Cells, Tissues and Organs

Transcription

1 Cells, Tissues and Organs You have already learned the basic function of cells, but how do these cells work together to make you the truly amazing organism that you are? Some of the key words you will need to use during this section are: Cell, tissue, organ, system, organism, specialisation Learning Outcomes You will be able to: Explain the term specialisation with reference to animal and plant cell. Describe how the structure of a cell can relate to its function. Describe the levels of organisation found in animals and plants. Specialisation Multicellular organisms are formed from a single fertilized egg (zygote) and are made of many genetically identical cells working together. These cells become specialised to form cells which are have a special shape or structure to carry out particular functions. Red blood cell Plant root hair cell 1 P a g e

2 Levels of Organisation Specialised cells that perform specific functions will group together and form tissues. These tissues will then work together to form organs and these organs will work collaboratively to form a system. Finally these systems will work together to form an organism. Learning Activity 1 1. Explain what is meant by the term specialisation of cells in animals and plants. 2. Describe the level of organisation found in animal and plants. 3. Collect and complete the specialised cells handout, paste into your notes. 4. Collect and complete the cellular organisation handout and paste into your notes. 2 P a g e

3 Challenge task Create a Plant or Animal cell owner s manual. Success Criteria 1. Two A4 pages have been halved and arranged into a booklet. 2. Each page contains a different type of plant cell. 3. Diagrams are to be at least half the page and drawn in pencil. 4. Diagrams/Organelles are labelled accurately. 5. The function of the cell is described. 6. Research is done into how the structure of the cell relates to its function. Peer Assessment Get another group to assess your completed work. They will give 2 positive comments and one thing that could have been improved. Use the above success criteria to evaluate the piece of work. 3 P a g e

4 Stem Cells and Meristems You know that many cells in an organism are specialised in order to perform particular functions, but just how do these cells become specialised? Some of the key words you will need to use during this section are: Stem cell, specialisation, embryonic stem cells, adult stem cells, meristems Learning Outcomes You will be able to: Explain what is unique about stem cells. Describe the role of stem cells in animals. Compare and contrast embryonic stem cells and adult stem cells. Give examples of the current uses of stem cells in medicine. Describe the role of meristems in plants. Stem Cells Stem cells are unspecialised cells in animals that have the potential to become different types of cells. Stem cells are involved in growth and repair. They can Reproduce themselves by repeated cell division while remaining unspecialised or undifferentiated. Differentiate into specialised cells when required to do so. There are two main types of stem cell: embryonic stem cells and adult stem cells. Formatted: Font: 8 pt 4 P a g e

5 Embryonic Stem Cells These stem cells are found in embryos and have the ability to develop into any type of body cell, allowing organisms to grow from a tiny organism into a fully formed individual. Adult Stem Cells These stem cells are found throughout the body and are slightly more specialised than embryonic stem cells. For example; stem cells found in the bone marrow are only capable of becoming a variety of blood cell types. Therapeutic value of stem cells Tissue stem cells present in bone marrow are used in bone marrow transplantation to treat cancers of the blood. Repair of corneal damage has been successfully carried out using the patient s own stem cells at the edge of their cornea. Human embryonic stem cells have been used to treat burn victims. Embryonic stem cells may be able to provide treatment for a range of disease like diabetes, Parkinson s disease, multiple sclerosis and Alzheimer s disease. 5 P a g e

6 Ethical Issues Research involving embryonic stem cells involves the destruction of embryos, many people believe it is wrong to destroy embryos because they have the potential to grow into a baby. Some people believe that the techniques used in stem cell research are similar to those used in cloning, which many people oppose. Many people have safety concerns and fear transplanted stem cells could become cancerous. Learning Activity 1 Formatted: Font: (Default) Comic Sans MS, 14 pt, Bold Your teacher will show you a short clip on stem cells. Watch the clip and answer the questions below in sentences What do scientists hope stem cells will enable them to do? 2. What is the easiest way to obtain stem cells at the moment? 3. What are stem cells? 4. Why are stem cells special? 5. How could stem cells be used to help the woman shown in the clip? 6. What are the two main ethical issues surrounding the use of stem cells? Formatted: Font: Comic Sans MS, 12 pt Learning Activity 2 Your teacher will give you each a different Stem Cell Opinion card. Following class discussion of each characters point of view, you will get into groups and create a 2 minute presentation to argue why your character s viewpoint is right. 6 P a g e

7 Stem Cell Therapy Assessment Outcomes 2.2 and Describing an application of biology What you need to do: Explain what stem cell are Explain where stem cells come from. 2.3 Describing a biological issue and its effect on society What you need to do: Identify an issue related to stem cell use. Identify the potential impact of stem cell therapy in the future. Explain what stem cell therapy is. Identify a specific use for stem cell therapy. 7 P a g e

8 Meristems Unlike animals, plant growth is restricted to special points called meristems. Meristems are the site of mitosis and produce nonspecialised cells, which have the potential to become almost any type of plant cell and contribute to plant growth. Meristems can be found at the tips of the roots and shoots (apical meristems) and within the stem and roots (lateral meristems). Learning Activity 3 1. What is a meristem? 2. Identify TWO locations in a plant where a meristem would be found. 3. Explain the difference between apical and lateral meristems. 4. Collect and complete the hand out Meristems and stick into your notes. Research Task Some plants can be cloned in a process called Mericloning. Your task is to find out the following: - What is Mericloning? - Describe the process of mericloning. - Give examples of plants which may be produced in this way. - What are the benefits of mericloning? 8 P a g e