Download SOLVING REAL WORLD PROBLEMS- - Uplift Summit International

Biology Ch 3- Cell Structure
History:
Cells first observed by – Robert Hooke in 1665
Described as _______________ (Tiny animals)/ Single celled organisms by – Anton
Van Leewenhoek in 1675
Measuring cell structures:
SI system – International system of measurement
Based on powers of 10
*** Refer to the 4 tables included in your Ch2 packet
MICROSCOPES
Light microscope
 light passes through one or more lenses to produce an enlarged image of specimen
 can view living cells
Compound microscope –
Light microscope with __________ lenses (________________, ___________________)
Electron microscope
 Uses a beam of electrons instead of light
 Can’t view living things as it uses a vacuum chamber
200000 X maximum magnification
Transmission Electron microscope


Black and white images only
Electron beam is directed at a very thin slice of a specimen stained with metal
ions
Scanning Electron microscope
 Black and white images only
 Electron beam is focused on a specimen coated with a very thin layer of metal and
it produces 3D images
Scanning Tunneling microscope
 Uses needle like probe to measure differences in voltage caused by electrons
that leak, or tunnel from the surface of an object
Micrographs Types of micrographs



Light Micrographs
Transmission Electron Micrographs
Scanning Electron Micrographs
Properties of a microscope:

Magnification -

Resolution-
Size of objects-
CELL THEORY
Schleiden, Schwann, Virchow



All living things are made of one or more cells
Cells are the basic unit of structure and function in organisms
All cells arise from pre existing cells
Cell Size


Smaller cells function better than larger cells
Can exchange substances more readily due to higher surface area to volume ratio
Common features of cells

Cell membrane

Cytoplasm



Regulates what enters/leaves the cell e.g. gases, water, nutrients

Ribosomes

DNA
Cytoskeleton
PROKARYOTES
Single celled organism with no nucleus or
compartments
EUKARYOTES
Not many specialized functions
Nucleus houses DNA, Organelles carry specific activities in the cell
Cytoplasm outside nucleus, inside cell membrane
Size:
Size:
e.g.
e.g.
Lived 3.5 billion years ago
Lived 2.5 billion years ago
Cells have nucleus
Genetic material - single circular molecule of
DNA
Cell wall surrounds cell membrane-gives
structure/support
Has polysaccharides and short chains of
amino acids
Capsule-helps cling to things like food etc.
Flagella - long threadlike structures that
enable movement
Flagella - for movement
Cilia- propel cell through environment
Cytoskeleton-made of protein fibers/holds cell membrane from collapsing
Cytosol -fluid surrounding cytoplasm's organelles etc.
Vesicles- formed from membranes-moves proteins from one place to another
CYTOSKELETON
 Framework of animal cell
 Protein fibers
 Supports the shape of cell/holds nucleus and organelles in place
Types of cytoskeleton fibers

Actin fibers-long, slender microfilaments

Microtubules-hollow tubes

Intermediate fibers-thick ropes of protein
CELL MEMBRANESelectively permeable due to phospholipids
LIPID BILAYER
Membrane proteins
e.g.
Marker proteins- indicate cell type e.g. liver cell
Receptor proteins-recognizes/binds to substances outside cells
Enzymes-speed up chemical reactions
Transport proteins-move substances across the cell membrane
CELL ORGANELLES(Refer to the table at the end of packet)

Nucleus

Nuclear envelope/nuclear membrane

Nuclear pore

Nucleolus

DNA

Ribosomes

Endoplasmic reticulum(ER)

Rough ER

Smooth ER

Vesicle

Golgi apparatus

Lysosomes

Mitochondria
PLANT CELL
Following are the unique features of a plant cell:

Cell wall

Chloroplasts

Central vacuole