Overview of Cells and Structure Flashcards
Functions of Cells
- Absorb nurtients
- Expel waste
- Sense and respond to environment
- Control internal environment
- Maintain shape
- Replicate
Most cells have the same organelles insided but the __________ differ.
proportions
Plasma Membrane
- Barriers to the external environment
- Lipid bilayer; Phospholipids, sterols, glycolipids
- Intracellular Components
- Water soluble
- Cell Communication
- Import/Export of Molecules
- membrane proteins
- Cell Growth/Motility
Pure phospholipids form spherical LIPOSOMES
Lipid Bilayer - in organelles
- Golgi
- ER
- Vesicles
- Lysosomes
- Peroxisomes
Double Membrane organelles
- Mitochondria
- Nucleus
Evolution of Mitochondria
- Endosymbiotic theory
- Evolved from engulfed bacteria
- Bacteria and an ancestral eucaryotic cell lived in symbiosis with one another
Endoplasmic Reticulum
- (A)Most extensive membrane system in a eucaryotic cellgreen
- (B)EM of a thin section of a mammalian pancreatic cell shows a small part of the ER.
- (C)The black particles studding the particular region of the ER shown here are ribosomes.
The Golgi Apparatus
- Composed of flattened sacs of membrane stacked in layers.
- Proteins and lipids are modified and sorted in the Golgi network (Packing station)
- Cargo is sorted and budded to spedific locations.
Cytoskeleton
- -Network of protein filaments – gives the cell its shape
- -Prominent in large and structurally complex eukaryotes
- -Responsible for for large-scale movement of cells, contraction of muscle cells
- -Wounds, sperm, muscles
- -Controls location of the organelles that conduct specialized function of cell
ropelike fibers with a diameter of around 10 nm; they are made of intermediate filament proteins, which constitute a lare and heterogeneous family.
Intermediate filaments
One type of intermediate filament forms a meshwork called the nuclear lamina just beneath the inner nuclear membrane. Other types extend across the cytoplasm, giving cells mechanical strength. In the epithelial tissue, they span the cytoplasm from one cell-cell junction to another, thereby strenghtening the entire epithelium.
long, hollow cylinders made of the protein tubulin. With an outer diameter of 25 nm, they are much more rigid than actin filaments
Microtubules
They are long and straight and typically have one end attached to a single microtube-organizing center (MTOC) called a centrosome
contain DNA, which codes the information needed to make most cell components
Control center of the cell (Nucleus)
Euchromatin:
Nucleolus:
Euchromatin – transcriptionally active cells
Nucleolus – makes ribosomal subunits
Allow communication between the nucleus and the cytoplasm
Controll import/export of nuclear proteins
Nuclear pores
Fertilization
