Unit 4.1-4.4 Flashcards
Draw a molecular diagram of alpha-D-glucose
a. hexagonal ring structure with O at one point (between C1 and C5);
b. correct orientation of OH groups (on carbons 1 to 4); Hydrogens not required
c. CH2OH group shown on fifth carbon with correct orientation;
OR
d. 6 carbon chain with oxygen on first C; e. H and OH groups correctly orientated;
Outline how carbon compounds are produced in cells using light energy. [5 marks]
a. occurs by the process of photosynthesis;
b. occurs in chloroplasts of plant cells/using chlorophyll;
c. chlorophyll absorbs red/blue light AND reflects green light; Both needed for marking point.
d. raw materials/starting products are carbon dioxide and water/shown in an equation;
e. water is split by photolysis;
Explain the transformations of carbon compounds in the carbon cycle. [7 marks]
a. autotrophs/producers convert carbon dioxide into carbohydrates/carbon compounds in photosynthesis;
b. carbon dioxide diffuses/moves from the atmosphere /water into autotrophs/plants;
c. carbon compounds are transferred through food chains/OWTTE;
d. carbon dioxide produced by respiration diffuses out of organisms into water/atmosphere;
e. decomposers release carbon dioxide during decay/putrefaction;
f. methane is produced from organic matter in anaerobic conditions (by methanogens);
g. some methane diffuses into the atmosphere/accumulates in the ground;
State the immediate consequence of a species producing more offspring than the environment can support. [1 mark]
competition/lack of resources
Explain the consequence of overpopulation on the survival and reproduction of better adapted individuals within a population. [3 marks]
a. «better adapted» tend to survive more ✔
b. «better adapted» reproduce/produce more offspring ✔
c. pass on characteristics to their offspring «when they reproduce» ✔
d. their frequency increases «within the population» due to natural selection ✔
Draw a section of the Singer-Nicolson model of an animal cell membrane. [4 marks]
a. bilayer of phospholipids with both “tails” towards the inside «of the bilayer» ✔ This can be taken unlabeled from diagram.
b. hydrophilic/polar and hydrophobic/non-polar annotation ✔ c. cholesterol between phospholipid tails ✔
d. glycoprotein ✔
e. integral proteins/channel proteins ✔
f. peripheral proteins ✔ Allow this if it does not extend across the membrane
Outline the principles used by scientists to classify organisms. [4 marks]
a. use of the binomial system ✔
b. agreed/developed by scientists / OWTTE ✔
c. hierarchy of taxa used ✔ Names of the seven taxa not required. d. three domains used/three domain names ✔ OWTTE
e. genome/DNA sequence similarities
Explain the movement of energy and inorganic nutrients in an ecosystem. [7 marks]
a. autotrophs/producers/plants obtain inorganic nutrients from the «abiotic» environment ✔
b. energy provided «mainly» by sunlight ✔
c. light energy converted «to chemical energy» through photosynthesis ✔
d. photosynthesis/producers/autotrophs convert inorganic carbon/carbon dioxide and water into carbon/organic compounds ✔
e. «these» carbon compounds/foods contain/are a source of «useable» energy «for life» ✔
f. carbon compounds/energy are transferred along food chains when eaten by consumers/heterotrophs ✔ Allow OWTTE for mpf for passed up trophic levels.
g. respiration returns carbon «dioxide» to the environment ✔
State two causes of the decrease of biomass along food chains in terrestrial ecosystems. [2 marks]
a. «cell» respiration/loss of CO2/biomass consumed to provide/as a source of energy ✔
b. loss of energy «as heat» between trophic levels means less energy available for building biomass ✔
Suggest how climate change can influence the natural selection of organisms that live in the Arctic oceans. [3 marks]
a. individuals in a population will show a variation of adaptations to climate change ✔
b. organisms that resist temperature changes
OR
current changes of the ocean/melting ice/more acidity/changes in food chains will survive better ✔
c. reproduce more and pass on their characteristics ✔
Outline the function of the structure labelled III.
[2 marks]
a. necessary for photosynthesis/converts light energy into chemical energy
b. contains chlorophyll to absorb light
The plant from which this cell was taken is in the group angiospermophyta. State one characteristic that is unique to this group of plants. [1 mark]
a. produce flowers
Distinguish between autotrophic nutrition and heterotrophic nutrition. [2 marks]
k
Explain how energy and nutrients are transferred in ecosystems. [3 marks]
a. energy enters ecosystems from the Sun / continuous supply from the Sun
b. light energy is converted into chemical energy and lost with movement along food chains
c. nutrients are recycled within ecosystems / nutrients in an ecosystem are finite and limited
Outline how acidified sea water could affect the shells of the oyster. [1 mark]
a. shell formation reduced / more difficult
