Bio 2 #2

Photosynthesis, Plant Transport

Xylem

used to transport water and minerals in plants

Definition of Phloem

used to transport sugars, hormones and amino acids in plants

anchors the plant and absorbs water, sometimes stores food

roots

has a waxy outer layer to limit water loss

upper epidermis

elongated cells with a high concentration of chloroplasts

palisade mesophyll

loosely arranged cells to allow gas exchange

spongy mesophyll

xylem and phloem make up the

vascular bundle

openings in the lower epidermis of a leaf that permit diffusion of CO2, water vapour and oxygen between the leaf and the atmosphere

stoma

the ___________ is the inner material of ground tissue

pith

the ____________ is the outer material of the ground tissue

cortex

the ______________ is located on the inner side of the vascular bundle

xylem

the _________________ is located on the outer side of the vascular bundle

phloem

the _____________________ runs through the middle of the vascular bundle

cambium

Stem tissues include:

vascular tissue, including both xylem and phloem, and sieve plates existing between cells of the stem.

the vascular bundles runs around the _____________ of a stem

outside

Root tissues

epidermis, cortex, vascular cylinder

the vascular bundle runs trough the _________________ of the root tissue

middle

Cortex (plants)

Specialized region in a plant root or stem for storage and support; *stores food*

What is the Casparian strip?

A water-impermeable ring of wax in the endodermal cells of plants.

What does the Casparian strip block?

The passive flow of water and solutes into the stele by way of cell walls.

Stele

The vascular tissue of a stem or root.

What is the endodermis in a root?

The region around the stele.

What is a key characteristic of the endodermis?

It is hydrophobic.

What does the endodermis restrict?

Movement of water between the cells of the stele.

water in the xylem moves in _______________________

one direction

What are tracheids?

A water-conducting and supportive element of xylem.

What is the structure of tracheids?

Composed of long, thin cells with tapered ends.

What material hardens the walls of tracheids?

Lignin.

when mature xylem tissue is ____________ allowing for __________________

dead, passive water transport

Lignin

substance in vascular plants that makes cell walls rigid

water flow from roots to leaves is called

transpiration stream

leaves have _________________ water pressure due to ___________________________

low, evaporation

roots have ________________ water pressure due to __________________

high, osmotic uptake

____________% of water is lost due to evaporation

99

water is pulled through the plant along an increasing gradient of solute due to ______________________________

sugar production

cohesion of water molecules is from the attraction of ____________________ in water

hydrogen bonds.

Adhesion of water to any surface is due to ________________________

oxygen molecules

increased surface are of roots is created by

root hairs

What is the symplast pathway?

The pathway taken by water as it moves from cell to cell.

How does water move through the symplast pathway?

By osmosis, via the cytoplasm and plasmodesmata.

What is the Apoplast Pathway?

It is a route for water movement between the cell membrane and the cell wall.

Define the Casparian Strip

It is a barrier that prevents water from crossing into the endodermis via the apoplast pathway.

How does water move into the cytoplasm of the endodermis?

Water is transferred to the cytoplasm of the endodermis through an osmotic gradient.

movement of sugars in plants is called

translocation

sources of sugar production are

leaves

storage organs of sugars are

fruits, seeds, roots

Phloem sap comprises of ______________ % sucrose

30

What are Companion Cells?

Cells adjacent to the sieve element of the phloem tube.

What is the function of Companion Cells?

They perform some of the metabolic functions of the sieve elements.

What do Companion Cells provide for the sieve elements?

Energy for active transport.

phloem loading is an _______________process and requires ___________

active, ATP

What is a hypertonic solution?

A solution in which the concentration of solutes is greater than that of the cell that resides in the solution.

How does a hypertonic solution affect a cell?

It causes the cell to lose water and shrink. Therefore drawing water by osmosis from the xylem

sap moves from _________________ to the _______________

source, sink

sieve plates are

areas where the cytoplasm of one cell makes contact with the next cell in the phloem

movement of fluid in the phloem is

bidirectional

What is a chloroplast?

Cell organelle in plants, site of photosynthesis

What are thylakoids?

inner membranes of a chloroplast, the location of photosystems I and II, and ATP synthase enzyme.

What is a Granum (pl. Grana)?

A stack of thylakoid membranes

What is a starch grain?

A storage of carbohydrate

What is stroma?

Chloroplast fluid containing chemicals (e.g. RuBP) and enzymes (eg. rubisco).

Where do the light-Dependent Reactions take place?

In the membranes of thylakoids.

What is photolysis?

Splitting of H₂O into H⁺ and O₂

What is the role of photosystem II (PSII)

It absorbs light to excite electrons, transfered between pigment molecules until they leaves PSII to enter electron transport chain.

What are chlorophyll A and B?

Photosynthetic pigments that absorbs light.

Electron Transport Chain in Thylakoid

Electrons are passed along the molecules in the membrane. Energy moves H⁺ into the thylakoid space creating a proton gradient.

What does Photosystem I (PSI) do?

Absorbs light to excite electrons from PSII which are used to reduce NADP⁺ into NADPH.

What is chemiosmosis (in photosynthesis)

H⁺ in the thylakoid space passes back into the stroma through ATP synthase.

What is ATP synthase and what does it do?

Enzyme in thylakoid membrane produces ATP when activated by H⁺ diffusing through it down the proton concentration gradient

What are the light-Independent reactions of photosynthesis?

Carbon dioxide is fixed to RuBP by rubisco in the Calvin cycle.

What is oxidative phosphorylation?

Production of ATP from ADP and Pi combining the electron transport chain and chemiosmosis

reflects

a green pigment likely ______ green light

absorbs

the chlorophyll_____best in red and blue light

blue

a 430nm pigment likely absorbs ______light

green

carotenoids absorb light in the blue and ______region of the spectrum

photosystem 1 only

P700

photosystem 2 only

oxidizes water and produce oxygen

photosystems 1 and 2

harvests light energy and contains chlorophyll

stages of calvin cycle (1,2,3)

___reduction and carbohydrate production

___carbon fixation

___regeneration of RuBP

light energy

photosynthesis is a process in which ______is used to produce ATP, NADH and O2

cholrophyl

the molecule _______captures the light energy for photosynthesis

calvin cycle

ATP and NADPH drive the _______

carbon fixation

the calvin cycle is responsible for _____ during photosynthesis

light reaction

water is converted to oxygen and releases electrons in the _________

sequence of photosynthesis in cyanobacteria

photosystem II-->ATP production--> photosystem I --> NADPH production

bacterial photosynthesis differ from plant

bacterial photosynthsis uses only one photosystem and does not produce oxygen

energy only

cyclic photophosohorylation produces

water

electrons passed down through the electron transport system are obtained from

photosystem ; water

the electrons excited by sunlight are replaced by electrons from______in photosystem I and by electrons from____in photosystem II

ferrodoxin

the high energy electrons of photosystem I are directly passed on to

stroma

the calvin cycle takes place in the ______of chloroplasts

ATP and NADPH

the calvin cycle uses______which are products of the light reaction of photosynthesis

RuBP

the calvin cycle begins by the attachment of CO2 to______

photosythesis

energy from light is captured & used to sythesis carbohydrates

non cyclic electron flow

favored when NADP is high and NADPH is low

cyclic electron flow

favored when ATP levels are low

rubisco

enzymes that catalyzes carbon fixation

photorespiration

ability of a plant to make carbohydrates and thereby limits plants growth