapphiregrasshopper619

1 Mar 2016

School

Department

Course

Professor

For unlimited access to Class Notes, a Class+ subscription is required.

Document Summary

N number of chromosomes = the haploid state. Pairing of homologous chromosomes is called synapsis and is often facilitated by formation of a synaptonemal complex. o. Crossing over involves breakage of chromatids and the exchange of the broken pieces between homologous chromosomes (non-sister chromatids). Following crossing over, homologous chromosomes start to pull apart, but remain joined at the cross over junctions (called chiasmata) o. The cell division in meiosis i is also called a reduction division. o. Meiosis i produces two haploid daughter cells that are genetically distinct o. Meiosis involves dna replication and two cell divisions. o. Meiosis ii resembles a mitotic division, but the products are haploid. o. Kinetochore position changes between prophase i and ii. o. Egg and sperm cell sizes are very different. o. The fates of haploid cells vary in different organisms. o. A true alternation of generations in plants o o. In flowering plants, the sporophyte is the conspicuous part of the life cycle.

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

1). If the diploid chromosome number of an organism is 2N=12, how many chromosomes will be found in this organism's sperm?

a).	6 replicated chromosomes

b).	12 replicated chromosomes

c).	6 unreplicated chromosomes

d).	12 unreplicated chromosomes

2). When do homologous chromosomes segregate into two different daughter cells?

a).	fertilization

d).	meiosis II

3). When do sister chromatids segregate into two different daughter cells? (Choose ALL correct answers)

[]

mitosis

[]	fertilization

[]

meiosis I

[]	meiosis II

4). When does crossing over (the formation of chiasmata) occur?

a).

meiosis I

b).	meiosis II

c).

mitosis

d).	fertilization

graypig334

-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.

BIOL 1090 Lecture Notes - Lecture 3: Synaptonemal Complex, Synapsis, Meiosis

Document Summary

Get access

Related Documents

BIOL 1090 Lecture Notes - Lecture 3: Cytokinesis, Spermatogenesis, Gametophyte

BIOL 1090 Lecture 2: BIOL 1090 LECTURE 2 NOTES

BIOL 1090 Lecture Notes - Lecture 3: Ovulation, Microtubule, Centromere

Related Questions