Week 5 (Intro)

Question 1

What is the definition of a cell?

Answer 1

A basic membrane bound unit that contains the fundamental molecules of life and which all living things are composed

Question 2

What are some universal features of cell?

Answer 2

• DNA (hereditary information) - RNA (transient info carrier) - proteins (structural, enzymes, transport) - central dogma of molecular biology (DNA->RNA->Protein) - template replication

Question 3

What are some universal requirements of cell?

Answer 3

• genetic information - free energy To live and replicate - plasma membrane: Selective barrier Concentrated desirable materials Exclude undesirable materials

Question 4

Why are model organisms useful? Give some examples

Answer 4

Cells have many similar features so they can be studied and the findings extrapolated to other organisms Used to exploit common features E.g: - prokaryotic unicellular: E.Coli - eukaryotic unicellular: yeast - eukaryotic multicellular: caenorhabditis elegans

Question 5

What are the identifying characteristics of prokaryotes?

Answer 5

• most diverse - small - 0.2-2 micrometers diameter - simple - elements that help them move through the environment e.g. flagellum - unicellular - DNA concentrated in one place in the cytosol (nucleoid) usually near the plasma membrane - cell wall surrounding plasma membrane

Question 6

What are the identifying characteristics of eukaryotes?

Answer 6

• large 10x bigger than prokaryotes - complex - true nucleus and membrane - multiple specialised membrane bound organelles - larger and complex ribosomes - larger genomes

Question 7

What are the theories origins of the eukaryotic cell?

Answer 7

• endosymbiosis, a large cell engulfed a small cell and remained that way due to new found advantage (proof: many eukaryotic organelles resemble that of prokaryotes)
• development of a membrane bound (enclosed) primitive nucleus by envagenation of plasma membrane and enclosing genetic material

Question 8

What features are shared between prokaryotes and eukaryotes?

Answer 8

• genetic material (DNA) - Cytoplasm - plasma membrane - Ribosomes - similar basic metabolism

Question 9

What organelles are present in eukaryotes and absent in prokaryotes?

Answer 9

• true nucleus - cytoskeleton - some organelles: mitochondria Golgi apparatus lysosomes

Question 10

What are the diameter of prokaryotic cells compared to that of eukaryotes?

Answer 10

Prokaryotes: 0.2-2 micrometers eukaryotes: 10-100 micrometers

Question 11

Describe the common ancestry between all living organisms

Answer 11