Foundations in Biology

1. Foundations in Biology Block 1A – 2.1 Cell structure The ultrastructure of eukaryotic cells

2. Spec

3. Starter Animal Cell Plant Cell In pairs - Identify the main similarities and differences between animal and plant cells

4. Animals vs. Plants Animal Cells Plant Cells Plasma membrane Nucleus Mitochondria Both types of ER Golgi Body Ribosomes Lysosomes Cell Wall Chloroplast Vacuole • Plasma membrane • Nucleus • Mitochondria • Both types of ER • Golgi Body • Ribosomes • Lysosomes

5. Animal v Plant cells Learning Objectives Success Criteria Compare the structure and ultra-structure of plant cells with that of animal cells (Grade E) Outline the functions of the structures found in cells (Grade C) Explain the function of structures found in cells (Grade A) • Produce a model comparing animal and plant cells • Describe the structure and function of organelles • Construct a mind map to show how the cytoskeleton allows stability and movement of and within cells.

7. What is a cell? Cells are the basic unit of life. They are small membrane-bound structures containing several smaller structures called organelles. There are two main categories of cell, each of which have important different structural properties: • eukaryotic cell, including the cells of animals and plants • prokaryotic cell, including bacterial cells.

8. What is a eukaryote? A eukaryote is any organism consisting of one or more cells that contain DNA in a membrane-bound nucleus, separate from the cytoplasm. Eukaryotes include: animals plants fungi a diverse group known as the protists (or protoctists). All eukaryotic cells contain a large number of specialized, membrane-bound organelles.

9. Animal cell Cell surface membrane Microtubule network vesicles ribosome centriole Rough nucleolus Endoplasmic reticulum Smooth nucleus cytoskeleton Golgi apparatus secretory vesicles mitochondria

10. Plant cell Label the organelles on the worksheet for plant and animal cell

11. The internal structures of a cell The structures within the cell are called ORGANELLES. Each type of organelle has a SPECIFIC FUNCTION. The types of organelle present in a cell, reflects the function of that cell. Task – Complete cut and stick page 36+ to help

12. Nucleus • The nucleus is the largest organelle (10-20m in diameter) and is surrounded by it’s own membrane called the nuclear envelope. • The nucleus contains the DNA of the cell and is the site of DNA replication, and controls protein synthesis. • The nucleus contains a small dark structure called the nucleolus, which synthesises ribosomes. • The DNA in a nucleus usually exists as CHROMATIN. • The nucleus controls all the activities of the cell.

13. Mitochondria • Mitochondria are the sites of aerobic respiration. • They provide all of the energy a cell requires – so more active cells (muscles) will have greater numbers of mitochondria. • They too, have a double membrane – the inner one is folded to form cristae – where ATP is produced.

14. Endoplasmic Reticulum (ER) • The endoplasmic reticulumis a series of membrane folds that connect to the nuclear envelope. • The space between these folds is filled with fluid, which transports substances around within the cell. There are 2 types of ER: • Smooth Endoplasmic Reticulum • This type of ER synthesis & processes lipids. • Rough Endoplasmic Reticulum • This type of ER is studded with ribosomes. It’s function is to process proteins produced by the ribosomes.

17. Ribosome • A ribosome are tiny organelles that either: • Float free in the cytoplasm • Attached to the endoplasmic reticulum (= RER) • Ribosome’s are the site where proteins are synthesised. • mRNA from the nucleus is read and used to assemble amino acids.

18. Golgi Body • The Golgi Bodyappears as flattened sacs that produce vesicles. • It is like the processing department of the cell. • All the substances produced by the smooth & rough endoplasmic reticulum are processed and packages by the Golgi body.

19. Lysosome • Lysosomes are small, round organelles. • They contain digestive enzymes which need to be kept separate from the rest of the cell by a membrane. • The digestive enzymes of the lysosome are used to digest invading cells or even destroy the cell itself when needed.

20. Centrioles • Two bundles of microtubules at right angles to each other • Essential to cell division – enables movement of chromosomes to opposite ends of cell • Involved in the formation of cilia and undulipodia. Involved in movement of substances outside of or of the whole cell

21. The cell wall The cell wall of a plant cell gives it support and structure. It is made of the polysaccharide cellulose, and can function as a carbohydrate store by varying the amount of cellulose it holds. The cell wall does not seal off a cell completely from its neighbours. There are pores within the walls called plasmodesmata. These connect two cells together by their cytoplasm, enabling the exchange and transport of substances.

22. Chloroplasts • Chloroplasts are organelles surrounded by a double membrane. • The inner membrane is folded into thylakoid membranes,which are where PHOTOSYNTHESIS TAKES PLACE. • The chloroplasts contain a light-absorbing pigment called chlorophyll which give plants their green colour.

23. Vacuole • Mature plant cells have a large permanent vacuole. • The vacuole contains liquid (water), pigments, waste etc. • It is important in keeping the cell turgid. When it is full, it provides support.

24. Task • Complete organelle structure and function worksheet • Optional cut and stick statements in or write them in – use pages 36-40 - help

25. Cell junctions Location – depends on junction type They are contact points between the plasma membranes of tissue cells eg. Gap junctions – Allows adjacent cells to communicate for electric and metabolic functions Desmosomes – fasten cells together Tight junctions – prevent leakage of extracellular fluid from layers of epithelial cells

26. Cytoskeleton - microfilaments • The cytoskeleton is both a muscle and a skeleton, and is responsible for cell movement, cytokinesis, and the organization of the organelles within the cell. The cytoskeleton is unique to eukaryotic cells. It is a dynamic three-dimensional structure that fills the cytoplasm. It holds organelles in place as well as allowing their movement. Three components: Microfilaments Microtubules Intermediate fibres

27. Cytoskeleton - Microtubules • Microtubules Microtubules are cylindrical tubes, 20-25 nm in diameter. They are composed of subunits of the protein tubulin--these subunits are termed alpha and beta. • Microtubules act as a scaffold to determine cell shape, and provide a set of "tracks" for cell organelles and vesicles to move on. • Microtubules also form the spindle fibres for separating chromosomes during mitosis. When arranged in geometric patterns inside flagella and cilia, they are used for locomotion.

28. Cytoskeleton – Microtubule motors • Proteins attached to microtubules – move organelles and other components along fibres • eg chromosomes during mitosis • ATP is required • Intermediate fibres – give mechanical strength to cells

29. Task – Mindmap • Construct a mindmap to show the roles of the cytoskeleton and how its components ensure stability and movement. • Use the textbook, Cells booklet, Cytoskeleton worksheet.

30. Plenary Smooth ER nuclear membrane mitochondria vesicles Rough ER nucleolus

31. What are these structures? F H G What is this organelle? What might D be? E } I

32. Animal v Plant cells Learning Objectives Success Criteria Compare the structure and ultra-structure of plant cells with that of animal cells (Grade E) Outline the functions of the structures found in cells (Grade C) Explain the function of structures found in cells (Grade A) • Produce a model comparing animal and plant cells • Describe the structure and function of organelles • Construct a mind map to show how the cytoskeleton allows stability and movement of and within cells.