Tag Archives: respiration

Distribution of Materials


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In this unit of work we are looking at the ways plants and animals distribute nutrients, hormones, gases, water and waste products to and from different cells throughout the organism. In animals, this involves the circulatory, respiratory and excretory systems. In vascular plants, we consider gaseous exchange, transpiration and substances moving through the xylem and phloem.

Circulatory System: Once food has been digested, these nutrients needs to be distributed to every cell within the body to enable cellular respiration to occur. These nutrients, as well as hormones, waste products (CO2 and urea), salts and heat are transported in the circulatory system. The circulatory system of mammals includes  a four-chambered heart, arteries, veins and capillaries that allow the movement of blood to every cell within the body.

Respiratory System: The mammalian respiratory system includes the lungs, trachea, bronchi and alveoli that allow the transfer of oxygen and carbon dioxide between the internal blood supply and the external environment. Insects have an open respiratory system in which the air and the internal cells are in close contact, oxygen entering through spiracles and passing in to branching tubes within the organism. Don’t get confused between cellular respiration and breathing! Cellular respiration is the process that converts glucose and oxygen to energy within the cells. Oxygen is supplied to those cells by the red blood cells, which carry oxyhaemoglobin to cells and remove carbon dioxide from cells.

Excretory System: Our kidneys are part of our excretory system, to remove nitrogenous wastes from our body. The nephron is the functioning unit that removes urea from the blood and allows water, nutrients and salts to be re-absorbed to the body. Ureters are the tubes that carry urea from the kidneys to the bladder and urine leaves the body via the urethra.

Gaseous Exchange in Plants: Plant cells need to exchange oxygen and carbon dioxide with the environment and they do so through stomata (pores) in their leaves.

Transpiration: How do the tallest trees draw water from the soil to hydrate leaves many metres in the air?

Xylem and Phloem in Vascular Plants: What are vascular plants and how do they transport water with dissolved minerals and nutrients to cells in the roots, stems and leaves?

Please let me know in the comments below if any of these links are no longer working!

Cellular Respiration by Video Conference from GTAC


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Today our Year 12 students had the opportunity to work with Fran and Catherine from the Gene Technology Access Centre to learn more about cellular respiration. They participated in a 90 minute Polycom session using models and interacting with experts to gain insight into how cells respire and how research into this biochemical pathway may lead to the development of treatments for cancer. It is a wonderful opportunity for small, rural and isolated schools to be able to connect with this world-class educational centre, without the expense and inconvenience of long travel times, permission slips, risk-assessment forms and arranging buses or train tickets. On Monday we will participate in another GTAC session: “The Many Colours of Photosynthesis”. Students’ comments included:

“The experiment that was demonstrated was something we couldn’t do at school, so it was good to learn how that was done and analyse the data.” – Kiri

“The slideshow and worksheets were clear and informative, allowing us to understand and visualize the process of respiration”. – Che

“It was all really good, especially knowing what is important for the exam”. – Stephanie

Photosynthesis and Respiration

Photosynthesis and cellular respiration are ‘opposite’ reactions in the carbon cycle – one is endothermic (requires the input of energy) and one is exothermic (releases energy). Once you have read Chapter 3 and answered the chapter review questions, watch these videos and test your understanding by completing the “Photosynthesis/Respiration” worksheet. Whereas photosynthesis occurs only in the chloroplasts of plants, cellular respiration occurs in the mitochondria of both plants, fungi and animals. You will need to know these biochemical processes in a good deal of detail for the exam.

Anaerobic vs aerobic respiration

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If you choose to study microbiology at University, you may be involved with experiments such as this, working in an anaerobic chamber. When you exclude oxygen from the environment, respiration takes place anaerobically – without oxygen. Read more here. Anaerobic respiration is used both in the brewing and baking industries, as alcohol and carbon dioxide are produced when specific organisms respire without oxygen. This is called fermentation. If you have access to YouTube, you can see a quick Food Science video about fermentation here.

This site, from Thomas M. Terry of the University of Connecticut, has some excellent, very detailed animations of cellular respiration. Chapter three also deals with enzymes – proteins that accelerate biological reactions. It is important to remember that enzymes are not reactants or products of a reaction – they are not ‘used up’ during the process. Enzymes facilitate, or speed up, a specific reaction. For a good tutorial check out: “What is an Enzyme?”.