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160 Cards in this Set

  • Front
  • Back

autotroph

uses inorganic substances such as water and carbon dioxide to produce organic compounds


- makes their own food


heterotroph

organism that obtains carbon by consuming preexisting organic molecules


-consumes other organisms

organisms that can produce their own food

underlie every ecosystem on earth

photosyntheis

process by which plants, algae, and some microbes harness solar energy and convert it into chemical energy

photosynthesis uses

water and releases oxygen gas as a byproduct

photosyntheisis is important beause

-animals, fungi and other consumers eat the leaves, stems, roots, flowers, nectar, fruits, and seeds of the worlds autotrophs


-provides food for the plan


-raw materials and oxygen that most heterotrophs need

this takes light energy to assemble co2 into glucose

photosynthesis

uses: carbon dioxide, water, and sunlight

makes: glucose and O2(oxygen)

photosynthetic pigments

capture sunlight

electromagnetic spectrum

range of possible frequencies of radiation


- contains discrete packets of kinetic enery called photons

photon

a discrete packet of kinetic energy in ll electromagnetic radiation

wavelength of a photon

the distance it moves during a complete vibration


the shorter the wavelength

the more energy it contains

the longer the wavelength

the less energy it contains

most abundant pigment molecule that captures light enery is

chlorophyll a

cholorophyll a

green photosynthetic pigment in plants, algae, and cyanobacteria

green photosynthetic pigment in plants, algae, and cyanobacteria

chlorophyll a

accesory pigments

energy capturing pigment molecules other than chlorophyll a

energy capturing pigment molecules other than chlorophyll a

accessory pigments

chlorophyll b and carotenoids are

accesory pigments in plants

chlorophyll a is

most abundent pigment molecule in plant cells

chlorophylls a and b absorb__________ wavelengths

red and blue

plants appear green because

they reflect green light

carotenoids

reflect longer wavelengths of light, so they appear red, orange, or yellow ( carrots, tomatoes, lobster shells)

only ______ is useful in photosynthesis

absorbed light

______ absorb wavelengths that chlorophyll a cannot

accesory pigments

visible light is in the _________ of the electromagnetic spectrum

middle range

wavelentghs in visible light: shortest to largest

violet, blue, cyan, green, yellow, orange, red

plants benefit by having multipe types of pigments because they can then

abosrb more wavelengths

chlorophyll molecules reflect green and yellow wavelenths of light and absorb the other wavelengths

each pigment absorbs some wavelentghs of light and reflects others

chloroplasts are the site of

photosynthesis

in plants, _____ are the main organs of photosynthesis

leaves

plants must exchange CO2 and O2 with the atmosphere through

stomata( stoma)

stoma/stomata

tiny openings in the epidermis of a leaf or stem


-tiny dent in membrane walls like seen in telescope of lab

tiny opening in the epidermis of a leaf or stem

stoma

the collective term for these internal cells of a leaf where most photosynthesis occurs

mesophyll

meso

middle

phyll

leaf

mesophyll cells contain

bbundant chloroplasts

stroma

gelatinous fluid containing ribosomes, DNA, and enzymes

gelatinous fluid containing ribosomes, DNA, and enzymes

stroma

stoma

leaf pore

in the stroma of each chloroplasts are

between 10 to 100 gana

grana( singular: granium)

-are in stroma of each chloroplast


-composed of thylakoids

thylakoid

consists of a membrane studded with photosynthetic pigments and enclosing a volume called the thylakoid space

tissue inside a leaf is called

mesophyll

each mesophyll cell contains multiple

chloroplasts

a chloroplast contains

light harvesting pigments

light harvesting pigments in chloroplast are embedded in

stacks of thylakoid membranes that make up each granum

pigments and proteins that particpate in photosynthesis are groupd into __________ in the thylakoid membrane

photosystems

photosystem

consists of chlorophyll a aggregated with other pigment molecules and the proteins that anchor the entire complex in the membrane

although all pigment molecules absorb light energy only

one chlorophyll a molecule per photosystem actually uses the energy in photosynthetic reactions

chlorophyll a molecule and its associated proteins

the photosystems reaction center

reaction center of a photosystem

is chlorophyll a molecule and its associated proteins

all other pigment molecules in the photosystem are called

antenna pigments

antenna pigments

- are all other pigment molecules int eh photosystems


-capture photon energy and funnel it to the reaction center

relationship among the chloroplast, stroma, grana, and thylakoid

thylakoids make up a granum, grana are found in stroma, stroma is the fluid part in the inside of chloroplasts double membrane

antenna pigments pass energy on to the reaction center

reaction center then participates in photosynthetic reactions

inside the chloroplast, photosynthesis occurs in two stages=

light reactions


carbon reactions

______ convert solar energy to chemical energy

light reactions

light reactions

photo-

in thylakoid membranes, pigment molecules in two linked photosystems capture kinetic energy from photons and store it as

potential energy in the chemical bonds of two molecules: ATP and NADPH

ATP

-energy rich product of light reactions


a nucleotide that stores potential energy in the covalent bonds between its phosphate groups


- forms when a phosphate group is added to ADP

NADPH

-energy rich product of light reactions


-a molecule that carries paris of enerized electrons... in photosynthesis these electrons come from chlorophyll molecules

O2 is released as a byproduct because

once the light reactions are underway, chlorophyll in turn, replaes its lost electrons by splitting water molecules

ATP

energy

NADPH

loaded electron carriers

_________ use ATP and the high energy electrons in NADPH to reduce CO2 to glucose molecules

carbon reactions

carbon reactions

-synthesis

ATP and NADPH come from the

light reactions

CO2 comes from

the atmosphere

photosynthesis strips electrons from the oxygen atoms in H2O, these electrons then reduce the

carbon in CO2

moving electrons from oxygen to carbon requires energy because

oxygen atoms attract electrons more strongly than do carbon atoms

energy source for moving electrons from oxygen to carbon is

light

in carbon reactions

co2 from the atmopshere enters the leaf and diffuses into a mesophyll cell and across the chloroplast membrane into the stroma where the carbon reactions occur

in light reactions

pigment molecules between two linked photosystems in thylakoid membranes capture kinetic energy from photons and store it as potnential energy in the chemical bonds of either ATP or NADPH

in light reactions

pigment molecules capture sunglight energy and transfer it to molecules of ATP and NADPH

carbon reactions use _______ to build glucose out of carbon dioxide

ATP and NADPH

H20 and light go in to ___________ and produce O2 (oxygen) as a byproduct, also produce ATP and NADPH

light reactions

co2 goes into ______ and uses ATP and NADPH to produce glucose

carbon reactions

_________ reactions begin photosynthesis

light

pigments and proteins of the chlorolasts thylakoid membranes are organized into

photosystems

the thylakoid memranes contain two types of photosystems

I and II


- electron transport chain connects the two photosystems

what connects the two photosystems

electron transport chain

a group of proteins that shuttle electrons from carrier to carrier, releasing energy with each step

electron transport chain

the electron transport chain that links photosystems I and II

stores potential energy used in ATP synsthesis

second electron transport chain extending from photosystem I ends with the production of

NADPH

order of light reactions

photosystem II, electron transport chain, photosystem I, electron transport chain, production of NADPH

in light reactions

chlorophyll molecules in photosystem II transfer light energy to electrons, electrons are stripped form water moelcules, releasing oxygen, the energized electrons pass to photosystem I via an electron transport chain. Each transfer releases energy that is used to pump hydrogen ions into the thyakoid space, the resulting hydrogen gradient is used to genereate ATP, in photosystem I the electrons absorb more light energy and are passed to NADP creating NADPH

photosystem II produces

ATP

photosynthesis begins in

-the cluster of pigment molecules of photosystem II


-these pigments absorb light and transfer the energy to a chlorophyll a reaction center, where it boosts two electrons to a higher energy level

the excited electrons in photosystem II are

ejected from this chlorophyll a molecule and grabbed by the first protein in the electron transport chain that links the two photosystems

how does chlorophyll a molecule replace the two electrons ejected and sent down the transport chain?

H2O, which dontes two electrons when it splits into oxygen gas and two protons(H+)


chlorophyll a picks up the electrons, and O2 is a waste product that the plant releases to the environment

chloroplast uses the potential energy in the electrons to

create a proton gradient

as the electrons pass along the elctron transport chain the energy they lose

drives the active transport of protons from the stroma into the thylakoid space

the proton gradient between the stroma and the inside of the thylakoid represents

a form of potential energy

ATP synthase

enzyme complex


-transforms the protons gradients protnetial energy into chemical energy in the from of ATP

in atp synthase

-a channel in atp synthase allows protons trapped inside the thylakoid space to return to the chloroplasts stroma


-as the gradient dissipates, energy is released


-the atp synthase enzyme uses this energy to add phosphate to adpm genereating atp

photosystem I produces

NADPH

ATP is produced in

photosystem II

in photosystem I

the electrons reduce a molecule of NADP+ to NADPH


- this NADPH is the electron carrier that will reduce carvon dioxide in the carbon reactions, the ATP generated in photosystem II will provide the energy

events from beginning of photosystem II to he production of ATP

pigments abosrb light and transfer the energy to a chlorophyll a reaction center where it boosts two electrons to a higher energy lvel. these two electrons are ejected from the chlorophyll a molecule and grabbed by the first protien in the electron transport chain. As the electrons pass along the electron transport chain, the energy they lose drives the active transport of protons from the stroma into the thylakoid space. The resulting proton gradiant represents a from of potential energy. ATP synthaze (enzyme complex) transforms the gradients potential energy into chemical energy in the form of ATP

carbon reactions produce

carbohydrates

carbon reactions

albin cycle

carbon reactions/ calvin cycle occurs in

chloroplasts stroma

calvin cycle is

the metabolic pathway that uses NADPH and ATP from the light reactions to assemble CO2 molecules into three carbon carbohydrate molecules

the metabolic pathway that uses NADPH and ATP from the light reactions to assemble CO2 molecules into three carbon carbohydrate molecules

calvin cycle/ carbon reactions

first step of calvin cycle is

carbon fixation- initial incorporation of carbon from CO2 into an organic compound

carbon fixation

- first step of the carbon reactions


- CO2 combines via rubisco with RuBP


initial incorporation of carbon from CO2 into an organic compound

carbon fixation

ribulose biphosphate(RuBP)

five carbon sugar with two phosphate groups

rubisco

an enzyme that catalyzes carbon fixation

carbon fixation combination of CO2 and RuBP

turns into PGA then PGAL then rearranged to form additional RuBP.


Cell can use PGAL to build larger carbs such as glucose and sucrose

plants cells use about ___ of the glucose as fuel for their own cellular respiration

half

_______ are the building blocks of the cellulose wall that surrounds every plant cell

glucose molecules

excess glucose than it immediatiely needs for respiration or buildig cell walls is stored as

starch

what happens in carbon reactions

CO2 combines with RuBP and is catalyzed by rubisco then turns into PGA then PGAL then rearranged to form additional RuBP

in calvin cycle

1.carbon dioxide is added to RuBP, creating an unstable molecule


2.the unstable intermediate splits to form PGAL


3.PGAL molecules are combined to form glucose which is used to form starch, sucrose, and other organic molecules


4.RuBP is regnereated by arranging the remainng molecules


5.cycle repeats

roles of CO2, ATP, and NADPH in the calvin cycle

co2- combines with RuBP to create an unstable balance and initiate the carbon cycle


ATP and NADPH- power calvin cycle

calvin cycle is also known as the

C3 pathway

C3 pathway

three carbon molecule, PGA, is the first stable compound in the pathway


all plants use the calvin cycle

true

C3 plants use

only c3 pathway to fix carbon from CO2

__% of plants are c3

95%

c3 photosnthesis is a succesful adaptation but it does have a weakness

inefficiency

photosysnthesis has a theoretical efficiency rate of

30%

photosrespiration

a series of reactions that begin when the rubisco enzyme uses O2 instead of CO2 as a substrate


- so plant loses co2 tat it has already fixed, wasting both ATP and NADPH

photorespiration is most likely in

hot, dry climates

under what conditions does photorespiration become much more likely and photosynthetic effieciency plumets

when the plant closes its stomata, CO2 supplies in the leaves run low while O2 builds up

in hot climates plants that minimize photorespiration may therefore have a

significant competitive adcantage

one way to imporve efficiency in photosynthesis is to

ensure that rubisco always encounters high CO2 concnetrations

C4 and CAM pathways are

two adaptations to imporve effiency of phototsynthesis through making sure rubisco always encounters high CO2 concentrations

C4 cells

-physically separate the light reactions and the carbon reactions into different cells


- light reactions occur in mosphyll cell, as does a carbon fixation reaction called the C4 pathways

C4 pathway

co2 combines with a three carbon molecule to orm a four carbon compound


- this molecule then moves into adjacent bundle sheath cells that surround the leaf veins


-co2 is liberated inside these cells, where the calvin cycle fixes the carbon a second time by the C3 pathway

bundle sheath cells

cells that surround the leaf veins


-are not exposed direcly to atmospheric O2


-making rubisco in bundle sheath ells more likely to bind CO2 instead of O2, reducint photorespiration


-the three cabon molecule returns to the meophyll to pick up another O2 at the cost of two TP molecules

__% of plants use the C4 pathway and those that do are flowring plants growing in hotm open enviornments( crabgrass, sugar cane, and corn)

1

another way to improve efficiency of phoosynthesis by rubisco having high CO2 concentrations is

CAM pathway

CAM pathway

crassulacean acid metabolism


-3-4% of plant species


-pineapple and cacti


In cam pathway plants

-open their stomata to fix CO2 only at night when the temperature drops and the humidity rises


-CO2 diffuses in


-mosophyll cells incorporate the CO2 into a four carbon compound which they store in large vacuoles


-stomata close during the heat of the day, but the stored molecule moves from the vacuole to a chloroplast and releases its CO2.


-the chloroplast then fixes the CO2 in the calvin cycle

the CAM pathway reduces photorespiation by

generating high CO2 concentrations inside chloroplasts

all cam plants are adapted to

dry habitats

in cool environments _____ plants cannot compete with _____ plants

CAM, C3

CAM plants stomata are only open at

night... therefore they have much less carbon available to their cells for growth and reprodcution

calvin cycle is also called the C3 pathways becasue

three carbon molecule, PGA, is the first stble compound int the pathway

how does photorespiration counter photosynthesis

the rubisco enzyme uses O2 instead of CO2 as a substrate, so plant loss CO2 wasting both ATP and NADPH

describe how a C4 plant minimizes photorespiration

-co2 combines with a three carbon molecule= C4


-C4 then moves into bundle sheath cells that surround the leafs veins


-co2 is then liberated inside these cells where the calvin cycle fixes the carbon a second time by the C33 pathway

how is the CAM pathway like the C4 metabolism and how is it different

CAM pathway is like C4 metabolism in that they both take on different forms to counter the effects of photorespiration and they both result in the calvin cycle fixing the carbon, yet the CAM pathway plants only open their stomata at night so they get high humidity and low temperatures

c3 plant

co2 goes into mesphyll cell turns into 4 carbon molecule then into bundle sheath cell where it goes through calvin cycle and comes out glucose

CAM plant

co2 goes into mesophyll cell at night turns into 4 carbon molecules then into calvin cycle and out glucose at day

limitation of c3 plant

photorespiration

limitation of c4 plant

atp cost

limitation of CAM plant

reduced carbon availability

how c4 plants avoid photorespiration

light reactions and carbon reactions occur in separate cells

how CAM plans avoid photorespiration

co2 is absorved at night; light reactions and carbon reactions occur during the day

c3 plants habitat

cool, moist

c4 plant habitat

hot, dry

cam plant habitat

hot, dry

percent of c3 species

95%

percent of c4 species

1%

percent of cam species

3-4%