Cell Structure and Function
Cell - basic structural and functional unit of life.
Robert Hooke - discovered the tiny compartment in the thin slide of cork.
Matthias Schleiden and Theodore Schwann - Concluded that all living thing are made of cell. (Cell Theory)
Robert Brown - identified a dark-stained structure at the center of every cell that he observed. He referred
to it as nucleus.
Prokaryotic Cells - Lack distinct nuclei and few organelles that are not membrane bound.
Eukaryotic Cell - have distinct nuclei and contain several membrane bound organelles.
Organelles - are small membrane bound structures that perform specific functions that make life possible.
Cell wall (non living component) - provides mechanical support and maintains cell shape in plant cell.
Plasma membrane (flexible and elastic) - it regulates the entry and exit of materials.
- also serve as a boundary between the outside environment and inside of the cell.
Mitochondria (Powerhouse of the cell) - it provides energy for the cell in the form of Adenosine Triphosphate.
They are the center of cellular respiration.
Vacuoles (Storage Tank of the Cell) - A compartment covered by a single membrane called tonoplast.
- Stores water, food, or waste for the cells.
Golgi Apparatus or Golgi Bodies ( Packaging Counters of the Cell) - it sorts, packages and secretes materials.
- also involved in the processing and modification of proteins.
Cytoplasm -(Complex fluid that fills the cell) - allows the distribution of materials throughout the cell due to
cyclosis.
Exoplasm outer cytoplasm (gel like), inner cytoplasm is fluid (sol like)
Cyclosis - fluid part capable of streaming.
Nuclear membrane - double membrane that encloses the cell nucleus.
- It separates the nuclear contents from the contents of the cytoplasm.
Nucleolus - Dense spherical body inside the nucleus. It contains the nucleic acid RNA.
- It is responsible in the synthesis of RNA and production of ribosomes.
Nucleoplasm/ nuclear sap - gel like material that fills the nucleus.
- it function as the matrix of the chromosomes and nucleolus.
Chromosomes - Highly coiled structures that form a network over the nucleoplasm.
- these units carry genes responsible in transmitting hereditary characteristics.
Nucleus (Control Center of the Cell) - it directs and coordinates all cellular activities.
Endoplasmic reticulum (Manufacturers and Shippers of the Cell) - responsible for the translocation of
materials within the cell, and in and out of the nucleus.
- Rough ER contains ribosomes and Smooth ER does not contain ribosomes.
Chloroplast - A double membrane structure that contains chlorophyll pigments.
- It provides green pigment for plants and aid in photosynthesis.
Centrioles (Helper in Cell Division) - Forms the spindle fibers during cell division and functions as the anchor
for the cytoskeletons.
Lysosomes (Suicide bag of the Cell) - Single membrane compartment containing powerful hydrolytic enzymes.
- it is responsible in breaking down cellular waste.
Ribosomes (Protein Factories of the Cell) - Found attached to the endoplasmic reticulum or free-floating in
the cytoplasm.
- They use RNA synthesized by the nucleolus in making specific amino acid.
Cytoskeletons (Framework of the Cell) - are the network of fibers that are scattered throughout the entire
cytoplasm and interconnecting some organelles.
Two types of cytoskeleton: Microtubules help to maintain the shape of the cell and aid in the movement.
Microfilaments provides contractility to some cells and aid in changing the shape of some cells.
Microbodies - very tiny membrane bound organelles that are scattered throughout cytoplasm together with
the free ribosomes.
Shapes of Cell
Spherical - Round and oval (human red blood cells)
Squamous - flat or tile-like (Human squamous cells)
Stellate - star-like (nerve cell or neuron)
Spiderlike - with several cytoplasmic extensions (Bone Cells)
Columnar - rectangular set upright (Columnar cells)
Fusiform/Spindle - tapering at both ends (smooth muscle cells)