Bio 104 Test 3 Part 3

Front 1

Sugar transport

Back 1

-via phloem

-Phloem sap

-Movement from sugar source (where photosynthesis takes place) to sugar sink (where sugar is used or stored)

· ex. Of source: Leaves

· ex. Of sink: Roots

-Phloem sap moves from an area of greater water pressure (in source) to area of lower water pressure (in sink)

Front 2

Phloem sap

Back 2

-Phloem sap: sugars, hormones, inorganic nutrients

Front 3

Water pressure differences

Back 3

due to:

· High solutes in phloem around sugar source: water moves from xylem to phloem from osmosis

o Increases water pressure

· Low solute concentration in phloem in sink; water moves by diffusion into surrounding xylem.

o Decreases water pressure

Front 4

Plant hormones

Back 4

-Move through plant by diffusion from cell to cell, or transport through xylem/ phloem

-Bind to protein receptor on target cell and trigger cascade of events

Front 5

Auxins

Back 5

· Stem root elongation

· Control tropisms (growth patterns)

· Atypical dominance

Front 6

Cytokinins

Back 6

· Stimulate cell division in many plant parts

· Delay leaf shedding (can be used to extend shelf life of produce)

· Counter auxins by stimulating growth of lateral buds

Front 7

Gibberellins

Back 7

· Shoot elongation

· Also fruit growth (seedless grapes)

· Trigger seed germination

Front 8

Ethylene

Back 8

· Gas that triggers fruit ripening

o Artificial ripening for immature produce tomatoes

Front 9

Abscisic Acid

Back 9

· Counters many growth triggering hormones

· Maintains seed dormancy

· Triggers leaf, flower and fruit shedding

Front 10

Tropism

Back 10

Orientation of plant growth toward or away from stimulus

Front 11

Phototropism

Back 11

· Growth of plant toward or away from light

o Photoreceptors direct light, auxins migrate toward shaded part of plant.

o Cells on shaded part of plant elongate due to auxins

o Plant bends toward light

Front 12

Why are their seasonal differences in plants related to flowering and growth?

Photoperiods

Back 12

Relative length of day and night

Front 13

Photoperiods

Back 13

· Long night plants: bloom in late summer of fall

o Ex. Goldenrod; chrysanthemums

· Short night plants: flower in late spring or early summer

o Ex. Lettuce; irises

Front 14

Gravitropism

Back 14

· Growth in response to gravity

o Shoots point upward, and roots grow down

Front 15

Statoliths

Back 15

Gravity detecting, starch containing structures in roots that sink toward bottom of cells, stimulating downward growth

Front 16

Thigmotropism

Back 16

· Plant growth in response to touch

Involves specialized epidermal cells that detect contact; cause bending of tendrils

Front 17

Photosynthetic organisms

Back 17

Plants, algae, bacteria

Front 18

Photosynthesis

Back 18

-Site of photosynthesis in plants: chloroplasts

-Site of photosynthesis in plants: chloroplasts light energy to carbon dioxide + water results in glucose + oxygen

Front 19

Cyanobacteria

Back 19

-Cyanobacteria: a phylum of bacteria that obtain their energy through photosynthesis

Front 20

Chloroplasts

Back 20

-Concentrated in leaves (mesophyll tissue)

-Inner and outer membrane

Front 21

Thylakoid

Back 21

· membrane sacs inside chloroplasts

o Have chlorophyll: light capturing pigment

Front 22

Granum

Back 22

o Granum: stack of thylakoids

Front 23

Stroma

Back 23

· Stroma: fluid surrounding thylakoids

· Thylakoid space

Front 24

Visible light

Back 24

-Visible light: 380-750 nm (middle range of electromagnetic spectrum)

-Chlorophyll transmits or reflects green light and absorbs blue violet and red orange

Front 25

Photon

Back 25

-Photon: Packet of light; light absorbed in units. The shorter the wavelength, the higher the energy

Front 26

Wavelength

Back 26

distance moved during complete vibration

Front 27

Pigments

Back 27

Capture light energy

Front 28

Chlorophyll a

Back 28

· Chlorophyll a: green photosynthetic pigment in plants, algae, and cyanobacteria

o Absorbs blue violet and red light, reflect green

Front 29

Accessory pigments

Back 29

Accessory Pigments in plants; extended wavelength range to be used in photosynthesis

Front 30

Chlorophyll b

Back 30

· Chlorophyll b: absorb blue and orange; sends energy to chlorophyll a

Front 31

Carotenoids

Back 31

· absorb blue green light; reflect yellow orange

o Fall leaf colors; chlorophyll a concentration decreases in cool temperatures

Front 32

Photosystems

Back 32

pigment compartments; absorb photons; light energy passed from pigment to pigment

-final pigment is chlorophyll a

Front 33

Reaction center

Back 33

chlorophyll a

Front 34

Antenna Pigments

Back 34

accessory pigments

Front 35

Light reactions

Back 35

(produces ATP and NADPH)

· Thylakoid membrane

uses photosystem 1 and 2 embedded within thylakoid membranes

· Pigments and proteins

Front 36

Carbon reactions

Back 36

(produces sugars)

· Stroma

NADPH reduces CO2 to sugars

Front 37

Photosystem 2

Back 37

Photosynthetic reactions begin here

· Absorbance of light energy by chlorophyll a excited electrons then passed to electron transport chain

· Replacement of electrons comes from water splitting reaction, releasing oxygen

· Electrons traveling along electron transport chain generate proton (H+) gradient

· Enzyme ATP synthase uses gradient to synthesize ATP (later used in carbon reactions)

Front 38

Photosystem 1

Back 38

· Electrons excited from light energy absorbed by chlorophyll a

· Transport of electrons along electron transport chain generates NADPH (electron carrier; used in carbon reactions)

Front 39

Carbon reactions: first step

Back 39

-Carbon fixation

· CO2 changed to organic compound by action of enzyme rubisco

o CO2 combined with organic ribulose biphosphate

Front 40

Carbon reactions: Later steps

Back 40

· ATP energizes organic molecules to create glyceraldehyde-3-phosphate (3 carbons, can combine with another to form 6 carbon glucose)