Structure of Chloroplast and the Role of Pigments Flashcards
the process by which plants use sunlight, water, and carbon dioxide to create oxygen and energy in the form of sugar.
- occur in chloroplast
photosynthesis
plant cell organelles that convert light energy into relatively stable chemical energy via the photosynthetic process. By doing so, they sustain life on Earth
- is a cell organelle in most
autotrophs that can convert solar energy
into reusable chemical energy.
chloroplast
a pigment present in all green plants and a few other organisms. It is required for photosynthesis, which is the process by which light energy is converted into chemical energy.
- greenish pigment which
captures the energy of sunlight.
chlorophyll
a generic term for a molecule that absorbs light and has a color.
- also have importance related to food production in plants
- organic molecules
- selectively absorb light of specific wavelengths
- built in thylakoid membrane (for photosynthesis 1 and 2)
pigment/photopigment
What does reflected light do?
gives each pigment its characteristic color.
an organism that can produce its own food using light, water, carbon dioxide, or other chemicals. Because they produce their own food, they are sometimes called producers. Plants are the most familiar type
- they perform this in their chloroplast
autotrophs
parts of chloroplast
- inner and outer membrane (chloroplast envelope)
- intermembrane space
- stroma
- thylakoid (grana/granum)
- lamella
- lumen
part of chloroplast
contains porins and is therefore freely permeable to small molecules.
outer membrane
part of chloroplast
the region between the inner membrane and the outer membrane of a mitochondrion or a chloroplast. The main function is nucleotide phosphorylation, mitochondrial energetics and apoptosis
intermembrane space
part of chloroplast
fluid filling up the inner space of the chloroplasts which encircles the grana and the thylakoids. In addition to providing support to the pigment thylakoids, they are now known to contain chloroplast DNA, starch, and ribosomes along with enzymes needed for the Calvin cycle.
stroma
part of chloroplast
tiny compartments found inside chloroplasts. Their role is to help absorb sunlight in order for photosynthesis to occur. They contain all of the chlorophyll that the plant has which, in turn, allows for the absorption of sunlight.
thylakoid
part of chloroplast
- stack of thylakoid
- increases the surface area of thylakoid membranes thereby elevating the sugar production of plants through the process of photosynthesis.
grana/granum
part of chloroplast
connect thylakoids of two different grana. They increase the efficiency of photosynthesis by keeping grana at a distance so that they do not clutter together. They are also known as stroma thylakoids. They ensure that maximum energy from sunlight is captured in photosynthesis.
lamella
part of chloroplast
a continuous aqueous phase enclosed by the thylakoid membrane. It plays an important role in photophosphorylation during photosynthesis. During the light-dependent reaction, protons are pumped across the thylakoid membrane into this making it acidic down to pH 4
lumen
What does the color of the plants do?
- attract consumers
- allows them to become the primary producers in ecosystems by harnessing solar energy to produce high-energy organic molecules.
how do we see colors
through the photo receptors in our eyes (what we see is the reflected light)
principal pigment
chlorophyll A
this pigment participates directly in light reactions which absorbs mainly blue, violet, and red colors of visible light (Attached to functional group CH3 - methyl group)
- all plants, algae, and cyanobacteria
chlorophyll A (C55H72MgN4O5)
Accessory Pigments - light-absorbing compounds, found in photosynthetic organisms, that work in conjunction with chlorophyll a.
- Chlorophyll B, C, D
- Carotenoids
- Phycobilins
absorbs mainly blue and orange light but reflects olive green (attached to functional group CHO - Aldehyde)
- does not participate directly in light reactions
- present only in green algae and higher plants (volvox)
- breaks down faster than the other pigments
chlorophyll B (C55H70MgN4O6)
difference of chlorophyll a and b
functional group
where is chlorophyll c (C55H30MgN4O5) present
(blue-green color)
brown algae, members of family chromista, etc.
where is chlorophyll d present
red algae
various shades of red, yellow, and orange
- absorbs mainly violet, blue, and green light
- appear once the chlorophyll breaks down
- evident in autumn leaves in temperate regions and in many of our fruits and vegetables, such as ripe bell peppers.
- This pigment is essential in
photoprotection. These pigments also convey
light energy harvested from other bands of the
visible light from the sun.
carotenoids
the biochemical process that helps organisms cope with molecular damage caused by sunlight.
photoprotection
two types of carotenoids
- carotenes (alpha-carotene, beta-carotene, lycopene)
- xantophyll - lutein and fucoxanthin
xantophylls vs. carotenes
xanthophylls (yellow/brown) contain oxygen atoms in the form of a hydroxyl group (making them slightly more hydrophilic) or epoxides while carotenes (red/orange) are molecules with only hydrocarbons and no oxygen.
- found in red algae and cyanobacteria
- water-soluble, present in the aqueous cytoplasm or stroma of chloroplasts
- especially important for deep-sea red algae as they can utilize the blue light that can penetrate into deeper waters.
phycobilins
(phycobilin) the bluish pigment present in
cyanobacteria
phycocyanin
(phycobilin) the reddish pigment present in Rhodophyta
phycoerythrin
the brown pigment (ex: kelps, diatoms, brown algae)
fucoxanthin
yellow pigments (vegetables and fruits)
zeaxanthin
yellow-brown pigments (papaya, prunes, etc)
xanthophylls
purple/red pigments (berries)
anthocyanin
what compound in xanthophyll creates the yellow pigment in leaves
lutein
structure of chlorophyll
porphyrin head with magnesium core and phytol tail (hydrophobic)
