1 basic structure of a cell. 2 cell size and types cells, the basic units of organisms, can only be...
TRANSCRIPT
1
Basic Structure of a Cell
2
Cell Size and TypesCell Size and Types• Cells, the basic units of organisms,
can only be observed under microscope
• Three Basic types of cells include:
Animal Cell Plant CellBacterial
Cell
3
Number of CellsNumber of CellsAlthough ALL living things are
made of cells, organisms may be:
• Unicellular – composed of one cell
• Multicellular- composed of many cells that may organize into tissues, etc.
4
Which Cell Type is Which Cell Type is Larger?Larger?
_________ > _____________ > ___________Plant cell Animal cell bacteria
5
Multicellular OrganismsMulticellular Organisms• Cells in multicellular organisms
often specialize (take on different shapes & functions)
6
Cell SpecializationCell Specialization
•Cells in a multi-cellular organism become specialized by turning different genes on and off
•This is known as DIFFERENTIATION
7
Specialized Animal CellsMuscle cells Red blood cells
Cheek cellsSperm Cell
Nerve Cell
8
Specialized Plant cells
Xylem cellsPollen
Guard Cells
9
Simple or Complex Simple or Complex CellsCells
10
Prokaryotes – The first Prokaryotes – The first CellsCells
• Cells that lack a nucleus or membrane-bound organelles
• Includes bacteria• Simplest type of cell• Single, circular chromosome
11
ProkaryotesProkaryotes
• Nucleoid region (center) contains the DNA
• Surrounded by cell membrane & cell wall (peptidoglycan)
• Contain ribosomes (no membrane) in their cytoplasm to make proteins
12
Eukaryotes
• Cells that HAVE a nucleus and membrane-bound organelles
• Includes protists, fungi, plants, and animals
• More complex type of cells
13
Eukaryotic Cell
Contain 3 basic cell structures:
•Nucleus•Cell Membrane•Cytoplasm with
organelles
14
Two Main Types of Eukaryotic Cells
Plant Cell
Animal Cell
15
OrganellesOrganelles
16
OrganellesOrganelles
•Very small (Microscopic)•Perform various functions for
a cell•Found in the cytoplasm•May or may not be
membrane-bound
17
•Lies immediately against the cell wall in plant cells
•Pushes out against the cell wall to maintain cell shape
Cell Membrane in PlantsCell Membrane in PlantsCell membrane
18
•Nonliving layer•Found in plants, fungi, & bacteria
•Made of cellulose in plants
•Made of peptidoglycan in bacteria
•Made of chitin in Fungi
Cell wallCell WallCell Wall
19
Cell WallCell Wall• Supports and
protects cell• Found outside of
the cell membrane
20
•Jelly-like substance enclosed by cell membrane
•Provides a medium for chemical reactions to take place
Cytoplasm of a Cytoplasm of a Cell Cell
cytoplasm
21
•Contains organelles to carry out specific jobs
•Found in ALL cells
More on CytoplasmMore on Cytoplasmcytoplasm
22
•Controls the normal activities of the cell
•Contains the DNA in chromosomes
•Bounded by a nuclear envelope (membrane) with pores
•Usually the largest organelle
The Control Organelle - The Control Organelle - NucleusNucleus
23
•Each cell has fixed number of chromosomes that carry genes
•Genes control cell characteristics
Nucleus
More on the More on the NucleusNucleus
24
Nuclear EnvelopeNuclear Envelope
• Double membrane surrounding nucleus
• Also called nuclear membrane
• Contains nuclear pores for materials to enter & leave nucleus
• Connected to the rough ER Nuclear
pores
25
Inside the Nucleus -The genetic material (DNA) is
found
DNA is spread out And appears as
CHROMATINin non-dividing cells
DNA is condensed & wrapped around proteins forming
as CHROMOSOMES in dividing cells
26
What Does DNA do?What Does DNA do?DNA is the hereditary
material of the cell
Genes that make up the DNA molecule code for different proteins
27
Nucleolus
• Inside nucleusInside nucleus• Cell may have Cell may have 1 1
to 3to 3 nucleoli nucleoli• DisappearsDisappears
when cell when cell dividesdivides
• Makes Makes ribosomesribosomes that that make proteinsmake proteins
28
CytoskeletonCytoskeleton• Helps cell maintain
cell shape• Also help move
organelles around• Made of proteins• Microfilaments are
threadlike & made of ACTIN
• Microtubules are tubelike & made of TUBULIN
29
CytoskeletonCytoskeleton
MICROTUBULES
MICROFILAMENTS
30
CentriolesCentrioles• Found only in animal
cells• Paired structures
near nucleus• Made of bundle of
microtubules• Appear during cell
division forming mitotic spindle
• Help to pull chromosome pairs apart to opposite ends of the cell
31
Centrioles & the Mitotic Centrioles & the Mitotic SpindleSpindle
Made of MICROTUBULES (Tubulin)
32
MitochondrionMitochondrion(plural = mitochondria)(plural = mitochondria)
• “Powerhouse” of the cell
• Generate cellular energy (ATP)
• More active cells like muscle cells have MORE mitochondria
• Both plants & animal cells have mitochondria
• Site of CELLULAR RESPIRATION (burning glucose)
33
MITOCHONDRIASurrounded by a
DOUBLE membrane
Folded inner membrane called CRISTAE (increases surface areafor more chemical Reactions)
Has its own DNA
Interior called MATRIX
34
Interesting Fact ---Interesting Fact ---
• Mitochondria Come from cytoplasm in the EGG cell during fertilization
Therefore …• You inherit your
mitochondria from your mother!
35
Rod shape
Cell PowerhouseCell Powerhouse
Mitochondrion( mitochondria )
36
What do mitochondria What do mitochondria do?do?
Burns glucose to release energy (ATP)
Stores energy as ATP
“Power plant” of the cell
37
Endoplasmic Reticulum - EREndoplasmic Reticulum - ER
Two kinds of ER ---ROUGH & SMOOTH
• Network of hollow membrane tubules• Connects to nuclear envelope & cell
membrane• Functions in Synthesis of cell products
& Transport
38
Rough Endoplasmic Reticulum Rough Endoplasmic Reticulum (Rough ER)(Rough ER)
• Has ribosomes on its surface
• Makes membrane proteins and proteins for export out of cell
39
Rough Endoplasmic Rough Endoplasmic Reticulum (Rough ER)Reticulum (Rough ER)
• Proteins are made by ribosomes on ER surface
• They are then threaded into the interior of the Rough ER to be modified and transported
40
Smooth Endoplasmic Smooth Endoplasmic ReticulumReticulum
• Smooth ER lacks ribosomes on its surface
• Is attached to the ends of rough ER
• Makes cell products that are USED In the cell
41
Functions of the Smooth Functions of the Smooth ERER• Makes membrane
lipids (steroids)• Regulates calcium
(muscle cells)• Destroys toxic
substances (Liver)
42
Endomembrane System
Includes nuclear membrane connected to ER connected to cell membrane (transport)
43
RibosomesRibosomes• Made of PROTEINS and rRNA• “Protein factories” for cell• Join amino acids to make proteins• Process called protein synthesis
44
RibosomesRibosomes
Can be attached to Rough ER
OR
Be free (unattached
) in the cytoplasm
45
Golgi BodiesGolgi Bodies• Stacks of Stacks of flattened flattened
sacssacs• Have a shipping Have a shipping
side (side (cis facecis face) & a ) & a receiving side receiving side ((trans facetrans face))
• Receive Receive proteinsproteins made by ERmade by ER
• Transport vesiclesTransport vesicles with modified with modified proteins pinch off proteins pinch off the endsthe ends
Transport
vesicle
CIS
TRANS
46
Golgi BodiesGolgi BodiesLook like a stack of pancakes
Modify, sort, & packagemolecules from ERfor storage OR transport out of cell
47
Golgi Animation Golgi Animation
Copyright Pearson Publishers
48
Golgi AnimationGolgi Animation
Materials are transported from Rough ER to Golgi to the cell membrane by
VESICLES
49
LysosomesLysosomes• Contain Contain digestive digestive
enzymesenzymes• Break down Break down food, food,
bacteria,bacteria, and and worn out worn out cell partscell parts for cells for cells
• Programmed forProgrammed for cell cell death (APOPTOSIS)death (APOPTOSIS)
• Lyse & Lyse & release release enzymesenzymes to break down to break down & recycle cell parts)& recycle cell parts)
50
Lysosome DigestionLysosome Digestion
• Cells take in food by phagocytosis
• Lysosomes digest the food & get rid of wastes
51
Cilia & FlagellaCilia & Flagella
• Made of protein tubes called microtubules
• Microtubules arranged (9 + 2 arrangement)
• Function in moving cells, in moving fluids, or in small particles across the cell surface
52
Cilia & FlagellaCilia & Flagella
• Cilia are shorter and more numerous on cells
• Flagella are longer and fewer (usually 1-3) on cells
53
Cell Movement with Cilia Cell Movement with Cilia & Flagella& Flagella
54
Cilia Moving Away Dust Cilia Moving Away Dust Particles from the LungsParticles from the Lungs
55
VacuolesVacuoles• Fluid filled sacks for storage• Small or absent in animal cells• Plant cells have a large Central Vacuole• No vacuoles in bacterial cells
56
VacuolesVacuoles
• In plants, they store Cell Sap
• Includes storage of sugars, proteins, minerals, lipids, wastes, salts, water, and enzymes
57
ChloroplastsChloroplasts• Found only in producers (organisms
containing chlorophyll)• Use energy from sunlight to make
own food (glucose)• Energy from sun stored in the
Chemical Bonds of Sugars
58
ChloroplastsChloroplasts
• Contains its own DNA
• Contains enzymes & pigments for Photosynthesis
• Never in animal or bacterial cells
Amazing Interactive Cell
• Bill Nye Cells• Cell Organelles
59
60
Cell SizeQuestion:
Are the cells in an elephant bigger, smaller, or about the same size as those in a mouse?
61
Factors Affecting Cell Size
• Surface area (plasma membrane surface) is determined by multiplying length times width (L x W)
• Volume of a cell is determined by multiplying length times width times height (L x W x H)
• Therefore, Volume increases FASTER than the surface area
62
Cell Size•When the surface area is no
longer great enough to get rid of all the wastes and to get in enough food and water, then the cell must divide
•Therefore, the cells of an organism are close in size
63
Cell SizeQuestion:
Are the cells in an elephant bigger, smaller, or about the same size as those in a mouse?
About the same size, but …
The elephant has MANY MORE cells than a mouse!