CP 6 Photosynthesis Flashcards
what is the spectrum of visible light
400nm-700nm
light behaves like a ___ and like _______ of energy (photons)
wave, particles
TF short wavelengths = low energy, long wavelengths = high energy
F, the opposite
how does light interact with matter
it can:
- reflect off
- transmit through
- absorbed by
to be used as energy, light must be ____
absorbed
how is light absorbed
- Energy of photon is transferred to
an electron within a molecule - Energy transfer switches electron
from grounded state to excited
state
what is a pigment
molecules that absorb
photons of specific wavelengths
if in object it red it means that red is ___ and the other colours are ___
reflected, absorbed
what is an autotroph
Organisms that make required organic molecs from inorganic sources such as CO2 and water
what is a photoautotroph
Autotrophs that use light as the energy source to make organic molecules by photosynthesis
what is a heterotroph
Consumers and decomposers, which need source of organic molecules to survive
TF photosynthesis is a formation reaction
F, its Redox
what are the 2 stages of photosynthesis
Light reactions
Calvin Cycle
what is the light reactions step in photosynthesis
- ## Pigment molecules capture light energy and its used to synthesize both ATP and NADPH
what is the calvin cycle step in photosynthesis
NADPH and ATP used to fix CO2 into carbohydrates (glucose)
what is the aqueous environment of a chloroplast called
stroma
what is granum/granum
stacks of thylakoids
what 3 things eventually happen to an excited electron
- returns to its ground state, releasing energy as heat or as light
- Energy from excited electron in one pigment molecule is transferred to a neighboring pigment molec
- Excited-state electron itself is transferred to nearby electron-accepting molecule
what do carotenoids and chlorophylls do when absorbing light
act in combination, drives
reactions of photosynthesis
what is the main feature of the photosystem
Pigments bound precisely in thylakoid
membrane to specific proteins
what is a photosystem
Large antenna complex (light harvesting
complex) of pigments that surrounds reaction
centre
how does a photosystem work
- Acts as light funnel to chlorophyll A
- Moves it from 1 pigment molec to another
- Then gives an electron to the electron transport carriers to oxidize chlorophyll A
what is the difference in absorbtion between photosystem 1 and 2
- PS2 absorption max = 680nm
- PS1 absorption max = 700nm
what do PS1 and PS2 have in common
both have specialized chlorophyll A in reaction centre
what are the steps in the photosynthetic electron transport path
- PS2 –> cytochrome complex (plastoquinone)
- cytochrome –> PS1 (plastocyanin)
- PS1 –> NADP+ (ferredoxin Stroma side)
- NADP+ –> reduced to NADPH
- PS1 reduced to ground state
- PS2 reduced to ground state
what carrier is used to get the product of PS2 to the cytochrome complex
plastoquinone
what carrier is used to get the product of the cytochrome complex to the PS1
plastocyanin
what carrier is used to get the product of PS1 to the NADP+
Ferredoxin stroma side
who is the final electron acceptor in the Photosynthetic Electron Transport path
NADP+
how does PS2 return to ground state
using H2O
how does PS1 return to ground state
using electrons from PS2
how is ATP produced after electrons go thru the electron transport path (Chemiosmotic Synthesis of ATP)
Hydrogens that were released from the PS2 and the plastoquinone are taken by the ATP synthase molec at the end of the chain and produces the ATP
how does the cyclic electron transport cycle work
- Ferrodoxin donates electrons to plastoquinone (PQ)
- Redox of PQ and PQ pool keeps moving protons across thylakoid membrane without involvement of photosystem 2
what are the 3 steps to the calvin cycle
- Fixation
- Reduction
- Regeneration
what is fixation in the calvin cycle
CO2 added to RuBP to produce 6 PGA molecule
what is reduction in the calvin cycle
- NADPH and ATP are used to convert 6 PGA into 6 G3P (higher energy molecule used to build sugar)
- 1 GP3 released, other 5 move to next step
what is regeneration in the calvin cycle
Remaining 5x G3P molecules are used
to recreate RuBP
what is RuBisCo
- most abundant protein on earth
- provides organic carbon for earths oraganisms
whats the difference between photosynthesis and cellular respiration
- Photosynthesis = ATP produced via light energy (photophosphorylation) and used to make organic molecules
- Cell respiration = ATP produced by breaking down organic molecules (oxidative phosphorylation)
what is the relationship between photosynthesis and cellular respiration
Photosynthesis and cell respiration are in many respects the reverse of one another
Photosynthesis is an _____process
Cell respiration is a _____process
anabolic
catabolic
