BIOL 133 Chapter Notes - Chapter 3: Intellectual Disability, Placenta, Prenatal Development

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roseseal266

20 Jan 2014

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Meiosis why does it happen: cell division for reproduction, diploid cell (2n) 4 haploid cells(1n) Mitosis: 1(2n) 2(2n) = cloning: each daughter cell is different from others, generates genetic diversity. Meiosis i: prophase i, metaphase i, anaphase i. Telophase i: meiosis i: reduces ploidy level and separates homologous chromosomes, chromosomes w/ same size, shape, and linear arrangement of genes (can have. Crossing over: crossing over produces genetic diversity, chromosomes condense, homologous chromosomes synapse (attach to each other, crossing over can occur. # possible arrangements = 2n n=# of homologous pairs. Independent assortment: metaphase i, non-homologous chromosomes line up independently of each other. Spermatogenesis: spermatogonium (2n): precursor to sperm cells, spermatogonium (mitosis) primary spermatocyte (2n) primary spermatocyte (meiosis i) secondary spermatocyte (1n) secondary spermatocyte (meiosis ii) spermatid. Spermatogenesis: each spermatid then develops flagella and becomes individual spermatozoa, sperm are small and do not house many organelles (nucleus and mitochondria) Contains nucleus and acrosome (digestive enzymes to enter egg)

Related Questions

What is the purpose of meiosis?

To enable an organism to produce gametes

To allow for growth

To allow an organism to replace damaged cells

Question 2

Select one answer.

10 points

Mitosis results in ________ and meiosis results in ________.

gametes, somatic cells

gametes, gametes

somatic cells, somatic cells

somatic cells, gametes

Question 3

Select one answer.

10 points

Which of the following tasks is accomplished through the processof meiosis?

Cell growth

Production of sperm or eggs

Replacement of dysfunctional cells

Question 4

Select one answer.

10 points

What advantage does sexual reproduction have over asexualreproduction?

All other selections are true.

Sexual reproduction provides more genetic variability

Sexual reproduction doubles the number of chromosomes in aspecies

Sexual reproduction is more efficient

Question 5

Select one answer.

10 points

Crossing over occurs between homologous chromosomes during whatstage of cell division? (Read each option carefully.)

Prophase I of meiosis

Prophase of mitosis

Prophase II of meiosis

Interphase

Question 6

Select one answer.

10 points

Corn has 20 chromosomes. When corn undergoes meiosis how manychromosomes are found in the gametes?

Question 7

Select one answer.

10 points

Homologous chromosomes separate and are pulled to opposite sidesof the cell during what stage of cell division? (Read each optioncarefully.)

Metaphase I of meiosis

Anaphase II of meiosis

Anaphase I of meiosis

Anaphase of mitosis

Question 8

Select one answer.

10 points

Mitosis results in ______ cells and meiosis results in _______cells.

diploid, haploid

haploid, diploid

diploid, diploid

haploid, haploid

jadepug655

Determine if the following events occur during Mitosis, Meiosis I, Meiosis II, Mitosis and Meiosis, Mitosis and Meiosis I, or Mitosis and Meiosis II. (Answers may be used once, more than once or not at all. Be as accurate as possible with your answer.)

___ 1. The chromosome number is reduced by half.

___ 2. The amount of DNA in the cell is twice the amount of a normal diploid cell in G1.

___ 3. DNA is replicated during S phase.

___ 4. Homologous chromosomes separate.

___ 5. Sister chromatids separate.

___ 6. Chromosomes condense and align along the metaphase plate.

___ 7. Homologous chromosomes align and undergo crossing over.

___ 8. Has one round of division per round of DNA replication.

___ 9. The number of chromatids is equal to the number of chromosomes of a diploid cell in G1.

___ 10. Tetrads align on the metaphase plate.

a. Mitosis and Meiosis I only

b. Both Mitosis and Meiosis

c. Meiosis II only

d. Mitosis and Meiosis II only

e. Mitosis only

f. Meiosis I only

coppercattle579

-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 133 Chapter Notes - Chapter 3: Intellectual Disability, Placenta, Prenatal Development

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