chapter 2 Flashcards
who discovered cells
Robert Hooke. discovered cell on 1665
states that all living organisms
are composed of cells and cells form a
unifying structural basis of organization.
cell theory - Generally developed by Matthias Schleiden and
Theodor Schwann around 1838
discovered the nucleus
1831 - Robert Brown - was a Scottish Botanist who was responsible for discovery of the nucleus of the cell and he is responsible for discovering the Brownian motion which is the random movement of microscopic particles.
argued there is no
spontaneous generation of cells.
1858 - Rudolf Virchow - egarded as the root of modern pathology, introduced the third dictum in cell theory: Omnis cellula e cellula (“All cells come from cells”).
experimentally disproved
spontaneous generation in 1862.
Louis Pasteur
Increase magnification
as light passes through a series of
transparent lenses made of glass or calcium fluoride crystals
Light Microscopes- s a biology laboratory instrument or tool, that uses visible light to detect and magnify very small objects and enlarge them
Light passes through thinly sliced material
In general can distinguish organelles 2 micrometers
or larger in diameter
Can magnify up to 1500x
Compound Microscopes -A microscope with a high resolution and uses two sets of lenses providing a 2-dimensional image of the sample. The term compound refers to the usage of more than one lens in the microscope.
Allow three-dimensional viewing of opaque objects
Can magnify up to 30x
Dissecting Microscopes(Stereomicroscopes) - is used to view three-dimensional objects and larger specimens, with a maximum magnification of 100x. This type of microscope might be used to study external features on an object or to examine structures not easily mounted onto flat slides.
Use a beam of electrons produced when
high-voltage electricity is passed through a wire
Electron Microscopes - is a microscope that uses a beam of accelerated electrons as a source of illumination.
Up to 200,000x magnification, but material must be
sliced extremely thin
Transmission Electron Microscopes - is used to view thin specimens (tissue sections, molecules, etc) through which electrons can pass generating a projection image. The TEM is analogous in many ways to the conventional (compound) light microscope.
Up to 10,000x magnification
Surface detail can be observed on thick objects.
Scanning Electron Microscope - is one of the most widely used instrumental methods for the examination and analysis of micro- and nanoparticle imaging characterization of solid objects. One of the reasons that SEM is preferred for particle size analysis is due to its resolution of 10 nm, that is, 100 Å.
Uses a probe that tunnels electrons upon a sample
Produces a map of sample surface
Even atoms can become discernible
First picture of DNA segment showing helical
structure
Scanning Tunneling Microscope - is a type of microscope used for imaging surfaces at the atomic level. Its development in 1981 earned its inventors, Gerd Binnig and Heinrich Rohrer, then at IBM Zürich, the Nobel Prize in Physics in 1986.
Cells that lack a nucleus.
Prokaryotic - are organisms whose cells lack a nucleus and other organelles. Prokaryotes are divided into two distinct groups: the bacteria and the archaea, which scientists believe have unique evolutionary lineages. Most prokaryotes are small, single-celled organisms that have a relatively simple structure.
Cells contain a nucleus.
Eukaryotic -organisms whose cells contain a nucleus and other membrane-bound organelles. There is a wide range of eukaryotic organisms, including all animals, plants, fungi, and protists, as well as most algae. Eukaryotes may be either single-celled or multicellular.
Rigid boundary of cells
Cell wall - specialized form of extracellular matrix that surrounds every cell of a plant. The cell wall is responsible for many of the characteristics that distinguish plant cells from animal cells.
Membrane-bound bodies found
within eukaryotic cells
Organelles - specialized structures that perform various jobs inside cells. The term literally means “little organs.” In the same way organs, such as the heart, liver, stomach, and kidneys, serve specific functions to keep an organism alive, organelles serve specific functions to keep a cell alive.
All organisms are
composed of
cells
The protoplasm contains
organelles, such as
Nuclei
Mitochondria
Chloroplasts
is used in leaf cells to
convert carbon dioxide and water to carbohydrates
The energy of sunlight
They regulate the passage of molecules into
and out of cells and organelles.
They divide the cell into numerous
compartments, each with its own specialized
function.
They act as surfaces that hold enzymes.
MEMBRANES
Biological membranes
are composed of
proteins and a
phospholipid bilayer.
are at
least partially immersed
in the lipid bilayer.
INTRINSIC PROTEINS
are
located outside the membrane
Extrinsic proteins
can be bound to
intrinsic proteins, converting them into
Oligosaccharides
