Chaper 1

Question 1

Cell Theory

Answer 1

1) All organism are composed of one or more cells.
2) The cell is the basic unit of life.
3) new cells arise from pre-existing cells.

Question 2

Unity and diversity of cells

Answer 2

• Cells vary enormously in apperance and function.
• Living cells all have similar basic chemistry (sulfur, nitrogen, DNA).
• All present day cells have apparently evolved from rhe same ancestral cell.
• Genes provide the instructions for cell form, function, and complex behavior.

Question 3

Universal Features of Cells

Answer 3

• All cells store their hereditary information in the same linear chemical code.
• All cells replicate their hereditary information by templated polymerization (high fidelity, reliable)
• All cells transcribe portions of their hereditary information into the same intermediate form (RNA)
• All cells use proteins as catalysts.
• All cells translate RNA inro proteins in the same way (they use the same code)
• All living cells require a source f free energy (Gibbs)
• All cells function as biochemical factories dealing with the same basic molecular building blocks.
• All cell are enclosed in plasma membrane (differentiates the cell)

Question 4

Sources of Free Energy

Answer 4

• Organotrophic: organisms that feed on other organisms or their byproducts
• Phototrophic: organisms that harvest energy from sunlight.
• Lithotrophic: organisms that capture energy from systems rich in inorganic chemicals.

Question 5

The Prokaryotic Cell

Answer 5

• Prokaryotes are the most diverse and numerous cells on earth.
• The world of prokaryotes is divided into two domains: Archaea and Bacteria

Question 6

The Eukaryotic Cell

Answer 6

• The nuclus is the information store of the cell
• Mitochondria generate usable energy from food to power the cell.
• Chloroplasts capture energy from sunlight.
• Internal membranes create intracellular compartments with different functions.
• The cytosol is a concentrated aqueous gel of large and small molecules.
• The cytoskeleton is responsible for directed cell movements.
• the cytosol is far from static
• The eukaryotes cells may have originared as predators.

Question 7

Origin of Eukaryotic Cell?

Answer 7

• Lack of cell walls allows for shape changes, cytoskeleton needed for support and movement.
• Symbiosis developed between predator and prey

Question 8

Eukaryotic are often an Order of Magnitude larger than prokaryotes

Answer 8

• However, organims ‘complexity’ is not always related genome size.
• Up to 98.5% of the extra DNA is non-coding but may still serve a regulatory function
• How the genome is expresses from each cell will depend on environmenal signals