UNIT 4 LONG ANSWERS

1) 1. Saprobionts/saprophytes;

2. Digest/break down proteins/DNA/nitrogen-containing substances;

3. Extracellular digestion/release of enzymes;

4. Ammonia/ammonium produced;

5. Ammonia converted to nitrite to nitrate/ammonia to nitrate;

6. Nitrifying (bacteria)/ nitrification;

7. Oxidation;

1. Carbon dioxide concentration increases;

Clearing

2. No/Less vegetation so no/less photosynthesis / photosynthetic organisms;

3. No/Less carbon dioxide removed (from the atmosphere);

Burning

4. Burning releases / produces carbon dioxide;

1. Carbon dioxide combines with RuBP;

2. Produces two molecules of GP;

3. Reduced to TP;

4. Using reduced NADP;

5. Using energy from ATP;

6. TP converted to other organic substances/ribulose bisphosphate;

7. In light independent reaction/Calvin cycle;

1. (Colonisation by) pioneer (species);

2. Change in environment / example of change caused by organisms present;

3. Enables other species to colonise/survive;

4. Change in biodiversity;

5. Stability increases / less hostile environment;

6. Climax community;

Advantages

1. Specific (to one pest);

2. Only needs one application;

3. maintains low population;

4. Pests do not develop resistance;

5. no bioaccumulation;

Disadvantages

7. Does not get rid of pest completely;

8. May become a pest itself;

9. Slow acting/ lag phase/ takes time to reduce pest population;

1. Geographical isolation;

2. no interbreeding (between populations);

3. Variation due to mutation;

4. Different environmental conditions / selection pressures;

5. Selection for advantageous features/characteristics;

6.  (selected) organisms survive and reproduce;

7. Leads to change in allele frequency;

8. Occurs over a long period of time;

1. High concentration of carbon dioxide linked with night/darkness;

2. No photosynthesis in dark / light required for photosynthesis/light-dependent reaction;

3. (In dark) plants (and other organisms) respire;

4. In light plants use more carbon dioxide than they produce/ rate of photosynthesis greater than rate of respiration;

5. Decrease in carbon dioxide concentration with height;

6. At ground level fewer leaves/less photosynthesising tissue;

1. Carbon dioxide combines with RuBP;

2. To produce two molecules of GP;

3. Reduced to TP;

4. Requires reduced NADP;

5. Energy from ATP;

1. Microorganisms are saprobionts;

2. extracellular digestion;

3. Absorb products of digestion;

4. Respiration (by microorganisms) produces carbon dioxide;

5. Carbon dioxide taken into leaves;

6. Through stomata;

1 Light (energy) excites electrons in chlorophyll;

2 Electrons pass down electron transfer chain;

3 passage involves redox reactions;

4 Electron transfer chain takes place in thylakoids;

5 Energy released;

6 ATP generated from ADP and Pi;

1 Some light energy fails to strike/is reflected/not of appropriate wavelength;

2 Efficiency of photosynthesis in plants approximately

2% efficient;

3 Respiratory loss / excretion / faeces / not eaten;

4 Loss as heat;

5 Efficiency of transfer to consumers greater than transfer to producers/approximately 10%;

6 Efficiency lower in older animals/herbivores/ primary consumers;

7 Carnivores use more of their food than herbivores;

1 Slaughtered when still growing so more energy transferred to biomass;

2 Fed on controlled diet so higher proportion of (digested) food absorbed/lower proportion lost in faeces;

3 Movement restricted so less energy used;

4 Kept inside/heating so less heat loss / no predators;

5 Genetically selected for high productivity;

1 random selection of transect sites;

2 direction of transect across site;

3 quadrat size i.e. m² ;

4 count no of individual/estimate % cover/frequency of each species under investigation within quadrat;

5 Repeat transect at other sites/ repeat enough times for statistical analysis;

6 Calculate mean no/% cover/frequency of individuals per m2 at each position on transect;

Population size (no mark)

1 Increases over DT;

2 Decrease in DR/BR;

3 better medical care/ better nutrition/ better sanitation/ better pre-natal care/reduce infant mortality/better health education;

Population structure

4 Declining from...;

5 Falling birth rate/desire for smaller families/increased use of contraception; 

6 increasing number in of people surviving into middle age groups;

7 Lower mortality (rate)/higher life expectancy/better healthcare/named lifestyle factor/named socio-economic factor/immigration;       

8 Increasing 0ver 65:

9 Lower mortality (rate)/higher life expectancy /better healthcare

1 Reduced NAD/FAD;

 2 H+ ions across membrane

3 e- move down ETC by  series of redox reactions;

4  energy made available as electrons passed on;

5 H+ passed into intermembrane space;

6 H+ flow back through enzyme; 

7 energy used to synthesise ATP from ADP and phosphate /   using ATPase;

8 Oxygen is final electron acceptor 

1 only 2 ATP’s produced per glucose;

2 Glycolysis only;

3 Glucose to 2 pyruvate;

4 Energy released used to synthesis 2ATP;

5 and 2NADH;

In animals

6 pyruvate is reduced to lactate

In plants/microorganisms

7 pyruvate is reduced to ethanol in plants.