UNIT 4 Flashcards
State whats meant by tissue
group of same cells with same structure
Spongy mesophyll is a site of gas exchange. The arrows on the diagram show the direction of movement of carbon dioxide during the day. Using the information in the diagram and your own knowledge of the properties of gas exchange surfaces, suggest how spongy mesophyll is adapted for gas exchange.
- the gas exchange surface is the cell wall (and membrane) 2. so the diffusion distance is small (between air space and cytoplasm) ; 3. idea that the carbon dioxide can { continuously enter the leaf /circulate around the cells } 4. maintains a concentration gradient (between air space and cell) ;
Photosynthesis takes place in palisade mesophyll. Describe what happens to the carbon dioxide that enters this tissue.
- the gas exchange surface is the cell wall (and membrane) 2. so the diffusion distance is small (between air space and cytoplasm) ; 3. idea that the carbon dioxide can { continuously enter the leaf /circulate around the cells } ; 4. maintains a concentration gradient (between air space and cell) ;
Xylem transports ions and water molecules to the leaf. Describe the roles of these ions and water molecules in photosynthesis.
1.. CCEPT carbon dioxide is soluble (in moisture) 2. idea that carbon dioxide { diffuses / moves / enters } into the { chloroplasts / stroma } ; 3. idea that carbon dioxide binds to RuBP / reference to carbon fixation / { reduction of carbon dioxide / eq } ; 4. reference to { Calvin cycle / light-independent reaction } ; to produce gp
Describe the roles of the thylakoid membranes in the production of ATP in the light-dependent reaction.
- idea of {chlorophyll / photosystems / eq} in the (thylakoid) membrane ; 3. for the absorption of light (energy) ; 4. so that electrons are released (from chlorophyll) / eq ; 5. idea that there are electron carriers are in the (thylakoid) membrane ; 6. idea that electrons are {picked up by / passed down} electron {carriers / proteins / acceptors} ; 7. resulting in {hydrogen ions / H+ / protons} being {moved into / accumulated in} the thylakoid space / eq ;
Xylem transports ions and water molecules to the leaf. Describe the roles of these ions and water molecules in photosynthesis.
water for photolysis 2. { phosphate / Pi / PO43- } for ATP synthesis / eq ; 3. magnesium (ions) for chlorophyll ; 4. nitrate for { ATP / electron carrier protein / RUBISCO / ATP ase / enzymes involved in photosynthesis / chlorophyll / eq } ;
Describe how the membranes inside the chloroplast are involved in photosynthesis.
- idea of compartmentalisation (from stroma) ; 2. site of light-dependent reaction ; 3. credit named molecules {within / on / eq} membrane ; 4. idea of {ATPase / eq } in (thylakoid) membranes ; 5. idea that (thylakoid) membranes provide a space for accumulation of H+ ; 6. reference to photophosphorylation

bottom left box:
oxygen
- top middle box:
(inorganic) phosphate (ions) /
3.top right box:
GALP

Molecule P - water /
Molecule Q - oxygen

D ATP and reduced NADP
Describe the role of RUBISCO in the production of GALP in the light-independent
reaction.
- reference to RUBISCO as an {enzyme / catalyst} ;
- in the Calvin cycle ;
- involved in {carbon fixation / bonding of CO 2 to RuBP /
reaction between CO 2 and RuBP / eq} ; - to form GP / eq ;
- GP converted to GALP / eq ;
- using ATP and {reduced NADP / NADPH} (CO 2 to
GALP / GP to GALP) ;

Stroma
Using the information in the graph, describe the overall changes in the
population sizes of elk and grey wolves between 1995 and 2010.
Give explanations for these overall changes.
- elk decrease and wolves increase / eq ;
- . N
- idea that elk decrease as they are { being
killed / eaten / predated } by the wolves at a
faster rate than they are reproducing ;
2.. GNORE hunted
- idea that the number of wolves increase as
they are reproducing faster than they are
dying ;
Suggest two reasons for the decrease in the population of grey wolves
between 2011 and 2012.
- birth rate less than death rate / eq ;
2.accept wolves will starve /
competition for food - disease ;
- idea that the wolves are being { shot / hunted } ;
- movement of wolves out of the Park ;
Explain why, since 1995, the areas of forest in Yellowstone National Park have
increased.
- idea that there is less grazing (as there are fewer elk) ;
- idea that (secondary) succession can now take place ;
- resulting in a climax community ;
Suggest how the populations of other animals in Yellowstone National Park
might be affected by the reintroduction of the grey wolves.
Give explanations for your answer.
- idea that other animals (prey of wolves) might decrease
in number ; - as they are also being {killed / eaten / predated} by the
wolves / eq ; - idea that other {carnivores / predators of elk / eq }
might decrease in number ; - as there are {fewer elk to eat / more competition for the
elk} ;

D
State two variables, other than the food source, that should be controlled in
this investigation.
- { age / time of laying / batch } of eggs ;
- { species / type } (of butterfly / caterpillar / egg) ;
Describe how the growth rates of the caterpillars could be determined in this
investigation.
- measure { length / mass / eq } of caterpillar ;
- idea of measuring several caterpillars to calculate the
mean (change in growth measurement) ; - idea of taking measurements over a period of time ;
- growth rate = change in { length / mass } divided by
time / eq ;
Suggest why the food source of the caterpillars could affect their growth rate.
1.. CCEPT a different content of
a named nutrient / energy
2. idea different {carbohydrate / lipid / eq} content will provide different yields of energy ; 3. idea that {respiration / metabolism / production of ATP} is affected (by energy content / carbohydrate / lipid) ; 4. idea that the (ATP) energy used for {synthesis of new molecules / cell division} ;
- idea that protein content will affect (rate of) {protein /
enzyme / named example} synthesis ;

Explain the meaning of the term net primary productivity.
- (rate of) {production of / energy incorporated into / eq}
{biomass / organic material / eq} ;
by plants ;
- ACCEPT autotrophs / producers
- (NPP) = GPP – R / eq ;
Name two inorganic ions and explain why each of these ions will affect the net
primary productivity.
- e.g. {calcium / magnesium}
ions, nitrates , phosphates
IGNORE incorrect formulae - idea that calcium ions used in synthesis of {calcium
pectate / middle lamella / cell wall / eq} ; - when cells are {dividing / growing / eq} ;
- idea that nitrates are used in synthesis of {nucleic acids
/ DNA / RNA / amino acids / protein / enzymes /
chlorophyll / eq} ; - credit appropriate link with NPP
- e.g. enzymes used in Calvin
cycle, DNA for synthesis before
mitosis, RNA for translation,
proteins for enzymes, - idea that magnesium ions needed to produce chlorophyll ;
- chlorophyll used for {photosynthesis / light absorption /
synthesise glucose / eq } ; - idea that phosphates are used in synthesis of {nucleic acids /
DNA / RNA / ADP / ATP / NADP / eq} ; - credit appropriate link with NPP
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