Notes On Disease

Submitted By Wenwen-Jia
Words: 1086
Pages: 5

ISB 204 SS14 Lecture 9; February 11, 2014

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Creutzfeld-­‐Jacob disease

• A prion disease • Prions are misfolded proteins • Prions are infec8ous: can be transferred from organism to organism, and ‘convert’ normal proteins • Results in ‘plaques’ of proteins and holes in brain 8ssue 3

Last time

Figure 5.16-1

Lower solute concentra
ATP Higher solute concentra
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Figure 5.19
Outside
of cell Recep
Cytoplasm Transduc
Proteins of signal transduc
pathway Epinephrine (adrenaline) from adrenal glands

Response Hydrolysis of glycogen releases glucose for energy

Plasma membrane

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Chapter 8

Cellular Reproduction: Cells from Cells
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Last time

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Chromosome (one long piece of DNA)
Centromere

Centromere
Sister
chromatids

Duplicated chromosome

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S phase
(DNA synthesis; chromosome duplication)

Figure 8.6
Interphase: metabolism and growth (90% of time)
G1

G2

Mitotic
(M) phase: cell division
(10% of time)

Cytokinesis
(division of cytoplasm) Mitosis
(division
of nucleus)

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THE CELL CYCLE AND MITOSIS
Objec8ves:

• Outline the stages of the cell cycle, describing the events that occur (figure 8.6) • Describe the checkpoints of the cell cycle, what is ‘checked’, and what happens if a cell ‘fails’ a checkpoint • Outline the stages of mitosis, describing the events that occur during each stage (Figure 8.7)

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The Cell Cycle

• Highly controlled – Ensures there are no errors mostly
– Ensures condi8ons are right for cell division

• Cell cycle control is via proteins – Cyclins Bind to
– Cylin-­‐dependent kinases – Integrate informa8on from the environment and other cells and send ‘stop’ and ‘go’ signals at checkpoint using signal transduc8on pathways 11

The Cell Cycle Control System
Figure 5.19
Outside
of cell

Cytoplasm

Receptor protein

cdk Response

Proteins of signal transduc
pathway

Binds to a cyclin protein

Plasma membrane

Signal transduction pathway: Chain reaction of passing a signal along via one or more molecules

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S phase
The Cell Cycle
Control (DNA synthesis; chromosome duplication)
System

G1 checkpoint
G1

Are conditions right for cell division? Is the DNA undamaged? Interphase: metabolism and growth (90% of time)

Mitotic
(M) phase: cell division
(10% of time)

G2

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S phase
The Cell Cycle
Control (DNA synthesis; chromosome duplication)
System

Interphase: metabolism and growth (90% of time)

G1

Is the DNA undamaged? Are there enough of the proteins needed for M phase?

Mitotic
(M) phase: cell division
(10% of time)

G2

G2 checkpoint

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S phase
The Cell Cycle
Control (DNA synthesis; chromosome duplication)
System

Interphase: metabolism and growth (90% of time)

G1

Checks that spindle apparatus (moves and sorts chromosomes) is intact Mitotic
(M) phase: cell division
(10% of time)

G2

Metaphase checkpoint

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The Cell Cycle Control System

• Checkpoint proteins

– delay the cell cycle un8l problems are fixed – prevent cell division if the problem cannot be fixed

• This prevents division of cells with DNA damage or the wrong number of chromosomes

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Mitosis and