Week 9

Question 1

What are the three roles of a skeleton?

Answer 1

1-Structural support
2-Protection
3-Facilitation of movements

Question 2

Describe the cytoskeleton:

Answer 2

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

Question 3

What are the three types of cytoskeletal filaments?

Answer 3

1-Microfilaments
2-Intermediate Filaments
3-Microtubules

Question 4

Describe microfilaments:

Answer 4

They are assembled from monomers of actin and oftern interact with strands of other proteins

Question 5

What are the two major roles of microfilaments?

Answer 5

• They help the cell to move (or just part of the cell)

- They help stabilize the shape of the cell

Question 6

Describe intermediate filaments:

Answer 6

They are made of fibrous proteic subunits organized in a rope-like structure

Question 7

What are the two structural functions of intermiedate filaments?

Answer 7

• They help anchor the cell structure in a place

- They act to resist tension (so they help mantain the rigiditiy of tissues and organs)

Question 8

Describe microtubules:

Answer 8

They are long hollow cilinder made up of dimers of tubulin (α-Tubulin and ß-Tubulin)

Question 9

What are the two structural functions of microtubules?

Answer 9

• They form a rigid internal skeleton of the cell

- They serve as track for motor proteins to carry other proteins within the cell

Question 10

Describe what is a Extracellular Skeleton:

Answer 10

Many cells are sorrounded or in contact with an extracellular matrix.

Question 11

What are the two common components of an extracellular matrix?

Answer 11

• Collagen

- Proteoglycan

Question 12

What are the three types of cells that multicellular organisms have evolve to produce components of the extracellular matrix?

Answer 12

• Fibroblasts
• Chondrocytes
• Osteoblasts and osteclasts

Question 13

Describe Fibroblasts:

Answer 13

Cells that produce and secrete collagen in the extracellular matrix

Question 14

Describe Chondrocytes:

Answer 14

They secrete the extracellular matrix of cartilage

Question 15

Describe osteoblast:

Answer 15

They build and rebuild the bone tissue

Question 16

Describe osteoclasts:

Answer 16

They degrade the bone tissue

Question 17

What’s a sessile organism?

Answer 17

An organism that is attached to something and unable to move

Question 18

What’s a motile organism?

Answer 18

An organism that is able to move

Question 19

Wha’ts locomotion?

Answer 19

Movements from one place to another that differe from flattening, shape changing or cytokinesis

Question 20

What are the three types of locomotion that you can find in prokaryotes?

Answer 20

Swimming with flagella, movements through axial filaments and gas vescicles

Question 21

What are flagella?

Answer 21

Slender filaments that extend at one or both ends of the cell (they are different in eukaryotes and prokaryotes)

Question 22

Describe the structure of flagella:

Answer 22

A single hollow filaments made of flagellin is attached to a comples motor protein structure that spins the flagellum on its axis (360°)

Question 23

Describe the movement of Helical Bacteria (Spirocheates):

Answer 23

They move with a corkscrew motion made possible by axial filaments that run along the entire body within the periplasmic space

Question 24

What are the two roles of axial filaments in spirocheates?

Answer 24

Motility and skeletal structure

Question 25

Describe the movement of cyanobacteria:

Answer 25

They move by adjusting the amount of gas in their gas vescicles

Question 26

What are the three different types of locomotion in protists?

Answer 26

• Ameboid movement
• Swimming with flagella
• Swimming with cilia

Question 27

Describe ameboid movement:

Answer 27

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.

Question 28

Describe the swimming with flagella in protist:

Answer 28

They moves like a whip, that can either pull or push the cell body in one direction

Question 29

Describe cilia in protist:

Answer 29

Tiny, hairlike organelles that beat in a coordinated fashion

Question 30

What are the three types of muscoskeletal systems?

Answer 30

1-Hydrostatic system
2-Exoskeletal system
3-Indoskeletal system

Question 31

Describe the hydrostatic skeletal system:

Answer 31

A fluid filled body cavity that transfer forces from one part to another when muscles are contracted

Question 32

What are the properties of coelomates in movement?

Answer 32

• Circural and longitudinal body muscles
• Bristles
• Segments

Question 33

What’s the function of circural and longitudinal body muscles?

Answer 33

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.

Question 34

Why are segment important for movements?

Answer 34

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.

Question 35

Describe exoskeletal skeletal structures:

Answer 35

The outer surface called cuticle its attached to muscle that contract allowing the joint segments to move relatively to one another