Plant Bio Growth And Development

Front 1

When going over the growth and development of plants there are three terms that should be known, morphology, differentiation and growth. Just briefly describe these terms:

Back 1

Growth is simply the irreversible increase in mass and involves cell expansion and cell division.

Differentiation is the change from a generalized cell type to a specialized cell type with specific functions

---Development = Growth and Differentiation

Morphogenesis is the development of form and shape of a cell, organ, or entire plant

Front 2

What are some unique characteristics for plant growth?

Back 2

A plant has indeterminate growth
Differentiation can be easily reversed
There is localized and arithmetic growth
There is open growth- can initiate new organs throughout lifespan

Front 3

What is totipotency?

Back 3

This is when a single differentiated cell can de-differentiate and give rise to a whole new plant

Front 4

Describe how totipotency was used in cloning plants?

Back 4

F.C Steward took the carrot phloem cells (differentiated cells), place these cells in a coconut milk(this medium is rich in cytokinins). These cells then became a callus ( a mass of undifferentiated cells) and form a another carrot(plantlet)

Front 5

What is a plantlet?

Back 5

This is a small plant that was grown from cells off the original plant.

Front 6

What are some plants that make plantlets by themselves?

Back 6

Ferns and kalanchoe plants

Front 7

What are some values of plant tissue culture?

Back 7

Propagate individual plants while maintaining desirable traits
Develop new genotypes with desired traits(genetic engineering-cloning)
Study genetics of somatic cells
Immortality

Front 8

What is are some of the oldest plants?

Back 8

Bristlecone pines in SC

Front 9

Where is the zone of cell elongation and division located on the apical meristem?

Back 9

The bottom is elongation
The top is division

Front 10

What are the pocket of meristematic cells left behind in a apical meristem?

Back 10

The axillary buds

Front 11

In the zone of cell elongation, what else can occur here?

Back 11

Cell differentiation and it is mostly further away from apical meristem

Front 12

In the apical meristem, what remains undifferentiated?

Back 12

The axillary buds

Front 13

What makes up interphase in cell division?

Back 13

G1, S, G2

Front 14

What causes plants to break dormancy” and re-enter cell cycle

Back 14

This is sometimes done by some plant hormones within the G1-Go phase

Front 15

What is the driving force for cell expansion/growth?

Back 15

Osmotic pressure (Turgor pressure)

Front 16

Describe how the protons play a pivotal part in cell expansion/growth?

Back 16

The protons are pumped into the cell wall via H-ATPase, which in effect lowers the pH. This will then:
-Weaken interactions between wall components (pectins and cellulose, etc)
-Stimulate expansins (proteins involved in wall loosening)

Also some plant growth hormones stimulate cell enlargement or elongation, such as auxins

Front 17

When does cell differentiation occur?

Back 17

After cell division (and enlargment and elongation), in order to keep progenitor

Front 18

Give an example where cell division itself is involved in differentiation?

Back 18

Trichome initials

Front 19

The plant has several responses to the environment, which are coordinated growth and differentiation. One of these is vernalization, explain vernalization?

Back 19

Vernalization is the period for seed germination and needs a pronlonged cold period. Without this will not flower

Front 20

In gravitropism which way do the roots grow, negative or positive?

Back 20

Positive, towards gravity

Front 21

What is thigmotropism?

Back 21

This is how the plant grows around a substance.
-Will grow faster on one side vs. other
-will increase tugor to fold leaves

Front 22

There are many responses plants have towards lights, name some of these?

Back 22

Photosynthesis

Photomorphogenesis(presence of light)-controls development (Leaves, greening)

Phototropism (direction)-grow towards and away from light

Photoperiodism (quantity/duration--daylength)
-controls flowering in many

Front 23

What are some miscellaneous environmental factors that can effect plants?

Back 23

Pathogens, herbivores, symbionts and other plants

Front 24

Quickly say the four ways plants respond to light, one of them is presence?

Back 24

Duration/quantity (daylength)
Quality (wavelength)
Direction
Prescence

Front 25

What are the three system components involved with how the plant responds to light?

Back 25

Photoreceptor-detects light

Signal Transduction system-secondary messengers transmit and amplify signal

Response system- gene activation or de-repression

Front 26

What are the three major photoreceptors?

Back 26

Phototropin
Cryptochrome
Phytochrome

Front 27

What is the proposed role of the anthocyanins?

Back 27

They attract pollinators or are used as seed/fruit dispersers and photoprotection

Front 28

What are the three photosynthetic and accessory pigments?

Back 28

Chlorophylls, carotenoids, and xanthophylls

Front 29

What color light does phytochrome absorb and what is its main role?

Back 29

It absorbs red light and is involved in the daylength and shading (quality)

Front 30

What phenomena are pytochromes involved in:

Back 30

Promote stomatal opening
Promote leaf development
Stem elongation in young seedlings
Seed germination on surface of soil

Front 31

What is usually the active phytochrome wavelength and color?

Back 31

Far red(Pfr) and it is 730nm
The inactive is 660nm and is red (Pr)
--Red is useable in photosyntheis but the longer wavelength isn't. So if there is a longer wavelength it will pass through leaves, representing shade!!!!

Front 32

What features of hormones are similar to humans?

Back 32

Act in small quantities/amounts-very potent

Release into plant "circulatory system"-mostly the phloem

Target cells/tissues have receptors for the hormones

Binding triggers response in target cells

Front 33

What are the main differnences between plant and animal hormones?

Back 33

Hormones are simple organic molecules

They function alone or in conjunction with other hormones

Different tissues may respond very differently to same hormone

Some are transported, others have effects where produced

Front 34

What are the five major plant hormones?

Back 34

Cytokinins
Gibberellins
Auxins
Abscisic acid
Ethylene

Front 35

What is the coleoptile and what does it bend towards?

Back 35

It is the sheath of cells that cover grass seedlings, it grows mostly be cell elongation and bends towards light, SPECIFICIALLY BLUE LIGHT

Front 36

Describe how the coleoptile will bend towards light?

Back 36

The tip of the grass has the phototropin receptor that will receive the blue light.
The auxin, diffusible chemical will travel down and cause the grass to "not show its ass to the light"

Front 37

What were the two auxin asymetrical distribution hypothesis?

Back 37

Redistribution hypothesis-the light moves auxin to one sides

Auxin destruction-the light kills auxin on side

Front 38

Which scientist proved the auxin redistribution hypothesis and how?

Back 38

Winslow Briggs-To disprove thee auxin destruction he took an agar block (with tip) and another agar block (tip exposed to light). He then both of the agar blocks, placed in dark but still saw the plant bended the same amount.

The auxin redistribution was proved because with a mica sheet present preventing all flow, the plant bended the same amount. With the mica sheet preventing a reduced flow of auxin, and one side being exposed to light and the other shaded, there was a difference in bending. The side that was shaded bent the most, showing that auxin moved to other side.

Front 39

If the agar block was placed on leftside of grass, which way would it bend?

Back 39

Bend right

Front 40

What is the auxin made of both synthetic and natural?

Back 40

Natural= Indole Ring and Acetic Acide----Indole Acetic Acid (IAA)

Synthetic- Naphthalenacetic acid (NAA)

Front 41

What amino acid associated with thanksgiving is used in a pathway to make auxin?

Back 41

Tryptophan

Front 42

What is the function of auxin?

Back 42

Apical dominance
phototropisms and gravitropism
Promotes cell elongation

Front 43

How is auxin related to expansins?

Back 43

They will overexpress expansins and there is greater plant growth

Front 44

In what two forms can auxin be represente?

Back 44

Free form or conjugated to aa/sugars (inactive)

Front 45

Not only does Auxin have a different response to certain tissues it has different sensitivities. 10^-5 M is required for_________ and 10^-7-10^-9 is required for ________

Back 45

Stem
Root

Front 46

Where is auxin produced?

Back 46

Shoot apex, leaf tips

Front 47

What is agent orange composed of?

Back 47

2,4-D
2,4,5-T
and also has dioxin (teratogen) which causes birth defects

Front 48

Describe the acid growth hypothesis of Auxin?

Back 48

The auxin will bind to receptors, causing to produce AND activate H-pumps. Pump protons out of cell (K+ brought in to maintain turgor) this will then drop the pH (5.5-4.5), breaks bonds in wall matrix loosens cell wall.
The drop in pH also activates expansins

Front 49

What are statoliths?

Back 49

Amyloplasts -colorless chloroplasts that store starch

Front 50

What does Auxin do to root elongation in horizontal roots?

Back 50

It will inhibit cell elongation on side with most auxin so the root will bend down.

Front 51

What is believed to triger the auxin redistribution to the lower side of a horizontal root?

Back 51

The statoliths are believe to contact membrane-bound receptor molecules and the statoliths movement will cause the auxin redistribution

Front 52

What is apical dominance?

Back 52

This is how auxin will delay the outgrowth of axillary buds until they are some distance away from the shoot apical meristem.

Front 53

If there are more cytokinins than auxins willl there be apical dominance?

Back 53

With more cytokinins there will be an outgrowth of the auxiliary buds

Front 54

What is essentially responsible for the effects of Auxin?

Back 54

The tissue that auxin targets, auxin is just the switch

Front 55

Summarize the three efffects of auxin?

Back 55

Apical dominance
The gravitopism
The plant's morphology in regard to light

Front 56

Name the two naturally occurring cytokinins and name the synthetically produced one?

Back 56

Zeatin
Isopentyl adenine

Synthetic-kinetin

Front 57

Finish:
Cytokinins are chemical variations on ___________

Back 57

Adenine

Front 58

Where are cytokinins primarilly produced?

Back 58

In the root apical meristem, transported to shoot system & axillary buds

Front 59

Name this hormone:
Promote cell division in target cells

promote axillary bud outgrowth

balance root/shoot growth
so vigorous root growth can support greater shoot system

important in seed development

may delay senescence in leaves

role in stimulating differentiation & activity of vascular cambium (in conjunction with auxin)

Back 59

Cytokinin

Front 60

Describe how cytokinin works with auxin?

Back 60

appear to work in conjunction with auxin in many cases
tobacco pith tissue culture:
high aux:cyt = stimulates development of roots

low aux:cyt = stimulates development of shoots

Front 61

Where is Gibberellins primarilly produced?

Back 61

In the upperparts of leaves

Front 62

What are the functions of gibberellins?

Back 62

Stem elongation and cell division

Growth and differentiation in vascular cambium

transition from vegetative to reproductive state in some plants

significant roles in seed germination
a. stimulate embryo to renew development
b. increase α-amylase levels (for starch breakdown)
c. activate α-amylase

Promote the cell wall extensibility but different than auxin

Front 63

What hormone works with auxin to cause phloem differentiation in the vascular cambium?

Back 63

Gibberllin

Front 64

Describe how gibberellin modulates gene expression, use DELA in this expression?

Back 64

GA once bound to a receptor will degrade the DELA, which is bound to the transcription factor for the alpha amylase.

Front 65

What is produced in the leaves and dry roots?

Back 65

ABA

Front 66

What hormone(growth inhibitor), promotes dormancy in seed and promotes response to stress, such as closing stomata.

Back 66

ABA

Front 67

What hormone is a gas and involved in fruit ripening?

Back 67

Ethylene

Front 68

Ethylene cause the following:

kinases neutralize acidity to
hydrolases break down chl.
amylases “ “ starch
pectinases “ “ pectin
hydrolases “ “ organics

Back 68

Tastier make less acidic
Make colors stand out
Make sweeter
Make softer
Make sweet smelling

Front 69

What two plant hormones have medical significance?

Back 69

Acetylsalicylic Acid= create aspirin

Paclitaxel = most widely used anti-cancer drug

Front 70

Describe how auxin and ethylene are correlated?

Back 70

As there is a reduction in auxin concentration, ethylene will then futher decrease auxin and increase ethylene which will create the leaf abscision zone.
Once leaf drops there will be production of corky cells at site of abscission/

Front 71

What are the two patterns of gene expression?

Back 71

Spatial-space of regulation
-Cell specific
-organ specific
-Every cell type
Temporal-Time
-on all time
-rhythmic, repressible

Front 72

What was gained from molecular cloning of genes?

Back 72

Permitted initial studies of individual gene expression

Front 73

Where does developmental regulation of genes occur?

Back 73

Transcription
mRNA stability/degradation
Translation
Post-Translation
Protein stability/degradation

Front 74

How is gene expression studied?

Back 74

NoRthern blots
Microarrays
Nuclease Protection Assay

Front 75

Describe the pathway of microarray?

Back 75

mRNA---cDNA(incorporate fluorescent-labeled nucleotides)---clone and partially sequence many of them----hyberdize to microarray---then wash away unbound DNA's----identify by sequence homology

Front 76

Are most expressed genes developmental?

Back 76

No

Front 77

What are strategies to finding key regulatory genes in development?

Back 77

Isolate developmental mutants of a model genetic organism

Map and clone the gene

Study gene's structure and function

Front 78

What do homeotic genes control?

Back 78

They control the overally body plan of an organism

Front 79

Why is Arabidopsis thaliana used as a model plant system?

Back 79

small organism
short reproductive cycle
n = 5 (chromosomes)
smallest known genome of angiosperms (flowering plants)

Front 80

The shoot apical meristem produces a primordium, giving rise to 4 whorls. What are theses whorls?

Back 80

1-sepal
2-petal
3-stamen
4-carpils

Front 81

What is the relation with class A and class C homeogenitic?

Back 81

They are anatagonistic
If one not expressed, the other is expressed

Front 82

What photoreceptor plays a role in the circadian rhythms, is made of FAD, and absorbs blue light

Back 82

Cryptochrome

Front 83

What photoreceptor absorbs blue light and has the LOV domain, also in phytochrome and cryptochrome?

Back 83

Phototropin

Front 84

What receptor is important for circadian rhythm and floral initiation

Back 84

Cryptochrome

Front 85

What receptor is important in daylength and shading, stem elongation, seed germination, promote stomatal opening and promotes leaf development?

Back 85

Phytochrome