BI226 Chapter Notes - Chapter 2: Spindle Apparatus, Y Chromosome, Centriole

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11 Apr 2013

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Eukaryotic chromosomes: genetic material of eukaryotes is often distributed among multiple linear chromosomes, chromosome (definition): in eukaryotic cells, a linear structure composed of a single dna molecule complexed with protein. Each species has a characteristic number of chromosomes in the nucleus of its cells. Eukaryotes that have two copies of each type of chromosome in their nuclei. Eukaryotes that have only one set of chromosomes usually the gametes. Haploid or n (actually 1n but we leave off the 1 since it is understood). Example: human somatic cells have 46 chromosomes, while our gametes have 23. In diploids, chromosomes that contain the same genes and that pair during meiosis are called homologous chromosomes. One homolog is inherited from each parent. In humans, one is the paternal homolog while the other is the maternal homolog: chromosomes that contain different genes and that do not pair during meiosis are called nonhomologous chromosomes.

Related Questions

M2A1 Worksheet: Mitosis and Meiosis

A dog is a diploid organisms and has 39 pairs of chromosomes (2n = 78), where n = 39 chromosomes from each parent. Use this example to answer the following question regarding chromosomal number.

INTERPHASE

How many chromosomes are present in the somatic cell?

What do they look like?

What are they âdoingâ in G1 of this phase?

What is happening in the S phase?

What is happening in the G2 phase?

What follows G2 phase in a somatic cell?

What follows G2 phase in a gamete cell?

MITOSIS

Number of chromosomes in the parent cell.

Number of chromatids in the parent cell.

Number of chromosomes in the daughter cell.

Number of chromatids in the daughter cell.

How many daughter cells are produced?

Are the daughter cells haploid or diploid?

How many cell divisions take place?

In what type of cell does this division occur?

Meiosis 1:

Number of chromosomes in the parent cell.

Number of chromatids in the parent cell.

Number of chromosomes in each Meiosis I daughter cell.

Number of chromatids in each Meiosis I daughter cell.

Are the daughter cells haploid or diploid at the end of Meiosis 1?

Meiosis II:

Number of chromosomes in the âparentâ cell (which is a daughter cell from Meiosis I).

Number of chromatids in the âparentâ cell.

Number of chromosomes in each Meiosis II daughter cell.

Number of chromatids in each Meiosis II daughter cell.

Are the daughter cells haploid or diploid at the end of Meiosis II?

Which phase or phases of Meiosis account for the genetic variability among the daughter cells? Howâ¦ what happens in this phase to create the diversity?

Comparing Mitosis and Meiosisâ¦..

How many daughter cells result from Mitosis? Are they diploid or haploid?

How many daughter cells result from Meiosis? Are they diploid or Haploid?

Cell structures and function: Match each organelle to its function:

Organelle Function

Lysosome 1. Lipid synthesis

Rough ER 2. Houses DNA

Nucleus 3. Energy extraction

Smooth ER 4. Dismantles debris

Golgi apparatus 5. detoxification

Mitochondria 6. Protein synthesis

Peroxisome 7. Processes secretions

What is the function of checkpoint proteins in the cell cycle?

How can all of a personâs cells contain exactly the same genetic material, yet specialize as bone cells, nerve cells, muscle cells and connective tissues?

What are the 3 primary germ layers?

Briefly, in one or two sentences, distinguish between

a bacterial cell and a eukaryotic cell

interphase and mitosis

mitosis and apoptosis

an autosome and a sex chromosome

homologous pair of chromosomes and a sister chromatid

centromere and centriole

chromosome and chromatid

monozygotic and dizygotic twins

allele and gene

1). Explain the significance of the fact that gametes contain half of the chromosome complement of somatic cells. Tell me something about variation, if you have a sibling (if you don't imagine you do) - how is your sibling's genetic make-up similar and/or different from yours? What about your mom and dad?

2). Explain the terms reductional division and equational division. What is reduced or kept equal? To which nuclear divisions do these terms refer?

3). What is the diploid number (2n = ?) of an organism if it has
a) 12 chromosomes at Anaphase of Mitosis?
b) 12 chromosomes at Anaphase I of Meiosis?
c) 12 chromosomes at Anaphase II of Meiosis?

4). Compare/contrast Metaphase I of Meiosis with Metaphase of Mitosis.

5). What are the two mechanisms of variation in Meiosis, and during which stage(s) does each occur?

6). Draw a diagram of a bivalent and label the following parts: centromere, sister chromatids, non-sister chromatids, homologous chromosomes, chiasma.

7). A diploid cell has 1 pair of acrocentric chromosomes (Chromosome 1) and 1 pair of submetacentric chromosomes (Chromosome 2).
Â· Gene X is on Chromosome 1. Gene Y is on the short arm of Chromosome 2 and Gene Z is on the long arm of Chromosome 2.
Â· The maternal chromosomes have the X, y, z alleles, whereas the paternal chromosomes have the x, Y, Z alleles.
Draw these chromosomes, labeling ALL alleles, as they might appear in Metaphase I of Meiosis.

Question 1 (2 points)

In which phase of cell division is marked by the dissolution of the nuclear membrane, the condensation of chromosomes, and the formation of the mitotic spindle?

Question 1 options:

	prophase
	metaphase
	telophase
	anaphase

Question 2 (2 points)

The physical separation of cells during cell division is called:

Question 2 options:

	Cytokinesis
	Telophase
	Interphase
	Chromosome
	Cell plate

Question 3 (2 points)

Meiosis is necessary for sexual reproduction; the gametes formed during this process before fertilization are _______________.

Question 3 options:

	Haploid
	Diploid
	Zygote
	Homologous
	Tetrads

Question 4 (2 points)

Mitosis is the process by which a ___________ cell separates the chromosomes in its nucleus into two identical sets of nuclei.

Question 4 options:

	eukaryotic
	prokaryotic
	bacterial
	all of these are correct

Question 5 (2 points)

Which of the following statements about crossing over is INCORRECT?

Question 5 options:

	It occurs between homologous chromosomes
	It allows for two parents to produce many different types of offspring
	It contributes to genetic diversity in a population
	It occurs during prophase I of mitosis

BI226 Chapter Notes - Chapter 2: Spindle Apparatus, Y Chromosome, Centriole

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