Module 6 - Plant Form and Function Flashcards Preview

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Flashcards in Module 6 - Plant Form and Function Deck (58):
1

Autotroph vs heterotroph

Autotroph
- self-sufficient without eating other living organisms
- produce their own energy
- plants, algae, certain protists, some prokaryotes

Heterotroph
- live on compounds produced by other organisms
- humans, cows, meerkats etc.

2

Chlorophyll a vs Chlorophyll b

What is the name of other accessory pigments?

a - main photosynthetic pigment

b
- an accessory pigment
- absorbs different wavelengths of light
- pass the energy to chlorophyll a

3

What is the name of other accessory pigments?

Carotenoids

4

What happens when a pigment absorbs light?

It goes from a ground state to an excited state which is unstable.

5

What are photosystems?

a reaction centre in the plasma membrane surrounded by a number of light-harvesting complexes

6

How is type I different from type II?

Photosytem II comes before photosystem I in the thylakoid membrane, so energy flows from II to I.

7

What are light-harvesting complexes? What is their role?

- pigment molecules bound to proteins
- funnel the energy of photons of light to the reaction centre

8

What happens when a reaction-centre chlorophyll molecule absorbes energy?

One of its electrons get pumped up to a primary electron acceptor

9

How do C4 plants minimize the cost of photorespiration?

C4 plants spatially confine the Calvin cycle to very internal cells
- CO2 is incorporated into four carbon organic acids (C4_ in mesophull cells rather than three carbon chains by Rubisco as in C3 plants
- C4 is exported to bundle sheath cells where they release CO2 used in Calvin Cycle

10

5 differences between C3 and C4 plants

- C4 photosynthesis uses two extra ATP molecules
- C4 plants have a lot less photorespiration
- Optimum temperature for C4 photosynthesis is higher than C3 photosynthesis
- C3 plants produce a 3 carbon sugar whereas C4 plants produce a 4 carbon sugar.
- C4 plants use PEP carboxylase instead of Rubisco to fix carbon

11

CAM vs C4 plants

CAM
- 4 carbon sugar
- temporal separation
- carbon fixation and the Calvin cycle occur in the same cells at different times
- stoma open at night to incorporate CO2 into organic acids - carbon fixation
- stoma closed during the day, and CO2 released from the organic acids used in Calvin cycle

C4
- 4 carbon sugar
- spatial seperation
carbon fixation and calvin cycle occur in different types of cells
- mesophyll cell - carbon fixation, organic acids produced
- bundle-sheath cell - calvin cycle

12

Light reactions vs Calvin cycle (dark) reactions

Light
- take place in thylakoid membranes
- convert light energy to the chemical energy of ATP and NADPH
- split H2O and release O2 to atmosphere

Dark
- take place in stroma
- use ATP and NADPH to convert CO2 to the sugar G3P
- returns ADP, inorganic phosphate and NADP+ to light reactions

13

Three basic organs of plants and their function

Roots
- anchors the plant
- absorbs minerals and water mainly through root hairs
- often stores organic substances

Stems
- Consist of alternating system of nodes were leaves are attached:
- internodes - stem segments between nodes
- axillary buds - structures with the potential to form a lateral shoot or branch
- terminal bud - located near the shoot tip, cause elongation of the shoot
- flowers are a modified stem

Leaves
- the main photosynthetic organ of most vascular plants

14

How many times more efficient are C4 plants at photosynthesising than C3 plants at optimal temperature?

2 to 3 times

15

Three tissue systems in plants and role

Dermal tissue
- outer layer for protection

Vascular tissue
- long-distance transport of materials
- two tissues: xylem and phloem

Ground tissue
- specialised cells for functions such as storage, photosynthesis and support
- fill up the plant body

16

eudicot vs monocot

Eudicot - embryo with 2 cotyledons

Monocot - embryo with 1 cotyledon

17

Tissue organisation of stems (eudicot vs monocot)

Eudicot
- vascular bundles arranged in a ring

Monocot
- vascular bundles scattered throughout the ground tissue rather than in a ring

18

Xylem vs Phloem

Xylem
- empty dead cells (cellulose)
- conveys water and dissolved minerals upward from roots into the shoots
- moves bottom to top ONLY

Phloem
- live cells
- transports organic nutrients from where they are to where they are needed
- either direction

19

Apical vs lateral meristems

Apical meristems
- located at the tips of roots and in the buds of shoots
- elongate shoots and roots through primary growth
- grow up or down

Lateral meristems
- add thickness to plants through secondary growth
- restricted to woody plants
Includes cork cambium and vascular cambium

20

2 types of lateral meristem and roles

Cork cambium
- adds secondary dermal tissue
- outer

Vascular cambium
- adds secondary xylem and phloem
- inner

21

Primary vs Secondary growth

Primary growth
- produces primary plant body including roots and shoot systems by apical meristems

Secondary growth
- adds girth to steams and roots in woody plants
- rarely in leaves

22

Primary growth of roots

- tip is capped
Process
- zone of cell division
- zone of elongation (cells increase in size)
- zone of maturation (cell differentiation)

23

Phase changes in plants

Juvenile phase
- first set of true leaves

Adult vegetative phase
- more shoots, branches, leaves etc.

Adult reproductive phase
- flower to fruit or nut

24

Four concentric whorls of a flower, position and ABC model combination

Sepals - outside - A
Petals - A + B
Stamens (male) - B + C
Carpels (female) - inside - C

25

What is cotransport?

A mechanism in which a transport protein couples the passage of one solute to the passage of another

26

What is the apoplast?

the continuum of cell walls plus extracellular spaces

27

What is the plasmdesmata?

the cytoplasmic channels ('gap junctions' of plant cells)

28

What is the symplast?

The cytoplasmic continuum

29

Three transport pathways in plants

Transmembrane
- out of one cell, across a cell wall and into another cell

Symplastic route - through the continuum of cytosol connected by plasmadesmata

Apoplastic route - through the continuum of cell walls and extracellular spaces

30

Role of Casparian strip

controls the kind and amount of molecules that enter the plant

31

Cohesion vs adhesion

Cohesion - stickyness between water molecules
Adhesion - attraction between water molecules and walls of xylem tissue

32

What is translocation?

transport of photosynthesis products in the plant

33

What is phloem sap?

- an aqueous solution that is mostly sucrose
- travels from a sugar source to a sugar sink
- the direction of travel is variable

34

Sugar source vs sugar sink including examples

Source - a plant organ that is a producer or sugar e.g. mature leaves

Sink - an organ that is a net consumer or storer of sugar e.e. roots, growing buds, stems, growing eaves, tubers, fruit

35

What is etiolation?

growing in darkness

36

What is tropism?

any growth response that results in curvatures of whole plant organs toward or away from a stimulus e.g. phototropism - response to light

37

6 plant hormones

- Auxin
- Cytokinins
- Gibberellins
- Brassinosteroids
- Abscisic Acid (ABA)
- Ethylene

38

Role of the plant hormone ethylene

- produced in response to stresses
- apoptosis (programmed cell death)
- fruit ripening
- slows down primary growth but NOT secondary growth
- regulated by ACC synthase

39

Role of plant hormone Abscisic Acid (ABA)

- stress hormone
- seed dormancy
- drought tolerance

40

Role of the plant hormone Brassinosteroids

- the plant sex hormones
- induce cell elongation and division
- plants die without it

41

Role of the plant hormone Gibberellins

- stem elongation
- fruit growth
- seed germination

42

Role of the plant hormone Cytokinis

- stimulates cell division
- works together with zuxin in apical dominance
- retard the aging of some plant organs

43

Role of the plant hormone Auxin

- promotes cell elongation

44

Define photomorphogenesis

effects of light on plant morphology

45

2 types of photoreceptors

Blue-light
- control hypocotyl elongation, stomatal opening and phototropism

Phytochromes
- regulate many of a plant's response to light throughout its life
- dimer

46

2 types of phytochrome

Pr
- sensitive to red light
- starting state
- dimers seperate

Pfr
- sensitive to far-red light
- signals responses
- dimers together

47

Define photoperiod

photoperiod - the relative lengths of night and day used by plants to detect the time of year required for certain developmental processes such as flowering

48

define photoperiodism

physiological response to photoperiod

49

Short day vs long day plants

Short day - flower in autumn and winter
Long day - flower in spring and summer

50

Define gravitropism, and explain how is can be positive or negatice

Gravitropism - response to gravity

Positive - go with gravity e.g. root growth
Negative - go against gravity e.g. shoot growth

51

Define thigmomorphogenesis
Give example

changes in form that result from mechanical perturbations
e.g. daily disturbance such as wind results in short, bushier trees

52

What is a GM plant?

A plant to which we had added extra DNA using recombinant techniques in the lab

53

What bacterium transfers genes to plant genomes? What does it typically cause?

Agrobacterium tumefaciens

Causes 'crown gall' disease and is natures genetic engineer

54

What is the role of phytohormone synthesis genes in GM plant procedures?

cell proliferation to create the bacterium's gall

55

What is the role of opine biosynthesis genes in GM plant procedures?

Nutrient secretion for Agro bacterium

56

What is the 3 step process of inserting a gene into a plant?

1. Cut out the disease-producing DNA
2. Insert the DNA that we want to transfer
3. Let Agro bacteria do its work (which is to infect the plant tissue)

57

Is Agrobacterium effective on dicots or monocots? Why?

Dicots as they are its natural host

58

What are the four parts of the flower from outer most to inner most?

Sepals
Petals
Stamens
Carpels