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Flashcards in A: topic 5 and 6 Deck (49)
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1

plant cell specifications

Cell wall – plasmodesmata form a communication between the plant cells

Plastids

Vacuoles

Inclusions

2

Ploidy

Ploidy level: Number of chromosome sets in a cell

Polyploid: more than two sets (haploid, diploid)

Triploid species: bigger vegetative body, better resistance

Tetraploid species: increased production of reproductive organs Goal of breeding: better attribution

3

vacoules
1. how are they made and of what
2. different types

1.
tonoplast membrane storing solid or fluid compounds and gases

Vesicles of ER and dictyosomes(many together form the gogi apparatus) -> provacuoles

The provacuoles fuse into larger ones -> central vacuole

(In animal cells the vacuoles are of little importance)

2.
Storage(isolating metabolites), cell lysis, maintaining hydrostatic pressure and pH, dispertion and protection

4

lysosomes

Thick membrane

Hydrolytic enzymes in the middle – autophagy

5

vegetative (storage) vacoules

Diluted water solution, mildly acidic pH 5-6 (BUT pl. lemon pH 2)

Ions, by-products, waste products, nutrient storage

6

inclusions

No constant, but not essential substances

No metabolic activity

no membranes

Protein inclusions; globoid-, crystalloid forms, aleurone layer

Carbohydrate inclusion; mainly stach

oil inclusions: oil droplets

7

crystals

Accumulation of inorganic compounds: Oxalates, carbonates

silicates Digestion problems, irritation

8

plastids
1. fuctions and types

1.
Assimilation, synthesising metabolic processes, storage functions

Coloured plastids: chloro- and chromoplastids

Colourless plastids: leukoplastids

2.
Plastid development

Originates from prokaryotes
Proplastid

No sunlight: Etioplastids(an example of leukoplastids)

Sunlight: chromoplastids

9

Leucoplastid

Colourless plastids in organs not exposed to sunlight

Storage function!

The plant uses the stored nutrients or plastids can turn into green ones (potato)

Globular or fusiform shape

Examples:

Proteinoplastids – protein

Simple or compound types

storing and modifying proteins

In modified stems, seeds

10

Chromoplastids

Originated from proplastids or amiloplastids or chloroplastids (ripening, aging leaves)

Less developed inner membranes

11

Carotenoid pigments


carotene, xanthophylls: the two classes of carotenoid pigments

autumn leaf pigment

Globular, fibrillar or chrystalline forms

In flowers, fruits, leaves, roots Pollination, dispersal

12

Chloroplast

1. Structure and function of thylakoid

2. Compounds and functions of stroma

3. plastid for C4 plants

1.
Outer membrane similar to cell membrane

Photosystems: intergal proteins and pigments(chlorophyll on membrane)

Electron transport chain: proteins ATP and NADPH production -> photosynthesis (light dependent reactions)

2.
RuBisCO enzyme (protein complex)

Photosynthesis (light independent reaction, calvin) – production of glucose and intermediate products

3.
For C4 plants mesophyll cells has a granum structure, but it’s absent from the bundle-sheath cells!

Mesophyll cell and bundle sheath cell are much more closely related: unique step first in mesophyll cell, where CO2 and PEP is the first step to making malate, which will diffuse into the bundle sheath cell where the calvin cycle will happen as normal just with malate as a starting product instead of CO2. glucose is made

the first step in the mesophyll cell is there because PEP can only use CO2 even in low concentrations, while rubisco would have used O2 instead. this way the O2 is also separated form the calvin cycle so that only CO2 is used even in high temp., drought, low CO2

13

cell wall: major functions - 6

Protection (environmental stress, pathogenes, water loss)

Gives a definite shape

Enables information transport to the exterior

Helps in osmotic-regulation, prevents water loss

Transport processes

ion exchange, mineral uptake (root hairs)

14

what is the "skeletal structure" of the cell wall

The cellulose:

1,4 linked β–D glucose chain

15

1. primary cell wall

2. secondary cell wall

3. what can decompose the cell wall?

1.
Primary cell wall:
web of microfibrils + auxin ->loosened structure, formation of new fibrils -> increasing cell wall surface (the "original", basic cell wall)

2.
Secondary:
new transverse layers of cellulose fibrils (increased strenght) (layers on top of the primary wall – like padding a brick wall, more secondary wall, decreasing digestibility)

Outer (centrifugal) thickening In case of spores and pollens Spikes, grains, appendages…

Inner thickening: strengthening and protection

3.
Cellulase enzymes ->decomposition of cell wall (secretory ducts, transport vessels)

16

matrix substances of the cell wall: 3

Pectins (soluble fiber)
- high proportion in fruits and storage organs

Hemicellulose
- cross-link between pectins and cellulose (e.g.: arabinoxylan)

Proteins
- soluble (hydrolitic enzymes, peroxidases)
- insoluble (=extensins) – web-like structure

17

incrustations of the cell wall: 3

Pigments, Mucilage
- storage of water, gelling effect, Inorganic compounds – in plant hairs -> irritation

Lignin (wood)
- phenolic polymers consists of coumaryl alcohol, coniferyl alcohol, sinapyl alcohol Mainly in the secondary wall (lignification) Increase rigidity Decrease digestibility!

Suberin (cork)
- polymers of aromatic and aliphatic compounds Waterproof layer, decreasing evaporation Decreasing digestibility!

18

adcrustations
where, what: 2

On cell wall surface

lipid coating: Wax or cutin
Water insulators: decreasing evaporation

19

plasmodesmata

Channels traverse the cell walls – smooth ER tubes and protein filaments Direct transport between cells

Large number in young cells, later decreasing abundance

20

Permanent tissues: dermal tissues

External part of the plant

Primary dermal tissue: epidermis

Secondary dermal tissue: epidermal cells + stomata

Stomata types: amaryllis type bean shaped, grass-type dumbbell shape

21

nutritional value of dermal tissues

Function: absorb water and minerals

Gas exchange for photosynthesis=nutrition

Contains chlorophylls

Subsidiary cell: water and ion reservoirs

22

the digestibility of dermal tissues

1. about the morphology (8)

2. functions and chemicals (3)

1.
Often multiple cell layers, but in general one

Outer cell wall can be covered with cutine, wax/cork

Papillae(raised thickeng)

petal cells (epidermal appendages, outbulgings)

for grass and sedge plants are sharp and coarse-> irritation

Trichomes (epidermal appendages, hair-like)

Bristle hairs (stiff hair)

Clinging hair

2.
Function: protection against herbivores

In sec. Dermal tissue: accumulation of tannins, glycosides in bark!

Cause irritation, bezoars, rough texture-> animals reluctant to eat

23

rhizodermis (root epidermis)

Prim. Dermal tissue of young roots

Major differences from epidermis

Root hairs, no stomata/cuticule/chlorophylls

24

secondary and tertiary dermal tissues

1. secondary, how made

2. tertiary, how made

1.
Layer of cork cells are prod. Of the cortex bleow the epidermis, these cells willl later multiply as result of cell division and prod. Sec. Dermal tissues = periderm
(secondary growth incr. thickness)

2.
If phloem(living tissue) prod. the dermal tissue: tertiary
-->Accumilation of sec. Metabolites in bark aka phloem

25

ground tissues: parenchyma (4)

Most abundant tissue w/slightly differentiated cells

Cells are isodiametric

Have only primary wall, large vacoules and prominent intercellular cells

Function: basic metbolism, storage, aeration

26

chloroenchyma

Parenchymal cells that contain chloroplast -> photosynthetic function

Palisade, spongy

27

storage parenchyma

Lots of leukoplastids – fatty acids, starch, protein-> high nutruitive value

28

water storage parenchyma

Tissue of succulent plants

Thin cell wall, large vacuoles, water absorption in the form of mucilage

29

aerenchyma

Parenchyma of waterplants and species living in moist habitats

Large intercellular cavities – important for oxygen supply and gas exhange

Low nutritive value

Secretory tissues

30

secretion types of parenchyma

1. intracellular secretion

2. extracellular secretion

3. other: 3

1.
Intracellular secretion:
- Metabolites secreted into vacuoles or cell wall

2.
Extracellular secretion:
- A cellgroup that secrete metabollites into intercellular space

- Endogenous: ducts, cavities (Ducts: for protection and to seal wounds from insect and disease entry)

- Exogenous: onto epidermal surface through glands

3.
Hydathodes: water through pores

Salt glands

Nectar glands: sugar rich liquid w/amino acids for pollinators