Cell Structure & Function

1. Cell Structure & Function

2. Cell Theory • All living things are made up of cells. • Cells are the smallest working units of all living things. • All cells come from preexisting cells through cell division.

3. Cells are small so they can exchange materials with their surroundings.

4. Definition of Cell A cell is the smallest unit that is capable of performing life functions.

5. Examples of Cells Amoeba Proteus Plant Stem Bacteria Red Blood Cell Nerve Cell

6. Two Types of Cells Prokaryotic Eukaryotic

7. Living cells classified into 2 different types based on internal structure • Prokaryotic cells – little defined internal structure. Lack a clearly defined structure to house their DNA. Organisms made up of prokaryotic cells are called Prokaryotes (all bacteria, all archaeans) • Eukaryotic cells – more complex structure. Contain many different kinds of membrane-bound structures called organelles suspended in cytosol.

8. Types of Cells

9. REVIEW • What are the main differences between Prokaryotic and Eukaryotic cells? • List one key point from the cell theory • What is the definition of a cell? • Why does a small cell have more surface area to volume?

10. Prokaryotic • Do not have structures surrounded by membranes • Few internal structures • One-celled organisms, Bacteria

11. Prokaryotic Cells • Prokaryotic cells include the bacteria and archaea. • Bacterial cells have these constant features: • Outer Boundary: Cell wall • Plasma membrane • Cytoplasm: Ribosomes • Thylakoids (Cyanobacteria) • Many enzymes • Nucleoid: Chromosome (DNA only)

12. Eukaryotic Cells • Eukaryotic cells have a nucleus that controls the workings of the cell. • All cells are surrounded by a plasma membrane made of phospholipids and proteins.

13. Eukaryotic • Contain organelles surrounded by membranes • Most living organisms Plant Animal

14. The plasma membrane regulates what enters and exits the cell. Inside the plasma membrane, the nucleus is surrounded by cytoplasm. Cytoplasm is a semi-fluid medium. Plant cells have a cell wall in addition to the plasma membrane. Primary cell walls are made from cellulose. The secondary cell wall, which forms inside the primary wall, is formed from lignin. Its purpose is to give strength to the cell.

15. REVIEW • List one main difference between plant and animal cells • Do plant and animal cells have organelles? • What is the function of organelles?

16. Animal cell anatomy

17. “Typical” Animal Cell

18. Plant cell anatomy

19. “Typical” Plant Cell

20. REVIEW • What are the main similarities and differences between plant and animal cells?

21. Cell Parts Organelles

22. Animal and plant cells have organelles. Organelles compartmentalize functions within the cell. The organelles of animal and plant cells are similar to each other except that centrioles are present only in animal cells, and chloroplasts are present only in plant cells.

23. Surrounding the Cell

24. Cell Membrane • Outer membrane of cell that controls movement in and out of the cell • Double layer

25. Cell Wall • Most commonly found in plant cells & bacteria • Supports & protects cells

26. REVIEW • Which structure surrounds a cell? • Briefly outline the cell theory

27. Inside the Cell

28. Nucleus • Directs cell activities • Separated from cytoplasm by nuclear membrane • Contains genetic material - DNA

29. Nuclear Membrane • Surrounds nucleus • Made of two layers • Openings allow material to enter and leave nucleus

30. Chromosomes • In nucleus • Made of DNA • Contain instructions for traits & characteristics

31. Nucleolus • Inside nucleus • Contains RNA to build proteins

32. Cytoplasm • Gel-like mixture • Surrounded by cell membrane • Contains hereditary material

33. Endoplasmic Reticulum • Moves materials around in cell • Smooth type: lacks ribosomes • Rough type (pictured): ribosomes embedded in surface

34. Ribosomes • Each cell contains thousands • Make proteins • Found on rough endoplasmic reticulum & floating throughout the cell

35. Mitochondria • Produces energy through chemical reactions – breaking down fats & carbohydrates • Controls level of water and other materials in cell • Recycles and decomposes proteins, fats, and carbohydrates

36. Golgi Bodies • Protein 'packaging plant' • Move materials within the cell • Move materials out of the cell

37. Cilia and flagella • Cilia and flagella - 9 + 2 pattern of microtubules • Involved in movement (cell, eggs, debris) • Each cilium and flagellum has a basalbody at its base.

38. Structure of a flagellum or cilium

39. Lysosome • Digestive 'plant' for proteins, fats, and carbohydrates • Transports undigested material to cell membrane for removal • Cell breaks down if lysosome explodes

40. Vacuoles • Membrane-bound sacs for storage, digestion, and waste removal • Contains water solution • Help plants maintain shape

41. Chloroplast • Usually found in plant cells • Contains green chlorophyll • Where photosynthesis takes place

42. REVIEW • List 5 structures within a cell • What do golgi do? • What does the mitochondria do? • What is the function of the cytoplasm? • What is the function of the nucleus? • What does the nuclear membrane allow to happen? • What is the function of the nucleolus? • What is the function of the lysosome? • What is the function of the endoplasmic reticulum? • Why don’t animal cells contain chloroplasts?