Chapter 4: overview of cell structure
2 types of cells :
Prokaryotes
Eukaryotes
No nucleus
It has a simple cell structure
There are 2 categories of prokaryotic cells
Archaea
Bacteria
Very abundant in environment and our bodies
majority are not harmful to humans
Small cells, 1 μm –10μm in diameter
Some species cause disease
Less common
small cells, 1μm –10μm in diameter
found in extreme environments
Typical bacteria cell
Plasma membrane: encloses the cytoplasm
cell wall: provides support and protection
site where the DNA is found
Glycocalyx: Outer gelatinous covering
Flagella: Helps the bacteria to move / swim
pili: Allows the bacteria to attach to surfaces and to each other.
Cytoplasm: site of metabolism
Ribosomes: synthesizes polypeptides
Each organelle has a unique structure and function
Compartmentalized functions
Shape, size, and organization of cells vary considerably
2 types:
Plant cells
Animal cells
9-Chromatin: a complex of protein and DNA
10-Plasma membrane: It controls the movement of substances in and out of the cell
8-Ribosome: synthesizes polypeptides
11-Peroxisome: site where harmful molecules are broken down
7-Golgi apparatus: site of modification, secretion, and sorting of proteins and lipids
6-Cytosol: site of many metabolic pathways
12-Mitochondrion: Site of ATP synthesis.
5-Smooth ER: Site of detoxification and lipid synthesis.
13-Rough ER: site of protein sorting and secretion.
4-Centrosome: site where microtubules grow and centrosome found.
14-Nuclear pore: It's a passageway for molecules into and out of the nucleus.
3-Nucleus: Area where the genetic material is organized and expressed.
15-Nuclear envelope: It's a double membrane that encloses the nucleus
2-Nucleolus: site for ribosome subunit assembly.
1-Lysosome: Area where macromolecules are degraded.
It has a similar structure to the animal cells, except for these 3 organelles:
Cell wall: provides cell support.
Chloroplast: site of photosynthesis
Central vacuole: it's a site where it provides storage and regulation of cell volume.