Cell Organelles Flashcards
What is the structure and function of the nucleus?
- has double membrane with pores allowing things to enter and leave
- stores DNA and coordinates cell activity
What is the structure and function of the nucleolus?
- found within the nucleus. made of proteins and RNA
- produces ribosomes
What is the structure and function of the rough endoplasmic reticulum?
- a series of membrane bound sacs called cisternae with ribosomes on the surface
- protein synthesis and folding of proteins
What is the structure and function of the smooth ER?
- a series of membrane bound sacs, no ribosomes present
- produces and processes lipids
What is the structure and function of the golgi apparatus?
- flat curved fluid-filled sacs surrounded by vesicles
- processes and packages proteins and lipids, produces lysosomes
What is the structure and function of the mitochondria?
- bound by double outer membrane, inner membrane folded to increase SA
- site of respiration and ATP production
What is the structure and function of the centrioles?
- two hollow cylinders at a right angle, contain micro tubules
- involved in cell division
What is the structure and function of the ribosomes?
- composed of 2 sub units, can be membrane bound or in cytoplasm
- site of protein synthesis
What is the structure and function of the lysosomes?
- vesicles filled with digestive enzymes and bound by a membrane
- breakdown cell waste and destroy disease causing organisms which enter the cell
What is the structure and function of the prokaryotic cell wall?
- forms a rigid outer covering over the cell, made up of peptidoglycan
- provides strength, support and protection against damage
What is the structure and function of the capsule?
- thick slimy layer of polysaccharides that covers the cell wall
- prevents cell from drying out, helps adhesion to surfaces
What is the structure and function of the plasmid?
- circular molecules of DNA
- DNA replication, transfers DNA between bacteria
What is the structure and function of the flagellum?
- long thin projection attached to cell wall
- movement, propels cell forward using corkscrew movemtn
What is the structure and function of the pili?
- hair like extensions on the surface of bacterial cells
- help cells adhere to various surfaces like each other
What is the structure and function of the mesosomes?
- infolds of the plasma membrane, associated with an enzyme
- site of respiration in prokaryotes
How is the rough ER involved in packaging proteins?
- the polypeptide chain passes from ribosome to the RER lumen
- polypeptide chain folds to tertiary structure , passes through RER and can be modified
- finally polypeptide is packaged into a vesicles and transported to the Golgi apparatus
How is the Golgi apparatus involved in packaging of proteins?
-Polypeptide travels through Golgi apparatus and may be further modified
- protein is packaged into secretory vesicles which can fuse with cell membrane and protein is secreted from cell
How does a TEM work?
Transmission electron microscope - electron beam instead of light, revealing smaller details; use electromagnetic or electrostatic lenses which focus electrons; produces 2D and greyscale images
How does a SEM work?
Scanning electron microscope - scan beam of electron across specimen; beam bounces off surface + detects electrons, producing 3D images; images only show specimen surface so don’t have to be as thin
Describe differences between SEM and TEM
Images - TEM = 2D, SEM = 3D
Specimen - TEM = thin, SEM = coated with metal
Beam - TEM = goes through sample, SEM = goes across and bounces off
Resolution TEM = Higher, SEM = Lower
How is magnification calculated?
image size / actual size
