Chapter 6: The Cell

Question 1

Cell motility

Answer 1

mobility/movement of the cell as a whole AND movements of its parts

Question 2

Motor Proteins

Answer 2

Interact with cytoskeleton inside the cell to enable motility

Question 3

Microtubules

Answer 3

made of centrosomes > centrioles
shape and support the EUKARYOTIC cell
provide “track” on which motor proteins to travel
direct secretory vesicles from golgi to plasma membrane
may be assembled and reassembled in different locations

exp: flagella (long/tail like) and cilia (short/hair like)

Question 4

Primary cilliim

Answer 4

Non-motile microtubule used as atenna rather than for movement

Usually occurs once per animal cell

Question 5

Basal body

Answer 5

anchors the flagella and cilia microtubule to the cell

Question 6

Dynein “walking” motor proteins

Answer 6

Move flagella and cilia by bending the microtubules’ “doublet” pairs

Question 7

Microfilament aka actin filaments

Answer 7

rods; shape and support the EUKARYOTIC cell (membrane)
made of actin globular protein
may be assembled and reassembled in different locations

Bear pulling forces/tension
Found in contractile apparatus of muscle cells

Question 8

Cortical Microfilaments

Answer 8

Matrix of microfilaments that occur inside the plasma membrane to keep the cell’s shape

enables the membrane to have a semi-solid/gel consistency (rather than a more fluid consistency like what the cytoplasm deeper inside the cell has)

Question 9

Myosin “walking” motor proteins

Answer 9

protein

moves/contracts muscles cells by sliding past actin MICROFILAMENTS’

Question 10

Pseudopodia (crawling amoeba)

Answer 10

Amoeba version of “walking” motor proteins

Question 11

Cytoplasmic Streaming (plants)

Answer 11

…p/118

Question 12

Intermediate Filaments

Answer 12

Similar to microtubals and microfilaments in EUKARYOTIC cells, except their positions are more fixed

Reinforce cell shape, fix the position of organelles, persist after cells die

keratin

Question 13

Cell wall

Answer 13

Keeps shape/holds the organism up against gravity, controls water intake

(mostly in plants but also in some prokaryotes, fungi and some protists

Question 14

Primary cell wall

Answer 14

thin, flexible, “baby” version of a cell wall

Microtubules guide cellulose to the baby wall to make it grow stronger/more rigid

Question 15

Middle Lamella

Answer 15

Middle space between cell walls that is full of pectin (polysaccharide) that ‘glues’ the walls together

Question 16

Secondary cell wall

Answer 16

Structure sometimes used to strengthen the primary cell wall (rather than infusing the primary with hardening substances)

frequently have channels between them (plasmodesmata)

Question 17

Extracellular Matrix

Answer 17

System that strengthens ANIMAL cells similar to how cell walls work in plants

Composed of glycoproteins (carbs covalently bound to proteins) like collagen

Question 18

Proteoglycans

Answer 18

Network (of core proteins with carbs covalently attached) where collagen is integrated

Question 19

Fibronectins and Integrins

Answer 19

p 120

Question 20

4 types of cell junctions

Answer 20

Tight Junctions (when ANIMAL plasma membranes are pressed tightly together, creating a seal like how skin cells are essentially water tight)

Desmosomes (when ANIMAL cells are anchored together in strong sheets like how muscle fibers move together

Gap Junctions (when ANIMAL cells have channels/pores between them for passing molecules and communicating, similar to plant plasmodesmata)

Plasmodesmata (channels between PLANT cell walls that enable them to exchange cytoplasm/experience an environmental continuum between adjacent cells)