respiration and photosynthesis Topic 5 Flashcards
define photosynthesis
is a reaction using light energy to produce glucose
requires water and carbon dioxide to form glucose and oxygen
what are the four stages photosynthesis occurs
photolysis
photo ionisation
chemiosmosis
production of ATP and reduced NADP
what is photolysis
the splitting of a molecule of water in the presence of light.
occurs in the light dependent reaction
how are the products of photolysis used
the hydrogen ions are picked up by NADP to from reduced NADP
the electron is used in electron transport chain
oxygen is used for respiration
describe the photoionisation of chlorophyll
light energy is absorbed by the photosystem ,where the energy causes the electrons to be excited
energy released is used to make ATP and reduced NADP in chemiosmosis
describe chemiosmosis
electrons when they gain energy they move past electron transport chain on thylakoid membrane
when the electrons move down the chain they release energy used to pump the proton pump
where it is actively transported from stroma to thylakoid
producing electrochemical graident
how is ATP formed in light dependent reaction
hydrogen ions move down from thylakoid space into the stroma
using ATP synthase by facilitated diffusion
this ATP synthase
catalyses the phopsphorylation of ADP into ATP
how is NADPH formed in the light dependent reaction
NADP combines with hydrogen to form NADPH
which is final electron acceptor
where does the calvin cycle occur
in the stroma
what catalyses the whole reaction in the Calvin cycle
Rubisco found in the stroma
what are the first part of the calvin cycle
carbon dioxide reacts with RUBP (a 5 carbon molecule)
catalysed by rubisco
to produce 2 molecules of glycerate 3 phosphate
describe the formation of TP in Calvin cycle
GP picks up hydrogen from NADPH which goes onto reform NADP
GP is reduced into TP
using energy from ATP
how is RUBP regenerated
One Carbon is removed from of of the TP molecules
leaving with five carbons
then the second ATP is used to regenerate RUBP
how many times does calvin cycle occur
it happens six times where in total 6 carbons are removed
what are the three limiting factors in photosynthesis
light intensity
CO2 concentration
temperature
what does RUBP stand for
ribulose bisphosphate
what are agriculture practices to overcome limiting factors
artificial lighting
artificial heating
addition of CO2 by burinng fuels
outline a method for extracting pigment from leaf
use a pestel or motar to extract part of the leaf
using extraction solvent propanone
use capillary tube to spot the pigment on the pencil line
what are the four main stages of respiration
1.glycolysis
2.link reaction
3.krebs cycle
4.oxidative phosphorylation
outline the stages of glycolysis
glucose is phosphorylates into glucose phosphate
then glucose phosphate is split into triose phosphate
triose phosphate oxidised into pyruvate
whilst TP is oxidised NAD picks up H ion to form NADH
and also forms ATP
how does pyruvate and NADH move out the cytoplasm
active transort
where does glycolysis occur
in the cytoplasm
where does the link reaction occur
in the mitchondrial matrix
outline the stages of the link reaction
- pyruvate is oxidised
per pyruvate molecule net gain of CO2 - in this reaction NAD is reduced to form NADH
3.acetate combines with co enzyme A to produce acetyl co enzyme
what are the products of glycolysis
2x pyruvate
2x NADH
2x ATP
what are the products of the link reaction
2x acetyl co enzyem A
2X CO2
2x NADH
outline stages of the krebs cycle
acetyl coenzyme enters kreb cycle and then reacts with 4 carbon molecule
this then forms a six carbon molecule
2 carbon dioxide removed
then co enzyme FADH removed and NADH
series of redox reactions occur using energy from ATP
what are the total products of krebs cycle
4 xCO2
2 xATP
2 xFADH
6 xNADH
How do the electrons move into the electron transport chain in oxidative phosphorylation
the reduced co enzyme produced from the krebs cycle release their hydrogens
hydrogen split into protons and electrons
,those electrons move down electron transport chain
how does the proton gradient occur in respiration
energy released from the electron transport chain is used to actively transport proton pump of Hydrogen ions
from mitchondrial matrix to the intermembrane space
how is ATP produced in the oxidative phosphorylation process
the hydrogen ions move down concentration gradient from intermembrane space into the mitchondrial membrane using ATP synthase
this casuse ADP to be phophorylated into ATP
catalyses the formation of ATP
how is water formed in the oxidative phosphorylation process
electrons from the elctron transport chain is picked up by oxygen along with hydrogen ion
what is the role of water in the process of respiration
it is the final electron acceptor
describe anaerobic respiration
it is respiration in the absence of water
describe anaerobic respiration in animals
pyruvate is reduced to form lactate
reduced by NADH
NAD is used again in glycolysis
where does lactate go agter produced in anaerobic respiration
goes to the liver
describe anaerobic respiration in plants
pyruvate is decarboxylated to form ethanal
ethanal is reduced to ethanol using NADH
what are the advantages of the products of respiration
they convert NADH into NAD for glycolysis
what are the disadvatages of producing Lactate
acidic so decreases PH
causes muslce fatigue
what is the disadvantage of producing ethanol
when ethanol conc is above 12% they die
ethanol dissolves cell membranes
how is respiration measured
using a respirometer
what is the purpose of sodium hydroxide in a respirometer
Absorbs CO2 so there is a decrease in pressure
as O2 is consumed
What is biomass
Biomass can be measured in terms of dry mass of tissue per given area.
How do you measure biomass
Heat a sample of biomass until it is dry, then weigh it
Scale up the mass to work out the mass of the entire organism
How do you ensure all the water has been dried up
Weigh and heat
Until mass is constant
How do you measure energy content in biomass
Weigh a sample of biomass and then burn it completely
Use the heat to heat a sample of water and measure the temperature change
Use this value to work out the energy content of the biomass
What is GPP
GPP (Gross Primary Production
It is the chemical energy stored in plant biomass in a given area or volume.
What is NPP
Some of the Energy will be lost as heat during respiration, and this is called R (respiratory losses
NPP (Net primary production) is the store of energy that is available for growth and reproduction
NPP = GPP - R
How is NPP calculated
Net production is calculated as N = I - (F +R)
N = net production
I = energy in ingested food
F = energy lost in faeces and urine
R = energy lost through respiration
How do you calculate the % efficiency of energy transfer
To calculate the % efficiency of energy transfer, work out the net production as a percentage of the ingested energy
What types of farming practices make energy transfers more efficient
Farming practices like using herbicides and pesticides can eliminate losses because of pests
Keeping animals indoors in a warm environment reduces energy losses through respiration
What are two examples of nutrients cycles
Two examples of this are the nitrogen and phosphorus cycles
What are the four processes of nitrogen cycle
Nitrogen fixation
Ammonification
Nitrification
Denitrification
Describe nitrogen fixation
Nitrogen fixation is when the nitrogen gas in the atmosphere is turned into nitrogen compounds in the soil, e.g. nitrates.
Bacteria can do it in the root nodules of plants such as peas, beans, and clover.
It can also take place during lightning strikes.
Describe ammonification
Ammonification is when nitrogen compounds in animal waste or dead organisms are turned into ammonia by decomposing bacteria called saprobionts.
Describe nitrification
Nitrification is when ammonium ions in the soil are changed into nitrogen compounds (e.g. nitrates) by nitrifying bacteria.
What is denitrification
Denitrification is the opposite of nitrogen fixation: when nitrates in the soil are converted into nitrogen gas by denitrifying bacteria.
What types of conditions are needed for nitrogen cycle
This process takes place in anaerobic conditions such as waterlogged soils.
Out line the phosphorus cycle
1.Phosphate ions in rocks are transferred to the soil by weathering.
2.Mycorrhizal bacteria in plant roots take phosphate ions into the plants
3.Phosphate ions are then transferred to animals when they eat the plants and lost from the animals in waste products
4.When plants and animals die, saprobionts release phosphate ions back into the soil, where plants can take them up
5.Fertilisers also release phosphate ions into the ground so plants can take them up.
What is the role of fertilisers
Fertilisers are used to replace nutrients that are lost when crops are harvested.
What are two types of fertilisers
They can be natural (e.g. manure) or artificial.
What is one disadvantage of using fertilisers
Using too much fertiliser can cause the minerals in them to leach out into waterways, where they can cause serious environmental issues such as eutrophication.
Outline eutrophication
1.Mineral ions are leached from the soil and wash into rivers and lakes
2.This causes the rapid growth of algae on the surface of the lake
3.Large amounts of algae block out light to the aquatic plants below
4.These plants die as they are unable to carry out photosynthesis
5.Bacteria feed on the dead plants and respire, using up the dissolved oxygen in the water
6.Fish and other animals die as there is not enough oxygen left for them
