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Biology > Plants Response To Internal And External Signals > Flashcards

Plants Response To Internal And External Signals Flashcards

1
Q

Exogenous signal

A

A signal coming from outside the body such as light

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2
Q

Endogenous signal

A

A chemical signal within the body

Can be hormones or neurotransmitters

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3
Q

What did Darwin notice with plants ( what was his experiment)

A

That they bend towards light

This led to the question of what pet was responsible in bending the plant towards the light. They thought the tip so the cut it off. To further support they put an opaque cap that covered light and the plant didn’t respond. To go even further they got a translucent cap and the plant did bend. Adding a collar to the middle of the plant didn’t prevent the bending either further supporting the tip of the plant causing the bend

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4
Q

Boysen jenson experiment

A

Used gelatin slaps because it’s not solid so molecules can diffuse through it. They tested if the tip senses the light and then sends a signal in the form of a molecule to the other part of the plant. They cut the tip off and put a slap of gelatin between stock and tip and put it back in place. Even though tip was removed the stem still bender towards the light further supporting the tip sensing the light for the bend. Solid mica slab was also used in the same way and no bending occurred so it is most likely molecular signal.

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5
Q

Signal transduction

A

Tone signal get converted in another signal. Light to plant that causes the plant to release a signal to bend

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6
Q

Agar cubes allowed for

A

The plant tip to be put on and left for a while so the molecule could be absorbed and then the agar cube was put on to the cut stem and the plant still bent without its tip.

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7
Q

What are chemical signals

A

Just molecules

They have no effect unless there is a specific receptor where a chemical signal can bind

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8
Q

How are chemical signal categorized

What are the ones in humans

A

How they work

Hormones

and neurotransmitters

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9
Q

Neurotransmitters

A

They work locally ( cell to cell) and release by Newton’s and work right next to that

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10
Q

Hormones

A

Work through the bloodstream to broadcast a signal.

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11
Q

What kinds of molecules are receptors

A

Proteins

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12
Q

Auxin (IAA)

A

First hormone discovered
(Indolasedic acid)

Growth hormone -stem elongation from low concentration only(

Promotes lateral and adventitious roots

Enhances apical dominance

Rudimentary releases and the receptor turns on a proton pump that pumps proton near cell wall make the fluid on the outside more acidic. Acidity promotes enzymes that clip parts of the cell way but only happens on the sides and not the ends so stretches for stem elongation

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13
Q

Does how much of a hormone matter to the effect

A

Yes certain concentration of the same hormone can do different or opposite things. Can do different things to the body possibly based on the receptor

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14
Q

Cytokinins

A

Plant hormone

Regulate cell division In Roots and shoots

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15
Q

Gibberelellins

A

Stimulates growth and fruit growth

Used to make grapes way bigger without molding by also growing the stems

Can cause booting in certain kinds of species and stem elongation

In seeds these chemical signal is release by the endosperm and reaches the aluerone cells that respond to the chemical and make amylase which break down glucose to break down starch in the embryo to feed the embryo

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16
Q

Brassinosteroids

A

Phytosterol.

At high concentrations they inhibit root growth and at low concentration they promote root growth

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17
Q

What are the major steroid hormones in humans

A

Sex hormones

Initial steroid that gets modified and turns into something else is cholesterol

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18
Q

What get slightly modified in animals regarding their steroids

A

Cholesterol is the base of all steroids

19
Q

For plants what is the base of their steroids

A

Phytosterol

20
Q

Abscisic Avis (ABA)

A

Named for the process of abscission which is the loss of leaves.

But doesn’t cause leaves to fail so misnomer

Inhibits growth
Stomata closure
Promote leaf senescence or aging

21
Q

Ethylene

A

Responsible for the ripening of fruit

22
Q

Bolting In plate is what

A

Very rapid growth

23
Q

What tells seeds to germinate

A

A sufficient amount of water. Which is an exogenous signal

24
Q

What is starch made out of

A

Glucose

25
Q

Ethylene controlls the

A

Triple response

26
Q

What are the triple responses

A

The root slows down its lengthening and get wider.

The root is shoot with start growing horizontally for a while and will

then grow down if a root if it can

These are cause by ethylene

27
Q

Constitutive triple response

A

Always turned on gene

Turn a gene on when it shouldn’t always be on so can cause a root or shoot to think ethylene is there are will always undergo triple response

28
Q

Abscission is caused by how many hormones

A

Two

Ethylene and Auxin

29
Q

Abscission

A

Ethylene Auxin ratio causes it

Leaf produces auxin and stem produces ethylene

Petiole has a ratio

Leaf my produce less auxin and the and the same ethylene by the stem so the ratio gets bigger cause the leaf to gradually fall off

30
Q

Photomorphogenesis

A

The bringing about a change in shape in response to light.

This is what happens in potatoes. If you put them in light they will sprout green leaves and stems but In dark they grow white stout stems because it thinks its growing through the ground in the dark

31
Q

Blue light receptors

A

Responds to blue light

32
Q

Phytochrome’s

A

Responds to red light or red light receptors

Can cause a seed to germinate but if far red light( light past red we can see) is shined onto a seed then the seed will not germinate. Only if you shine the red light again without the far red after will it germinate. The receptors act as light switches for germination

It is a protein, operates based on its shape or conformation. One shape that is for red light is called Pr and Pfr shape is for far red light

Shinning light on Pr will change its shape to Pfr and viceversa

33
Q

Tropism ( phototropsim

A

Refers to a response to a signal so phototropism means response to light

34
Q

Circadian rhythms

A

Built in clocks in rhythms that are not exactly a day per day clock. Organisms reset their clocks so they are exactly 24 hours

Plants use light to reset

35
Q

Circanual rhythms

A

Animals have these sometime for mating seasons. Plants need these to know what time of year it is.

Phytocromes also reset these life through the presence of light and how long it light or dark

36
Q

Angiosperms can be classified based on their flowers that move

A

Short day or long night plants Unless night is long enough the plant will produce a flower

Long day plants and short night plants
Won’t produce a flower unless night is short.

They can be fooled by a blast of light by either thinking there is 2 short night so will produce or not produce flowers based on what type of response they have

37
Q

Gravitropism

A

A response to gravity

Roots that response to this are positive tropism

38
Q

Positive and negative tropism

A

The response to that stimulus is towards that stimulus - positive

The response to the stimulus is away from it -negative

39
Q

How do roots sense gravity

A

Statoliths - is a little gradual of densely packed starch that is there to make the statolith dense so it’s heavier than its surrounding. It falls to the bottom of the cell and wherever it lands tells the cell that is down. Can tell plant where to drop roots and shoots

40
Q

Otoliths in humans

A

Little sand like particles in our ears that are responsible for telling our brain what position our head is in space.

41
Q

Thigmatopism

A

Is the response to touch

Leaflets that fold up on a certain plant

42
Q

Electrochemical signals used in organism are called

A

Used in neurons and muscle cells are called action potentials. Voltage signals because they vary ions which have charge
Very fast in animals but not as fast in plants

43
Q

Drought is a

A

Environmental stressor. Plants deal with this by producing abscisic acid because they control the opening and closing of stomata

44
Q

Saturated fatty acids don’t have any

A

Bends in them

Unsaturated fates have bend in them and can loosen up sell membrane allowing them to live in cold places

Biology (23 decks)

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