Cell Structure
Chapter 5
Typical Animal Cell
Cell Membrane
Please Label this Diagram
• What separates the cell from the outside
environment
• “Fluid Mosaic” model
• Functions
– Transportation of materials in and out of cell
– Cell recognition
– Cell communication
– Homeostasis
Fluid Mosaic Model
• Cell membrane has both solid and liquid
properties
• Membrane made of lipid and protein
• Phospholipid bilayer – fluid part
– Hydrophobic tail
– Hydrophilic head
• Proteins, carbohydrates, cholesterol, etc
embedded in bilayer – mosaic part
• Membrane is selectively permeable
Cell Wall
• Surrounds cell membrane in plant, algae, and
some bacterial cells
• More protection and support
• Is very porous
– Allows water, oxygen, carbon dioxide, and other
substances to pass through
• Made of cellulose
Nucleus
• Information center of the cell
– Controls metabolism, growth, differentiation,
structure and reproduction of the cell
• Contains DNA (in chromosomes)
• Controls actions of
the
cell including
cell
reproduction
Parts of The Nucleus
• Nuclear Envelope
– 2 membranes that surround the nucleus
• Nuclear Pores
– Openings in the nuclear envelope that allow
molecules to move in and out of the nucleus
• Nucleolus
– Small region made up of RNA and proteins
– Where ribosomes are made
• Chromosomes
– DNA in the nucleus
– Contains genetic information
Organelles
• Small bodies with specific structures and
functions within the cell
Cytoplasm
• Liquid substance between the nucleus and the
cell membrane
• Contains organelles of the cell
“Mighty” Mitochondria – energy
makers
• Largest organelle (after nucleus)
• Double membrane
• Change energy stored in food into compounds that can
be used by the cell
• Cristae – folds of inner membrane to increase SA for
cellular respiration
• Matrix - inner part, similar to cytoplasm of cell
• Contain some of their own DNA and ribosomes
• Can self replicate
• Other functions
– Control water/ion concentration
• Cellular Respiration
– C6H1206 + 6 O2
ATP + 6 C02 + 6 H20
Chloroplasts – food makers for the
world
• In plant cells only
• Trap energy from sunlight and convert it into
energy that can be used by the cell
• Photosynthesis (reverse cell respiration)
– 6 C02 + 6 H20 + ATP
C6H1206 + 6 O2
Ribosomes
• Structures where proteins are made
• Made of rRNA and protein
• One of the smallest organelles
• Polysomes: free floating
groups of ribosomes
Endoplasmic Reticulum (ER)
• Complex network of sacs
• Begins just outside the nucleus
• Function: transports materials through the inside
of the cell
• 2 types
– Smooth ER: no ribosomes on the walls
• Lipid (hormone and steroid) synthesis
• Detoxifies drugs and chemicals in the cell
– Rough ER: ribosomes on walls
• Protein synthesis
Golgi Body (Apparatus)
• Proteins are sent to Golgi (from RER) for more
modifications
• Proteins then used in other parts of cell or
transported out of cell
• Golgi functions
– Modifier
– Collector
– Packager
– Distributer
Lysosomes – “clean up crew”
•
•
•
•
Contain chemicals and enzymes
Formed by Golgi
Not found in plants
Functions
–
–
–
–
Cellular digestion
Auto-digestion/disposal of cell components
Breakdown of whole cells
Destroy bacteria
• Endocyctosis – cells that “engulf” other material
– Process that allows larger
items to enter the cell
Vacuoles – “storage tanks”
• Saclike structures formed from other
membranes within the cell
• Store/transport water, salts, proteins, carbs
• Plants usually have a single large vacuole
• Vesicles are small vacuoles
Cytoskeleton
• Made of filaments and
fibers
– Microtubules – support for
cell shape, form centrioles
(used in cell division)
– Cilia/flagella – made of
multiple microtubules
• Used for cell movement
– Microfilaments – long fibers
for movement and support
Centrioles
• Near the nucleus
• 2 cylinder shapes
• Are part of cell division
Prokaryotic vs Eukaryotic
Prokaryotes
• Single celled organisms
• Lack nucleus
• Lack membrane bound
organelles
Eukaryotes
• Multi- celled organisms
• Have a nucleus
• Have membrane bound
organelles