4.16-4.22

Question 1

What is the cytoskeleton?

Answer 1

Network of protein fibers throughout the cell.

Question 2

What does the cytoskeleton do?

Answer 2

Organizing structures and activities: structural support, internal movement of cell parts. *In motile cells, they help with the crawling and swimming.

Question 3

What are the three types of fibers in the cytoskeleton, from thickest to thinnest?

Answer 3

microtubules, intermediate filaments, and microfilaments. (25, 10 and 7 nanometers respectively)

Question 4

A nanometer is ______ of a meter

Answer 4

one billionth.

Question 5

What is the shape and material of microtubules?

Answer 5

Straight, hollow tubes made of GLOBULAR proteins called tubulins. Easily dissembled and moved to other parts of the cell.

Question 6

Where do microtubules create in animal cells?

Answer 6

A centrosome, which is made of two centrioles. Surrounds the nucleus? (Plant cells organize their microtubules by other means)

Question 7

What are some of the functions of microtubules?

Answer 7

1. They are the “tracks” for motor organelles to get to one place from another.
2. Guide movement of chromosomes during cell division (centrosomes).
3. Make up cilia and flagella (motor)

Question 8

Where are intermediate filaments found?

Answer 8

In most animal cells.

Question 9

What are intermediate filaments made of?

Answer 9

Cable-like and coiled fibrous proteins

Question 10

What are the function of intermediate filaments?

Answer 10

1. Secure organelles (ex.
   nucleus) in place. They are not as easily dissembled as microtubules.

Question 11

Where are microfilaments found?

Answer 11

Just inside the plasma membrane.

Question 12

What are microfilaments made of/what are they like?

Answer 12

Made of globular proteins called actin which create a twisted double chain.

Question 13

What are the function(s) of microfilaments?

Answer 13

1. Supports cell shape in the plasma membrane (esp. imp for animal cells which lack cell walls)
2. Actin interaction with the motor protein myosin causing contracting of muscle cells. Help amoeboid (crawling) movements of Amoeba and white blood cells.

Question 14

What component of the cytoskeleton is most important in 1. holding the nucleus in place 2. guiding transport vesicles from the Golgi to the plasma membrane 3. contracting muscle cells?

Answer 14

1. intermediate filaments 2. microtubules 3. microfilaments.

Question 15

How were biologists able to see the cytoskeleton for the first time in 1974?

Answer 15

Immunofluorescence microscopy. Antibody proteins that attack to actin and glow when they bond.

Question 16

What was the technique that immunofluorescence microscopy created?

Answer 16

Molecular cytochemistry. Allowed them to watch cells change in real time?

Question 17

Difference between molecular cytochemistry and immunofluorescence microscopy

Answer 17

In the former, fluorescently labeled antibodies show the locations of specific molecules. In the latter, the molecules themselves are labeled, and their behavior within a living cell can be tracked.

Question 18

Where are cilia found?

Answer 18

On the outside of protist cells.

Question 19

What is the function of cilia?

Answer 19

1. Short and numerous “legs” that move the protist.
2. Signal receiving antenna (If inmotile). Called the primary cilia, important to embroyonic development.

Question 20

What is a flagella?

Answer 20

A tail like version of cilia for swimming. Many less.

Question 21

Example of cilia?

Answer 21

In the trachea, cilia on cells sweep off mucus.

Question 22

Example of flagella?

Answer 22

sperm.

Question 23

What are cilia and flagella made of?

Answer 23

microtubules wrapped in an extension of the plasma membrane.

Question 24

What is the 9+2 pattern?

Answer 24

In eukaryotic cells, this is how microtubules in flagella and cilia organize themselves. pg. 67

Question 25

How is the 9+2 pattern anchored in a cell?

Answer 25

By a basal body very similar to a centriole.

Question 26

How do cilia and flagella move?

Answer 26

Dynein proteins walk between pairs of microtubules. One side has feet, the other a body. This causes bending...I'm confused

Question 27

What hold the microtubules in their place?

Answer 27

Proteins

Question 28

What makes a cilia nonmotile?

Answer 28

lacking central pair of microtubules.

Question 29

Primary ciliary dyskinesia (PCD), also known as immotile cilia syndrome, is a fairly rare disease in which cilia and flagella are lacking motor proteins. PCD is characterized by recurrent respiratory tract infections and immotile sperm. How would these seemingly unrelated symptoms be explain?

Answer 29

Without motor proteins, microtubules cannot bend. Thus cilia cannot cleanse the trachea, and sperm cannot swim.

Question 30

Where is the extracellular matrix found?

Answer 30

Outside the cell.

Question 31

What is the extracellular matrix made up of?

Answer 31

Mainly collagen, a glycoprotein. Collagen is 40% of protein in body. Collagen weaves itself into thick fibers, and is surrounded in the ECM with other glycoproteins.

Question 32

What is the function of the extracellular matrix.

Answer 32

1. Holds cells together in tissues. 2. Protects and supports plasma membrane

Question 33

Shortening for extracellular matrix?

Answer 33

ECM

Question 34

add all groups,

Answer 34

endomembrane

Question 35

What is the name of the protein responsible for binding the ECM to the cell?

Answer 35

Integrins.

Question 36

What do integrins bind to on the inside of a cell? What do they do?

Answer 36

The cytoskeleton. Transmit signals between the ECm and cytoskeleton.

Question 37

Don't forget

Answer 37

to add notes about cell-cell bonding.

Question 38

How does the integrins connection between the ECM and the cytoskeleton affect the cell?

Answer 38

ECM can regulate cell behavior: direct the movement of embryonic cells, changing activity of genes.

Question 39

What structures provide support for the plasma membrane?

Answer 39

The membrane is attached through membrane proteins (integrins) to microfilaments in the cytoskeleton and collagen fibers of the ECM.

Question 40

What are the three types of cell-cell junctions?

Answer 40

Tight junction, anchoring junction and gap junction.

Question 41

Describe the qualities of a tight junction.

Answer 41

Plasma membranes knit together by tight junctions. prevents leakage of fluid between cells.

Question 42

Describe the qualities of an anchoring junction.

Answer 42

Intermediate filaments act as the anchors between cells here. They make cells into strong sheets. They can stretch, as skin and muscle.

Question 43

Describe the qualities of a gap junction.

Answer 43

AKA communicating junctions. Allows for passage of ions. These ions cause the heart to contract, and this type of junction is commonly found in embryos.

Question 44

A muscle tear injury would probably involve the rupture of which type of cell junction?

Answer 44

Anchoring junction.

Question 45

Where is the cell wall found?

Answer 45

ONLY plant cells.

Question 46

What are the functions of the cell wall?

Answer 46

1. Protects cell 2. Skeleton support 3. Keeps plants upright on land.

Question 47

What is the cell wall made up of?

Answer 47

Cellulose fibers embedded with other polysaccharides and proteins. It is like steel reinforced concrete.

Question 48

How does the cell wall grow and develop?

Answer 48

When the cell is still growing, the wall is more flexible. After it stops growing, it hardens

Question 49

Function of pectins in a cell wall?

Answer 49

Sticky polysaccharides between cells, glue the cells together.

Question 50

What is lignin (cell wall)

Answer 50

A secondary wall of strength in plant cells. Wood uses

Question 51

Even with there thick cell walls, what is the name of the process which connects plant cells?

Answer 51

Plasmodesmata.

Question 52

Define plasmodesmata and their function.

Answer 52

Channels that allow water cytosol and other small molecules through. Essential to nourishment and chemical messaging.

Question 53

Which animal cell junction is analogous to a plasmodesma?

Answer 53

A gap junction.

Question 54

What are the four functional groups within a cell?

Answer 54

The Genetic Control, the Manufacturing, distribution and breakdown, the energy processing, and the structural support and communication between cells.

Question 55

What organelles are within the genetic control group? What do they do?

Answer 55

Nucleus and ribosomes that create the proteins from genetic instructions.

Question 56

What organelles are within the manufacturing, distribution and breakdown group?

Answer 56

The endomembrane system; ER, Golgi Body, lysosomes, vacuoles, and a couple others??

Question 57

What organelles are within the energy processing group?

Answer 57

mitochondria and chloroplasts

Question 58

What organelles are within the structural support, movement and communication between cells group?

Answer 58

Cytoskeleton, ECM.

Question 59

Remember that structure mirrors

Answer 59

function

Question 60

How do mitochondria, smooth ER and the cytoskeleton all contribute to the contraction of a muscle cells?

Answer 60

Mitochondria supply energy in the form of ATP. The smooth ER helps regulate contraction by the uptake and release of calcium ions. Microfilaments function in thee actual contractile apparatus.