(3 marks) (3 marks)
(3 marks)
Questions
1 Suggest what would happen to the fish if they had no homeostatic mechanism.
2 The branchial MR cells are rich in mitochondria,
a Use information in Figure 1 to suggest the importance of the mitochondria.
b Suggest how the cell maintains a sufficient oxygen supply for the
mitochondria
3 Na /K-ATPase is a protein in the cell membrane. This protein is regulated by pH
changes. Use the information in the diagram to suggest a mechanism for
switching on the Naf/K-ATPase linked to cell surface membrane.
4 Use Figure 1 to predict the changes to the internal environment of the cell when
the Na'/K'-ATPase is active. Suggest a mechanism for maximum sodium uptake
from the water by the cell.
5 Suggest a function for the channel protein B.
6 Bafilomycin A1 is an antibiotic that specifically inhibits V-ATPase.
a What is meant by the term "specific" in this context?
b Predict how the water potential of the blood of the killifish might change in the
presence of this antibiotic.
(4 marks)
(5 marks)
(2 marks)
(1 mark)
(3 marks)

one centimetre is equal to 0.01 metres

question#1

ans:

cell is the basic unit of organization of all living things. cells are often called the building block of life and it is the smallest unit of life. the study of cell is called cell biology. cell consists of cytoplasm enclosed within membrane, which contain bio-molecules such as proteins and nucleic acid.

two third of cell is water, which means that two-third of your whole body is water. the rest is the mixture of molecules, mainly proteins, lipids and carbohydrates.

question#2

ans:

organ:

an organ is a group of tissues specialized to form a functional unit. an example is the heart in animals.

organ system:

an organ system is a group of several organs whose functions are synchronized to release an effective action in a living organism. an example is digestive system.

question#3

different systems perform different function at tissue level. for example, the respiratory system facilitates breathing. in the alveoli tissue of the lungs, the exchange of oxygen and carbon dioxide molecules between the air and the bloodstream occurs by passive transport, so that oxygen is taken in and carbon dioxide and water are removed. different systems of the body carry out different functions. for example, your digestive system is responsible for taking in and processing food, while your respiratory system working with your circulatory system is responsible for taking up oxygen and getting rid of carbon dioxide.

question#4

different systems perform different function at tissue level. for example, the respiratory system facilitates breathing. in the alveoli tissue of the lungs, the exchange of oxygen and carbon dioxide molecules between the air and the bloodstream occurs by passive transport, so that oxygen is taken in and carbon dioxide and water are removed. different systems of the body carry out different functions. for example, your digestive system is responsible for taking in and processing food, while your respiratory system—working with your circulatory system is responsible for taking up oxygen and getting rid of carbon dioxide.

question#5

our body works because of the interactions that happen between organs and organ systems.  

for example:  

the heart to regulate blood flow throughout the body. the blood carries oxygen and nutrients to the cells and carries carbon dioxide and waste away from the cells. body systems work together in maintaining a constant internal environment. when this balance is disrupted, the body systems may not function properly, and human health can suffer.   you start to feel bad.