Intro to Cell Biology Flashcards
Light Microscope
- Up to 1000X bigger
- Resolve as low as 0.2μm
- Specimen must be prepared to allow light to pass through it
Fluorescent Microscope
- Fluorescence microscopy
makes use of fluorophores –
special dyes - These dyes are ‘excited’ by
one wavelength and ’emit’ at
a higher wave length
TEM
- Same principle as light but uses beam of
electrons rather than light. - Specimen fixed and plastic embedded
- Stained with salts of uranium and lead
SEM
- Specimen coated in thin film of heavy
metals - Electrons scattered or emitted as electrons
bombard surface of specimen - Creates 3D images – detail between 3nm
and 20nm
Function of a microscope
Magnifies a specimen.
* LM = X40 – X1000
* EM = X1000 – x 1,000,000
* Illuminates a specimen.
* Light or Electrons are focussed through (or on to)
a specimen by a series of condenser lenses
Resolution
effective distance two
points/objects must be apart before they are
perceived as being separate objects.
Original Cell Theory
All organisms are composed of one or more cells
(Schleiden & Schwann 1838-39).
* The cell is the basic unit of life in all living things
(Schleiden & Schwann 1838-39).
* All cells are produced by division of pre-existing
cells (Virchow 1858)
Modern Cell Theory
-Cells contain hereditary information (DNA) which is passed onto cells via cell division
-Cells are basically the same in chemical composition and metabolic activities
-All basic chemical and physiological functions are carried out inside cells e.g. digestion
cells
self-replicating structures that are
capable of responding to changes in their
environment
Prokaryotes
simplest forms of cells.
* Bacteria and Archea
do not have
membrane bound organelles or a cytoskeleton. DNA
is restricted to a region called the nucleoid
Eukaryotes
complex cells capable of
forming multicellular organisms.
* Plants, animals and fungi
DNA is contained in a membrane bound nucleus. A
cytoskeleton, and membrane bound organelles
such as mitochondria, occur within the cytoplasm.
Responding to changes in environment
Maintenance of the internal
environment
Sensing the external
environment
Controlling the flow of
molecules into and out of the
cell
Catalyzing chemical reactions
Generating useful energy
Accessing genetic information
Synthesis of biological
molecules
Regulating information flow
Eukaryotic compartmentalisation
Internal membranes result in a
number of different compartments
(organelles).
Helps regulate local conditions e.g.
PH.
Compartmentalisation allows
different activities to be carried out in
different parts of the cell.
Organelles
structures that are
surrounded by at least one distinct
membrane:
Nucleus
- DNA housed in nucleus as
chromatin (Mass of DNA
and proteins) - Genome
- Nuclear envelope - nucleus
has a double membrane
with nuclear pores to allow
substances to pass to/from
the cytoplasm - Within the nucleus, in the
nucleolus (a sub-organelle):
rRNA and proteins are
assembled to form
ribosomes - Ribosomes are the
machinery for protein synthesis
Mitochondria
Double membrane.
Folds of inner membrane
forms cristae.
Energy rich molecules
such as glucose ATP
synthesis
The rough and smooth Endoplasmic
Reticulum
Outer layer of nuclear
envelope continues into
ER
* Maze of membrane
enclosed, interconnected
spaces – ER lumen
* Expand to form cisternae
Relationship between nuclear envelope and ER.
RER (rough): Protein synthesis, Post-
translational modification
- SER (smooth): Phospholipid
synthesis, Calcium storage, Glucose
formation, Toxin removal
Golgi
Cis, medial and trans
- Glycosylation (add carb),
Phosphorylation (add phosphate)
Proteolysis (break down)
- Trans –buds off to form ‘transport
vesicles
Vesicles
Membrane trafficking – movement of cargo-
containing vesicles between organelles
(ERGolgi)
Exocytic: From inside the cell to the outside.
Endocytic: From outside into the cell
peroxisome
Small membrane enclosed
organelle contain at least 50
enzymes
Oxidizes molecules (long chain
fatty acids) and generates
hydrogen peroxide (H2O2) as a
byproduct
Contain an enzyme called catalase
that efficiently degrades hydrogen
peroxide into water and molecular
oxygen
Can also oxidize toxic chemicals
amongst many other functions
Chloroplast
Double membrane.
Stacks of thylakoid membranes
forming structures called
grana.
Contains chlorophyll
Use light energy to create the
carbon polymers for
macromolecules (Autotrophs).
Plant cells then extract stored
energy, by oxidizing these
sugars in their mitochondria
Tissue Types
1)epithelial tissue
2) connective tissue
3) muscle tissue
4) nervous tissue
* Combinations of tissues that work closely
together are called organs e.g. lungs, heart, liver,
brain, intestines
Diseases and Tissue structure and Function
Diseases often diagnosed
when they begin to affect
cells:
Cancer
Heart diseases
Leads to cell/tissue
dysfunction/death
Early detection: biomarkers
Biofilms
‘Aggregate’ of microorganisms
Embedded within a self-produced matrix of extracellular
polymeric substance
Can be adapted to environmental conditions by its
inhabitants
