BIOL10004 Lecture Notes - Lecture 5: Plant Cell, Prometaphase, Metaphase

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jadebutterfly872

28 Jun 2018

School

University of Melbourne

Department

Biology

Course

BIOL10004

Professor

All

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LECTURE 5 - CELL DIVISION AND MITOSIS

CELL DIVISION IN PROKARYOTES

Binary Fission – rapid cell division

oFtsZ protein (filament temperature sensitive) – mutant protein

Homologue (ancestor/relative) of the eukaryotic cytoskeletal protein tubulin

Essential for cytokinesis b/c the FtsZ ring pinches the cell apart

Also involved in division of chloroplast + mitochondria

Starts with singular tube of double-stranded DNA

oReplicates

oAttaches itself to plasma membrane

oCells pinch apart to create 2 daughter cells

FtsZ form cytokinetic ring where cells are about to divide

oConstrict middle of cell

oRecruits other proteins, allow membrane to pinch off

Mutations in FtsZ – Alter bacterial cell shape & division frequency

oi.e. can cause cell to be abnormally long or twisted divisions

CELL CYCLE IN EUKARYOTES – 3 CHECKPOINTS

Interphase: occurs prior to mitosis. All organelles increase in number and DNA is replicated

during this process

oGap 1 phase: cell grows; organelles, enzymes and other molecules increase in number

First point of check before synthesis

G0 = cells that will never divide ever again

oSynthesis phase: DNA replicates by DNA polymerase. Chromosomes are not visible

oGap 2 phase: growth phase when chromosomes have been replicated

If there is an issue, cell must be terminated

Second checkpoint

Mitosis – the process of chromosome condensation, nuclear envelope breakdown, sister

chromatid separation dn formation of two daughter nuclei in eukaryotes

oAlready has replicated DNA

oProphase

Chromosomes fully condensed

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Document Summary

Binary fission rapid cell division: ftsz protein (filament temperature sensitive) mutant protein. Homologue (ancestor/relative) of the eukaryotic cytoskeletal protein tubulin. Essential for cytokinesis b/c the ftsz ring pinches the cell apart. Also involved in division of chloroplast + mitochondria. Starts with singular tube of double-stranded dna: replicates, attaches itself to plasma membrane, cells pinch apart to create 2 daughter cells. Ftsz form cytokinetic ring where cells are about to divide: constrict middle of cell, recruits other proteins, allow membrane to pinch off. Mutations in ftsz alter bacterial cell shape & division frequency: i. e. can cause cell to be abnormally long or twisted divisions. All organelles increase in number and dna is replicated during this process: gap 1 phase: cell grows; organelles, enzymes and other molecules increase in number. G0 = cells that will never divide ever again: synthesis phase: dna replicates by dna polymerase. Chromosomes are not visible: gap 2 phase: growth phase when chromosomes have been replicated.

Related Questions

1)What experiment was performed that allowed for scientists to finally agree that DNA is the genetic material within living organisms?

a.Understand the materials and scientific techniques used to come to this result.

2)What group of experiments led to the discovery of the mechanism used in DNA replication?

a.Understand the materials and scientific techniques used to come to this result.

i.What is a cesium chloride gradient?

ii.Where do 14N and 15N respectively fall along this gradient?

b.The results revealed that DNA replicates using which of the three proposed models?

i. Describe the mechanism of each model.

3)What is the role of the following proteins in DNA replication?

a.Helicase

b.Single strand binding proteins

c.Topoisomerase

d.DNA polymerase III

e.DNA polymerase I

f.Primase

g.Ligase

4)What extra steps are taken to be sure the lagging strand does not shorten each time DNA is replicated?

a.What is the role of telomerase in these âstepsâ?

5)In DNA repair, which enzyme has âproof-readingâ capabilities?

1)Which type of cells within our bodies use mitosis to reproduce?

2)Does mitosis create a cell that is different or the same as the parent cell undergoing division?

3)Describe the DNA found in sister chromatids.

4)Describe the DNA found in homologous chromosomes.

5)What occurs during the following stages of the cell cycle?

a.G₁ Phase

b.S Phase

c.G₂ Phase

d.M Phase

What are the phases of mitosis? What events occur in each phase?

1)Does mitosis separate homologous chromosomes, sister chromatids, or both?

2)What is cytokinesis?

a.Which fibers of the cytoskeleton contract to pinch parent and daughter cells apart from one another in animals?

b.How do microtubules move chromosomes to the two poles of a dividing cell?

3)How are centrioles involved in this process?

a.How do plants form two complete cells during cytokinesis?

4)How do bacterial cells reproduce?

5)The cell cycle is controlled at âcheckpointsâ. What occurs at each of the following checkpoints?

a.G₁ Checkpoint

b.G₂ Checkpoint

c.M Checkpoint

6)How do cyclin and cdk act to control the G2 checkpoint?

7)If presented with the schematic of the M checkpoint, you should be able to explain perturbations to the system as well as if the cell will divide or stall at metaphase.

8)Cancerous cells form when the cell cycle checkpoints do not function correctly and continues to divide even though it is damaged in some way. How does the protein p53 function to keep these cells from dividing?

9)Normal cells follow certain rules of growth that cancerous cells do not follow. What are these rules (provide a short definition for each as well)?

10)What is the difference between a benign tumor and a malignant tumor?

indigohedgehog242

1)What are the inputs of photosynthesis?

2)What are the outputs of photosynthesis?

3)Light-Dependent Reactions

Where does the first stage of photosynthesis, the light-dependent reactions, occur within a chloroplast?

Where does the energy come from that drives these reactions?

What molecule donates an electron to the reaction center of photosystem II?

How is the energy of an electron changed as it moves along the ETC?

How does the electrical charge of the thylakoid membrane affect protons (H+) within the chloroplast?

Where does the electron that is donated to photosystem I come from?

What are the final products of this series of reactions?

What happens to each of the final products from this series of reactions?

4)Light-Independent Reactions (Calvin Cycle)

a.Where does the second stage of photosynthesis, the Calvin Cycle, occur within a chloroplast?

b.What are the direct inputs for these reactions?

c.What are the three steps to the Calvin cycle?

d.What are the final products of this reaction?

e.What role does rubisco play in the Calvin Cycle?

1)What experiment was performed that allowed for scientists to finally agree that DNA is the genetic material within living organisms?

a.Understand the materials and scientific techniques used to come to this result.

2)What group of experiments led to the discovery of the mechanism used in DNA replication?

a.Understand the materials and scientific techniques used to come to this result.

i.What is a cesium chloride gradient?

ii.Where do 14N and 15N respectively fall along this gradient?

b.The results revealed that DNA replicates using which of the three proposed models?

i. Describe the mechanism of each model.

3)What is the role of the following proteins in DNA replication?

a.Helicase

b.Single strand binding proteins

c.Topoisomerase

d.DNA polymerase III

e.DNA polymerase I

f.Primase

g.Ligase

4)What extra steps are taken to be sure the lagging strand does not shorten each time DNA is replicated?

a.What is the role of telomerase in these âstepsâ?

5)In DNA repair, which enzyme has âproof-readingâ capabilities?

1)Which type of cells within our bodies use mitosis to reproduce?

2)Does mitosis create a cell that is different or the same as the parent cell undergoing division?

3)Describe the DNA found in sister chromatids.

4)Describe the DNA found in homologous chromosomes.

5)What occurs during the following stages of the cell cycle?

a.G₁ Phase

b.S Phase

c.G₂ Phase

d.M Phase

What are the phases of mitosis? What events occur in each phase?

1)Does mitosis separate homologous chromosomes, sister chromatids, or both?

2)What is cytokinesis?

a.Which fibers of the cytoskeleton contract to pinch parent and daughter cells apart from one another in animals?

b.How do microtubules move chromosomes to the two poles of a dividing cell?

3)How are centrioles involved in this process?

a.How do plants form two complete cells during cytokinesis?

4)How do bacterial cells reproduce?

5)The cell cycle is controlled at âcheckpointsâ. What occurs at each of the following checkpoints?

a.G₁ Checkpoint

b.G₂ Checkpoint

c.M Checkpoint

6)How do cyclin and cdk act to control the G2 checkpoint?

7)If presented with the schematic of the M checkpoint, you should be able to explain perturbations to the system as well as if the cell will divide or stall at metaphase.

9)Normal cells follow certain rules of growth that cancerous cells do not follow. What are these rules (provide a short definition for each as well)?

10)What is the difference between a benign tumor and a malignant tumor?

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BIOL10004 Lecture Notes - Lecture 5: Plant Cell, Prometaphase, Metaphase

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