Parts of the Cell Flashcards
According to Cell Theory, cell is the
fundamental structural and functional unit
of life.
The activity of an organism depends on
the individual and collective activity of its cells and by subcellular structures.
The number of cells in an organism can vary from
1-1,000,000
Basic characteristics of all cells
1) Plasma membrane
2) Semifluid substance called cytosol
3) Chromosomes (carry genetic information)
4) Ribosomes (make proteins)
Please Stop Creating Ribosomes
Types of Cells
Prokaryotic Cells and Eukaryotic Cells
Prokaryotic Cells
Characteristics
i) No nucleus—DNA in an unbound region called the nucleoid
ii) No membrane-bound organelles
iii) Cytoplasm bound by the plasma membrane
Examples of prokaryotic organisms
i) Bacteria
ii) Archaea
Eukaryotic Cells Characteristics
i) DNA in a nucleus that is bounded by a membranous nuclear envelope
ii) Membrane-bound organelles
iii) Cytoplasm in the region between the plasma membrane and nucleus
iv) Eukaryotic cells are generally much larger than prokaryotic cells
The plasma membrane is made of:
i) Phospholipid bilayer
ii) Transport and receptor proteins
iii) Cholesterol (a steroid)
iv) Glycolipids (lipids with attached carbohydrates)
Plasma membrane function:
) Separates intracellular fluids from extracellular fluids
ii) Control what enters and leaves the cell
iii) Communication
Cell wall structure:
i) Carbohydrate fibers in a carbohydrate or protein matrix.
ii) Not a membrane
Cell wall function:
Protection, Structural support
Cilia and Flagella structure:
i) Extension of the plasma membrane containing a complex of proteins (i.e.
microtubules) that support and move the structure.
ii) Structural differences result in very different movement patterns between flagella
and cilia.
iii) Generally only one or two flagella per cell, whereas there may be many cilia per cell.
Cilia and Flagella function:
Move the cell through fluid (cilia and flagella) or move fluid past the
cell (cilia)
Tight junctions (in animal cells)
Nothing is going through.
Desmosomes junctions (in animal cells)
Little rivets for mechanically strong bonds.
Gap junctions (in animal cells)
Channels stuff can go through
Plasmodesmata (in plant cells)
Channels stuff can go through
Nuclear envelop
Double-layered membrane surrounding the nucleus
Chromosomes/Chromatin
Contains genetic information in the form of DNA
(Deoxyribonucleic acid) that provides the blueprints for proteins
Nucleolus
Nucleolus—Contains structures for assembling rRNA and imported proteins into
ribosomal subunits
