EduNinjaMeasurements of the lung capacity of a student were recorded using a spirometer and displayed with a data logger. Initially the student was at rest, then changed to carrying out strenuous exercise. The results are displayed in the graph.
Outline the function of pneumocytes in the lungs.
Stargardt's disease, a genetic disorder that causes vision loss, is being treated using retinal cells derived from human embryonic stem cells. Why are embryonic stem cells used?
They are already specialized for this function.
They are able to differentiate into the required cell type.
They retain stem cell properties after specialization.
There are no ethical issues concerning their use.
When compared to other body cells, which characteristic of stem cells is the most important for therapeutic uses?
Less differentiation
Less excretion
Lower rate of reproduction
Lower rate of metabolism
What happens to the cell surface area to volume ratio as a cell grows?
It decreases, so production of waste material is reduced.
It increases, so mineral ion absorption is increased.
It increases, so osmosis is reduced.
It decreases, so rate of gas exchange is too low.
Which characteristic of stem cells makes them useful for treating Stargardt's disease?
They can differentiate into retinal cells.
They are readily available from especially created embryos.
They transport white blood cells to the eyes.
They divide by binary fission so provide sufficient cells.
Which method provides biochemical evidence that cells have begun to differentiate?
Observation with a light microscope
Observation with an electron microscope
Examination of the DNA sequence
Analysis of the proteins
The micrograph shows part of a cell.
Which principal function is this cell likely to have, as judged by its cell structure and organelles?
High rate of protein processing
High rate of absorption
High rate of photosynthesis
High rate of movement
Three cell types are shown in the micrographs.
What feature distinguishes striated muscle fibres from the three cell types shown in the images?
Mitochondria
Nucleoid regions
Multinucleate structure
Membrane-bound organelles
Why are stem cells useful in repairing diseased or damaged organs?
They are specialized
They reproduce
Unlimited quantities are available from adult tissue
They can be transferred between species
What features of a cell favour efficient removal of waste products?
