gaseous exchange

4

Click here to load reader

description

gaseous exchange

Transcript of gaseous exchange

Page 1: gaseous exchange

H Respiration What are the properties of a respiratory surface? [4]

��������� ������ �� �� ��� ������ ������ ����������� ������������������ Describe the mechanisms involved in the ventilation movement of the following: (i) inspiration [3] ����������� ��� ����������� ���� ��������� ��������� ��������� �� ���� ��������� ����������������� ������������ ����������������������������� ������� ������� (ii) expiration [3] ����������� ������������� ���� ��������� ������������������ �� ���� ��������� ��������� ��������������������� ������ ���������������������� ������� �������

The gaseous exchange surface of the mammalian lung possesses a number of features which allow efficient diffusion. State how each of the following feature assists in producing an efficient gaseous exchange system. The surface is composed of many alveoli. [1] ��� ��������� The wall of each alveolus is 0.1µm thick. [1] ������������� �� ��� ������ ��� A dense network of capillaries covers the outside of each alveolus. [1] ��� ��������� ���������� �� The surface is well ventilated. [1] ��� ���������������� �������

The following figure shows the structures involved in gaseous exchange in mammals. (pic) (i) Name the structure X. [1]

���������� (ii) Name the process by which gases cross the gas exchange surface. [1] ���������� (iii) The arrows show the direction taken by gas crossing the gas exchange surface. Name the gas moving in this direction. [1] ���� �� �!�" # Name the gas moving in the opposite direction. [1] ������� ���������!�$" #

Page 2: gaseous exchange

Structure X, shown in the figure, is very delicate. The surface tension of the water film shown in the diagram would cause X to collapse if it were not for a substance in the film that lowers the surface tension. This substance is secreted in the fetal lungs late in pregnancy. Premature babies sometimes display breathing difficulties, a condition known as Respiratory Distress Syndrome. Without treatment, premature babies may become exhausted. Suggest the cause of this condition and suggest why premature babies may become exhausted. [3] �� ��� ������ �����!�� ��������������������� ������ ��������� ��� ��� ����� ���� ���� ��������������� ��� ���� �������������� ������������������������� ������ � ��� �����% �!� & ����� ������� ��

The drawing shows an electron micrograph of a section through part of an alveolus from a lung.

(pic)

Describe the path of a molecule of oxygen from the air in the alveolus at X to the plasma membrane of cell A. [1] ������������ �������������� �� ����������� ����� � ����'�� ���������������#�(�)�� ��� Cell A is a eukaryotic cell. Give two features that may be found in a prokaryotic cell which are not found in cell A. [2] �������� ��������������������������� ��������� ���������������* + Cells A and B are biconcave discs. Explain one advantage of a biconcave disc over a spherical cell of the same volume in transporting oxygen. [1] ��������,�������-������������������ ������� �����������!����������� ������ The diameter of a human red blood cell is 7µm. Calculate the magnification of the drawing. Show your working. [2] ��� � ����'�,��������� -.,� �� ��-�� ����

��� �� ������� �(�/01 ���/0)��� �!�2�3� ���2)4#���2#5/ ���� � ����'���� ����������� ������������ ������� 6���������� ������� � ����/0/���

/07��� 8�� �� ������25/2���5111�

In the lungs, the alveoli are the site of gas exchange. A large number of small alveoli is more efficient in gas exchange than a smaller number of larger alveoli. Explain why. [2] ������������������������� ����������������������� ���� ��������������������� ���� The diagram shows part of an alveolus and a capillary.

Page 3: gaseous exchange

(pic) (i) Name the type of cells in layer B. [1] ����������� �!���������������� (ii) What is the minimum distance a molecule of carbon dioxide diffuses from the blood plasma to the air space in the alveolus? [1] ��10))�9� ���� � ����'����������� ������ ���������� ���(�,1014.101#.101/-�3� �(�10))�3�

K Ecology Phytoplankton are microscopic photosynthesising organisms which live in water. In favourable

environmental conditions they have a very high rate of reproduction. They are eaten by microscopic animals called zooplankton. The graph below shows samples of water were removed from a lake at intervals over 12 months and their biomasses.

(pic)

The diagram shows the relationship between the biomass of the phytoplankton and the biomass of the zooplankton for one of the months during this investigation.

(pic) Use the graph to give one month in which this relationship would have been found. [1] ��: � �!�; � ��!�; ��

Explain why the biomass of the primary consumers is less than the biomass of the producers in most communities. [2] ����������� ��� �!�����!��������� ��� �!���������� ��������!���������� ������� ���������� �!�� ���� � �!�������� �!��������!������� �!���������������� ��� �!�� ����!�� ��������������� ��������������!�������������� ����� ������������!� � <�������������� Explain why the biomass of the phytoplankton in the lake could be less than that of the zooplankton, as shown in the diagram. [1] ���� ���� �� �����������������=��������������� ��� ���

The diagram represents the energy flow in kJ m-2 year-1 through the community in one area of sea in the English Channel.

(pic) (i) What percentage of the energy at the sea surface is fixed by the phytoplankton? [1] ��� � ����'�,��������� -.,� �� ��-�� ����

������� ����(�7>11!)0#7�)17��)11 ���10/? �(ii) Give two reasons for the ‘loss’ of energy at this stage. [2] ��������� ����������� �� �������� ��� ���� �� ����� ����� ���� ����������������� ����� Calculate (i) the net primary production. [1] ��,7>11<)#71-�/141��; �� <#� ���<) (ii) the total energy available to decomposers. [1] ��,)115.@#.41>.2)-�)/24 ��; �� <#� ���<)

Page 4: gaseous exchange

The diagram shows the energy flow through a fresh-water ecosystem. (pic) All units are kJ m-2 year-1.

Name (i) process A. [1] ����������� (ii) the group of organisms represented by Box B. [1] ������� �������!��� ���!��������

Showing your working in each case, calculate (i) the percentage efficiency with light energy is converted into energy in producers. [2] ��� � ����'�,��������� -.,� �� ��-�� ����

��,5241>!)02�)17-���)11? ����/0)? (ii) the amount of energy which goes to tertiary consumers. [2] ��� � ����'�,��������� -.,� �� ��-�� ����

��)71@�A�,)>#5�.�)@>-����55��; �� <#� ���<)

The diagram shows part of the nitrogen cycle. (pic) Name processes P and Q. [2]

����(��� ��������� ������(�+ ����� ������� It is estimated that, each year, a total of 3 × 109 tonnes of ammonia are converted to

nitrate. Only 2 × 108 tonnes of ammonia are produced from nitrogen gas. Explain the difference in these figures. [2] ���� � � ������� ���� ����� �!������ ������ �!������ � ��!��� � � �� � ����� ����� ��������� �������!��������� ������ � ����� ����� ����!��������� ����� ������� ��� ���,�0�0������ �6��� � �������6�* + 6� & �-

The conversion of ammonia to nitrate involves oxidation. What evidence in the diagram supports this? [1] ���� �� ���������� ����� ���� ����