CELLS II Flashcards
Discribe the Endomembrane system?
Interconnected system of membrane-
enclosed compartments.
* Tiny, membrane-surrounded vesicles shuttle substances between the
various components.
* In the living cell, the membranes and the materials they contain are in
constant motion.
What Organelles are in the Endomembrane system
Rough Endoplasmic Reticulum (RER)
* Smooth Endoplasmic Reticulum (SER)
* Golgi apparatus
* Lysosomes
What is the function of Rough endoplasmic reticulum (RER)?
Rough endoplasmic reticulum (RER): Ribosomes are attached.
* Newly made proteins enter the RER lumen and are modified, folded, and
transported to other regions
What is the function of smooth endoplasmic reticulum (SER)?
Smooth endoplasmic reticulum (SER): No ribosomes.
* Chemically modifies small molecules such as drugs and pesticides
* Site of glycogen degradation in animal cells
* Synthesis of lipids and steroids
What is the function of the Golgi apparatus? What does it look like?
Golgi apparatus: Flattened sacs (cisternae) and small vesicles.
* Receives proteins from the RER—can further modify them
* addition of carbohydrates (glycosylation)
* Addition of phosphates (phosphorylation)
* Protein modifications may form a signal sequence that determines the final destination
of the protein
* Concentrates, packages, sorts proteins
* In plant cells, polysaccharides for cell walls are synthesized here
What is the function of Lysosomes? What organelle does it primarily work with?
Lysosomes: Contain digestive enzymes that hydrolyze macromolecules into
monomers.
* Primary lysosomes originate from the Golgi apparatus.
* Food molecules enter the cell by phagocytosis—a phagosome is formed.
* Phagosomes fuse with primary lysosomes to form secondary lysosomes. Enzymes
hydrolyze the food molecules.
* Wastes are ejected by exocytosis
What is the function of Mitochondria?
Mitochondria: Energy in fuel molecules such as glucose is transformed to the bonds of energy-rich ATP (cellular respiration).
* Cells that require a lot of energy have many mitochondria.
* They can reproduce and divide independently of the central nucleus.
The Cell: Organelles
Name the different types of Plastids.
Chloroplasts, Chromoplasts, Leucoplasts
What do Chloroplasts do?
Chloroplasts: Site of photosynthesis; have a double membrane.
-inner membrane forms thylakoids which contain chlorophyll and other pigments that harvest light energy.
What is the function of Peroxisomes?
Peroxisomes: Collect and break down toxic byproducts
of metabolism such as H2O2, using specialized enzymes.
Break down long chain fatty acids. (found in both
animal and plant cells)
