All About The Cell
by Judy Hildebrand
What is a Cell?
A cell is the smallest structural and functional unit of an organism. All living things are composed of cells, they are the building blocks of life.
The Types of Cells
- All living things are composed of two types of cells.
- A prokaryote cell is a cell which does not have nucleus, like bacteria.
- A eukaryote cell is a cell which does have a nucleus.
- Both types of cells have cytoplasms, plasma membranes, chromosomes, and ribosomes.
The Organelles of a Cell
- Nucleus- Contains the genetic information, directs protein synthesis and cell reproduction
- Nucleolus- Assembles Ribosomes, Site of genes for rRNA synthesis
- Plasma Membrane- Regulates what passes into and out of cell
- Rough Endoplasmic Reticulum (ER)- transports and storage
- Smooth Endoplasmic Reticulum (ER) - Creates lipids and fats
- Golgi Apparatus- Packages proteins for export from the cell; forms secretory vesicles
- Lysosomes- Digest worn-out organelles and cell debris
- Mitochondria- Sites of oxidative metabolism; provides ATP for cellular energy
- Chromosomes- Contain hereditary information
- Ribosomes- Site of protein synthesis
- Flagella and Cilia- Motility or moves fluid over surfaces
- Cytoskeleton- Structural support, cell movement
- Centrioles- For cellular division and reproduction
Reproduction In Cells
- Mitosis is the Reproduction of somatic cells.
- There are 7 different stages of Mitosis, Interphase, Prophase, Pro-metaphase, Metaphase, Anaphase, Telophase, and Cytokinesis.
- Mitosis produces two daughter cells.
- Meiosis is the reproduction of sex cells.
- It only occurs in eukaryote cells.
- During the formation of gametes, the number of chromosomes are reduced by half; they return to the full amount after being fused during fertilization.
- Meiosis produces four daughter cells.