Biology 1001A Lecture Notes - Sister Chromatids, Spindle Apparatus, Nuclear Membrane

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sangriafly958

19 Nov 2012

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Document Summary

Mitosis: splits eukaryotic cells into two genetically identical cells. Metaphase: each chromosome is attached to both spindle poles. Prophase: dna (chromatin) condenses into chromosomes (spindle poles form) Prometaphase: nuclear envelope dissolves; spindle elongates and attaches to chromosomes: spindle moves chromosomes to midline, halfway between spindle poles. Anaphase: cohesion holding sister chromatids together dissolves, allowing separation: sister chromatids pulled to opposite sides. Telophase/cytokinesis: cell membrane pinches inward, forming two cells: nuclear envelope reforms, sister chromatids decondense, each daughter cell has one of each sister chromatid pair! Stage of cell division (given micrograph of dividing cell) Molecular machine that moves chromosomes during mitosis. Have two spindle poles that move to opposite sides of cell, one for each resulting daughter cells. Made of microtubules that radiate outward from microtubule organizing centres. Cannot pierce through nuclear envelope, so nuclear envelope must be dissolved first. Can only grab chromosome when very end touches the chromosome and only remain attached.

Related Questions

Question 3 (5 points)

Match the terms to the definitions provided.

Question 3 options:

	telophase II
	meiosis II
	telophase I
	anaphase I
	anaphase II

1.	Division, beginning without DNA replication, that resembles and produces four haploid cell.s
2.	Phase of meiosis when chiasmata are broken as spindle fibers shorten and homologous pairs are pulled apart.
3.	Phase of meiosis when sister chromatids are pulled to opposite poles of the cells.
4.	Phase of meiosis in which homologues cluster at the poles of the cells and the nuclear envelope reforms.
5.	Phase of meiosis in which four different haploid cells are present.

Question 4 (7 points)

Match the terms to the definitions provided.

Question 4 options:

	G0
	telophase
	G2
	mitosis
	cytokinesis
	cell cycle
	S

1.	The phase in which the cell synthesizes a replica of its genome
2.	The overall process of genome duplication
3.	The phase in the cell cycle during which mitochondria and other organelles replicate.
4.	The phase in mitosis when chromosomes are clustered at opposite poles and the spindle apparatus disappears
5.	A resting state that cells often enter before resuming cell division.
6.	The phase in the cell cycle when the cytoplasm divides creating two daughter cells.
7.	The phase in the cell cycle in which the spindle apparatus assembles and sister chromatids move apart.

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Question 5 (6 points)

Put the events of a MAP kinase cascade in the correct order.

Question 5 options:

	MAPKKK phosphorylates and activates another kinase
	MAPKK phosphorylates and activates MAPK
	Binding of MAPKKK to Ras
	External signal binds to membrane receptor and activates receptor kinase.
	MAPK phosphorylates an inactive response protein and activates it.
	Phosphorylation of receptor kinase and interaction with RAS

Lab 11 Mitosis

Interphase - Chromosomes are not visible because they areuncoiled

Prophase- The chromosomes coil. The nuclear membranedisintegrates. Spindle fibers (microtubles) form. The drawing showsa cell with 8 chromosomes. Each chromosome has 2 chromatids for atotal of 16 chromatids.

Prometaphase

Metaphase - The chromosomes become aligned. The drawing shows acell with 8 chromosomes. Each chromosome has 2 chromatids for atotal of 16 chromatids.

Anaphase- The chromatids separate; the number of chromosomesdoubles. The drawing shows a cell with 16 chromosomes. Eachchromosome has 1 chromatid for a total of 16chromatids

Telophase- The cell divides into two. The chromosomes uncoil.The nucleus reforms. The spindle apparataus disassembles. Thedrawing shows a cell with 16 chromosomes. Each chromosome has 1chromatid for a total of 16 chromatids.

Ques(ons

1. What stage were most of the onion root p cells in? Does thismake sense?

2. As a cell grows, what happens to its surface area : volumerao? (Think of a balloon being blown up). How is this changing raonrelated to cell division?

3. What is the function of mitosis in a cell that is about todivide?

4. How accurate were your met predictions for each stage of thecell cycle?

5. Discuss one observation that you found interesting whilelooking at the onion root p cells.

6. What would happen if mitosis were uncontrolled?

for escience lab 11 bio 113

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