ch 17

Question 1

a microscopic network of protein filaments and tubules in the cytoplasm of cells, gives shape and structure

Answer 1

cytoskeleton

Question 2

hollow tubes like a macaroni noodle, made of tubulin proteins

Answer 2

microtubules

Question 3

microtubules function

Answer 3

support and shape for cell, railroad tracks to transport organelles, vesicles and proteins.

Question 4

microtubules are polarized true or false

Answer 4

true

Question 5

where do microtubules grow out from?

Answer 5

a centrosome: microtubule factory, makes and organizes microtubules

Question 6

small tubes inside centrosome guides to organize microtubules

Answer 6

centrioles

Question 7

what is a nucleation site?

Answer 7

starting point where microtubules begin to grow (aka the centrosome)

Question 8

what are the 2 protein subunits that join together to form a tubulin dimer?

Answer 8

alpha (-) and beta (+) - tubulin

Question 9

which end does assembly/disassembly of microtubules occur?

Answer 9

positive end

Question 10

what is the unit added to a growing microtubule?

Answer 10

GTP tubulin (tubulin dimer + GTP)

Question 11

What are Microtubule capping proteins?

Answer 11

bind to the (+) end of microtubules to stop them from growing/shrinking

Question 12

What are the 3 anti-cancer treatment drugs that affect microtubules?

Answer 12

1. Taxol: binds and stabilizes microtubules
2. Colchincine/Colcemid: binds and prevents polymerization/growth
3. Vinblastine/Vincristine: binds and prevents polymerization, induces breakdown of microtubules

Question 13

Determine polarity for axon and dendrites

Answer 13

Axon (+) sends signals, Dendrites (-) receives signals

Question 14

In neurons, towards which end is inward transport and outward?

Answer 14

Inward = towards (-) dendrites
Outward = towards (+) axons

Question 15

Microtubules act like ____ _____ in neurons.

Answer 15

train tracks

Question 16

drive intracellular transport of vesicles, organelles, and large complexes

Answer 16

motor proteins

Question 17

What type of protein is kinesin and dynein? which direction do they move?

Answer 17

both are motor proteins.
Kinesis: moves to (+) end toward axon
Dynein: moves to (-) end to cell body (return)

Question 18

what process drives movement of motor proteins to “walk” along microtubules?

Answer 18

ATP hydrolysis

Question 19

which motor protein causes flagella in eukaryotic cells to bend

Answer 19

dynein

Question 20

What is an adaptor protein?

Answer 20

connect cargo to motor protein

Question 21

Strong ropelike fibers that give mechanical strength to cells

Answer 21

intermediate filaments

Question 22

T/F: intermediate filaments help cell with movement

Answer 22

false, only with mechanical strength, resisting damage

Question 23

Intermediate filaments are made of smaller protein units called ______ that form together to form a long, strong fiber

Answer 23

tetramers (2 dimers in antiparallel fashion) so 4 monomers total

Question 24

what does having tensile strength mean and which filament has it?

Answer 24

high resistance to stretching, think tense = not enough stretching. intermeidate filaments

Question 25

proteins that stabilize structure and make the intermediate filaments stronger by holding their shape

Answer 25

cross-linking accessory proteins

Question 26

give an analogy using a piece of rope to compare intermediate filaments, tetramers, and cross-linking accessory proteins

Answer 26

Intermediate filaments = strong rope made of threads, tetramers = individual threads linked together to give rope strength, cross-linking proteins = extra knots that hold threads together

Question 27

an intermediate filament found in epithelial (outer skin) cells or internal organs

Answer 27

keratin

Question 28

an intermediate filament found in connective tissue, muscle cells, and glial cells

Answer 28

vimentin/vimentin-related

Question 29

intermediate filament found in nerve cells

Answer 29

neurofilaments

Question 30

what are nuclear lamins, where are they found in the cell?

Answer 30

in the nucleus, an intermediate filament inside the nucleus's membrane, provides structure and function to the nucleus

Question 31

What is Epidermolysis bullosa and what type of filament does it affect?

Answer 31

intermediate filament, causes fragile skin that blisters and tears easily. affects protein used to make collagen, which is essential to connective tissue

Question 32

what disorder causes rapid aging in children due to a defect in nuclear lamin

Answer 32

progeria

Question 33

What is another word for actin filaments?

Answer 33

microfilaments

Question 34

a thin, flexible protein fibers made of actin

Answer 34

actin filaments

Question 35

allow cell movement, shape, and function Muscle contraction, cell division, cytokinesis

Answer 35

actin filaments

Question 36

T/F: actin filaments allow animal cells to adopt a variety of shapes and functions

Answer 36

True

Question 37

2 stranded helix of identical globular ______ molecules, parallel fashion so each filament has same orientation and polarity

Answer 37

actin

Question 38

what is the unit added to BOTH ends of actin strands?

Answer 38

globular actin protein WITH ATP, ATP hydrolysis causes disassembly

Question 39

builds, breaks, organizes, controls, moves actin strands

Answer 39

actin-binding proteins

Question 40

Functions of actin filaments are controlled by the different types of ______.

Answer 40

acting binding proteins

Question 41

give the function of all 7 actin binding proteins 1. nucleating protein (formin, ARP complex) 2. monomer-sequestering protein 3. bundling protein (filopodia) 4. myosin motor protein 5. side-binding protein (tropomyosin) 6. cross-linking proteins (in cell cortex) 7. severing protein

Answer 41

Nucleating Protein (Formin, ARP complex): starts formation of actin filament Monomer-Sequestering Protein: stores actin in an inactive form, controls when and where actin filaments grow Bundling Protein (Filopodia): ties actin filaments in tight parallel bundles Myosin Motor Protein: uses ATP to move along actin filaments, muscle contraction & cell movement + transport Side-Binding Protein (Tropomyosin): binds to sides of actin filaments, stabilizes and blocks/regulates interactions with other proteins like myosin Cross-Linking Proteins (In cell cortex): forms dense web of actin filaments, flexible mesh gives cell shape and resists mechanical stress Severing Protein: cuts actin filaments into shorter pieces

Question 42

What is substratum?

Answer 42

the surface a cell is crawling on

Question 43

what are focal contacts

Answer 43

the attachment points where a cell sticks to substratum

Question 44

what is lamellipodium

Answer 44

the flat sheet at front of the cell made of fast growing actin filaments, pushes membrane forward as actin polymerizes

Question 45

what is the simplest myosin

Answer 45

Myosin I

Question 46

which motor protein specifically sticks together to form a thick filament that will pull on actin filaments to help cell contract

Answer 46

myosin II

Question 47

what is a sarcomere?

Answer 47

basic unit of contraction in muscle cells

Question 48

what is the boundary of a sarcomere, where the actin filaments are anchored and marks the ends of a sarcomere

Answer 48

Z-disc

Question 49

_________ of intermediate filaments during mitosis causes them to disassemble so the cell can divide and then reassemble after mitosis.

Answer 49

Phosphorylation