Biology 1115 chapter 10
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Biology 1115 chapter 10
What is photosynthesis?
the process that converts
What are autotrophs? (2)
of the biosphere
sustain themselves without eating anything from other organisms
Photosynthesis occurs in _____________ (4)
plants, algae, certain other protists, and some prokaryotes
-protists don't have chloroplasts
What are heterotrophs? (3)
they obtain their organic material from other organisms
food and oxygen
Describe the structure of a chloroplast. (5)
: outer and inner membrane
: surrounded by thylakoid space
: stacked thylakoid
: jelly like substance
How do leaves get their green colour?
, the green pigment within chloroplasts
Where is the major location of photosynthesis?
in the leaves
pores on the surface of the leaves
Where are chloroplasts usually found in the leaves?
found mainly in the cells of
, the interior tissue of the leaf
Where is chlorophyll located on the leaf?
membranes of thylakoids
What is the equation for photosynthesis?
6carbon dioxide +light energy ---> glucose and 6oxygen
What reactant is oxidized and reduced in photosynthesis?
What are the two reactions in photosynthesis?
light reactions and dark reactions (Calvin cycle)
What is the brief overview of the light reaction? (4)
generate ATP from ADP by
Where does light reaction take place?
where does dark reaction take place?
What is the function of the Calvin cycle (dark reactions)?
from CO2, using ATP and NADPH
What is made in the light reaction and consumed in the dark reaction?
Light is a form of ________________.
What is visible light?
consists of wavelengths that
we can see
How does the size of the wavelengths effect levels of energy?
: more energy
: less energy
Define wavelength. (2)
distance between crests an waves
determines the type of electromagnetic energy
What are photons?
discrete particles in light
What are pigments?
are substances that
absorb visible light
Why do leaves appear green?
because chlorophyll absorbs all colours and reflects/transmits green light
What happens to wavelengths that are not absorbed?
they are reflected or transmitted
Define chlorophyll a. (2)
main photosynthetic pigment
violet-blue and red light work
best for photosynthesis
What is the function for chlorophyll b?
accessory pigment that
the spectrum used for photosynthesis
What is the function for carotenoids?
accessory pigment that
absorbs excessive light
that would damage chlorophyll
When a pigment absorbs light, it goes from _________ to ___________, which is unstable.
a ground state
an excited state
How does fluorescence occur?
excited electrons fall back to the ground state,
photons are given off
What is a
consists of a
(a type of protein complex) surrounding light-harvesting complexes.
Define light-harvesting complexes.
pigment molecules bound to proteins that
funnel the energy of photons to the reaction center
what is the function of primary electron acceptor? where is found?
is in the reaction centre
accepts an excited electron from chlorophyll a
(first step of light reaction)
Define photosystem 2.
functions first and best at absorbing a wavelength of
Reaction center called P680
Define photosystem 1.
functions second and is best at absorbing a wavelength of
reaction center called P700
What are the two possible routes of electron flow in light reactions?
linear electron flow
cyclic electron flow
What is linear electron flow?
the primary pathway,
involves both photosystems
ATP and NADPH
using light energy
What is cyclic electron flow?
only photosystem 1
, but NOT NADPH
generates surplus ATP
What happens when a photon hits a pigment in photosystem 2? (1st step)
is passed among the pigment molecules until it
What happens to the excited electron from P680 in photosystem 2? (2nd step)
the excited electron is
primary electron acceptor.
P680+ is a very strong ______________.
what happens in the 3rd step of linear electron flow in photosystem 2, involving water?
water is split by enzymes, and the electrons are transferred from the hydrogen atoms to P680+, reducing it from P680+ to P680.
What is released as a by-product in the third step of linear electron flow, involving water?
What happens in the 4th step of linear electron flow, where does the electron go from PS2?
electron falls down an
electron transport chain
primary electron acceptor from PS 2 to PS 1
What happens in step 5 of the linear electron transport flow, as the electron falls down the electron transport chain? (2)
energy released by the fall drives the creation of a
Diffusion of H+ across the membrane drives ATP synthesis
What happens in step 6 of the liner electron flow, after the electron has gone down the electron transport chain? (2)
electrons reach PS 1, where the
transferred light energy excites P700
, which loses an electron to an electron acceptor.
accepts an electron passed down from PS 2
via the electron transport chain
What happens in step 7 of the linear electron flow, after the electron has hit P700 in PS 1?
down another electron transport chain
from the primary acceptor of PS 1
protein ferredoxin (Fd)
What happens in step 8 of the linear electron flow, after the electron reaches protein ferredoxin (Fd)?
the electrons then reduce NADP+ to NADPH
What are the 2 proteins used in the cyclic electron flow?
__________ has a lower pH than ________.
What are the products and reactants in the Calvin cycle? (2)
Carbon enters the cycle as
and leaves as a sugar named
does not release oxygen
What are the 3 phases in the Calvin cycle?
carbon fixation (catalyzed by rubisco)
regeneration of the CO2 acceptor (RuBP)