Plant Biology test questions

How does photochrome system control short and long day flowering plants?

* Used to detect periods of light and darkness * For some plants phytochrome that has been exposed to red light turns on the flowering genes while other plants turn them off

What are some of the main function of auxin?

- help plants grow and elongate - Elongates them in response to environment - Auxin will help elongate the cells on the dark side so that plants bend - After getting a signal from phototropisms

What is the function of the lateral marestematic cells? Where do you find them?

1) Secondary growth occurs makes stem wider and stronger 2) Occurs laterally between the phloem and the Xylem 3) Found in the stem further down

What is gravitropism?

A growth response to gravity

What is the difference between active transport and osmosis?

Active transport requires( ATP), while osmosis and diffusion require a concentration gradient

Sieve tubes alive or dead?

Alive

Autotrophic?

All green plants are called autotrophs- They make their own food from carbon dioxide

What is more common angiosperms or Coniferphyta?

Angiosperms

Where can you find apical meristematic cells? Two locations

At the tip of a plant shoot or root

What is meant by gene expression?

Auxin binds to the protein inside the cell. These proteins turn genes on in the plant chromosomes.

why do plants use energy to transport sugar but not water?

Because the amount of sugar they want goes against the concentration gradient.

Why does it take energy for the root cells to get mineral ions but not water?

Because you need energy when going against the concentration gradient.

How do Xerophytes slow down Transpiration?

Cam Physiology, waxy cuticle, Reduced leaves, low growth

What are the two techniques to study Translocation?

Carbon 14 measurement's and using aphids drilling into the Phloem tissue

How can sink in the summer become a source next spring?

Growing leaf

Phototropism

Growth of a plant shoot toward or away from light.

What does the structure of the xylem look like?

Hollow Impregnated with linen cells Thickened cellulose Pits( Pores) which enables water to be transferred between cells

How does auxin help a plant carry out phototropism?

In response to light - Auxin will elongate cells on the dark side so that the plant ends towards the light

What is the name for plants stem cells?

Meristematic cells

Important minerals for a plant to take up in the roots cells?

Nitrogen, Potassium and calcium

Water is almost always moving from the soil to into the roots, why?

Osmosis

How does the Pfr change back to the original Pr form of Phytochrome?

Pfr is broken-down into inactive form when it absorbs far red light( 725 nm) Will gradually revert to Pr in absence of light

In a cross section of a plant stem where do you find xylem and phloem?

Phloem and xylem around the inner. layer of the pith with phloem cells on the outside of the xylem

What is the difference between pollination and Fertilization?

Pollination: - Process when pollen is placed on the stigma - A physical Process - Achieved by pollination * Water, wind and insects Fertilisation: - When the male and female sex cells unite to form a diploid zygote - A biochemical process - Does not require external agents

When is Pfr a gene promoter and when does it turn off flowering genes?

Shdp- autumn, Pfr inhibits flowering- Has to go below the threshold level Ldp - Spring/ summer Pfr promotes flowering. Has to be above the threshold - During winter below the threshold- inhibits flowering

For flowers the form a gene expression changes occur in the?

Shoot apex

Short day vs long day plants

Shortly plants Flower duroing autumn- when the nights are longer- so that they each the threshold level for per - Pfr ( inhibits flowering) Long day plants- summer (spring) short nights - Pfr promotes flowering * During the winter the Pfr falls below the threshold level

Why do some flowering plants have big showy petals while other have no coloured petals?

So that they can or not attract the right pollinator EX: Wind- Stigmas large and feathers to catch grain EX: Large red or orange- birds

What is the difference in sugar transport between source and sink

Source- Where the sucrose comes from Sink- Where the sucrose is dumped of Pressure flow hydrolysis

Why is there both negative and positive gravitropism in a typical growing plant?

Stems grow upward( Negative gravitropis) Roots grow downward( Positive gravitropism)

Where do pollen grains germinate?

Stigma

Where is the stomata located on a leaf?

Stomata and the guard lief tend to be beneath the leaves- Less water loss

Which form of sugar is used for translocation?

Sucrose

Apoplast vs symplastic water movement in plants root system?

Symplastic= through cytoplasm and plasmodesmata( slow) Animal Apoplastic= Through cell wall( Fast) Plant

How does phytochrome Pr get changed into Pfr

The Inactive form Pr is converted into the active form when it absorbs red light ( 730 nm)

Why is it impossible for plants to pump water up a tall tree?

There is no way the plant can have a biological pump that can create that much positive pressure upwards.

What is the function of the sieve plates? What do they connect?

They connect the sieve tube elements- hole to allow organic molecules

How does sugar get loaded into sieve tubes?

They enter the sieve tube through active transport

Why does the phloem system need an extra cell called companion cell?

To store the nucleus etc. So it is easier for the sucrose to translocate .

Sugar movement In plants?

Translocation

What abiotic factors change the rate of transpiration?

Wind, humidity and light

flowering plants

angiosperms

Female structure of flower?

carpel( Stigma,style and ovary and Oval)

Is xylem tissue dead or alive?

dead

How does a potometer work?

it is filled with submerging water, air bubble is allowed to form in capillary tube and distance moved by a bubble is a measure of the rate of water uptake

male structure of the flower

stamen, anther, filament

What do phloem cells transport?

sugars and organic molecules such as amino acids

Transpiration

the emission of water vapor from the leaves of plants

What is moving in osmosis?

water