Lecture 4 Flashcards
Who were cells discovered by?
Robert Hook in 1665.
Who proposed the cell theory?
Mathias Schleiden and Theodor Schwann.
What is the Cell Theory?
- All organisms are composed of cells
- Cells are the smallest living thing
- Cells arise only from pre-existing cells.
Why is the size of cells limited?
Because they rely on diffusion of substances in and out of cells.
What does high surface to volume ratio promote efficiency of in a cell?
- Acquisition of nutrients
- Disposal of wastes
What is resolution?
The minimum distance two points can be apart and still be distinguished as two seperate points.
How far apart must two objects be for the naked eye to tell them apart?
100 micrometers.
What are 2 types of microscopes?
- Light microscopes
- Electron microscopes
What are 4 structural similarities of cells?
- Nucleoid or nucleus where DNA is located
- Cytoplasm
- Ribosomes
- Plasma membrane
What are structural components of prokaryotic cells?
- Plasma membrane
- No nucleus
- Cytoplasm (fluid within membrane)
- No true organelles
What are structural components of Eukaryotic cells?
- Plasma membrane
- Nucleus
- Cytoplasm
- Organelles
What is cytoplasm?
fluid within membrane in a cell.
What is the nucleus of a cell?
A membrane bound information center.
What are organelles?
membrane bound structures with specialized functions.
Are human cells prokaryotic or Eukaryotic?
Eukaryotic.
Which kind of cell is simpler?
Prokaryotic.
What are flagella?
Structures which rotary motion is used to propel the cell.
What is the nucleus?
The control center of the cell.
What do ribosomes do?
Make proteins.
What is the endoplasmic reticulum (ER)?
The manufacturing center.
What are 2 types of ERs?
- Rough Endoplasmic Reticulum (RER)
- bound ribosomes - Smooth Endoplasmic Reticulum (SER)
- unbound ribosomes
What is the golgi apparatus?
The packing and shipping center.
What are lysosomes?
Recycling and trash centers.
What are peroxisomes?
The reaction center.
What are vacuoles?
Storage and reaction center.
What are 3 types of vacuoles?
- Central vacuole (in plant cells)
- Storage vacuoles (in plants)
- Contractile vacuole (in some fungi and protists)
What is the mitochondria?
The power plant of the cell.
What are chloroplasts?
Organelles present in cells of plants and some other eukaryotes.
What is cytoskeleton?
Structural support and transport.
What are 3 types of fibers?
- Microfilaments (actin filaments)
- Microtubules
- Intermediate filaments
What are centrosomes?
Microtubule-organizing center.
What are 3 types of cell connections?
- Adhesive junctions
- Septate (or tight) junctions
- Communicating junctions
What are adhesive junctions?
They attach the cytoskeletons of neighboring cells
What are septate (tight) junctions?
They connect the plasma membrane of adjacent cells in a sheet (water proof, so nothing leaks).
What are communicating junctions?
Chemical or electrical passes directly from one cell to another.
What are plasmodesmata?
Specialized openings plant cells have adjoining cytoplasm of adjacent cells.