independent study questions Flashcards
where precisely on a cell does the Calvin cycle take place?
stroma
Explain the decrease in the amount of GP after the carbon dioxide concentration was reduced (1 mark)
less RUBP combined with CO2
the scientist carried out a similar experiment but increased the carbon dioxide concentration from 1% to 2%. The relative amounts of GP and RuBP remained the same.
Suggest two reasons why (2 marks)
temperature is a limiting factor
limited by RuBP
Some bacteria use hydrogen sulfur, H2S to produce organic compounds. The hydrogen sulfide has a similar role to that of water in photosynthesis (2 marks)
hydrogen sulfide is used as an oxidising agent
they add a source if H+ ions to reduce the CO2
energy enters most ecosystems through the light dependent reaction of photosynthesis. Describe what happens during the light independent reaction. (5 marks)
chlorophyll absorbs light energy
excites electrons
electrons move along carriers releasing energy
energy used to join ADP and Pi to form ATP
photolysis of water produces protons, electrons and oxygen
changes in ecosystems can lead to speciation. A high concentration of copper in soil is toxic to most plants. In some areas where the soil is polluted with copper, populations of grasses are found to be growing. These populations of grass belong to a species also found growing on unpolluted soils.
It has been suggested that a new species of grass may evolve on soil that has been polluted with copper. Explain how this new species might evolve
(5 marks)
variation
mutation
some plants have allele to survive in polluted soils
adapted organisms reproduce
increase in frequency of allele
During the light independent reaction of photosynthesis, carbon dioxide is converted into organic substances. Describe how ( 6 marks)
carbon dioxide combines with RuBP
produces 2 glycerate 3 phosphate
GP reduced to triose phosphate
Using reduced NADP
Using energy from ATP
TP converted to glucose
Beech trees have two types of leaves called sun leaves and shade leaves. Sun leaves grow on branches exposed to direct sunlight, shade leaves grow on branches exposed to light that has passed through leaves. An ecologist collected sun leaves and shade leaves from beech trees and determines the mean mass of each photosynthetic pigment, in both types of leaf.
Describe how you would present the data in the table as a graph (2 marks)
bar chart
error bars to represent standard deviation
the ecologist collected shade leaves at random from a branch. Suggest a method he could have used to collect shade leaves at random from a branch ( 2 marks)
Number the leaves on the branch
use random number generator to determine which leaf to pick
the ecologist concluded that there is a significant difference of chlorophyll b in sun leaves and shade leaves of beech trees (2 marks)
no stats test carried out
95% confidence
each type of chlorophyll is produced by a specific enzyme controlled pathway. Use this information to suggest how the same beech trees can produce more chlorophyll b in some leaf cells than others (2 marks)
in shade leaves greater amount of enzyme activity for production of chlorophyll b
more mRNA produced
The solution that the student used to produce the chloroplast suspension had the same water potential as the chloroplasts. Explain why it was important that these water potentials were the same ( 2 marks)
osmosis does not occur
chloroplast does not burst
explain why the student set up tube 1 (2 marks)
to show light does not affect DCPIP
to show chloroplasts are required
explain the results in tube 3 (2 marks)
reduction of DCPIP by electrons
from light dependent reaction
explain the advantage of the student using the IC50 in this investigation (1 mark)
provides a reference point
