IMPORTA
IMPORTANT NT TERMSTERMS
•• Absorption spectrumAbsorption spectrum- A graph of the relative ability of a pigment to absorb different- A graph of the relative ability of a pigment to absorb different wavelengths of light.
wavelengths of light.
•• Action spectrum-Action spectrum- A graph of the relative rates of reaction of A graph of the relative rates of reaction of a process as influenced bya process as influenced by different wavelengths of light.
different wavelengths of light.
•• Anabolic reactions-Anabolic reactions- Reaction where large molecules are constructed from Reaction where large molecules are constructed from small ones.small ones. •• Anoxygenic Photosynthesis-Anoxygenic Photosynthesis- Photosynthesis that doesn’t Photosynthesis that doesn’t require oxygenrequire oxygen
•• ATP synthetaseATP synthetase- he entire complex of en!ymes that converts AP to A"P and- he entire complex of en!ymes that converts AP to A"P and phosphate
phosphate
•• BacteriochlorophyllsBacteriochlorophylls- #ight harvesting pigments involved in bacterial photosynthesis- #ight harvesting pigments involved in bacterial photosynthesis •• ! "al#in$Benson% ycle-! "al#in$Benson% ycle- conversion of carbon dioxide to carbohydrates. conversion of carbon dioxide to carbohydrates.
•• & metabolism-& metabolism- a set of a set of metabolic reactions in which carbon dioxide is fixed temporarilymetabolic reactions in which carbon dioxide is fixed temporarily into organic acids that are
into organic acids that are transported to bundle sheaths$ where they release the carbontransported to bundle sheaths$ where they release the carbon dioxide and %&
dioxide and %& photosynthesiphotosynthesis occurs.s occurs.
•• hemiosmotic Phosphorylation-hemiosmotic Phosphorylation- he synthesis of AP to A"P and phosphate usinghe synthesis of AP to A"P and phosphate using the energy of an osmotic gradient and a gradient of electrical charge' occurs in
the energy of an osmotic gradient and a gradient of electrical charge' occurs in chloroplast and
chloroplast and mitochondriamitochondria..
•• hlorophyll-hlorophyll- Pigment involved in capturing light energy that drives photosynthesis.Pigment involved in capturing light energy that drives photosynthesis. •• rassulacean aci' metabolism "AM%(rassulacean aci' metabolism "AM%(- A metabolism in which carbon dioxide is- A metabolism in which carbon dioxide is
absorbed at night and fixed temporarily into organic acids.
absorbed at night and fixed temporarily into organic acids. "uring daytime$ the acids"uring daytime$ the acids brea(down
brea(down$ carbon $ carbon dioxide is released$ and %& dioxide is released$ and %& photosynthephotosynthesis occurs.sis occurs.
•• yclic electron transport-yclic electron transport- he flow electrons from P)** bac( to plastoquinone in he flow electrons from P)** bac( to plastoquinone in photosynthesis$ such that there is proton pumping but
photosynthesis$ such that there is proton pumping but no synthesis of +A"P,no synthesis of +A"P, •• ytochromes-ytochromes- mall electron carriers that contain ironmall electron carriers that contain iron
•• Electron Transport hain-Electron Transport hain- A se A series of electron caries of electron carriers that transfer erriers that transfer electrons from alectrons from a donor$ which becomes oxidi!ed$ to a receptor which becomes reduced.
donor$ which becomes oxidi!ed$ to a receptor which becomes reduced. •• EntropyEntropy- A measure of disorder in a system.- A measure of disorder in a system.
•• )luconeogenesis-)luconeogenesis- ormation of ormation of glucose from &-phosphoglyceraldehyglucose from &-phosphoglyceraldehydede
•• )reenhouse e**ect-)reenhouse e**ect- /armin/arming of g of the surface and lower atmosphere of a the surface and lower atmosphere of a planet due toplanet due to the un’s radiation that is absorbed by the surface of the planet and is given bac( off as the un’s radiation that is absorbed by the surface of the planet and is given bac( off as radiation and heat.
radiation and heat.
•• +eterotrophs+eterotrophs- An organism that obtains its carbon from - An organism that obtains its carbon from organic molecules$ not fromorganic molecules$ not from carbon dioxide.
carbon dioxide.
•• ,ight compensation point,ight compensation point- he level of - he level of illumination at which photosynthetic fixation ofillumination at which photosynthetic fixation of carbon dioxide 0ust matches
• ,ight 'epen'ent reactions- Reactions directly driven by light.
• Non cyclic electron transport(- he flow of electrons from water to +A"P, during the light dependent reactions of photosynthesis.
• Oxi'ation state- A measure of the number of electrons added to or removed from a molecule during a Redox Reaction.
• Oxi'ati#e phosphorylation- he formation of AP from A"P and phosphate$ powered by energy released through respiration.
• Oxi'ie' compoun's- %ompounds in which electrons are removed and oxidation state is raised.
• Oxygenic photosynthesis- Photosynthesis that generates oxygen as a result of metabolic reactions.
• Oone- A triatomic very reactive form of oxygen that is a ma0or air pollutant in the lower atmosphere but a beneficial component in the upper atmosphere for it absorbs 12 radiation coming from the sun.
• !-phosphoglyceral'ehy'e- type of carbon present in the two identical molecules when Ru3P and carbon dioxide reacts.
• Photoautotrophs( An organism that obtains its energy through photosynthesis. • Photons- A unit of intensity of light.
• Photophosphorylation- he formation of AP from A"P and phosphate by means of light energy.
• Photorespiration(- he oxidation of phosphoglycolate produced when Ru3P carboxylase adds oxygen$ not carbon dioxide$ to Ru3P
• Photosystem I- he pigments and electron carriers that transfer electrons from P)** to +A"P,
• Photosystem II- he pigments and electron carriers that transfer electrons from water to P)** in photosynthesis.
• Pigment- A coloring matter in plant tissues or cells. • Plastocyanin- A copper-containing electron carrier. • Plasto.uinones- A class of lipid-soluble electron carrier.
• /uality o* sunlight- Refers to the colors or wavelengths the sunlight contains. • /uantum- A particle of electromagnetic energy.
• Reaction center- A special chlorophyll a molecule actually involved in the transfer of electrons in photosynthesis.
• Re'uce' compoun's- %ompounds that are added with electrons.
• Re'ucing po0er- he ability of an electron carrier to force electrons onto another compound
• Ribulose-12 3-bisphosphate "carboxylase% - he en!yme in photosynthesis that carboxylates Ru3P thus bringing carbon into the plant’s metabolism.
• R4BISO- Ribulose-4$ 5- 3iphosphate %arboxylase.
• Stroma- he colorless proteinaceous matrix of a chloroplast in which chlorophyll-containing lamellae is embedded.
• Stroma reactions- he set of reactions that occur in the stroma and are not directly powered by light.
• Substrate-le#el-phosphorylation(- he formation of AP from A"P by having a phosphate group transferred to it from a substrate molecule.
• Thyla5oi' lumen- he spaces inside the thyla(oids$ which are the photosynthetic membranes of the chloroplast.
6 7 scheme- a diagram that depicts the redox reactions of the molecules from photosystem 66 to photosystem 6.
RE8IE9 /4ESTIONS:
1; 9hat is the meaning o* the 0or' entropy< =oes the entropy i* a plant increase or 'ecrease 0hile it is ali#e< A*ter it is 'ea'<
7ntropy is a measure of a disorder in a system. 7ntropy in a plant while it is alive it decreases.
After it is dead$ it undergoes the process of decaying where its molecules become
disordered and its entropy increases.
>; Name se#eral examples o* photoautotrophs an' se#eral o* heterotrophs; +o0 'o photoautotrophs obtain energy< an a plant be heterotrophic 0hile see'ling an' photoautotrophic 0hen ol'er<
Photoautotrophs8 green plants$ all cyanobacteria$ and few bacteria capable of
photosynthesis.
,eterotrophs8 All animals$ all completely parasitic plants$ all fungi$ and nonphotosynthetic pro(aryotes.
Photoautotrophs obtain energy by means of the sunlight coming from the sun. A plant
can be a heterotrophic while it’s a seedling and be photoautotrophic when it’s older.
!; ATP is an important chemical in#ol#e' in many o* a plant an' animal?s metabolic reactions; @et any plant has only a small amount o* it; an you explain this< 9hen ATP enters a reaction an' *orces it to procee'2 0hat is ATP con#erte' into< 9hat then happens to the molecule<
AP is an important chemical involved in many of a plant and animal’s metabolic
reactions. 9et any plant has only a small amount of it. he reason behind this is because each molecule is recycled and reused repeatedly$ thousands of times per second. AP is converted to A"P :Adenosine diphosphate; and phosphate by
metabolic reactions$ but the phosphate can be attached with a high energy bond by the reactions of either photosynthesis or respiration.
&; Name three metho's o* phosphorylation
Metho's o* phosphorylation: 4. Photophosphorylation
<. ubstrate-level phosphorylation &. =xidative phosphorylation
3; 9hat is re'uction reaction< 9hy 'oes a re'uction reaction al0ays occur simultaneously 0ith an oxi'ation reaction<
Reduction Reaction- it is a type of reaction where an atom is added with an electron. Reduction reaction occur simultaneously with oxidation reaction because oxidation
reaction contains a great amount of oxygen which has a strong tendency to pull electrons away from an atom and raise that atoms partial positive charge while reduction reaction contains hydrogen which is more stable and tends to give up electrons reducing the atom’s partial positive charge so after an atom has been oxidi!ed$ it is also reduced at the same time.
; In organic molecules2 0e calculate the oxi'ation state o* carbon by assuming that each oxygen has an oxi'ation state o* -2. Each hy'rogen has an oxi'ation state o* +1; alculate the oxi'ation state o* carbon in each o* the *ollo0ing: O>2 +>O an' malic aci';
%=<> ?@ %,<= > ?* alic acid > ?@
; T0o o* the *ollo0ing are oxi'iing agents an' t0o are re'ucing agents; 9hich are 0hich: NA=C2 NA=PC2 NA=+2 an' NA=P+<
=xidi!ing agents8 +A"?$ +A"P? Reducing agents8 +A",$ +A"P,
D; In photosynthesis2 0hat is the ultimate source o* electrons< 9hat are the bene*its o* this molecule in terms o* its toxicity an' the cost o* the plan to obtain it<
• he ultimate source of electrons in photosynthesis is water and carbon dioxide. • /ater and %=< molecules are non-toxic so it is safe to absorb them in large
quantities.
• /ater and carbon dioxide is abundant and inexpensive occurring almost everywhere.
; =escribe the absorption spectrum o* chlorophyll; 9hy 'oes it match the action spectrum o* photosynthesis<
• %hlorophylls absorb little of the very short wavelength light at @** nm$ and little photosynthesis occurs$ however lights at slightly longer wavelengths$ about @<5 nm$ is absorbed well by chlorophyll a$ and photosynthesis proceeds. his matches the
action spectrum of photosynthesis because the action spectrum of photosynthesis shows which wavelengths are most effective at powering a photochemical process.
1F; hlorophyll 'oes not use high-energy .uanta; 9hy not< 9hat 0oul' happen to the chlorophyll i* it 'i'< It also 'oes not use long 0a#elength ra'iation either; 9hy not<
• %hlorophyll does not use high energy quanta because they have too much energy. 6f chlorophyll used high energy quanta$ then it won’t be able to absorb pigments
because the energy would 0ust (noc( them off. 6t also does not use long wavelength radiation either because they have so little energy per quantum that they cannot appreciably boost an electron’s energy.
11; The most common accessory pigments in lan' plants are chlorophyll b an' the carotenoids; Algae that li#e in 'eep 0ater ha#e other accessory pigments because only GGGGGG-GGGGGGG light penetrates 'eeply in 0ater;
3lue - green
1>; Name the electron carriers that transport electrons *rom photosystem II to photosystem I; 0hich one contain metal atoms2 an' 0hich 'o not<
a.; Phaeophytin B a chlorophyll a molecule that does not contain magnesium atom b.; C- a molecule of quinone
c.; Plastoquinone B does not contain metal atoms d.; %ytochrome bDE complex- contains an iron atom e.; Plastocyanin- contains a copper atom
1!; 9hen photosystem I pro'uces NA=P+2 its reaction center PFF chlorophyll a loses electrons; 9hat 0oul' happen i* photosystem II 'i' not supply ne0 electrons to PFF<
6 6f photosystem 66 did not supply new electrons to P)**$ there won’t be any production of AP;
1&; 9hen electrons are remo#e' *rom 0ater2 protons are liberate'; =oes this occur in the stroma or insi'e the thyla5oi' lumen< an protons mo#e 'irectly across the membrane< =escribe the chemiosmotic mechanism o* ATP synthesis in
• /hen electrons are removed from water$ protons are liberated. his occurs inside the thyla(oid lumen. Protons cannot move directly across the membrane because they may need to pass through the intrinsic protein channel :of AP synthase;.
%hemiosmosis is the movement of ions across a selectively permeable membrane$ down their electrochemical gradient. ore specifically$ it relates to the generation of AP by the movement of hydrogen ions across a membrane during cellular
respiration. ,ydrogen ions :protons; will diffuse from an area of high proton
concentration to an area of lower proton concentration. Peter itchell proposed that an electrochemical concentration gradient of protons across a membrane could be harnessed to ma(e AP. ,e lin(ed this process to osmosis$ the diffusion of water across a membrane$ which is why it is called chemiosmosis. AP synthase is the en!yme that ma(es AP by chemiosmosis. 6t allows protons to pass through the membrane and uses the (inetic energy to phosphorylate A"P$ ma(ing AP. he generation of AP by chemiosmosis occurs in chloroplasts and mitochondria as well as in most bacteria and archaea.
13; Is A=P con#erte' to ATP 'irectly by the reaction center chlorophylls< =o the enymes that synthesie ATP obtain the necessary energy by interacting 'irectly 0ith the reaction center cholorophylls<
+o$ A"P is not directly converted to AP by the reaction center chlorophylls. Proton
flows through AP synthase channels and powers phosphorylation of A"P to AP.
1; 9hat chemical is the acceptor o* carbon 'ioxi'e in the ! cycle< 9hat enyme catalyes the reaction2 an' 0hat is the pro'uct<
he chemical acceptor of carbon dioxide in the %& cycle is RuBP "ribulose 123-biphophate%
he en!yme that cataly!es the reaction is RuBP carboxylase "R4BISO% he product is
1; RuBP arboxylase is by no means an i'eal enyme; =escribe some o* the
problems 0ith its acti#e site an' its substrate speci*icity; I* 0e compare the amino aci' se.uences o* this enyme *rom many 'i**erent species2 they are almost
#i(e chlorophyll a$ Ru3P carboxylase is by no means ideal. 6ts active site recogni!es
and binds to carbon dioxide only poorly$ and it has lo0 substrate speci*icity$ frequently putting oxygen rather than carbon dioxide onto Ru3P. 9et its en!yme is highly conserved evolutionary. he amino acid sequences of Ru3P carboxylase from all plants are virtually identical. Apparently$ all mutations that cause any change in structure$ however slight$ disturb the active sites and are selectively
disadvantageous.
1D; 9hich chemicals are use*ul *or energy storage on a short-term basis< 9hich are *or interme'iate term an' 0hich are *or long term<
Short-term storage8 ATP an' NA=P+ can be used within the cell and last only briefly. Interme'iate-term storage8 he simple sugar glucose and the disaccharide sucrose
are stable enough to be moved from cell to cell$ either in the vascular tissue of a plant or in a blood stream. hey are also sufficiently stable to last for wee(s or months. A
problem with storing large quantities of monosaccharide or disaccharide is that they cause cells to absorb water by osmosis.
,ong-term storage: Starch is large$ high-molecular-weight polymer of glucose$ too
large to be transported. 6t is even more stable than glucose$ lasts for years$ and does not cause the cell to absorb water. ,ipi's are an even more concentrated storage form of energy that can be synthesi!ed rapidly and stored in large quantities.
1; 9hat is the H.uality o* light< +o0 'oes it 'i**er *or plants in 'eserts2 grasslan's2 an' the canopy o* a *orest #ersus *or plants in the un'erstory< +o0 'oes it 'i**er *or algae that gro0 near the sur*ace o* a la5e or ocean #ersus those that inhabit 'eep 0ater *ar belo0 the sur*ace<
/uality o* light refers to the colors or wavelengths it contains.
or plants in the 'eserts2 grasslan's an' the canopy o* a *orest it is evident that
during sunset and sunrise$ sunlight passes tangentially through the atmosphere$ and a large percentage of the blue light is deflected upward' consequently$ light at the ground level is enriched in red which is easily visible. his period of red-enriched light only lasts a few minute and probably has a little effect on photosynthesis. At noon$ light passes nearly vertically through the atmosphere$ more blue light is t ransmitted$ and even though the blueness of the s(y suggests that all reds$ greens and yellows have been bloc(ed$ in fact enough of all of these wavelengths penetrate to 7arth’s surface to allow
efficient photosynthesis. /hile un'erstory plants$ and the light that they receive has already passed through the leaves of the canopy.
or algae the gro0 near the sur*ace o* the l a5es or oceans receive complete light$ but water absorbs red and violet$ while algae at 'eep regions receive mostly green and blue light and must have special accessory pigments capable of absorbing these
wavelengths efficiently.
>F; +o0 is the .uantity o* light a**ecte' by a plant?s location relati#e to the e.uator or the poles< On one si'e o* a mountain or the other< On one si'e o* a #alley or the other<
Plants growing near the equator receive intense light because the sun is always more or
less directly overhead at noon$ whereas plants near the poles receive very little light.
Plants growing in the shadows of the mountains or in deep canyons receive much less
light than plants that grow on slopes that face the sun.
>1; Imagine a lea* in bright light but an atmosphere 0ith no carbon 'ioxi'e; 9oul' RuBP carboxylase be *unctioning< 9oul' NA=P be in re'uce' or oxi'ie' *orm<
A leaf in bright light but an atmosphere with no carbon dioxide$ the Ru3P
carboxylase would not be functioning because it needs carbon dioxide for it to function.
+A"P would not be reduced nor oxidi!ed because it also needs carbon dioxide.
>>; Name some o* the brightest en#ironments; =escribe some protecti#e a'aptations that plants may use to sha'e themsel#es;
ome of the brightest environments include the deserts$ grasslands$ tropical
rainforests and etc. he production of a thic( layer of dead trichomes may be necessary for them to protect themselves from extreme radiation or sunlight. A heavy coating of wax can also reflect light. %utin is very good at absorbing harmful short wavelengths.
>!; An important *actor *or plants is the amount o* 0ater lost *or each molecule o* carbon 'ioxi'e absorbe'; +o0 coul' the plant be harme' i* it loses a lot o* 0ater
*or each carbon 'ioxi'e molecule2 that is2 i* the ratio is high< 9oul' this be more important *or a plant in a rainy habitat or one in a 'esert<
6f the plant loses a lot of water for each carbon dioxide molecule$ it would dry out and
wither. his is only applicable to those inhabiting the rain forest where there is a large amount of water that the plants receive.
>&; In a & plant2 0here is PEP carboxylase locate'< 9here is RuBP carboxylase locate'<
he P7P carboxylase is located in the mesophyll of the leaf in a %@ plant. Ru3P is located exclusively in the bundle sheath chloroplast.
>3; In a AM plant2 are the stomata open 'uring the 'ay or the night< +o0 'oes this a**ect the amount o* 0ater the plant loses 0hen its stomata are open<
6n a %A plant$ the stomata are open at night where it is cool and closes during the
day where it is hot. he opening of the stomata at night is effective for conserving water.
>; As a AM plant ma5es an' stores aci's 'uring the night2 ho0 'oes this a**ect the plant?s aci'ity "its p+%< Thin5 about the aci'ity o* your o0n bloo'; =o you thin5 it is allo0e' to #ary by any large amount<
his greatly affects the plant’s acidity because %A metabolism is not #ery
e**icient$ that the total amount of carbon dioxide is so small that it may be entirely used in %& metabolism after 0ust a few hours of sunlight.
>; In habitats 0here 0ater conser#ation is not especially necessary2 is AM metabolism more or less a'#antageous than ! or & metabolism< 9hy<
1nder milder$ moister conditions$ %A metabolism is not selectively advantageous. /ater conservation is less of a benefit$ and the limited capacity to absorb and store carbon
dioxide is a distinct disadvantage. %& and %@ plants photosynthesi!e all day$ whereas %A plants may stop before noon.
>D; 9hat is global 0arming< 9hat is the main gas that causes it< 9hat 0oul' happen i* the Earth?s atmosphere ha' a lo0er concentration o* O> than it is no0< 9hat 0oul' happen i* it ha' more<
Flobal warming is a gradual increase in the overall temperature of the earthGs
atmosphere generally attributed to the greenhouse effect caused by increased levels of carbon dioxide$ %%s$ and other pollutants
Freenhouse gas :%=<$ etc.;causes global warming
/ith less carbon dioxide$ more heat would be lost and 7arth would be fro!en$ li(e ars. /ith more$ more heat would be trapped our world would be as hot as 2enus$ at H**
degrees %elsius.
>; 9hat is the Jyoto Protocol< +o0 many countries ha#e signe' it< Name one country that has not signe' it; 9hat are t0o substances burne' in the 4nite'
States "an' all other countries% that pro'uce O>< 9hich t0o countries ha#e large populations an' may soon surpass the 4nite' States in pro'uction o* greenhouse gases<
he Iyoto Protocol is a treaty designed to reduce production of greenhouse gases. 6t is signed by 4DD countries
1nited tates did not sign it.
Fas and =il :=r %oal and +atural Fas;
%hina and 6ndia have large populations and may soon surpass the 1nited tates in
