1. Eukaryotic Cell Structure and Organelles

2. Protoplasm is all material in a cell, nucleus and cytoplasm

3. Background information on cell structure
Cells differ greatly in size - from a pneumonia bacterium ( mm in diameter), to a human egg cell (0.2 mm in diameter) to a human nerve cell (which can reach 1 m in length) to an ostrich egg (75 mm in diameter). Because cells have many different functions, they also have many different shapes.

4. Scale of the Universe/Cell

5. Regardless of their size, shape or function, cells have the same basic structure.
Cells are highly organized and are very complex. All cells have the following 3 main parts:
1. The cell membrane.
2. The cytoplasm
3. The nucleus.

6. Cell Membrane
Nucleus
Cytoplasm

7. Cell membrane (plasma membrane)-
surrounds cytoplasm of plant and animal cells. Lies just inside the plant cell wall.
Function – holds contents of the cell in place
- regulates the passage of materials into and out of the cell, therefore is called 'selectively permeable’.

8. Cytoplasm everything inside the cell except the DNA region (nucleus)
Function - contains the cell structures (called organelles - parts of a cell are often called 'organelles' which means 'little organs') that are essential for the cell to function.
- Cytoplasm is contains a jelly-like material (Cytosol), like uncooked egg white, where many processes are occurring at once, rather like a factory – bathes organelles

9. Nucleus
Function – holds the cell’s DNA and directs all cell activities.
“Control Centre” of the cell.

10. The nucleus is composed of :
1. Nuclear membrane (envelope) - a double membrane (i.e. two membrane layers thick)
Function - to separate the nuclear material (DNA) from the rest of the cell
Has very large nuclear pores to allow RNA to move from the nucleus to the cytoplasm, but these pores are too small to allow the chromosomes through.

11. The nucleus is composed of:
2. Chromatin or Chromosomes - Chromatin is called chromosomes when it is coiled up into shorter lengths. It contains complex molecules of DNA (deoxyribonucleic acid) also known as genes.
During regular cell activities, the chromatin is uncoiled; it coils up into chromosomes prior to cell division.
Functions control all cell processes
2. carry the cell's heredity

12. The nucleus is composed of:
3. nucleolus - a dark region in the nucleus
Function - believed to be the site of synthesis of several kinds of RNA (ribonucleic acid)

13. Sometimes the DNA mutates that is, it changes spontaneously and causes new characteristics.

15. Mitochondria
sausage shaped organelles which move around with the cytoplasm.
Function - sites of cell respiration (release of energy from glucose and other foods for use in the cell).

17. Ribosomes small oval structures composed of RNA and protein
Function - site of protein synthesis in cell

18. Endoplasmic Reticulum (ER)
Canal-like arrangement of parallel membranes in the cytoplasm but not in the nucleus.
Rough Endoplasmic Reticulum has many ribosomes attached to it.
Function: 1. anchor ribosomes 2. carry proteins through the cytoplasm
Smooth Endoplasmic Reticulum - has no ribosomes attached
Function 1. anchor enzymes which synthesize fats or lipids 2. transport fats and lipids through the cytoplasm.

20. Golgi Apparatus (body, complex)
formed of layers of membranes stacked on top of each other, looks like a stack of pancakes.
Functions 1. stores and secretes (ships out) proteins and large molecules formed by the cell may be involved in forming the endoplasmic reticulum

22. Microfilaments – pipe-like structures made of protein
Microfilaments – pipe-like structures made of protein. Function – provide shape and movement for the cell.
Microtubules – thread-like protein. Function – Transport internal structures through cells (ie: chromosomes during cell division). Also make up cilia and flagella.

24. Lysosomes
Consist of a rounded membrane containing enzymes which can digest the cell.
Functions :
1. break down large molecules and cell parts within the cytoplasm
2. digest food particles which can then be used by the cell
3. destroy harmful substances which enter a cell
4. in white blood cells, destroy bacteria which have entered your body
5. destroy worn out cells

25. Centrioles
Tube-like structures found in animal cells, but not plant cells.
Function - appear to take part in cell division.

26. Vacuoles
A fluid filled structure surrounded by a membrane (called the vacuolar membrane) and filled with different substances such as fat (in animals) or water, salts and wastes.
The vacuoles in animal cells are generally small, but many plant cells have a large water-filled central vacuole.
Generally, vacuoles are not visible unless they contain coloured molecules In plant cells, the vacuole is often large and is found in the centre of the cell; therefore it is called a central vacuole

28. Crash Course Eukaryotic Cells

29. Structures and Organelles in Plant Cells Only:

30. Plastids
Plastids- Membrane sacs. Function: involved in producing or storing food.
Types of plastids
a) Chloroplasts – complex membrane structures which contain chlorophyll. Function:Perform photosynthesis (use Carbon Dioxide, water, and sunlight to produce food and oxygen)
b) Chromoplasts- contain pigments (color).
c) Amyloplasts – colorless and store starch.

32. Cell Wall
Non-living, made of cellulose molecules. Is formed outside the plasma membrane Function: surrounds, strengthens and protects the plant cell.
Primary cell wall – thin, flexible, formed first. Supports the plant
Secondary cell wall – is found around some cells (i.e: wood), is thick and rigid, is formed between the primary cell wall and the plasma membrane. Supports the Plant.

33. ?

34. In plant cells, the vacuole is often large and is found in the centre of the cell; therefore it is called a central vacuole and contains water.

35. Crash Course Plant Cells