Cell Structure and Organization: Nucleus, Ribosome, Endoplasmic Reticulum, Golgi Apparatus, Mitochondrion, Vacuole, Cyto

1. CHAPTER 2 CELL STRUCTURE AND CELL ORGANISATION

3. 1. Nucleolus 2. Nucleus 3. Ribosome 4. Vesicle 5. Rough endoplasmic reticulum 6. Golgi apparatus (or "Golgi body") 7. Cytoskeleton 8. Smooth endoplasmic reticulum 9. Mitochondrion 10. Vacuole 11. Cytoplasm 12. Lysosome 13. Centriole Diagram of a typical animal cell. Organelles are labelled as follows:

9. Chloroplasts are larger than mitochondria, and are surrounded by two specialized membranes. In plants and some other eukaryotes, chloroplasts are the sites of photosynthesis, a process in which atmospheric carbon dioxide is "fixed" into organic compounds, and oxygen is released into the atmosphere

10. Mitochondria are small, oval shaped organelles surrounded by two highly specialized membranes. Mitochondria are the sites of aerobic respiration, and are generally the major energy production center in eukaryotes

12. Cell Organisation • Organism can be categorised as unicellular or multicellular • Unicellular organism are organism with just one cell, for example Amoeba sp. and Paramecium sp. • Multicellular organisms are made up of more than one cell

13. Amoeba proteus

14. The Amoeba sp. Exhibits various living processes as follows: • Feeding • Locomotion • Reproduction Feeding • Amoeba sp. feeds on bacteria and algae much smaller than itself. • When the amoeba sp comes in contact with its food, it puts its pseudopodia all around the food to enclose it in a drop of water, forming a food vacuole • The cytoplasm secrete enzymes into the food vacuole to digest the food. • The digested substances are absorbed into the cytoplasm while the undigested material are removed when the vacuole comes in contact with the plasma membrane and breaks

16. Locomotion • The amoeba moves by putting out new pseudopodia in front withdrawing other behind. • Movement by means of pseudopodia is known as amoeboid movement • The shape of the amoeba changes as it move.

17. Reproduction • The amoeba reproduce mainly by binary fission • Binary fission is a method of asexual reproduction which does not involve the fusion of gametes. • When food is abundant, the amoeba reproduces by binary fission. When the amoeba reaches a maximum size, the nucleus divides into two and the cytoplasm constrict, forming two new amoeba. • The amoeba does not reproduce sexually.

18. Cell specialisation in multicellular organism • Being multicellular not only enables organisms to be larger, it also enables their to become specialised. • Each type of cell specialiseds in performing a particular function, for example the red blood cell in animal transports oxygen and the xylem vessel in plant transports water and mineral salt. This is known as division of labour. • The division of labour permits greater efficiency and enables multicellular organisms to exploit environments that are denied to unicellular organisms. Foe example, only multicellular organisms can adapt to life in terrestrial environment. • Multicellular organisms have a great potential for cell specialisation, leading to the development of tissues and organ

19. Cell organisation in the formation of tissues, organ and systems in the multicellular organism • The study of cells is known as cytology

20. Some of the human cell and their functions

21. Some of the human cell and their functions

22. The study of tissues is known as histology • In human and animal, there are four basic types of tissuesc Humans and animal tissues

23. There are three major plant tissues; epidermis, ground tissue and vascular tissue Plant tissues

24. Organ consists of several types of tissues and it is specialised to perform a specific function • Example of human organ include heart, stomach, kidney, liver and blood vessels • Organ system consists of a group of organs which carryout major function such as respiratory, nutrition and other • There are 12 organ system in human.

25. Circulatory system Function; Transport material such as nutrient, gases, metabolic waste and heat around the body Organs and structure; hear, blood vessels

26. Function; provides a means for gaseous exchange, that is oxygen Organs and structure; hear, blood vessels

27. Function; Breaks down complex food into simple substance for easy absorption by body cells Organs and structure; mouth, oesophagus, stomach, intestine, rectum and anus

29. Excretory system Function; Discard toxic waste product Organs and structure; Liver, kidney, urinary bladder

30. Intergumentary System Function; • Physically separates the body from the external environment • Protects the body against mechanical injuries, microbial infection and dehydration Organs and structure; Skin

31. Skeletal System Function; Provides bodily support and protection to soft internal organs Organs and structure; skull, rib cage, humerus, backbone, ulna, radius, femur, fibula and tibia

32. Muscular System Function; help in movement of the body Organs and structure; all muscle..

33. Lymphatic System Function; • Defend the body against infection • Return excess tissue fluid to the blood Organs and structure; all muscle..

34. Endocrine System Function; produces hormone that control the bodily activities Organs and structure; Pituitary gland, adrenal gland, thyroid gland, pancreas, testes and ovaries.

36. Female reproductive system

38. Cell organisation Plant tissue • Meristematic tissue consist of small cells which have thin walls, large nuclei, dense cytoplasm and no vacuoles. • Apical meristems are located at the tips of roots and the bud of shoots. The tissues undergo mitotic cell division to increase the number of cell division to increase the number of cell for plant growth. • Lateral meristems or cambium are found in the peripheral areas of stem and roots. They are responsible for secondary growth which adds girth to the plants.

39. Permanent tissues • Permanent tissues consist of more mature cells that are either undergoing differentiation or have already undergone differentiation. • There are three types of permanent tissues • Epidermal tissues • forms a layer to cover the entire surface of the plants and protects the surface of plants • Protect the underlying tissues from physical damage infection • Reduce water loss b) Ground tissues • Provide support and strengthens the plants c) Vascular tissues • Transport water and food • Provide support

40. The importance of maintaining an optimal internal environment in cells • The self-regulation of the internal environment of organisms have or cells is called homeostasis • Multicellular organisms have a series or organ and systems that functional in homeostasis • For a multicellular organisms to function efficiently, other factors in the internal environment also have to be maintained within narrow limits. Examples of these factors include the volume of water, temperature, acidity and concentration of salts. • Homeostasis is essential for the maintenance of health and its breakdown will inevitably result in disease

41. Appreciating the uniqueness of the cell • Each cell is unique and its organelles are specialised to perform specific roles to carry out the cell mechanisms • With the division of labour among the different types of cells, it ensures the efficient and smooth functioning of the life processes in the body and the survival of the organism. • The function of intracellular organelles such as mitochondria, lysosomes and the endoplasmic reticulum also depend on the integrity of their cell membrane (explain the function of each organelles) • Generally, any damage to the cell parts or organelles can effect the cell’s activities and this could be detrimental to the cell as it could lead to cell death.