eukaryotic cell structure 7.3 human cell nucleus nuclear envelope- double membrane that surrounds...
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Eukaryotic Cell Eukaryotic Cell StructureStructure
7.37.3
Human Cell
NucleusNucleus• Nuclear Envelope- double membrane that
surrounds the nucleus
• nuclear pores - regulates what enters andleaves the nucleus
• Chromatin- long strands of DNA that formchromosomes (grainy-looking in a cell)
• Nucleolus- spherical structures inside thenucleus, functions in making ribosomes
NucleusNucleus
Plasma MembranePlasma Membrane
• Found in all cells
• Flexible boundary:– Outer boundary in
animal cells
• Function: - regulates what enters and leaves the cell
Cell BoundariesCell Boundaries
Cell Wall:
-Found in bacteria, some protists, fungi and plants
Functions:-forms a rigid, strong boundary
-when present, it is outside the cell membrane
Cell WallCell Wall
• In plants, the cell wall is composed of cellulose
CytoplasmCytoplasm
• Jelly-like substance found between the plasma membrane and the nucleus
1. Suspends the cell organelles (membrane-bound structures)
2. Area where cell metabolism occurs
Organelles: Assembly, transport and store Organelles: Assembly, transport and store materialsmaterials
1. Ribosomes
-spherical structures where proteins are synthesized
-free-floating groups or attached to ER
2. Endoplasmic reticulum (ER)
-folded system of membranes
a. folds increases the exposed surface area
b. forms sheet-like and tube-like areas
c. functions to make and transport materials
Rough ER (RER)
Smooth ER (SER)
Rough ER (ER that has ribosomes attached)-’sheet-like’ area-proteins made here are secreted out of the cell
or incorporated into cell membranes
Smooth ER (no attached ribosomes)-’tube-like’ area-site of lipid and carbohydrate production-toxins and drugs broken down here
Endoplasmic Reticulum (ER)
3. Golgi Apparatus
-series of stacked, flattened sacs
-functions to process and packageproteins, lipids and carbohydrates
-some are stored in the cell and othersare secreted out of the cell
4. Vacuole (membrane sac)-functions to store food and waste*contractile vacuole – pumps out excess
cell water from unicellular animals
5. Plastids – (plants only)-store pigments and starchs
6. Lysosome- sac of digestive enzymes -break down old organelles and foreign bodies
Energy TransformersEnergy Transformers
1. Mitochondria-“power house of the cell” -site of Cellular Respiration
-Foods are converted into useable energy using oxygen
-double membranes-Inner membrane is folded to increase surface area-has own DNA and ribosomes
2. Chloroplast (plants only)-contains Chlorophyll-traps light energy then transforms CO2
and H2O into sugar.
-double membranes
-inner membrane forms stacks called grana
-fluid-filled space between the grana is called the stroma
-has own DNA and ribosomes
CytoskeletonCytoskeleton- - support structure support structure withinwithin the cytoplasm or “ skeleton of the the cytoplasm or “ skeleton of the cell”cell”
1. Microtubules
-thin hollow cylinders-give rigid support-can transport material (on the outside)
2. Microfilaments
–thin, solid helical fibers
-Contractile (contract to change cell shape)
3. Cilia - short, hair-like projections for:
-movement in free-swimming cells
-capture food in free-swimming animal cells
-moving materials across the surface of fixed cells (mucus in the lungs)
- composed of series of microtubules
4. Flagella- long, whip-like structure-for locomotion-composed of microtubules arranged
in the same pattern as in cilia
Centriole
-cell component that producesmicrotubules that are usedinside animal cells
-centrioles are not visible inplant cells