1 cell structure & function cells cells are the basic units of life. it is important to note...

1

Cell Structure & FunctionCell Structure & Function

Cells• Cells are the basic units of life.

• It is important to note that each cell in your body is alive all on its own.

• The cell theory (which you should have learned about in grade 8), states 3 very important things that we need to be familiar with:

2

Cell Theory

1. All living things are composed of cells.

2. Cells are the basic units of structure and function in living things.

3. All cells are produced from other cells.

3

Basic Structure of a Cell

4

First to View CellsFirst to View Cells• In 1665, Robert

Hooke used a microscope to examine a thin slice of cork (dead plant cells)

•What he saw looked like small boxes

5

First to View CellsFirst to View Cells•Hooke is

responsible for naming cells

•Hooke called them “CELLS” because they looked like the small rooms that monks lived in called Cells 6

Anton van Leeuwenhoek• In 1674,

Leeuwenhoek (a Dutch microscope maker), was first to view organisms (living things)

• Leeuwenhoek used a simple, handheld microscope to view pond water & scrapings from his teeth

7

History of Cells & the History of Cells & the Cell TheoryCell Theory

8

VirchowCell

Specialization

Introduction to CellsIntroduction to CellsCells are the basic units of organisms

Basic types of cells:

9Animal Cell Plant Cell

Bacterial Cell

Number of Cells

10

Organisms may be:• Unicellular – composed of one cell• Multicellular- composed of many cells that may organize

11

Cells May be Prokaryotic or Eukaryotic Prokaryotes include bacteria

& lack a nucleus or membrane-bound structures called organelles

Eukaryotes include most other cells & have a nucleus and membrane-bound organelles (plants, fungi, & animals)

Prokaryotes

12

Nucleoid region contains the DNA

•Cell membrane & cell wall

• Contain ribosomes (no membrane) to make proteins in their cytoplasm

Eukaryotic Cell

Contain 3 basic cell structures:

•Nucleus•Cell Membrane•Cytoplasm with

organelles

13

Two Main Types of Eukaryotic Cells

14Plant Cell

Animal Cell

OrganelleOrganelless

• Very small size

• Can only be observed under a microscope

• Have specific functions

• Found throughout cytoplasm

15

Control Organelle

16

Controls the normal activities of the cell

Contain the DNABounded by a nuclear membrane

Contains chromosomes

Nucleus

More on the More on the NucleusNucleus

17

Each cell has fixed number of chromosomes that carry genes

Genes control cell characteristics

Nucleus

Golgi Bodies• Stacks of Stacks of flattened flattened

sacssacs• Have a shipping side Have a shipping side

& a receiving side& a receiving side• Receive & Receive & modify modify

proteinsproteins made by ER made by ER• Transport vesiclesTransport vesicles

with modified with modified proteins pinch off proteins pinch off the endsthe ends

18

Transport

vesicle

Lysosome• Contain digestive Contain digestive

enzymesenzymes• Break down food and Break down food and

worn out cell parts worn out cell parts for cells for cells

• Programmed for cell Programmed for cell death (lyse & release death (lyse & release enzymes to break enzymes to break down & recycle cell down & recycle cell parts)parts)

19

Nucleolus• Cell may have Cell may have 1 1

to 3to 3 nucleoli nucleoli• Inside nucleusInside nucleus• DisappearsDisappears when when

cell dividescell divides• Makes ribosomesMakes ribosomes

that make that make proteinsproteins

20

Smooth & Rough Endoplasmic Reticulum

21

Smooth ER lacks ribosomes & makes proteins USED In the cell

Rough ER has ribosomes on its surface & makes proteins to EXPORT

Cell PowerhouseCell Powerhouse

22

Rod shapeSite of Cellular respiration

Mitochondrion( mitochondria )

In Animal Cells:In Animal Cells:

23

Active cells like muscles have more mitochondriaBurn sugars to produce energy ATP

Mitochondria

Surrounding the Surrounding the CellCell

24

Lies immediately against the cell wall in plant cells

Made of protein and phospholipids

Selectively permeable

Cell membrane

Cell or Plasma Cell or Plasma MembraneMembrane

25

Living layerControls the movement of materials into and out of the cell

Selectively permeable

Cell membrane

Cell WallCell Wall

26

Nonliving layerGives structure and shape to plant and bacterial cells

Cell wall

Cytoplasm of a Cytoplasm of a Cell Cell

27

Jelly-like substance enclosed by cell membrane

Provides a medium for chemical reactions to take place

Cytoplasm

More on More on CytoplasmCytoplasm

28

Contains organelles to carry out specific jobs

Examples: chloroplast & mitochondrion

Cytoplasm

Plant Cell OrganellesPlant Cell Organelles

29

Contain the green pigment chlorophyll

Traps sunlight to make to make sugars (food)

Process called photosynthesis

Chloropla

st

Plant CellPlant Cell

30

Dead layerLarge empty spaces present between cellulose fibers

Freely permeable

Cell wall

Plant CellPlant Cell

Made of cellulose which forms very thin fibers

Strong and rigidFound in plant cells

31

Cell wall

Plant CellPlant Cell

32

Protect and support the enclosed substances (protoplasm)

Resist entry of excess water into the cell

Give shape to the cell

Cell wall

Plant Cell OrganellesPlant Cell Organelles

33

Have a large central vacuole

Surrounded by tonoplast

Contains cell sapSugars, proteins,

minerals, wastes, & pigments

Vacuole

Different kinds of Different kinds of plant cellsplant cells

34

Onion Epidermal Cells

Root Hair Cell

root hair

Guard Cells

Animal cellAnimal cell

35

mitochondrion

nucleus

glycogen granule

cell membrane

cytoplasm

No cell wall or chloroplastStores glycogen in the cytoplasm for food energy

vacuole

Animal Cell OrganellesAnimal Cell Organelles

•Near the nucleus•Paired structures•Help cell divide

36

Different kinds of Different kinds of animal cellsanimal cells

37

white blood cell

red blood cell

cheek cells

sperm

nerve cell

muscle cell

Amoeba

Paramecium

Similarities between Similarities between plant cells and animal plant cells and animal

cellscellsBoth have a cell membrane surrounding the cytoplasm

38

Both have a nucleus

Both contain mitochondria

Differences between Differences between plant cells and animal plant cells and animal

cellscells

39

Animal cells Plant cells

Relatively smaller in

sizeIrregular shape

No cell wall

Relatively larger in size

Regular shapeCell wall present

Differences between Plant Differences between Plant Cells and Animal CellsCells and Animal Cells

40

Animal cells Plant cells

Vacuole small or absent

Glycogen as food storage

Nucleus at the center

Large central vacuole

Starch as food storage

Nucleus near cell wall