Plant cell biology

Question 1

What are the unique features of plants

Answer 1

Vacuole, chloroplast and cell wall

Question 2

Chloroplasts

Answer 2

Double membrane, inner membrane system and have their own genome
Use light and CO2 to produce sugar and oxygen

Question 3

Inside of chloroplase

Answer 3

thylakoid, geranium and stroma

Question 4

Stroma

Answer 4

Carbon fixation enzymes, chloroplast DNA, ribosomes

Question 5

Inner membrane

Answer 5

Chloroplast import and export machinery

Question 6

Thylakoid space

Answer 6

Light capturing system

ATP synthase

Question 7

Photosynthesis

Answer 7

Red light is absorbed by chlorophyll which cleaves water by generating oxygen, 4 protons
Electron is transferred across membrane pumping 1 proton
Electron is further excited in PSI
Electron is transferred onto NADP+ = NADPH

Question 8

Carbon fixation

Answer 8

Calvin cycle to turn CO2 into 2 phosphoglycerate
Export into cytosol - glycolysis to make glucose and fructose and to convert pyretic acid
Maintained in storm - inverted glycolysis, conversion into start thats stored in chloroplast

Question 9

Why are plants green?

Answer 9

absorbs blue and red light

Question 10

Why are plants not black?

Answer 10

Chlorophyll evolved from green algae, absorbing more light creates heat that plants have to deal with, absorbing all light would be what we would engineer

Question 11

What organelles do proplastids produce?

Answer 11

Chloroplast, amyloplast and Chromplasts and these turn into etioplast

Question 12

Chloroplast photo relocation movement

Answer 12

Photoreception: plant blue light photoreceptors perceived light
Signal transduction calcium signaling
Movement - motor dependent movement of chloroplasts

Question 13

Sliding theory of cytoplasmic streaming

Answer 13

A mobile endoplasm moves against a stationary ectoplasm the force is generated by myosin motors that move along actin cables (bundles of F-actin)

Question 14

Plant cell wall

Answer 14

Primary wall is flexible and secondary wall is formed in fully developed cells
Cellulose with alpha and beta glucose, hydrogen bonds between glucose polymers

Question 15

Plant vacuole

Answer 15

Generates outward pressure that is counter balanced by the cell wall
variation in cell wall ridgitiy direct cell expansion
Secondary cell wall

Question 16

What keeps the plant upright?

Answer 16

balance of turgor pressure and opposing cell wall

Question 17

Secondary cell wall

Answer 17

rigid and cellulose fibrils show a high degree of order, microfibrils are aligned costing in the same direction and form layers

Question 18

How is high ordering of microfibrils achieved?

Answer 18

Cellulose synthase enzyme complex forms a rosette in the plant plasma membrane - cesA forms a pore in the membrane where the gluten chain is extruded into the wall
Interact with microtubules which guide the cellulose synthase complex

Question 19

Plasmodesmata

Answer 19

GFP diffuses through the plant tissue
GFP expressed in the phloem diffuses into the root via plasmodesmata
Connect adjacent plant cells, allow free passage of small molecules

Question 20

How are plant cells connected?

Answer 20

cytoplasmic bridges

Question 21

What reveals cell-cell contact?

Answer 21

Plasmolysis

Question 22

Structure of plasmodesmata

Answer 22

large proteins, mRNA and viral genomes

Question 23

Mitosis

Answer 23

Cortical interphase microtubule array concentrates in the middle of the cell
The nuclear envelope breaks down and a spindle is formed
Cytokinesis is accompanied by de novo synthesis of plasma membrane and cell wall
array of microtubules guides and supports the formation of the cell plate
Microtubules guide secretory vesicles to forming the plate
Vesicles of cell plate form cell wall in interior, give rise to primary cell wall
Plasmodestmate are spared in the primary wall
Cell plate expands until it fuses at the cortical division zone

Question 24

Cytokinesis

Answer 24

Microtubules form a plant specific array

Question 25

How do cell plates form?

Answer 25

Fusion of vesicles, microtubules deliver secretory vesicle that fuse to give rise to the cell plate
Starts in the middle of the cell and expands until the plate is formed
ER crosses the cell plate

Question 26

Where are plasmodesmata formed?

Answer 26

during cytokinesis