Transcript the cell and cellular envrionment

THE CELL AND
CELLULAR
ENVRIONMENT
Cell
 Basic structural unit of all plants and
animals
 A membrane enclosing a thick fluid
and a nucleus
 Specialized to carry out all the body’s
basic functions
Procaryot
 Single-cell organism
 Bacteria
 Structures
Cell membrane
Cytoplasmic matrix
Nucleoid
Cell wall
Cell Membrane
 Absolute requirement for all living
organisms
 Cells must interact in a selective
fashion with their enviornment
 Cells must acquire nutrients, eliminate
waste and maintain their internal
environment based on external
changes
 Encompasses the cytoplasm
Cytoplasmic matrix
 Lacks organelles
 Subtance that lies between the plasma
membrane and the nuceloid
 Largely water
about 70% of bacterial mass is water
 Often packed with ribosomes
made of protein and RNA
protein synthesis {building of proteins}
The nucleoid
 Where the DNA is located
 DNA is a single circle, double stranded
 Composed of 60% DNA, some RNA
and a small amount of protein
Cell Wall
 One of the most important parts of the
procaryotic cell
 Gives shape
 Protects from osmotic lysis
lysis; breaking down of a cell
osmosis; movement of water
Functions of Procaryotic Structures
 Plasma Membrane
selectively permeable barrier
mechanical boundary
nutrient and waste transport
location of many metabolic processes
detection of cues for chemotaxis
Chemotaxis
 Directed movements according to chemicals
in their enviornment
 Finding of food
Gas vacuole
buoyancy
 Ribosomes
protein synthesis
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Periplasmic space
nutrient processing and uptake
Cell wall
shape
protection from lysis
Capsules and slime layers
resistance to phagocytosis
adherence to surfaces
Phagocytosis
Processing of engulfing or eating such as the
immune system consuming or destroying
pathogens
 Fimbriae and pili
attachement to surfaces
mating
 Flagella
movement
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Endospore
survival under harsh environmental
conditions
The Cell
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Eucaryotic Cell Structure
Multi-cell organisms
Structures, characteristics and functions
 Cytoplasmic Matrix
 Endoplasmic Reticulum
 Golgi Apparatus
 Lysosomes and endocytosis
 Ribosomes
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Mitochondria
Chloroplasts
Nucleus and cell division
External cell coverings
Cilia and flagella
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Eucaryotic cells contain organelles
Organelle
intracellular structures that perform
specific functions
Cytoplasmic matrix
 Featureless, homogenous substance
 One of the most important and
complex parts of the cell
 The environment of the organelles
 Location of many important
biochemical processes
 Several physical changes are due to
matrix functions
Several physical changes are due to
matrix activity
Water
 A eucaryotic cell is 70 to 85% water
by weight
 Two forms
bulk or free water
bound water or water of hydration
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Bulk or free water
 Osmotically active water
Bound water
 Bound to the surface of proteins
 Where water, nutrients and waste
products can be stored
Microfilaments
 Structure
 Movements
 Form the cytoskeleton
Contain structures such as flagella,
cilia and lamellipodia.
Plays important roles in transport
and division.
Lamellipodia
 Propels the cell across a substrate
Endoplasmic Reticulum
 Transport of materials
 Protein and lipid synthesis
Golgi Apparatus
 Packaging and secretions of materials
for use within the cell
 Lysosome formation
Lysosomes
 Intracellular digestion
Cells need to make proteins. Those proteins might be used as
enzymes or as support for other cell functions. When you
need to make proteins, you look for ribosomes. Ribosomes
are the protein builders or the protein synthesizers of the
cell. They are like construction guys who connect one amino
acid at a time and build long chains.
Ribosomes are found in many places around the cell. You
might find them floating in the cytoplasm (cytosol). Those
floating ribosomes make proteins that will be used inside of
the cell. Other ribosomes are found on the endoplasmic
reticulum. Endoplasmic reticulum with attached ribosomes is
called rough. It looks bumpy under a microscope. Those
attached ribosomes make proteins that will be used inside the
cell and proteins made for export out of the cell.
Intracellular digestion
 Breaking down of large molecules into
smaller ones
Mitochondria
 “powerhouse” of the cell
 Energy production
Chloroplasts
 Photosynthesis
Nucleus
 Ribosomal RNA synthesis
 Ribosome construction