Transcript The Cellular Structure of Eukaryotic Cells

You need your microbiology
textbook!
The Cellular Structure of
Eukaryotic Cells
Chapter 5
You need your microbiology
textbook!
Objectives
• Identify the structure of a typical cell
• Define the function of each part of the
eukaryotic animal cell
• Describe the processes that transport
materials in and out of a cell
Cells
• Basic structural unit of living things
• Eukaryotes
– Cells that have true nucleus held by a nuclear
membrane. Has chromosomes and divides by
mitosis.
• Prokaryotes
– Unicellular organism lacking a true nucleus
and nuclear membrane. Its genetic material
consists of a single loop of DNA and no
chromosomes
Cells
• Cytologists specialize in the pathology of
the cell, whose changes in internal
structures give important clues as to the
cause or source of disease
Cells
• Organelles – specialized structures
found with the cytoplasm of cells, each
with a specific function
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Cell Structure
• Nucleus
– Control center for all cell activity. Contains
the chromosomes and DNA.
• Cell Membrane
– A thin layer of plasma-like material that
surrounds the cytoplasm and the organelles.
It is located between the cell wall and the
protoplasm of the cell and allows molecules to
pass in and out of the cell
Cell Membrane
• Cytoplasm
Cell Structure
– Gel-like protoplasm of a cell that surrounds
the nucleus. It is bound by the cell membrane
and holds the organelles in place
• Nucleolus (and Ribosomes)
– A rounded body in the nucleus of most cells
that is the site of ribosomal RNA synthesis
Cell Structure
• Endoplasmic Reticulum
– Network of folded membranes in the
cytoplasm of a cell that transport
materials throughout the cell
• Mitochondria
– Rod-shaped organelle of cells that is
responsible for cellular respiration and
energy production
Open book to
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Cell Structure
• The Golgi Apparatus
– Packages and wraps proteins for export out of
the cell
• Lysosomes
– Aids in the digestion of proteins by secreting
digestive enzymes
Cell Structure
• Pinocytic Vesicles
– Pockets or folds in the cell membrane that
allow large molecules such as proteins and
lipids to be taken into the cell
Movement across the cell
membranes
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•
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•
A passive process –
Diffusion
requires no energy to
Osmosis
function
Filtration
Active transport
An active process
Phagocytosis
that requires an
energy source
Pinocytosis
Diffusion
• Process of spreading out or movement of
molecules through a substance. The
larger the molecules the slower the
movement.
Osmosis
• Passage of a solvent’s molecules through
a selective permeable membrane from a
solution of lesser solute concentration to a
solution of greater solute concentration
Filtration
• Process of a fluid passing through a filter
Active transport
• When cells must move materials in an
opposite direction - against a
concentration gradient. It requires Energy
• Phagocytosis
– "cell eating" - extensions off cytoplasm
surround a particle and package it within a
food vacuole and then the cell engulfs it.
Active transport
• Pinocytosis
– the process of taking up liquid from the
surrounding environment. Tiny pockets form
along the membrane, fill with liquid, and pinch
off