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Flashcards in plant cell biology Deck (40)
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1
Q

what are chloroplasts

A

plant specific organelles that use light and carbon dioxide to produce oxygen and sugar

2
Q

chloroplast are surrounded by a

A

double membrane

3
Q

chloroplasts have..

A

their own genme

4
Q

thylakoid

A

membrane compartment that surrounds the lumen

5
Q

granum

A

stack of thylakoid

6
Q

stroma

A

matrix of the chloroplast

7
Q

stroma contains

A
  • carbon fixing enzymes
  • chloroplast DNA
  • ribosomes
8
Q

inner mem. contains

A

chloroplast

0-import and export machinery

9
Q

thylakoid space

A

-light capturing system and ATP synthase

10
Q

how much sun light absorbed

A

1%

11
Q

28%

A

of the energy is chemically bound

12
Q

why are plants green

A

-chlorophyll absorbs blue and red light–> green plants do not use a large part of the visible spectrum

13
Q

photosynthetic electron transfer- light dependent reaction

A
  1. red light is absorbed by chlorophyll which cleaves water thereby generating: 1 O2, 4 protons and 1 electron
  2. e- is transferred across the mem. which pumps 1 proton across the membrane
  3. the electron is further excited in the Photosytem I
  4. Electron is transferred onto NADP+ resulting in NADPH
  5. Proton gradient is utilized to generate ATP
14
Q

how do chloroplasts and mitochondria cooperate

A

chloroplasts use sunlight t produce oxygen and sugar, which the mitochondria use to produce ATP to power the cell. this produces water and CO2 which is then used by the chloroplasts.

15
Q

chloroplasts

A

photosynthesis

16
Q

amyloplasts

A

starch storage

17
Q

chromoplast

A

colouring

18
Q

chloroplasts are

A

motile organelles and this helps them avoid photo damage

19
Q

when there is strong light

A

the chloroplasts go to the outside of the cell

20
Q

when there is weak light the chloroplasts

A

are equally distributed around the cell

21
Q

3 steps of the chloroplast photo relocation

A

1) photoreception: plants blue light photoreceptors perceive the light (phototropins)
2) signal transduction- calcium signalling
3) chloroplast movement: motor dependent movement of chloroplasts (myosin and kineins)

22
Q

which ion is used in signal transduction during photo relocation

A

calcium

23
Q

what occurs independent to chloroplast movement

A

cytoplasmic steaming

24
Q

cytoplasmic streaming depends on

A

energy and requires F-actin

25
Q

what does cytoplasmic streaming support

A

tip growth of pollen tubes

26
Q

cytoplasmic streaming in Nitella spec.

A

distributes nutrients and organelles- fastest directed transport at 50-100 um/s

27
Q

cytoplasmic streaming occurs

A

around the vacuole

28
Q

How doescytoplasmic streaming occur

A

myosin XI walk to organelle along the actin filament

29
Q

a mobile endoplasm moves against

A

a stationary exoplasm

30
Q

which mysosins do plants contain

A

XI, XIII and VIII

31
Q

plasmodesmata

A

plants are connected via cytoplasmic bridges, allowing free passage of small molecules –> proven by GFP diffusing through plants

32
Q

how many plasmodesmata connects cells

A

1000-10,000

33
Q

what molecules do plasmodesmata slow passage of

A

ions, water, sugars, amino acids and even some larger proteins

34
Q

plasmodesmata can be regulated or even closed by..

A

local formation of callose

35
Q

what widen the plasmadesmara

A

movement proteins

36
Q

during cytokinesis , microtubules form

A

a plant specific array

37
Q

cell plate formation starts in the

A

middle of the cell

38
Q

what crosses the cell pasta

A

endoplasmic reticulum

39
Q

when are plasmodesmata formed

A

during cytokinesis

40
Q

mitosis and cell division

A

o Cortical interphase microtubule array concentrate in the middle of the cell
o The nuclear envelope breaks down and a spindle is formed
o Cytokinesis is accompanied by de novo synthesis of plasma membrane and cell wall
o An array of microtubules (the phragmoplast, 1) guides and supports the formation of the cell plate (2)
o The microtubules guide secretory vesicles (3) to forming the cell plate