Download of the cell

Cells
Anatomy
and
Physiology
Mrs.
Bradbury
Human Cells – Eukaryotic
• Cytology – the study of cells
• Cells are the basic structural
and functional unit of the body.
– Vary greatly in SIZE and
STRUCTURE!
– About 60% water
– Surrounded by interstitial fluid
– Different cells have different
functions
Nerve Cell
• A cell’s structure often reflects its
function
– Three main regions
• Nucleus, cytoplasm, and plasma
membrane
Muscle Cell
Anatomy of a Cell
• Plasma Membrane
– Surrounds the cell
• acts as a barrier
– Composed of mostly
proteins and
phospholipids
– Facilitates contact with
other cells and controls
the passage of materials
into and out of the cell.
– Selectively Permeable
Anatomy of a Cell Continued…
Continued…
• Cytoplasm
– Substance inside that cell that
contains organelles
– Where most metabolic
reactions and activities take
place
– Filled with clear fluid called
cytosol
organelles
• Organelles
– Specialized portions of the cell
that carryon specific
activities.
• Nucleus
Cell Organelles
– Controls cellular activities
and contains the genetic
information (DNA)
– Contains nucleolus
• Nucleolus
– Produces ribosomes
• Ribosomes
– Sites of protein synthesis
– Located free in the cytosol or
attached to the Endoplasmic
Reticulum (ER).
Cell Organelles
• Endoplasmic Reticulum
– Network of interconnected
membranes
– Provides mechanical support
– Transports material around
the cell
– Two Types:
• Rough ER – protein synthesis
• Smooth ER - lipid synthesis
• Golgi Apparatus (Golgi Body)
– Stack of membranous sacs
– Refines and packages proteins
Cell Organelles
• Mitochondria
– Smooth outer membrane and
highly folded inner membrane
(cristae)
– Carries out cellular respiration
– “Powerhouse” of the cell produces ATP
• Lysosome
– Contains digestive enzymes
– Breakdowns and destroys
foreign particles,
microorganisms, damaged or
worn-out cells, and cell parts.
Cell Organelles
• Cytoskeleton
– Composed of microfilaments
and microtubules
– Involved in contraction,
support, and movement
• Centrioles
– Found near the nucleus in an
area called the centrosome
– Paired cylinders used in cell
reproduction
Cell Organelles
• Cilia
– Numerous hair-like
projections
– Move foreign matter along
cell surfaces
• Flagella
– few and long projections
– Moves the entire cell
Cell Physiology
• A cell is the smallest unit
of matter that carries
out ALL life processes.
– Reproduction,
development, growth,
energy production and
use, digestion, waste
excretion, response to
stimuli, movement, etc…
Membrane Transport
• Cells must constantly move material between
their internal and external environments.
• Passive Transport – Diffusion
– Movement of material from
an area of higher
concentration to an area
of lower concentration.
• Active transport
– Movement of material from
an area of lower concentration
to higher concentration.
– Requires Energy going against the gradient
Types of Passive Transport
• Facilitated Diffusion
– Using carrier proteins
to move material
through the
plasma membrane.
• Osmosis
– The diffusion of water
– Three Types of Solutions
• Hypotonic – more water moves into the cell
• Hypertonic – more water exits the cell
• Isotonic – water enters and exits the cell equally
Blood Cell Reaction to different Osmotic Solutions
Water is draw out of
the cells and into the
bloodstream. May
reduce swelling.
Cause no visible
changes to cells.
Most IV solutions
are isotonic.
Water rushes into
cells, causing cells
to swell. Used to
treat severe
dehydration.
Types of Active Transport
• Solute Pumping
– Using carrier proteins to move material against
the gradient (Uses ATP)
• Exocytosis
– Transport of large
particles out of the cell
• Endocytosis
– Transport of large
particles into the cell
– Pinocytosis
• Liquids taken in – cell engulfs a drop of water
– Phagocytosis
• Solids taken in by engulfing them in vesicles
The Life Cycle of a Cell
• Interphase
– Cell grows and carries on metabolic activities,
DNA synthesis occurs, and manufacturing of parts
for cell division.
• Mitosis – Cell Division
–
–
–
–
Prophase
Metaphase
Anaphase
Telophase/cytokinesis
• Ends with two daughter cells identical to each
other and the parent cell.
• Uncontrolled cell division may lead to Cancer!
The Cell
Cycle
Protein Synthesis
• Proteins (Enzymes) run all the chemical
reactions in your body.
• Proteins are responsible for all your traits.
• DNA serves as the master blueprint for
making proteins.
• Proteins are made
in two Steps:
– Transcription (DNA
(DNA RNA)
– Translation (RNA Protein)