cellular structure cell biology / genetics mr. foster
TRANSCRIPT
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 Model1. Phospholipids
• Phospholipid bilayer
forms membrane
Lipid- does not like H2O (hydrophobic)
Phosphate- likes H2O (hydrophilic)
• Structure (cont.)2. Proteins
Integral Proteins - embedded in phospholipid bilayer
Peripheral protein –
not embedded in bilayer
Cell Membrane (cont.)
Clicker ?’s 6-9
• 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)
Cell Membrane (cont.)
Cytoskeleton
• Functions– Support and protect cell
– Communicate with other cells
– Controls mvmt. of materials in and out of cell.• Selectively Permeable
Clicker ?’s 10-13
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
Endocytosis / ExocytosisClicker ?’s 14-17
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
• 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
Organelles (cont.)
Organelles (cont.)
• Golgi Apparatus - (Golgi bodies) modifies, sorts, and ships proteins in packages called vesicles.
What is this?
Clicker ? 18-22
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
• Peroxisomes– Sac that contain enzymes
that detoxifies harmful
products
– H2O2 H2O
– Alcohol– Abundant in liver cells
Organelles (cont.)
• Centrioles– Composed of microtubules– Contained in specialized
region = centrosome– Function in cell division
• Organize spindle fibers
Organelles (cont.)Clicker ? 23-26