Analysing adaptations for respiration Aseel Samaro They are

Analysing adaptations for respiration Aseel Samaro

§ They are both structures that transfer energy from type to another. § Mitochondria provides energy for our cells. § The power station provides energy for our homes. § The mitochondria in our cells act as a surface for respiration to take place § Both mitochondria and power station produce carbon dioxide in the process

Analysing adaptations for respiration § Cells contain several structures, each with a specific function – these are called organelles. § An example is the mitochondrion. § Mitochondria are described as ‘powerhouses’. This is because they are the site of respiration, the process by which energy is released. § The numbers vary in different cells depending on how much energy each cell needs.

Respiration powerhouses § Mitochondria are tiny sausage-shaped organelles found in most animal and plant cells. § You can use a powerful microscope (such as an electron microscope) to see their complex structure. § Each mitochondrion has two membranes.

§ The outer membrane surrounds the entire organelle. § The inner one is highly folded – the tips of the folds are called ‘cristae’. § Respiration takes place on the cristae. § Folding increases the number of cristae, maximising the amount of respiration that can take place. § The fluid inside the mitochondrion is called the matrix. It contains the enzymes essential for respiration.

Describe where mitochondria are found. Explain why mitochondria are called ‘powerhouses’. Explain how folding of the inner membrane helps mitochondria to produce more energy.

Counting mitochondria The numbers of mitochondria vary in different types of cell. Type of cell Average number of mitochondria per cell muscle cell 1900 red blood cell 0 liver cell 1300 skin cell 800 mucus cell 180

Why do muscle cells need lots of mitochondria?

Mitochondria can make copies of themselves if more are needed in a cell. Suggest when a cell may need more mitochondria.

What can go wrong? § If mitochondria do not function properly, then cells do not get the energy that they need. § When mitochondrial disease occurs, little or no respiration takes place in the mitochondria. § The organs most affected are those needing most energy such as the heart (and other muscles), liver and brain. § The symptoms are variable, depending on which mitochondria are affected. § Mitochondrial disease is caused by a fault in inherited material.

Suggest why sufferers of mitochondrial disease are often exhausted. Explain why it is wrong to think that we can ‘catch’ mitochondrial disease. Explain why the most severe symptoms may be seen when mitochondria in the brain are affected.

Did you know…? § Some scientists believe that mitochondria are descended from bacteria. § They think that bacteria similar to mitochondria once existed in their own right. § These bacteria are thought to have entered cells. § Over time, they evolved to exist within the cells and develop into mitochondria as we see them today.

Thank you