Honors Biology Chapter 11 - Photosynthesis

photosynthesis

converts light energy from the sun into chemical energy in the form of an organic compound

the organic compound formed in photosynthesis

carbohydrates

where does photosynthesis occur

in different parts of the chloroplast found in the cells of plants and algae

autotrophs use this process to…

obtain energy necessary to carry on life processes

label a chloroplast

grana

thylakoids connected and layered to form stacks

thylakoids

a system of membranes that are arranged as flattened sacs

stroma

the solution around the grana

photosynthesis equation (biochemical pathway)

6CO2 + 6H2O --→ 6O2 + C6H12O6

what does photosynthesis provide

energy necessary for life

2 stages of photosynthesis

Light dependent reactions; Calvin Cycle (Independent reaction)

visible spectrum

light appears white but is a variety of colors

white light can be separated…

into its component colors by passing through a prism

when white light strikes an object, it’s component colors can be…

absorbed, reflected, or transmitted by the object

which colors are visible? absorbed, reflected, or transmitted?

reflected

pigments

substances containing light-absorbing substances during photosynthesis

where are pigments found

in the thylakoids

chlorophyll

the primary pigment in photosynthesis

2 types of chlorophyll

chlorophyll A and chlorophyll B

chlorophyll A

absorbs less blue light but more red light and it’s the only chlorophyll directly involved in the light reaction of photosynthesis

chlorophyll B

an accessory pigments that assists chlorophyll A in capturing light energy

what color light does chlorophyll B absorb

blue

what color is not absorbed by chlorophyll and why

green; it is reflected

carotenoids

an accessory pigment; compounds that include yellow, orange, and brown

plants can’t change light energy directly…

into organic compounds

photosystem

group of pigments and proteins that help capture light to change into chemical energy

number of photosystems

2

the 2 photosystems: similarities and differences

contain similar kinds of proteins and pigments, but have different roles in the light reaction

light dependent reaction

energy is captured from sunlight and converted to chemical energy, which is temporarily stored in ATP

reactants of the light dependent reaction

sunlight and water

products of the light dependent reaction

ATP, oxygen, NADPH; (oxygen is released as a waste product)

where does the light dependent reaction occur

in the thylakoids of the chloroplast

the light dependent reaction steps (key words)

accessory pigment, photosystems, energy, electrons, chlorophyll A, energized electrons, excited electrons, oxidation reaction, primary electron accepter, electron transport chain, protons, H+ ions, NADP+, NADPH

step 4 of the light dependent reaction

Excited electrons have enough energy to leave the chlorophyll A molecules. Because they lost electrons, the chlorophyll A molecules have undergone an oxidation reaction

primary electron accepter

the accepter of electrons lost during the light dependent reaction

energy they (molecules that make up the ETC) lose is used…

to move protons (H+ ions) into the thylakoids

the electrons have to be replaced or…

photosynthesis stops

where do the electrons come from (full steps)

electrons in photosystem I are replaced by the electrons coming from photosystem II; the electrons in photosystem II are replaced by water when an enzyme splits water into electrons, oxygen, and H+ ions

H+ ions and ___ travel together

electrons

what do the combined oxygen atoms form

oxygen gas

H+ ions accumulate inside the…

thylakoids that provide energy to produce NADPH and ATP

the main energy currency of cells

ATP

An important part of the light reaction is the synthesis of ATP through a process called…

chemiosmosis

NADP

an electron accepter

nicknames for the Calvin Cycle

light independent reaction, dark reaction, carbon fixation

Calvin Cycle

organic compounds are formed using the CO2 and the chemical energy stored in ATP and NADPH

where did the ATP and NADPH needed for the Calvin Cycle come from

stage 1

how many times does the Calvin Cycle go through

twice

enzymes are needed for the..

Calvin Cycle

where does the Calvin Cycle occur

in the stroma of the chloroplast

reactants in the Calvin Cycle

CO2, ATP, and NADPH

products of the Calvin Cycle

glucose or another organic compound (ex: cellulose); ADP; NADP+

steps of the Calvin Cycle (key words)

CO2, 5-Carbon compound, 6-Carbon compound, 3-Carbon compound, 3PGA, G3P, organic compounds

stomata

small pores on the underside of the leaf that control water loss, amount of oxygen leaving, and amount of carbon dioxide coming in

3 things that affect photosynthesis

the amount of light, temperature, and the amount of CO2