Week 9 Flashcards
What are the three roles of a skeleton?
1-Structural support
2-Protection
3-Facilitation of movements
Describe the cytoskeleton:
It’s a network of microfilaments or microtubules that give a cell its shape and allows that shape to change or rearrange the position of organeless and move proteins within the cell
What are the three types of cytoskeletal filaments?
1-Microfilaments
2-Intermediate Filaments
3-Microtubules
Describe microfilaments:
They are assembled from monomers of actin and oftern interact with strands of other proteins
What are the two major roles of microfilaments?
- They help the cell to move (or just part of the cell)
- They help stabilize the shape of the cell
Describe intermediate filaments:
They are made of fibrous proteic subunits organized in a rope-like structure
What are the two structural functions of intermiedate filaments?
- They help anchor the cell structure in a place
- They act to resist tension (so they help mantain the rigiditiy of tissues and organs)
Describe microtubules:
They are long hollow cilinder made up of dimers of tubulin (α-Tubulin and ß-Tubulin)
What are the two structural functions of microtubules?
- They form a rigid internal skeleton of the cell
- They serve as track for motor proteins to carry other proteins within the cell
Describe what is a Extracellular Skeleton:
Many cells are sorrounded or in contact with an extracellular matrix.
What are the two common components of an extracellular matrix?
- Collagen
- Proteoglycan
What are the three types of cells that multicellular organisms have evolve to produce components of the extracellular matrix?
- Fibroblasts
- Chondrocytes
- Osteoblasts and osteclasts
Describe Fibroblasts:
Cells that produce and secrete collagen in the extracellular matrix
Describe Chondrocytes:
They secrete the extracellular matrix of cartilage
Describe osteoblast:
They build and rebuild the bone tissue
Describe osteoclasts:
They degrade the bone tissue
What’s a sessile organism?
An organism that is attached to something and unable to move
What’s a motile organism?
An organism that is able to move
Wha’ts locomotion?
Movements from one place to another that differe from flattening, shape changing or cytokinesis
What are the three types of locomotion that you can find in prokaryotes?
Swimming with flagella, movements through axial filaments and gas vescicles
What are flagella?
Slender filaments that extend at one or both ends of the cell (they are different in eukaryotes and prokaryotes)
Describe the structure of flagella:
A single hollow filaments made of flagellin is attached to a comples motor protein structure that spins the flagellum on its axis (360°)
Describe the movement of Helical Bacteria (Spirocheates):
They move with a corkscrew motion made possible by axial filaments that run along the entire body within the periplasmic space
What are the two roles of axial filaments in spirocheates?
Motility and skeletal structure
Describe the movement of cyanobacteria:
They move by adjusting the amount of gas in their gas vescicles
What are the three different types of locomotion in protists?
- Ameboid movement
- Swimming with flagella
- Swimming with cilia
Describe ameboid movement:
The cell form a pseudopod and then flow into it so that regions of cytoplasm goes from a liquid state to a more stiffer state.
Describe the swimming with flagella in protist:
They moves like a whip, that can either pull or push the cell body in one direction
Describe cilia in protist:
Tiny, hairlike organelles that beat in a coordinated fashion
What are the three types of muscoskeletal systems?
1-Hydrostatic system
2-Exoskeletal system
3-Indoskeletal system
Describe the hydrostatic skeletal system:
A fluid filled body cavity that transfer forces from one part to another when muscles are contracted
What are the properties of coelomates in movement?
- Circural and longitudinal body muscles
- Bristles
- Segments
What’s the function of circural and longitudinal body muscles?
The contraction of circular body muscles cause the segment to elongate and narrow while the contraction of longitudinal body muscles cause the segment to shorten and bulge.
Why are segment important for movements?
Because they allow an animal to control movement more precisely by chaning the shape of a single segment without altering the shape of the rest of the body.
Describe exoskeletal skeletal structures:
The outer surface called cuticle its attached to muscle that contract allowing the joint segments to move relatively to one another
