Cellular Structure
Cell Biology /
Genetics
Mr. Foster
Components of Cells
1. Nucleus-
2. Outer Boundary-
3. Cytoplasm/Organelles- cellular contents and
specialized structures that carry out functions
of the cell
Nucleus
• Prokaryote- cell w/o
nucleus
– (DNA in neucleoid)
• Eukaryote- cell with
nucleus
• Functions
– Contains genetic inform.
– Control Center- directs all
cellular activity
Nucleus (cont.)
• Structure / Components– Nuclear envelope- regulate
what enters and leaves nucleus
(Nuclear pores)
– Nucleolus-makes ribosomes
– Genetic Material- DNA
• Chromatin – DNA uncoiled,
threadlike, Not Divisional
• Chromosomes –DNA is
condensed, Divisional
– Nucleoplasm -fluid inside
nucleus
Clicker ?’s 1-5
Outer Boundary
• Cell membrane-lipid bilayer with
embedded proteins forming a selective
boundary
• All cells have a cell membrane
• Cell wall –
Plants and bacteria
Cell Membrane (cont.)
•
Structure- Fluid Mosaic Model
1. Phospholipids
Phosphate- likes
H2O (hydrophilic)
Lipid- does not like
H2O (hydrophobic)
•
Phospholipid bilayer
forms membrane
Cell Membrane (cont.)
• Structure (cont.)
2. Proteins
Integral Proteins - embedded in phospholipid
bilayer
Peripheral protein –
not embedded in bilayer
Clicker ?’s 6-9
Cell Membrane (cont.)
•
Structure (cont.)
3. Carbohydrates - attach to proteins (glycoprotein)
or lipids (glycolipid)
Cell surface carbs
communication –
recognize cell type
Cell Membrane (cont.)
• Structure (cont.)
4. Cytoskeleton –supports the membrane
a. microfilaments -strength, anchor cells
b. microtubules – mvmt.
c. intermediate filaments –not always
present, a lot in skin, strong framework
(Disease where cells collapse: pg 31)
Cytoskeleton
Clicker ?’s 10-13
• Functions
– Support and protect cell
– Communicate with other cells
– Controls mvmt. of materials in and out of cell.
• Selectively Permeable
Cell Transport
• Passive – energy not required to move
material across membrane
– Diffusion – molecules move from high to low
concentration to reach equilibrium
– Osmosis – type of diffusion involving H2O
molecules only
Cell Transport (cont.)
• Active – Energy required to move materials
across membrane
Low to High concentration
– Ion pumps/Channels- Cl-, Na+, K+, Ca+
– Endocytosis / Exocytosis –
membrane forms pockets to
move material
Ion pumps
Clicker ?’s 14-17
Endocytosis / Exocytosis
Cytoplasm / Organelles
• Cytoplasm – space between nucleus and cell
membrane
– Cytosol – semitransparent; jellylike substance that
surrounds organelles
• Organelles – “little organ”
Organelles
• Endoplasmic Reticulum– Transports materials through inside
of cell
– Modifies proteins and quality control
center
• Types of ER
– Rough ER
• Has ribosome attached
• Proteins to be sent outside cell
– Smooth ER
• No ribosomes
• Make lipids, detox cell
Smooth or
Rough?
Organelles (cont.)
• Ribosome– Synthesize proteins
– Free vs. attached
Organelles (cont.)
• Mitochondria
– Provides energy for the cell ATP
• Cellular respiration
– Own DNA
– Endosymbiont Theory
• Free living organism that
entered a relationship w/
Nucleated cells
– Inherited from mother only
– Folds increase surface
area
Clicker ?
18-22
Organelles (cont.)
• Golgi Apparatus (Golgi bodies) modifies,
sorts, and ships proteins
in packages called
vesicles.
What is this?
Organelles (cont.)
• Lysosomes
– Membrane bounded sacs that contain enzymes
– Clean up cell
– Lysosomal Storage disease
(Tay Sachs)- missing the
enzyme that breaks down the
lipid that surrounds the nerve
cell
Buries the nervous system
Organelles (cont.)
• Peroxisomes
– Sac that contain enzymes
that detoxifies harmful
products
– H2O2
H2O
– Alcohol
– Abundant in liver cells
Clicker ?
23-26
Organelles (cont.)
• Centrioles
– Composed of microtubules
– Contained in specialized
region = centrosome
– Function in cell division
• Organize spindle fibers