BM1000 Lecture Notes - Lecture 4: Cell Membrane, Cytokinesis, Prokaryote

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coffeebear832

16 Jul 2018

School

James Cook University

Department

Course

BM1000

Professor

Lionel Hebbard

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Document Summary

Before a cell divides, four events must occur: Reproductive signal: which can come from inside or outside the cell. Replication of dna: so eac h daughter cell is provided with the same genetic material. Segregation: distribution of the replicated dna to each of the daughter cells. Cytokinesis: division of the cytoplasm including organelles and enzymes and the plasma membrane. Reproductive signal: eukaryotic cells do not constantly divide, even when the enviro conditions are optimal. Replication of dna: most eukaryotic cells have more than one chromosome, therefo replication and segregation are more complex and only occur in a certain time perio divisions. Segregation: in eukaryotes, newly replicated chromosomes stay close together ("sis chromatids") and segregate by a mechanism called mitosis (nuclear division). Cytokinesis: in animal cells similar to prokaryotic cytokinesis but different in plant ce have a cell wall. Cells resulting from mitosis are identical to the parent cell. This contrasts another mechan division, called meiosis which occurs during sexual reproduction.

Related Questions

Carefully read the following statements about cell division (1) After meiosis, the number of chromosomes in the newly formed cell is the same as that in the parent cell. Whereas, in mitosis, the chromosome number in daughter cell is reduced to half. (2) Cytokinesis is a highly regulated event in which cellular organelles are evenly distributed forming two daughter cells. (3) In Meiosis, DNA replication occurs only once whereas the cells divide twice and it is the mechanism that produces genetic variation in daughter cells. (4) In diplotene, chiasmata are formed between homologous chromosomes followed by crossing over and segregation of sister chromatids. (5)The kinetochore is a DNA protein complex which serves as the attachment point for spindle fibers. Which of the above statement or combination of statements is correct?

Part A:

In prokaryotes and eukaryotes cell reproduction is similar in that it requires some kind of signal to proceed, DNA replication, careful separation of the DNA into two equal portions, and division of the cytoplasm. How is cell reproduction different in prokaryotes and eukaryotes?

Select one:

a. In a eukaryotic organism, the signals for cell division are usually not related to the environment but to the function of the entire organism.

b. Eukaryotic cells constantly divide whenever environmental conditions are adequate and the cells are large enough.

c. The linear chromosomes in prokaryotes are constantly being updated.

d. Prokaryotic cell division requires cytokinesis before mitosis because of their small size.

e. The sexual phase of most prokaryotes (bacteria) is essential to the rapid cell division required for infection.

Part B:

What does the name Cyclin Dependent Kinase stand for?

Select one:

a. A protein important to the cell cycle that is dependent on DNA synthesis.

b. An enzyme that cuts DNA so that chromosomes can segregate.

c. An enzyme that phosphorylates other proteins using ATP only when the protein Cyclin is bound to the enzyme.

d. An enzyme that rolls along microtubules dragging a vesicle.

e. An enzyme that connects chromosomes to the spindle fiber.

Part C:

The Cell Cycle is divided into Mitosis, Cytokinesis, and Interphase. Mitosis can be ordered into the following phases:

Select one:

a. Prophase/Prometaphase/Metaphase/Anaphase/Telophase

b. Anaphase/Prometaphase/Metaphase/Prophase/Telophase

c. Metaphase/Anaphase/Telophase/Prophase/Prometaphase

d. Telophase/Prophase/Prometaphase/Metaphase/Anaphase

e. Anaphase/Telophase/Prophase/Prometaphase/Metaphase

Part D:

The Cell Cycle is divided into Mitosis, Cytokinesis, and Interphase. Interphase can be ordered into the following phases:

Select one:

a. S/G1/G2

b. G2/G1/S

c. G1/S/G2

d. G2/S/G1

e. G1/G2/S

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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

BM1000 Lecture Notes - Lecture 4: Cell Membrane, Cytokinesis, Prokaryote

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