Light microscopy
Visible light is passed through a specimen and then through glass lenses
Electron microsopes
scanning electron microscopes and transmission electron microscopes
cell fractionation
cells apart and separates the major organelles from one another
Basic features of all cells
- Plasma membrane
- Semifluid substance
- Chromosomes (carry genes)
- Ribosomes (make proteins)
Plasma membrane
A selective barrier at the surface of cells that regulates the passage of oxygen, nutrients, and wastes to service the volume of every cell.
Endoplasmic Reticulum
Rough: has membrane bound ribosomes important for synthesis of proteins destined for other compartments or for secretion
Smooth: devoid of ribosomes, important for synthetic, metabolic, and storage functions
Golgi apparatus
Modifies and sorts proteins delivered to it from ER
Ribosomes
Location of protein synthesis
( Either free in cytosol or bound to rough ER or nuclear envelope)
Cytoskeleton
Provides structure to the cell and mediates cell movements (microfilaments, intermediate filaments, and microtubules)
Centrosome
- Only in animal cells
- Involved in cell division (mitosis & meiosis).
- Location of the initiation of the growth of microtubules
Flagellum
Only in animal cells
Involved in cell motility
Composed of a cluster of microtubules in an extension of the plasma membrane.
Microvilli
Increase surface area of the cell.
Helps to increase rate of uptake of molecules from extracellular space.
Central vacuole
only in plant cells, storage, hydrolysis of macromolecules
Chloroplasts
only in plant cells, photosynthesis
Plasmodesmata
Cytoplasmic channels between adjoining cells
Lysosome
only in animal cells
enzyme-filled vesicle that digests ingested molecules
importance of pH in cell organelles
allows enzymes to function in an isolated environment. enzymes mostly require low pH
ionic gradients in cell organelles
generation of ATP in mitochondria requires an ionic gradient that is established across the mitochondrial inner membrane
nucleolus
consists of ribosomes and ribosomal RNA (site of synthesis of ribosomes)
Chromatin
Consists of DNA and its associated proteins
- in particular a group of proteins called histones around which the DNA is wound. IN addition, there are many regulatory proteins that function in controlling gene expression.
Smooth ER
Synthesize lipids
Metabolize carbohydrates
Detoxify drugs and poisons
Store calcium ions
Where Do Newly Synthesized Proteins Go?
are released outside the cell.
are inserted into the plasma membrane.
become part of an organelle.
remain in the cytoplasm as soluble proteins.