Bell Work What is a centriole? What is the nucleolus?
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Transcript of Bell Work What is a centriole? What is the nucleolus?
Gap Junctions
• An opening from one cell to another, between two cells that are touching.
• Cytoplasm can move from one cell to another through “tunnels”.
Desmosomes
• Proteins that bond the membrane of one cell to its neighbor communicate.
• Cells are touching, but there is not an opening.
Tight Junction
• Two membranes actually bonded into one. • It makes a very strong barrier between two
cells. • Form solid walls to protect the contents of a
cell.
Cilia and Flagella
• Structural components of the cell• Maintained by microtubules• Considered part of the cytoskeleton
Examples of Cilia
• lining of the trachea (windpipe) - they sweep mucus and dirt out of the lungs
• Cilia in the Fallopian tubes moves the ovum from the ovary to the uterus
Flagellum
• Long, thick tails. • Used for “swimming”• They whip around and sometimes twirl,
pushing the cell along.
Types of Flagellum
• Prokaryotic• Eukaryotic
• Differ in protein composition, structure, and mechanism of propulsion.
Microfilaments
• Long, thin, and stringy proteins (mainly actin). • Work with microtubules to form the structure
that allows a cell to hold its shape, move itself, and move its organelles.
Microfilaments
• Also found in muscle tissue (called myofibrils)• The two proteins myosin and actin work
together to help the muscle cells relax and contract.
Myosin and Actin
• Together, they are called actomyosin. • All of the muscle cells work together to make
a muscle contract.
Where are Microfilaments?
• Attached to proteins in the cell membrane, floating free in the cytoplasm, or connected to other filaments or tubules.
How do they Cause Movement
• Binding proteins allow microfilaments to push and pull on the cell membrane to help the cell move.
The Cytoskeleton
• All of the microfilaments and microtubules combine to form the cytoskeleton of the cell
The Cytoskeleton
• The cytoskeleton provides structure. • The cytoskeleton connects to every organelle
and every part of the cell membrane.