Ultrastructure of Cells
Terms in this set (24)
- Very simple cells with no compartmentalised structures and no membrane bound organelles.
- Generally smaller 0.1-10 um
- No true nucleus, the DNA is in the nucleoid region and is not separated by a membrane.
- Example: Bacteria
Rigid structure made of peptidoglycan to protect the cell from lysis.
Encloses the cytoplasm, is semi-permeable so it determines which substances can enter and leave the cell.
Everything within the plasma membrane. 80% is water with dissolved DNA, RNA, Proteins, Lipids and ions.
Site of protein synthesis, ribosome is made of 2 subunits consisting of RNA and proteins.
'Naked' DNA, it is a single chromosome of circular double stranded DNA. Not surrounded by a membrane.
Protein tubes originating from the plasma membrane.
Short Pilli: Allows bacteria to stick to places.
Long Pilli: Allow bacteria cells to share genetic information, transfer plasmid or a small piece of circular DNA.
Long protein filament attached to the cell surface with a rotary molecule motor, allows bacteria cells to swim in liquid environments.
Prokaryotes are able to replicate relatively quickly through binary fission.
-Bacterial chromosome is replicated, producing 2 identical copies.
-The chromosomes attach to the plasma membrane and move to opposite ends.
-The plasma membrane and cell wall pinch inward, between the two chromosomes and separate the cell into 2 identical cells.
-Can occur in approx. 20 min
-More complex cells, compartmentalised structures, membrane bound organelles.
-Generally bigger 10-100 um
-Has a true nucleus where DNA is stored and separated by a membrane.
-Examples: Plants and Animals.
Plasma (Cell) Membrane for Eukaryotes
Acts as a barrier between cytoplasm and the outside environment. Controls what goes in and out of the cell. Composed of a phospholipid bilayer with embedded proteins.
Cytoplasm for Eukaryotes
Region of the cell that is inside the plasma membrane but outside the nucleus.
Protein fibres that support the structure of the cytoplasm.
Also involved with cell movement.
Control centre of the cell where the DNA is stored. The DNA contains information about the protein production of the cell. The DNA is surrounded by a nuclear membrane and is stored as chromatin/chromosomes.
Region inside the nucleus, site of ribosome production.
Site of protein synthesis. Made of RNA and protein. They are not membrane bound.
Tubular passageways that are involved in the modification and transport of proteins and other chemicals.
If ribosomes are attached, its called Rough ER.
If ribosomes are not attached, its called Smooth ER.
Flattened, membranous sacs that collect, modify and package chemicals (proteins) in the cell.
Sacs in a cell that store food, water, or waste. In plant cells water vacuoles fill to make the plant firm.
Contain enzymes to digest food particles or breakdown waste material.
Double membrane structure which is the site of aerobic respiration.
Produces usable energy for the cell in the form of ATP
Cilia and Flagella
Protein fibres that are involved with cell movement.
Double membrane that is the site of photosynthesis.
Contains the pigment chlorophyll to capture light energy and convert it into organic food
Cell Wall for Eukaryotes
Rigid structure surrounding the plasma membrane, provides strength and protection against osmotic stress.