Plant Bio 2

Question 1

What is the c ell wall made of

Answer 1

Cellulose

Question 2

How much dry weight of a plant does the cell wall take up

Answer 2

15-30% is the cell wall

Question 3

What is a primary cell wall

What is a secondary cell wall

Answer 3

A extracellular wall made outside the plasma membrane of a plant cell, all cells have

Made after the primary, only some cells have

Question 4

What cells have secondary cell walls

Answer 4

Rigid cells like xylem

Lignin (give strength to secondary cell wall)

Question 5

What is the middle lamella

Answer 5

It’s between cells wall and glued cells together

Ex. Pectin (a polysaccharide)

Question 6

What is the order of cell wall layers

Answer 6

Middle lamella
Primary
Secondary
Plasma membrane

Question 7

What is hydrostatic pressure

Answer 7

Pressure in plant cells due to water and turgor pressure

Plant cells have high hydrostatic pressure

Question 8

What does the primary cell wall help with in terms of hydrostatic pressure

Answer 8

Is stops the wall from bursting

Question 9

The inside of a cell has ____ solute concentration

Answer 9

High

Solutes: ions, sugar

Question 10

How does osmosis cause high turgor pressure

Answer 10

Water goes in cell since high solute pressure

Then cause turgor pressure in the cell

Question 11

How does turgor pressure help

Answer 11

It’s important in keeping the leaf shape

If water level decreases, the plant wilts

Question 12

What is the cell wall made of

Answer 12

Polysaccharide and protiens

1. Cellulose microfibrils
2. Hemicellulose
3. Pectins
4. Protiens

Question 13

What are Cellulose microfibrils

Answer 13

1000s of Polymers of glucosyl subunits (beta 1,4 linkages of glucose) bundled together

Give strength and structure

Question 14

What is Hemicellulose

Give example

Answer 14

Through hydrogens bonds, it cross links cellulose microfibrils together

It’s a linear polymer of glucose and another sugar

For example. Xyloglucan. A hemicellulose made of glucose and xylose (sugar)

Question 15

What are pectins

Answer 15

They determine the porosity of the cell wall

If more pectins, less porous wall

They also bind protiens

Question 16

What are protien roles in the cell wall

Answer 16

Wall stability and loosening

Question 17

What is the expansin protien

Answer 17

It breaks the hydrogen bonds between cellulose and hemicellulose

To loosen the cell wall

Question 18

How are cellulose microfibrils made

Answer 18

Made by cellulose synthase in the plasma membrane

So cellulose synthase in The form of a 6 membered rosette takes glucose from the cytoplasm and turns it into cellulose microfibrils

The microtubules guide the direction of the cellulose synthase movement

Question 19

How are hemicellulose and pectin made

Answer 19

They’re made in the golgi stacks

Question 20

How are protiens of the cell wall made

Answer 20

Made in the rough ER, move through the golgi, and are deposited into vesicles at the trans golgi network

Then the vesicles fuse with the plasma membrane and are deposited in the cell wall

Question 21

How do cellulose microfibrils help in growth of a cell that’s elongating

Answer 21

Ex. In root cells

The microfibrils are In the shape of hoops and so are the microtubules

This slinky shape lets it grow vertically but not laterally so over time the cell would grow upward

Question 22

What things cause cell elongation

Answer 22

Turgor pressure

Cell wall loosening

Orientation of the cellulose microfibrils (curve shape)

Question 23

In what manner does plant elongate their cells

Answer 23

In a circular manner where it finds something to grab onto and elongate