Sapling Chapter 8
component of chloroplast that is the site of light-dependent reactions
thylakoids
all the events that occur during light-dependent reactions
- a concentration gradient forms as excited electrons help move H+ ions - light energy is used to excite electrons on specific chlorophyll molecules H+ ions are used to help produce energy carriers, ATP and NADPH
heterotrophs
- consumers - unable to produce organic compounds from inorganic materials - obtain their food by consuming other organisms - rely on other organisms for energy
characteristics of photsynthesis
- occurs in the chloroplasts of plant cells -requires sunlight to proceed - synthesizes carbohydrates to store energy
Unique to Photosystem II
- the hydrogen atoms from water molecules are split, producing H+ and replacement electrons for chlorophyll molecules - energy from electrons excited in this photosystem is used to help pump H+ ions into the thylakoid for ATP production
Thylakoid
A flattened membrane sac inside the chloroplast, used to convert light energy into chemical energy.
arrange the events of the light dependent reactions of photosynthesis
1. electrons on specific chlorophyll molecules are excited by light 2. electrons escape from chlorophyll molecules and move down an electron transport chain 3. hydrogen ions are pumped into the interior of the thylakoid 4. H+ ions pass through an enzyme as they move out of the thylakoid 5. ATP and NADPH are produced
Carotenoids
Absorb violet-blue light Reflect and transmit yellow, orange, and red light
NADPH
An electron carrier involved in photosynthesis. Light drives electrons from chlorophyll to NADP+, forming NADPH, which provides the high-energy electrons for the reduction of carbon dioxide to sugar in the Calvin cycle.
Molecules brought in and used in the Calvin Cycle
Carbon dioxide NADPH
molecules produced during the calvin cycle and leave the cycle
NADP few G3P
Chlorophyll a absorbs
blue and red light
Molecules brought in and used in the Calvin Cycle
carbon dioxide molecules carrying energy from the light-dependent reactions
photosynthesis reactants
carbon dioxide and water
in which phase of the Calvin cycle is 3PGA created
carbon fixation
molecules produced in the Calvin Cycle that leave the cycle
energy rich 3- carbon molecules energy-carrier molecules that have lost some energy
Stroma
fluid portion of the chloroplast; outside of the thylakoids
both photosynthesis and respiration.
generates ATP generates energy using a proton H+ gradient occurs in plants requires an electron transport chain
molecules made in the cytoplasm from the products of the Calvin Cycle
glucose
Photosynthesis products
glucose and oxygen
both light-dependent and calvin cycle
happen inside the chloroplasts in plants
produced by light dependent reactions
high-energy NADPH and ATP
Consider what happens to energy in photosynthesis. How does this differ from what happens in to energy in cellular respiration?
in photosynthesis, energy is captured from light, whereas in cellular respiration energy is transferred from storage molecules to ATP
energy source for photosynthesis
light
unique to both photosystems
light energy is used to excited an electron on specialized chlorophyll molecules
Chlorophyll b absorbs
mainly blue and orange/red light (reflects yellow-green)
molecules used and regenerated within the Calvin Cycle
most G3P RuBP
characteristics of stomata in plants
permit carbon dioxide to enter and oxygen to escape from a plant are pores enclosed by guard cells that are located on plant surfaces
Why do most plants appear green?
pigments in plant cells absorb blue and red light, but much of the green light is reflected
autotrophs
producers many use photosynthesis to produce organic compounds use inorganic materials to produce energy synthesize their own food
which of the following statements describe photosynthesis?
produces sugars for the plant using the energy from the sunlight is a cellular process that occurs in the chloroplasts of plant cells converts carbon dioxide to sugars, releasing oxygen
characteristics of cellular respiration
released carbon dioxide occurs in both plant and animal cells
Granum
stack of thylakoids
What is a direct effect of the absence of carbon dioxide during photosynthesis?
the carbon fixation stage of the Calvin Cycle would be unable to synthesize the sugar 3-PGA
unique to photosystem I
the energized electrons are used to form NADPH after leaving this photosystem electrons from the electron transport chain are used to replace electrons lost from chlorophyll molecules
which statement describes the function of photosynthetic pigments in leaves
they capture light energy and remove electrons from a donor
light-dependent reactions
use H20 capture light energy synthesize ATP and NADPH generate oxygen gas
Calvin Cycle
use carbon dioxide produce sugars need ribulose bisphosphate
Needed for light dependent reactions
water, sunlight, chlorophyll
