Summary Cell Biology – Chapter 1
Unity and diversity of cells
Three essential features of a cell () is not what all cells have.
Membrane
(DNA)
(RNA
(Divide)
Cytosol
Cytoskeleton
(Mitochondria)
Cells are the fundamental units of life.
Cell biology is the study of cells and their structure, function and behavior
Cells vary enormously in size, shape and chemical requirements (e.g some require
oxygen to live, for other is gas deadly).
These differences often reflect differences in cell function
Although cells vary from outside, they are fundamentally similar inside.
In all organism’s genetic information is carried in DNA molecules.
Cell genome; entire sequence of nucleotides in DNA, it provides a genetic program
that instructs the cell how to behave.
Central dogma; flow of information form DNA RNA protein (these are
biomolecules)
All present-day cells evolved from the same ancestral cell
Copying is not always perfect, they are corrupted by mutations that change the DNA.
variation in cells comes from this.
Cells under the microscope
2 types of microscopes
1. Light microscopes; using beams of visible light through the sample to
illuminate (verlichten) specimens (exemplaren) moving cells
2. Electron microscopes; using beams of electrons through the sample NOT
moving cells/ wet cells
o Highest magnification (vergroting) and best resolution
3. Fluorescence microscopes; use sophisticated (geavanceerde) methods of
illumination and electronic image processing to see fluorescently labeled cell
components. moving and fixed (vaste) cells
Advantage of EM over LM;
Superior resolution
Visualize the whole cell, not only a fluorescent probe
Huge magnification range
Disadvantage of EM compared over LM
Requires fixation of cells (operates under vacuum, the small pieces otherwise
go through the environment)
Only small pieces of tissue can be imaged
Unity and diversity of cells
Three essential features of a cell () is not what all cells have.
Membrane
(DNA)
(RNA
(Divide)
Cytosol
Cytoskeleton
(Mitochondria)
Cells are the fundamental units of life.
Cell biology is the study of cells and their structure, function and behavior
Cells vary enormously in size, shape and chemical requirements (e.g some require
oxygen to live, for other is gas deadly).
These differences often reflect differences in cell function
Although cells vary from outside, they are fundamentally similar inside.
In all organism’s genetic information is carried in DNA molecules.
Cell genome; entire sequence of nucleotides in DNA, it provides a genetic program
that instructs the cell how to behave.
Central dogma; flow of information form DNA RNA protein (these are
biomolecules)
All present-day cells evolved from the same ancestral cell
Copying is not always perfect, they are corrupted by mutations that change the DNA.
variation in cells comes from this.
Cells under the microscope
2 types of microscopes
1. Light microscopes; using beams of visible light through the sample to
illuminate (verlichten) specimens (exemplaren) moving cells
2. Electron microscopes; using beams of electrons through the sample NOT
moving cells/ wet cells
o Highest magnification (vergroting) and best resolution
3. Fluorescence microscopes; use sophisticated (geavanceerde) methods of
illumination and electronic image processing to see fluorescently labeled cell
components. moving and fixed (vaste) cells
Advantage of EM over LM;
Superior resolution
Visualize the whole cell, not only a fluorescent probe
Huge magnification range
Disadvantage of EM compared over LM
Requires fixation of cells (operates under vacuum, the small pieces otherwise
go through the environment)
Only small pieces of tissue can be imaged
