Cell Diversity• Cells come in lots of sizes & shapes – based on their

FUNCTION!• Most are square or round (WBC- can change their shape to

help them kill bacteria)• Size is limited by the ratio between its volume & surface

area• Materials enter & wastes exit the surface-cell’s volume

grows faster than the surface area – it can’t bring enough food in or get enough waste out –surface area limits it

3 Structures Found in ALL cellsCell Membrane (plasma membrane)DNACytoplasm

2 Types of Cells

Prokaryotic (“before the nucleus”)

-cells that LACK a nucleus (still have DNA) and organelles that lack a membrane

-only organelle they have is the ribosome (it lacks a membrane)

- ONLY found in bacteria

Eukaryotic (“true nucleus”)

-cells that HAVE a nucleus and organelles with a membrane

- EVERY organism has eukaryotic cells EXCEPT bacteria

The differences between prokaryotes and eukaryotes is HUGE – so much that there are 2 different kingdoms just for PROKARYOTES

The KingdomsProkaryotes (used to be in 1 Kingdom called Monera)

Kingdom Archaebacteria ProkaryotesKingdom Eubacteria

Kingdom ProtistaKingdom Fungi EukaryotesKingdom PlantaeKingdom Animalia

Organization• Eukaryote (true nucleus) – organism with cells that have a

nucleus & membrane bound organelles

• Prokaryote (before nucleus) – organism with cells lacking a nucleus & membrane bound organelle

• Organelle “little organ” – Cell component that performs a specific function in the cell

Prokaryotic vs Eukaryotic CellsProkaryotic

No nucleusNo organelles w/ membraneSingle chromosome (loop)Cell division by binary fissionSimple flagellaSmall ribosomesSimple cytoskeletonCell wall- peptidoglycan

Eukaryotic

Has a nucleusHas organelles w/ membranesMany chromosomesCell division by mitosis/meiosisComplex flagellaLarger ribosomesComplex cytoskeletonCell wall - cellulose

Section 2 – Cell Parts-Cell membrane (plasma membrane)-Cytoplasm-Organelles

-“little organs” – Cell component that performs a specific function in the cell

Cell Membrane• Also called ‘plasma membrane’• Outer boundary of the ANIMAL cell• Gives shape & flexibility to the cell• Is selectively permeable – a barrier that keeps some

molecules out, allows others in• Made of 2 layers of LIPIDS (fats) with PROTEIN embedded• Has special lipid steroid – CHOLESTEROL• MODEL = Fluid Mosaic Model – it flows, and moves & the

proteins change positions-so the pattern (mosaic) is always changing

Proteins of Cell Membrane• Peripheral proteins – proteins located on both the inside

and outside of the cell membrane

• Integral proteins- proteins that are embedded in the lipid bilayer• Some create pores to allow things to pass through• May help hold cells together & give bacteria and viruses places to

attach to

Cytoplasm

• Cytoplasm – jelly like substance inside the cell membrane that surrounds the organelles- made of water & nutrients

• Cytoplasmic streaming – the constant motion of the cytoplasm that moves organelles around

Summary of Organelles• 1. Ribosome- (the “protein factory”)• 2. Endoplasmic Reticulum- (“the highway”)• 3. Golgi Apparatus – (the ‘factory’)• 4. Mitochondria – (the ‘powerhouse’)• 5. Lysosomes – (the ‘clean-up’ crews)• 6. Microtubules & Microfilaments (the cytoskeleton)• 7. Cilia & Flagella (structures for movement)• 8. Nucleus (the ‘control center’)

Ribosomes• “Protein factory” of the cell

• Small, round structures that make protein (protein synthesis)

• Made of RNA & protein

• Found floating in cytoplasm (proteins used in the cell)• also on the rER (proteins used outside of cell)

Endoplasmic Reticulum (ER)• Membrane system of folded sacs & tunnels

• Acts like an intracellular “highway”

• Is a path for molecules to move around the cell and stores proteins that will be exported

• 2 kinds – rough (with ribosomes),smooth (without ribosomes)

Golgi Apparatus (body)“Factory of the cell”

Processing, packaging & secreting organelle

Made of a stack of sacs filled with fluid

Production line: ribosome makes protein protein moves to smooth area it gets enclosed in a vesicle – a membranous pouch that pinches off the sER vesicle travels from golgi sac to golgi sac being changed as it goes at last sac it moves to cell membrane and gets dumped outside

Mitochondria“powerhouse” of the cellRespiration centers of the cell

respiration – process that releases chemical ENERGY from food for cells to use

Has cristae – inner folded membrane- folded to increase surface are for ATP- ATP = cell’s energy – made on the cristae

More numerous in cells needing lots of energy like LIVER & MUSCLES

Has own DNA – prokaryote came to live in eukaryote – protection for energy!

Lysosomes“Clean-up” crews of cell

Small round organelles containing digestive enzymes that break things down- food particles, bacteria & worn out cell parts

Rare in plants

Plays role in early embryos – “chisels” away unnecessary tissue -

CytoskeletonSupport cell & give it shape (like ours does!)2 parts – microtubules & microfilaments

Microfilaments – fine protein threads made of actin

• lie just under cell membrane, help cytoplasmic streaming

Microtubules- Long slender protein tubes-spindle fibers – specialized microtubules that aid in the movement of chromosomes during cell division

Structures for Movement• Cilia- short, whisker like extension occurring in large

numbers over surface of some cells• Found lining surface of organs- move fluids & mucus

• Flagella – long whip like extensions of a cell that occur either singly or in pairs

Nucleus• “Control center” of the cell• Site where nucleic acids are made• Nuclear envelope – double membrane with pores that

surrounds the nucleus• Nucleoplasm – dense protein rich substance inside the

nuclear membrane- contains chromatin – fine strands of uncoiled DNA - chromatin coils & becomes chromosomes during cell

division- chromosome – structure made of coiled DNA- nucleolus – round structure in nucleus that makes &

partially assembles ribosomes

Centrioles- Centrosomes: small dark bodies near the nucleus that contain centrioles-Centrioles: Barrel shaped structures containing -9 triplets of microtubules right angles to each other with spindle attached

-only seen during active cell division- in animal cells, but not plants

• Function: Forms spindle fibers to separate chromosomes

Parts of a Plant Cell• Plant cells have the same organelles as animal cells with 3 additions:

• 1. Cell Wall• 2. Vacuoles• 3. Plastids

Cell Wall• Rigid covering that surrounds the plant cell and helps

support and protect it• Made of long chains of cellulose with pectin & lignin

embedded• 2 types of Cell walls

1. primary – formed during cell growth- made of cellulose

2. secondary – formed after cell growth stops- made of cellulose & lignin (makes plants ‘woody’)

Middle Lamella – intracellular “glue” between plant cells-made of pectin – stuff that makes jelly a gel

VacuolesLargest plant organelle – takes up 90% of cellSimilar to lysosomes as they have enzymes & store wastes

Plastids• Organelles similar to mitochondria and they capture light & convert it

to chemical energy• 3 types

1. Chloroplast - contains chlorophyll – green pigment- has thylakoids –flat sacs where PS occurs

2. Chromoplast- stores pigments for fall colors

-carotene – orange pigment- anthocyanin- red pigment- xanthophyll- yellow pigment

3. Leukoplast- stores foods as starches (which are white)

Division of Labor• Cells carry out their own function to keep the

organism alive- they divide the jobs

• Also called CELL SPECIALIZATION• - each cell specializes in it’s task

Tissues• Tissue – group of cells that carry out a common function

• Ex) Nerve tissue- transmit messages

Muscle tissue – contract to cause movementEpithelial tissue (skin) - protects

Organ• Organ – group of tissues that carry out a common function• Ex)

• Stomach • Liver• Kidney• Spleen• Heart

Organ System• Organ system – group of organs that carry out a common function

• Ex) digestive system • Mouth – stomach- s. intestine – lg intestine- rectum

3 Tissue Systems of Plants1. Dermal tissue system

- forms the outer layer of plant (like skin)

2. Ground tissue system- makes up most of the roots and stems (they are in the ‘ground’)

3. Vascular tissue system- vessels through which water is transported

4 Plant Organs• 1. Roots

• 2. Stems

• 3. Leaves

• 4. Flowers

Dividing it up in Organisms• Unicellular organism

- 1 cell carries out ALL the life functions

Multicellular organism- ALL cells divide up life functions

Colonial organism- Group of similar cells that live together but function independently of each other