Bio 212 Final Iowa State University
Howell/Sakaguchi Questions Fully
Solved.
Age of universe - Answer 13.7 billion years
Age of earth - Answer 4.6 billion years
Characteristics of earliest life forms - Answer - Unicellular
- Self-replicating
- Acquire and/or convert energy
- Isolate themselves from environment (cell membrane)
First life on Earth - Answer - Prokaryotic cells
- 3.6 billion years old
- blue green bacteria (cyanobacteria)
Cell Theory - Answer - Cells are basic unit of life
- Founded by Schleiden and Schwann (1839)
- All living organisms are composed of cells
- New cells come from pre-existing cells by cell division
Prokaryotic cells - Answer - Bacteria
- Lack a membrane-bound nucleus
- Vary in size, but smaller than Eukaryotic cells
- Plasma membrane (external membrane)
- Single chromosome
- Ribosomes to synthesize proteins
- Stiff cell walls
- Few internal membrane-bound organelles
Eukaryotic cells - Answer - Larger than Prokaryotic cells
- Can be uni or multicellular
- Range in size
, - Contain chromosomes
- "true" nuclei (membrane-bound nucleus)
- Membrane-bound organelles in cytoplasm
- Compartmentalize various functions
Nucleus - Answer - Contain cell's DNA
- Surrounded by a double-membrane nuclear envelope
- Envelope is studded with pores
- RNA leaves through pores into cytoplasm
- Proteins made in cytoplasm get in through pores
Cytoskeleton - Answer - Network of fibers
- Help maintain cell shape
- Not a static structure
- Fibrous proteins move and change to alter cell's shape and support cell movement
Three types of cytoskeleton elements - Answer Microtubules, Intermediate filaments, Actin
filaments
Microtubules - Answer - Large, hollow tubes made of tubulin dimers
- Two proteins: a-tubulin and B-tubulin
- Has polarity
- Dynamic
- Grow at positive ends
- Disassemble at negative ends
Cilia - Answer - Contain microtubules
- Involved in cell movement
- Short
- Multiple
Flagella - Answer - Contain microtubules
- Involved in cell movement
- Long
- Only one or two
Howell/Sakaguchi Questions Fully
Solved.
Age of universe - Answer 13.7 billion years
Age of earth - Answer 4.6 billion years
Characteristics of earliest life forms - Answer - Unicellular
- Self-replicating
- Acquire and/or convert energy
- Isolate themselves from environment (cell membrane)
First life on Earth - Answer - Prokaryotic cells
- 3.6 billion years old
- blue green bacteria (cyanobacteria)
Cell Theory - Answer - Cells are basic unit of life
- Founded by Schleiden and Schwann (1839)
- All living organisms are composed of cells
- New cells come from pre-existing cells by cell division
Prokaryotic cells - Answer - Bacteria
- Lack a membrane-bound nucleus
- Vary in size, but smaller than Eukaryotic cells
- Plasma membrane (external membrane)
- Single chromosome
- Ribosomes to synthesize proteins
- Stiff cell walls
- Few internal membrane-bound organelles
Eukaryotic cells - Answer - Larger than Prokaryotic cells
- Can be uni or multicellular
- Range in size
, - Contain chromosomes
- "true" nuclei (membrane-bound nucleus)
- Membrane-bound organelles in cytoplasm
- Compartmentalize various functions
Nucleus - Answer - Contain cell's DNA
- Surrounded by a double-membrane nuclear envelope
- Envelope is studded with pores
- RNA leaves through pores into cytoplasm
- Proteins made in cytoplasm get in through pores
Cytoskeleton - Answer - Network of fibers
- Help maintain cell shape
- Not a static structure
- Fibrous proteins move and change to alter cell's shape and support cell movement
Three types of cytoskeleton elements - Answer Microtubules, Intermediate filaments, Actin
filaments
Microtubules - Answer - Large, hollow tubes made of tubulin dimers
- Two proteins: a-tubulin and B-tubulin
- Has polarity
- Dynamic
- Grow at positive ends
- Disassemble at negative ends
Cilia - Answer - Contain microtubules
- Involved in cell movement
- Short
- Multiple
Flagella - Answer - Contain microtubules
- Involved in cell movement
- Long
- Only one or two
