Photosynthesis Flashcards
What is the purpose of photosynthesis?
To synthesize carbohydrates
(i.e glucose) using the Sun’s energy
Where is photosynthesis located?
chloroplast
What is the general equation for photosynthesis?
6CO2 + 6H2O 🡪 C6H12O6 + 6O2
What is light also known as?
electromagnetic radiation
A form of energy that travels in wave
packets are called ….
photons
Photons w/ short wavelengths have
____________, long wavelengths have _____________
high energy, low energy
Sunlight contains photons of
every ___________________.
wavelengths
What is visible light?
A small part of the electromagnetic
spectrum and utilized for photosynthesis
What does the range 380-750
nm mean?
That pigments absorb light in this
range
What is Photoelectric Effect?
Formation of electrically charged
particles in matter when illuminated
by light.
What are chloroplasts?
A cell organelle found in plants and algae.
Site of photosynthesis, where light energy is converted into chemical energy
What is stroma?
rich semi-liquid inside the chloroplast where calvin cycle occurs
What is Thylakoids?
membrane bound sacs
Membranes contain ________ & ________.
chlorophyll & ETC’s
Stacked thylakoids are called
grana (plural)
What is chlorophyll
Green colored pigment found in
chloroplasts, it reflects a green light
What is Lamellae?
unstacked thylakoid
On average, in one chloroplast
there are __ grana, with ________
thylakoids each
60 grana, 30-50 thylakoids
What are Pigment molecules?
They are molecules that absorb light.
Why do plants have many different types of pigment molecules?
Because each absorbs light in a different region of the spectrum.
Pigment molecules appear the color of the light wavelength they _______.
Reflect
What does chlorophyll do?
Absorbs light energy and begins the
process of Photosynthesis
2 Types of Chlorophyll?
a and b
What is Chlorophyll a?
Primary pigment for photosynthesis.
Reflects green light (why plants appear green).
What is Chlorophyll b?
Acts as an accessory pigment that helps capture more light energy.
Absorbs photons that chlorophyll a
absorbs poorly or not at all
What are Carotenoids?
Orange and yellow accessory pigments
Example: β-carotene = orange colour
of carrots and autumn leaves.
What do Carotenoids do?
Absorb light which would
otherwise damage chlorophyll
Then loses the energy as heat
Where are Photosystems located?
In the thylakoid membrane
What are photosystems made up of?
Made up of chlorophyll molecules,
accessory pigments and proteins
Photosystems contains…
Antenna complex and reaction centre
What is Antenna complex?
A group of pigments (including chlorophylls and carotenoids) that capture light energy and transfer it to the reaction center. It acts like a “light-harvesting” system.
What is reaction centre?
The part of the photosystem where light energy is converted into chemical energy. It’s where chlorophyll a absorbs light and excites electrons, starting the electron transport chain.
PSI (P700) also known as photosystem 1 – chlorophyll a absorbs wavelengths of light at _____
700nm
PSII (P680) also known as photosystem 2 – chlorophyll a absorbs
wavelengths of light at _____
680nm
P/S is most efficient when..
PSI and PSII work
together (called non-cyclic
photophosphorylation)
3 components of light reactions
Photoexcitation
ETC
Photophosphorylation
What is Photophosphorylation?
Photophosphorylation is the process of generating ATP using light energy during the light-dependent reactions of photosynthesis.
In simple terms, it’s the creation of ATP using the energy from sunlight.
What is photoexcitation?
Photoexcitation is when a particle, like an electron, absorbs light energy and moves to a higher energy state.
What is chemiosmosis?
The process of using proton gradient (H+) across a membrane to produce ATP. Ex. ETC with ATP synthetase
What is gradient?
The buildup of protons (H+) on one side of the inner membrane, more buildup = higher concentration of protons (H+).
