IB Biology '15 - Plant Quiz

cohesion

water molecules bond to themselves through hydrogen bonds. creates surface tension on the water

adhesion

water molecules form hydrogen bonds with the xylem cell wall & pulls water toward other molecules

how are fluids transported in the xylem and the phloem

xylem - away from the root only phloem - away from and towards the root

what are the adaptations of plants in deserts and plants of saline soils

- a thick, waxy cuticle covering the leaf - hairs on the underside of the leaf - smaller air spaces in the mesophyll than other plants - few stomata, that are sunk in pits - cells that can change to make the leaf roll up, with the lower epidermis and stomata on the inside

be able to identify xylem and phloem in microscope images of stem and root

LOOK IN BOOK

draw the structure of primary xylem vessels in sections of stems based on microscope images

LOOK IN BOOK

how do plants replace losses from transpiration

Plants transport water from roots to leaves to replace losses from transpiration. Water leaving through stomata by transpiration is replaced by water from xylem. Water in the xylem climbs the stem through the pull of transportation combined with the forces of adhesion and cohesion. Water moves from soil into roots by osmosis due to the active transport of minerals into the roots. Once the water is in the root it travels to the xylem through cel walls and through cytoplasm.

lateral meristems

occurs at the cambium, adds lateral growth to stem to add length, responsible for secondary growth, produces secondary xylem and phloem, produces the bark on trees

describe the metabolic events of germination in a starchy seed

The first step in the germination process is the absorption of water, which causes gibberellin - or gibberellic acid (GA) - to be produced Gibberellin causes the synthesis of amylase, which breaks down starch into maltose Maltose is transported to the embryo, where it is either hydrolysed to glucose (for energy) or polymerised to cellulose (for cell wall formation) Stored proteins and lipids will also be hydrolysed by the addition of water to form enzymes, triglycerides and phospholipids Germination uses the food stored in cotyledons as an energy source until the developing shoot reaches the light and can begin to photosynthesise

what is the consequence of gas exchange in the leaf

Transpiration is the inevitable cause of gas exchange in the leaf.

apical meristems

occurs at the tips of roots and shoots, adds vertical growth to roots/shoots to add length, responsible for primary growth, develops into primary xylem and phloem, produces new leaves and flowers

Monocotyledons

one cotyledon, parallel venation, fibrous adventitious roots, floral organs come in multiples of 3, scattered stem vascular arrangement, pollen come in single furrow / pore (monosulcate)

explain how abiotic factors affect the rate of transpiration in a terrestrial plant

abiotic factors affect the rate of transpiration in terrestrial plants by light, temperature, humidity, and wind. light speeds up transpiration by warming the leaf and opening stomata. decreasing humidity increases transpiration bc of the greater difference in water concentration. as temp rises so does the rate of transpiration. a rise in temp leads to increase in evaporation rate

how do organic compounds into phloem sieve tubes the source

active transport is used to load organic compounds into phloem sieve tubes at the source

state two types of meristem found in plants

apical and lateral

what does the active uptake of mineral ions in the roots cause

as a result of active transport the cytoplasm of root cells has a higher overall solute concentration than the water in the soil. root cells therefore absorb water from the soil by osmosis

state two methods by which terrestrial plants support themselves

cell turgor, lignified xylem

describe the transport of water through an angiosperm root system

epidermal cells take up water by osmosis. it goes through symplastic pathways through the cytoplasm by diffusion down the concentration gradient by capillary action. the casparian strip blocks the apoplatic pathway, the water passes into the xylem and the transpiration causes the pull of water through the plant

light and temperature affect

heat and light cause water to become vapor in the spaces of the mesophyll. this escapes through the stomata higher. higher temp increases the rate of transpiration by increasing the rate water molecules diffuse.

explain why when the hydrostatic pressure increases the causes the contents of the phloem to flow toward sinks

high concentrations of solutes such as sugars in the phloem sieve tubes at the source lead to water uptake by osmosis and high hydrostatic pressure. low solute concentrations oh phloem sieve tubes at the sink lead to exit of water by osmosis and low hydrostatic pressure. there is therefore a pressure gradient that makes sap inside phloem sieve tubes flow from sources to sinks.

humidity affect

increasing rate of evaporation and pressure. when air conditions are very humid, there is little difference between humidity inside and outside the leaf so transpiration is low.

abiotic factors that affect the rate of transpiration

light, temp, humidity, wind

what is phloem

lines of living cells w/ water, sucrose and other dissolved biochemicals; pores between cells role - active translocation of sugar and amino acids from source (photosynthetic tissue, storage organs) to sink (fruits, seeds, roots)

define the term transpiration and explain the factors that can affect transpiration in a typical terrestrial plant

make sure you know this

outline the role of phloem in the active translocation of biochemicals

phloem allows the moving around of food. phloem have sieve tubes that transport organic compounds. column cells develop into sieve tubes by breaking down nuclei and cytoplasm, making large pres in their walls to allow the flow of sap. the plasma membrane pumps organic compounds of solute causing water to diffuse, resulting in a positive oppresive gradient allowing organic compounds to be pumped anywhere in the plant and sucrose and use of compounds

outline the role of the phloem in the active translocation of biochemicals

phloem is composed of sieve tubes. sieve tubes are composed of specialized cells. Phloem transports organic compounds throughout the plant. the transport process is called translocation. phloem links parts of the plants that need a supply of sugars and solutes to other parts that have a surplus. they transport organic compounds from sources to sinks.

xerophytes

plants that are adapted to grow in very dry habitats such as deserts (ex: cactus)

state two types of meristem found in plants

shoot apical and lateral

explain how manipulation of day length is used in the production of flowers

some flowering plants are short day plants, others are long day plants, important variable is length of darkness/photoperiod, some plants grown in greenhouses w controlled light condition, short day plants kept in dark during daylight hours, long day plants are artificially lit during the night, possible to expose only for bright periods to keep costs down but long enough to interrupt the dark period

where do plants transport organic compounds to and from

sugars and other organic compounds are unloaded from phloem sieve tubes in parts of the plant called sinks.

what generates tension forces in leaf cell walls

tension causes the water to move up to the leaves. tension forces generated in the leaves by transpiration are due to the adhesive properties of water. when water evaporates from mesophyll cell walls in the leaf, more water is drawn through narrow cellulose-lined pores in leaf cell walls from the nearest xylem vessels to replace it, generating the tension.

explain how high concentrations of solutes in the phloem at the source lead to water uptake by osmosis

the high concentrations of solutes such as sugars in the phloem sieve tubes at the source lead to water uptake by osmosis and high hydrostatic pressure.

what characteristic of water allows transport along hydrostatic pressure gradients

the incompressibility of water allows transport along hydrostatic pressure gradients. hydrostatic pressure is pressure in a liquid

structure labeled y and its function

the inner one is xylem - function is mechanical support

what causes stomata to close

the presence of abscisic acid

what is xylem

the vascular tissue in plants that conducts water and dissolved nutrients upward from the root and also helps to form the woody element in the stem. function - water and mineral transport from roots to aerial parts of the plant

three adaptations of xerophytes that allow them to conserve water

thick waxy cuticle covering leaves, few stomata that are sunken in pores, cells that allow the lead to curl up

state two methods by which terrestrial plants support themselves

thickened cellulose and lignified xylem

dicotyledons

two cotyledons, reticulated ventilation, tap loops with lateral bunches, floral organs come in multiples of 4 or 5, stem vascular arrangement in a ring, pollen comes in three furrows/pores (trisulcate)

wind affect

under dryer conditions w/wind to blow away the boundary layer, the concentration gradient of water vapor is greater so transpiration increases

what role does the cohesive property of water and the structure of the xylem vessels play

xylem is a tissue in plants that provides support and transports water. xylem vessels are the main transport route for water. the main movement in xylem is from the roots to the leaves, to replace water losses from transpiration. pulling forces cause the water to move up to the leaves. tension can be transmitted from one water molecule to the next because of the cohesive property of water molecules that results from hydrogen bonding.