Mucus traps pathogenic bacteria. Mucus also attracts viruses that attack pathogenic bacteria.
[Source: EYE OF SCIENCE/SCIENCE PHOTO LIBRARY]
What part of the immune system do these viruses resemble in their function?
Label the following diagram of the side view of the human elbow joint.
Label the diagram of the side view of the human elbow joint.
State the function of structures I and II.
State an injury that might occur in this joint.
Outline the first three levels of protein structure, including the types of bonding within each and the significance of each level.
Using a table, compare competitive and non-competitive inhibition and give one named example of each.
Explain the production of antibodies.
The following shows an electron micrograph of a liver cell. The electron micrograph is a higher magnification of a liver cell.
Calculate the magnification of the liver cell.
Calculate the actual diameter of the nucleus as marked on the electron micrograph.
State the name of the organelle labelled X.
State its main function.
Outline the significance of the relationship between the surface area and volume of a cell.
Liver cells store extra glucose as glycogen. Explain two steps that have to occur to release energy from glycogen during aerobic respiration.
Outline how the properties of water make it an effective coolant for the body.
Describe how changes in weather conditions affect the transport and loss of water in plants.
Explain how water balance is restored in mammals when they are dehydrated.
Which correctly describes the role of the epididymis in semen production?
In an investigation to compare the elasticity of arteries and veins, rings of the same diameter (20 mm) of artery and vein tissue were cut from blood vessels obtained from a mammal. Each ring was attached to a clamp. Multiple masses of 10 g were added and removed. The vertical diameter of the artery and the vein was measured, both with the mass and once the mass had been removed. The results are shown in the table. | | Diameter of vein / mm | | Diameter of artery / mm | | |:---|:---:|:---:|:---:|:---:| | Mass / g | With mass | Mass removed | With mass | Mass removed | | 0 | 20 | 20 | 20 | 20 | | 10 | 26 | 26 | 26 | 22 | | 20 | 34 | 33 | 30 | 23 | | 30 | 38 | 36 | 35 | 23 | | 40 | 40 | 37 | 38 | 24 |
State the independent and dependent variables in this experiment.
State one feature of the rings that has to be kept constant apart from their initial diameter.
Explain the differences between the results shown for vein and artery.
The following is a diagram of a flower.
[Source: © International Baccalaureate Organization 2014]
What structures are indicated by the letters X, Y and Z?
X | Y | Z |
---|---|---|
stigma | style | sepal |
anther | style | ovary |
stigma | filament | ovary |
anther | filament | ovary |
What is a similarity between human and insect muscles?
Describe the role of ADH in human osmoregulation.