Computer Information Processing

Input Output

Unorganized Data Organized Data

Computing

www.gls.gov.uk/

Computer Programming

Cellular Information Processing

Biological

scienceprofonline.googlepages.com

Input

Unorganized Signals

Output

Cell Function

Biological Programming

Role of Cell Function in Biology

The cell is the fundamental unit of living things

Everything that that happens in the organism happens at the level of the cell

Biological molecules dictate cell function

To understand cells (biological information processing) must understand biological molecules

Cell Function

Understand Cell Function in Molecular Terms

Begin with a question: Are your skin cells different from your heart cells? If so, how?

Skin Cells Heart Cells

Central Dogma of Biology

DNA RNA PROTEINInfo Info Carrier Functional Product

What kind of cells are these?

Making Skin into Heart

Alter gene expression of skin cells to make them pluripotent stem cells Pluripotent – capable of becoming different kinds of cells Like embryonic stem cells

Grow under conditions that induce differentiation into heart cells (new gene expression)

Accomplished by two groups in 2007 One in Japan and one in U.S.

Making Stem Cells

Expression of four genes change skin cells into pluripotent embryonic stem cells Oct3/4, Sox2, Klf4, Myc

Holm Zaehres and Hans R. Schöler, Cell, Vol 131, 834-835, 30 November 2007

Once Skin and Now Heart

First Observation of Cells

Occurred 150 yrs before cell theory (1670)

Antonie van Leeuwenhoek (animalcules)

Robert Hooke (cells in cork)

Remarkable Variety of Cells

200 different types in the human body All cells can be categorized into 2 basic plans

Prokaryotic (before kernel, before nucleus) Eukaryotic (true kernel, true nucleus)

Eukaryotic Cell (animal)

Nucleus

Command center for gene expression

• Contains 95% of the cell’s DNA (genes)

• Genes are selected for expression

Site of RNA synthesis (transcription)

Produces mRNA

DNA is in a complex called chromatin

Nucleus Structure

Chromatin

DNA-Protein complex (1:1 mass ratio)Proteins are histones (basic amino acids)Histones help to pack DNA (146 bp +linker)

ER and Golgi 10.11

Cytosol (Cytoplasm)

Everything that is not an organelle

Much of cellular metabolism occurs in the cytosol

Protein synthesis occurs in the cytosol

Cytosol is highly compartmentalized Compartments and trafficking is controlled by

the cytoskeleton