photosynthesis in plants Flashcards
autotrophic organisms
make energy containing organic compounds out of inorganic sources like carbon dioxide and water
-photosynthesis
what is photosynthesis
process by which living organisms capture energy of sin using chlorophyll and use it to convert carbon dioxide and water to simple sugars
what happens with energy produced from photosynthesis
energy is transferred into the chemical bonds of organic molecules such as glucose and starch
-compounds then used as energy source by cells of plant and building blocks of other molecules like proteins
autotrophic bacteria
not photosynthetic
-use energy from chemical reactions to synthesise their food
heterotrophic organisms
eat plants or other animals that have eaten plants
-they use products of photosynthesis indirectly for making molecules and as fuels to supply energy for activities
the sun
ultimate source of energy for chemical reactions in almost all organisms
equation for photosynthesis
carbon dioxide + water = glucose + oxygen endothermic
chemical explanation of photosynthesis equation
energy from light energy split strong H-O bonds in water molecules
-hydrogen released combined with carbon dioxide to form fuel for cells (glucose)
-oxygen released into atmosphere as waste product
link of photosynthesis and cellular respiration
-photosynthesis takes in energy and used carbon dioxide and water to synthesise glucose and oxygen- endothermic
-respiration- uses glucose and oxygen to produce energy in form of ATP for cell with carbon dioxide and water as waste products- exothermic
how much chloroplast does average plant have
10-50
what is each chloroplast surrounded by
an outer and inner membrane
whats the chloroplast envelope
space between the outer and inner membrane
grana
inside chloroplast they are a system of membranes that are arranged in stacks
what is an single granum made of
made up of stacks of membrane discs called thylakoids
thylakoids
stacks of membrane discs that make up single granum
where is chlorophyll found
in the thylakoids
arrangement of chlorophyll
pigment molecules are arranged on membranes in best position for trapping light energy
what does evidence from electron micrographs show
that the granal membranes are covered in particles that seem to be involved in ATP synthesis
lamella
extensions of thylakoid membranes which connects two or more grana
what holds grana together
held together by lamellae
role of lamellae
act as skeleton within chloroplast maintaining a working distance between the grana so they get maximum light and function as efficient as possible
what are lamellae surrounded by
the stroma
what are the stroma
matrix that surrounds membrane stacks
function of the stroma
contains all enzymes needed to complete process of photosynthesis and produce glucose
use of glucose after it is made by photosynthesis
used in cellular respiration
-converted to starch for storage
-used as intermediate for synthesis of other organic compounds like amino acids and lipids
adaptation of chloroplast
their light capturing photosynthetic pigment chlorophyll
what is chlorophyll made up of
chlorophyll a
-chlorophyll b
-carotenoids
-phaeophytin
chlorophyll a
a blue green colour
-found in all photosynthesising plants and most abundant pigment
chlorophyll b
yellow green
chlorophyll carotenoids
orange carotene and yellow xanthophyll
phaeophytin
grey pigment which is breakdown product of other pigments
what do the pigments do
they capture light from particular areas of the spectrum
benefits of having multiple pigments make up chlorophyll
more energy from light falling on the plant can be used than if only one pigment was involved
what is the absorption spectrum
describes the range of amount of light of different wavelengths that a photosynthetic pigment absorbs
how are absorption spectra of pigments found
found by measuring their absorption of light of differing wavelengths
-possible to produce absorption spectrum for intact chloroplast with all pigments combined
T.W engelmann comparing rate of photosynthesis with wavelength of light
-set up strand of filamentous alga in light of different wavelengths
-used bacteria that move towards oxygen to show where the most oxygen was given off which is directly related to the amount of photosynthesis taking place
action spectrum
a way of demonstrating the rate of photosynthesis against the wavelength of light
modern action spectra
use electronic data logging rather then bacterial movements to measure rate of photosynthesis at different wavelengths of light
what do action spectra show us
that the rate of photosynthesis is very closely related to the combined absorption spectrums of all the photosynthetic pigments in a plant
what can we conclude from action spectra
range of photosynthetic pigments makes a much bigger portion of wavelength of light available to plants and gives them adaptive advantage
how can you show plants have different pigments
paper chromatography
carrying out paper chromatography
suitable solvent pigments travel up paper at different speeds and are separated
equation for Rf value
distance travelled by solute (photosynthetic pigment) / distance travelled by solvent
labels of paper chromatography
baseline
-distance travelled by pigment=B
-total distance travelled by solvent=x
-distance travelled by pigment= A
how to calculate for A Rf
A/X
how to calculate Rf for B
B/X
chlorophyll complexes
photosystem 1 and photosystem 2 in roman numerals
why are chlorophyll complexes formed
because photosynthetic pigments carry out the absorption of light in 2 complexes
why does each system absorb light in slightly different area of spectrum
because each system has a different combination of chlorophyll pigments
photosystems identified by electron micrographs
identified as different sized particles attached to membranes in the chloroplast
where are PS1 particles found
on the intergranal lamellae
where are PS2 particles found
on the grana themselves
