1. Holt Cells, 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. First Observations of Cells
Simple Microscope
One lens
Compound Microscope
More than one lens

6. Robert Hooke English scientist / inventor
One of the first people to observe cells
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-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.
organs organelles
- 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 out bodily 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 3 The 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.

51. Tissues Animals have 4 basic types of tissues: Nerve tissue
Muscle tissue
Connective tissue
Protective tissue

52. TIssues Plants have three types of tissues: Transport tissues
Protective tissues
Ground tissues – where photosynthesis takes place

53. Tissues Working Together
A structure that is made up of two or more tissues working together to perform a specific function is called an organ
Plants also have organs – example a leaf is a plant organ

54. Organs working together
A group of organs working together to perform a particular function is called an organ system.

55. Organisms
Anything that perform life processes by itself is an organism.
An organism can be single celled or multicellular.

56. Organization of Cells
cell
tissue
organ
organ system

58. Structure and Function
In organisms, structure and function are related.
Structure is the arrangement of parts in an organism.
Function is the job the part does.