Holt Cells, Heredity and Classification

1. HoltCells, Heredity and Classification Chapter 1: The Basic Units of Life

2. Section 1: Diversity of Cells • Cell – the smallest unit that can perform all the processes necessary for life - cells are covered by a membrane and have DNA and cytoplasm

3. Section 1: Diversity of Cells • Cells - the basic units of structure and function in living things. Form the parts of an organism Carry out all of organism’s processes, such as: obtaining oxygen, getting rid of waste, obtaining food, growing

4. First Observations of Cells • Microscope - an instrument that makes small objects look larger. • Made it possible to discover / learn about cells

5. Simple Microscope One lens Compound Microscope More than one lens First Observations of Cells

6. Robert Hooke • English scientist / inventor • One of the first people to observe cells • 1665 - used his microscope to observe a piece of cork • Called the empty spaces cells - “little rooms” • Thought animals weren’t made of cells since their cells didn’t have walls

7. Anton van Leeuwenhoek • Dutch businessman • 1673 built his own microscopes • Observed fast-moving one-celled organisms in pond scum/water… called these animalcules • Also observed blood, bacteria and yeast cells

8. Anton van Leeuwenhoek • Leeuwenhoek is a long, unusual word like animalcules

9. Development of The Cell Theory • Almost 200 years passed before scientists concluded that cells are present in all living things • 1838 – Matthias Schleiden concludes that all plants are made of cells

10. Development of The Cell Theory • 1839 – Theodor Schwann concluded that all animal tissues were made up of cells • Schwann wrote first 2 parts of Cell Theory • All organisms are made of one or more cells • The cell is the basic unit of all living things.

11. Development of The Cell Theory • 1858 – Rudolf Virchow, a doctor, stated that all new cells could form only from other cells that already exist • This then added the third part of the Cell Theory 3) All cells come from existing cells

12. The Cell Theory • The cell theory states that: 1) All organisms are made of one or more cells 2) The Cell is the basic unit of all living things. 3) All cells come from existing cells.

13. Cell Size • Most cells are too small to be seen without a microscope • No one knew cells existed until they could see them with a microscope Skin cells

14. Cell Size • As a cell’s volume increases, it’s surface area grows too. surface area surface area-to-volume ratio = volume

15. Parts of a Cell • Cell membrane = a protective layer that covers the cell’s surface and acts as a barrier between inside of a cell and the cell’s environment (outside)

16. Parts of a Cell • Cell membrane - controls what substances enter or leave the cell. 1 = cell wall 2 = cell membrane

17. Parts of a Cell • cell membrane - controls what substances enter or leave the cell. - all cells have them - acts like a window screen

18. Parts of a Cell • cytoplasm = fluid inside a cell

19. Parts of a Cell • organelles - structures that perform specific function within the cell. organsorganelles - structures that - structures that carry out functions carry out functions in a body in a cell

20. Different types of cells have different organelles

21. Parts of a Cell • Nucleus – in a eukaryotic cell; a membrane bound organelle that contains the cell’s DNA and has a role in processes such as growth, metabolism and reproduction • the cell’s control center • Acts as the brain of the cell

22. Two Kinds of Cells • prokaryote = an organism that consists of a single cell that does not have a nucleus • Eubacteria and Archaebacteria

23. Two Kinds of Cells • eukaryote = an organism made up of cells that have a nucleus enclosed by a membrane • animals, plants and fungi

24. Section 2:Eukaryotic Cells

25. Cell Wall • cell wall - a rigid structure that surrounds the cell membrane and provides support to the cell • Plants and algae have cell walls made of cellulose • Fungi –yeast and mushrooms Onion cells

26. Eukaryotic Cells • cell wall - a rigid layer of nonliving material that surrounds the cells of plants and some other organisms. • Helps to protect and support the cell • Made mostly of cellulose (a strong material) • Allows some materials (such as water and oxygen) to pass through

27. Cell Membrane • All cells have a cell membrane • Protective barrier that encloses a cell • Separates contents from environment • a gel-like fluid • Contains proteins, lipids, and phospholipids

28. Lipids – include fats and cholesterol, are a group of compounds that do not dissolve in water • Phospholipids – a lipid that contains phosphorous

29. Cytoskeleton • a web of proteins in the cytoplasm • acts as both a muscle and a skeleton • keeps the cell’s membranes from collapsing • helps some cells move • made of 3 types of proteins

30. Nucleus • all eukaryotic cells have a nucleus • a large organelle • contains the cell’s DNA = genetic material

31. Nucleus • Nucleus has a dark area of many cells called the nucleolus which is where a cell begins to make its ribosomes

32. Ribosomes • ribosomes – cell organelle composed of RNA and protein; the site of protein synthesis (small, grainlike bodies that produce proteins)

33. Ribosomes • ribosomes - small, grainlike bodies that produce proteins. important chemicals needed to carry outbodily functions.

34. Protein Jobs

35. Endoplasmic Reticulum • endoplasmic reticulum – a system of folded membranes that in which proteins, lipids and other materials are made

36. Endoplasmic Reticulum • The internal delivery system of the cell • Its folded membranes contain many tubes and passageways • Substances move through the ER to different places in the cell

37. Rough ER • Covered in ribosomes • Usually found near nucleus • Ribosomes on rough ER make many of cell’s proteins • ER delivers these throughout the cell

38. Smooth ER • Not covered in ribosomes • Functions include making lipids and breaking down toxic materials that could damage cell

39. Mitochondria • mitochondria – main source of power in a cell - where sugar is broken down to produce energy

40. Mitochondria • energy released by mitochondria is stored in a substance called ATP which a cell used to do work

41. Chloroplasts • chloroplasts – where photosynthesis takes place sunlight + CO2 + H2O =(makes) sugar + O2

42. Chloroplasts • only found in plant and algae • contain chlorophyll = makes plants green

43. Golgi Complex • Golgi complex - receives proteins and other newly formed materials from the endoplasmic reticulum, packages them, and distributes them to other parts of the cell, or outside the cell.

44. Golgi Complex • Lipids and proteins from ER may be modified to do different jobs • Final products are enclosed in a piece of golgi complex’s membrane that is pinched off – forms a bubble and is transported to other parts of cell or out of cell

45. Vesicle • The bubble that forms from the golgi complex’s membrane is a vesicle • A small sac that surrounds material to be moved in or out of cell

46. Lysosomes • lysosomes – vesicles responsible for digestion inside a cell • contain digestive enzymes • destroy worn out or damaged organelles, get rid of waste materials and protect cell from foreign invaders • mainly in animal cells

47. Organelles in the Cytoplasm • vacuoles – large vesicle • In plants & fungi may act like lysosomes • Store digestive enzymes and aid in digestion within cell • Other vacuoles in plant cell store water and other liquids to help support cell (or will wilt)

48. Section 3The Organization of Living Things

49. Benefits of Being Multicellular Larger size: even if small still larger than single celled organisms Longer life: life span not limited to that of a single cell Specialization: each type of cell has a particular job making the organism more efficient

50. Cells Working Together • A tissue is a group of cells that work together to perform a specific job.