A Student Investigated the Effect of Three Inhibitors on the Growth of Pollen Tubes

Topic 10 Questions Mixed

Questions

Q1.

A student investigated the effect of three inhibitors on the growth of pollen tubes.

Pollen grains were incubated in a control medium.

In addition, some pollen grains were also incubated in three media, each containing one inhibitor.

The inhibitors used were actinomycin D (act D), cycloheximide (CHX) and cytochalasin B (CB).

The results of this investigation are shown in the graph.

The student made the following conclusions from these results:

Conclusion 1: all three inhibitors affected pollen tube growth
Conclusion 2:pollen grown in CB grew the slowest
Conclusion 3:the control result was the least repeatable
Conclusion 4:more pollen grains germinated in the control group

Analyse the results of this investigation to comment on each of these conclusions.

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(Total for question = 4 marks)

Q2.
Human diseases can be caused by many different types of organism, such as bacteria and viruses.

(a) Give two differences between the genetic material of bacteria and viruses.

(2)

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(b) Tuberculosis (TB) is caused when droplets, containing the bacterium Mycobacterium tuberculosis, are inhaled into the lungs.

In the lungs, large numbers of the bacterium are formed rapidly. These can be ingested by macrophages. Eventually, tubercles (tissue masses), containing dormant bacteria inside macrophages, may form.

(i) Describe how macrophages ingest the bacteria.

(2)

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(ii) Suggest why treatment with antibiotics may not be effective against the dormant bacteria in the tubercles.

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(iii) TB can be prevented by vaccination. Explain how a person can develop artificial active immunity following vaccination.

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(c) In a person with TB, the dormant bacteria in tubercles may be activated after several years. The bacteria multiply rapidly, resulting in severe lung damage.

The bacteria are released from the tubercles. These bacteria can inhibit the activity of T cells and infect other organs.

Explain why the activity of these bacteria and the inhibition of T cells means that a person may quickly develop severe symptoms leading to death.

(4)

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(Total for Question = 13 marks)

Q3.

In December 2013, a boy died of Ebola Virus Disease (EVD) in Guinea, West Africa.

However, it was not until March 2014 that health officials reported a mysterious haemorrhagic fever that 'strikes like lightning'.

By the end of 2014, an estimated 20 000 cases had been reported.

The graph shows the number of deaths reported in the months following the outbreak in December 2013.

(i) Give an estimate of the percentage of reported cases who had died by the end of 2014.

(1)

Answer ...... %

(ii) Analyse the data for July to August 2014, and December 2014 to January 2015, to explain whether the measures taken to control the spread of Ebola have been effective.

(2)

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(iii) The table shows the number of reported cases and deaths from Ebola in three different countries by March 2015.

Explain the difference between the percentage of reported cases who had died in these three countries.

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Q4.

Of the five rhino species, Javan rhinos (Rhinoceros sondaicus) are the most in threat of extinction, with as few as 35 individuals surviving in Ujung Kulon National Park in Java, Indonesia.

This national park is highly vulnerable to tsunamis and volcanic activity. In Java, large areas have been planted with Arenga pinnata, which is a source of palm oil. This plant has now colonised 50% of this national park.

(a) Give one biotic factor which contributes to Rhinoceros sondaicus becoming a critically endangered species.

(1)

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(b) Explain why a species may become endangered when its population falls to a very low number.

(2)

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Conservationists are working with the national park in order to conserve the Javan rhino.

Give two methods that could be used to conserve the Javan rhino.

(2)

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(Total for question = 5 marks)

Q5.

The graph below shows how the depth of water in a freshwater lake affects the net
primary productivity (NPP).

Place a cross in the box next to the equation that describes the relationship
between NPP, gross primary productivity (GPP) and respiration (R).

(1)

A GPP = R – NPP

B NPP = GPP – R

C NPP = GPP + R

D R = GPP + NPP

Q6.

Sea plantain and bog sedge grow at a range of latitudes. A student carried out an investigation into the effect of temperature on the growth of seedlings of these two species.

Sets of seeds from each species were germinated at 18 °C. As soon as they germinated, the seedlings were placed in three temperature-controlled rooms at 10 °C, 14 °C and 18 °C.

They were allowed to grow for 50 days. Samples of seedlings were taken at 10-day intervals and their mean dry masses were recorded.

The results of this investigation are shown in the tables below.

Analyse the data to explain which of the two species is better for growth at a wider range of latitudes (distance from the equator).

(4)

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(Total for question = 4 marks)

Q7.
The Sylt-Rømø Wadden Sea, shown in the diagram below, has a high gross primary productivity (GPP) which is monitored constantly.

The Sylt-Rømø Wadden Sea is protected from the North Sea by an island.

There are no large rivers flowing into the Sylt-Rømø Wadden Sea.

(a) Explain the meaning of the term gross primary productivity (GPP).

(2)

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(b) Seagrass, microphytobenthos and phytoplankton are the producers found in the Sylt-Rømø Wadden Sea.

The chart below shows the distribution of GPP between these producers.

(i) Using the chart, describe the distribution of GPP in this sea.

(2)

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(ii) The total GPP for this sea is 840 × 106 kJ m−2 y−1.

Explain how GPP for the phytoplankton could be calculated.

(2)

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(iii) Suggest why GPP for this sea is very high.

(2)

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(2)

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(Total for Question = 10 marks)

Q9.

During the construction of a motorway in the 1970s, an area of Hampshire heathland, previously used for grazing, was abandoned. With the loss of the grazing animals, succession towards a climax community took place on this heathland.

By the 1990s, a scrubland community had developed. A characteristic of this scrubland is the presence of young trees, such as the Birch (Betula pendula).

(a) Explain what is meant by each of the following terms.

(i) Succession

(2)

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(ii) Climax community

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(b) In the 1990s, a management strategy was put in place to conserve the rare and endangered heathland plants.

(i) Suggest why it is important to conserve rare and endangered plants.

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(ii) Using the information given on page 18, suggest one management strategy that could have been used to conserve the heathland.

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In this study, a line of 8 people at 2m intervals walked across the study area. They recorded the position, height and width of each specimen of Petty Whin. The direction of the line was changed several times to ensure that the whole area was covered.

(i) Place a cross () in the box next to the term that describes the method used to collect data in this survey.

(1)

A permanent

B random

C systematic

D trial-and-error

(iii) A statistical analysis of the data obtained gave a correlation value of 0.565 between height and width of Petty Whin. This correlation was not statistically significant.

Suggest reasons why the correlation was not statistically significant.

(2)

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...... (Total for question = 10 marks)