Cells Flashcards
Three original tenets of cell theory
- All living things consist of cells
- The cell is the smallest and basic unit of life
- All cells originate from pre-existing cells
Tenets of modern Cell Theory
- All living things consist of cells
- The cell is the smallest and basic unit of life
- All cells originate from pre-existing cells
Modern additions:
- The activity of an organism depends on the total activity of independent cells.
- Energy flow (metabolism and biochemistry) occurs within cells.
- Cells contain DNA, the hereditary information.
- All cells are basically the same in chemical composition in organisms of similar species.
Function of chromatin network
- Made of DNA and proteins
- Contains genes (hereditary information)
- Instructs all the activities of the cell
- Packaged as chromosomes for cell division
All eukaryotic cells have…
- Cell membrane
- Cytoplasm
- Organelles
- Nucleus
Only plant cells have…
- Cell wall (though fungi also have a cell wall)
- Large central vacuole
- Plastids e.g. chloroplasts
Structures making up the cell wall of plants
- Primary cellulose wall
- Secondary lignin wall
- Middle pectin lamella
- Pits
- Plasmodesmata
Primary cellulose wall function
shape
Secondary lignin wall function
strength
Middle pectin lamella function
joins cells together
Pits in cell wall function
ease transport between cells
Plasmodesmata function
joint cell cytoplasms for communication and transport between plant cells
Useful substances made from plant cell walls
- Wood
- Paper
- Cork
- Cotton
Structures of cell membranes
- Phospholipid bi-layer
- Carrier and channel proteins
- Carbohydrates
Function of carrier and channel proteins in a cell membrane
control movement of larger substances into and out of a cell
Function of the carbohydrates on the surface of a cell membrane
cell recognition
Parts of the phospholipid bi-layer
- Hydrophilic head
- Hydrophobic tail
- Hydrophobic tail
- Hydrophilic head