3. Voice of the Genome (1) Flashcards
Cell ultrastructure 3.1 - 3.5
What are eukaryotic organisms?
Multicellular organisms that are complex and include animal and plant cells.
What are prokaryotic organisms?
Single cellular organisms that are more simple.
Example: Bacteria
What organelles do animal cells have?
Nucleus, nucleolus, ribosomes, rough endoplasmic reticulum (rER), smooth endoplasmic reticulum (sER), mitochondria, centrioles, lysosomes, Golgi apparatus.
What does the nucleus contain?
DNA wrapped around histone proteins in a complex called chromatin.
What is the function of the nucleolus?
Where ribosomal RNA genes are transcribed and where the cell’s ribosomes are produced and assembled.
What is the nuclear envelope?
The membrane surrounding the nucleus.
What are 80s ribosomes?
The site of protein synthesis.
What is the function of the rough endoplasmic reticulum (rER)?
Folds proteins that have been made at the ribosomes.
What is the function of the smooth endoplasmic reticulum (sER)?
Synthesizes and processes lipids.
What is the function of mitochondria?
The site of aerobic respiration where ATP is produced.
What are centrioles?
Hollow cylinders made of microtubules involved with the separation of chromosomes during cell division.
What are lysosomes?
Contains digestive enzymes that digest invading cells and break down waste products in the cell.
What is the function of the Golgi apparatus?
Modifies and packages proteins produced in the endoplasmic reticulum. Fluid-filled, membrane-bound sacs.
What is protein trafficking?
- Proteins are produced on the ribosomes. 2. Proteins produced on the ribosomes on the surface of the rER are folded and processed in the rER.
- Proteins are then transported to the Golgi apparatus in vesicles pinched off the rER.
- Proteins are modified (i.e., carbohydrates are added to form glycoproteins) in the Golgi apparatus.
- Golgi apparatus packages the proteins into vesicles (they are pinched off the sacs on the rER) to be transported around the cells.
- Some proteins leave the cell by exocytosis.
What is endocytosis?
Vesicles fuse with the cell’s plasma membrane and substances are absorbed. Size of cell increases as the membrane of vesicle fuses to/ adds to membrane.
What is exocytosis?
Cell membrane pinches off to form a vesicle, transporting proteins. Cell size shrinks.
Does the cytoplasm of a prokaryotic cell contain any membrane-bound organelles?
No.
What is the ultrastructure of prokaryotic cells?
Peptidoglycan cell wall, pili, circular DNA, plasmids, mesosomes, slime capsule, flagellum, 70s ribosomes.
What is the function of the peptidoglycan cell wall?
Supports the cell and prevents it from changing shape.
What are pili?
Helps prokaryotes stick together and is used for the transfer of genetic material between cells.
What is circular DNA?
Long coiled DNA that is not attached to any histone proteins and contains the genetic information of the cell.
What are plasmids?
Small loops of DNA containing the cell’s genetic information, including genes for antibiotic resistance.
What are mesosomes?
Inward folds of the plasma membrane involved in some cellular processes, i.e., respiration.
What is the function of the slime capsule?
Protects the bacteria from attack by immune cells and retains moisture.
What is a flagellum?
A hair-like structure that rotates to make the prokaryotic cell move.
What are 70s ribosomes?
The site of protein synthesis.
