The CellCHAPTER 2 LESSON 2P.51-58

Vocabulary

•Cell membrane•Cell wall•Cytoplasm•Cytoskeleton•Organelle•nucleus

Outline

• Review Cells and cell Theory

• Cell Shape• Cell Types

– Pro/Eu– Types of Eu cells

• Cell Parts– Cell Membrane– Cell Wall– Cell Appendages– Cytoplasm and

Cytoskeleton

• Cell Organelles– Nucleus

• Chromosomes• Nuclear envelope

– Ribosomes– Rough ER– Smooth ER– Mitochondria

• ATP– Chloroplasts

• Glucose– Golgi Apparatus

• Vesicles– Vacuoles

Cells

• Smallest living unit• Most are microscopic

Cell Size

Cell Diversity- ShapeCell Diversity- Shape

• Cells differ widely in shape.

• Size and shape relate to their function.

Principles of Cell Theory

• All living things are made of cells

• Smallest living unit of structure and function of all organisms is the cell

• All cells arise from preexisting cells

(this principle discarded the idea of

spontaneous generation)

Characteristics of All Cells

• A surrounding membrane

• cytoplasm – cell contents in thick fluid

• Organelles – structures for cell function

• Control center with DNA

Cell Types

• Prokaryotic

• Eukaryotic

Prokaryotic Cells

• First cell type on earth• Cell type of Bacteria and Archaea• Most are unicellular organisms

called prokaryotes

Prokaryotic Cells

• No nucleus

• DNA floats freely in the cytoplasm

• No organelles, only free floating proteins

Eukaryotic Cells• Nucleus – DNA surrounded by a nucleus• Include fungi, protists, plant, and animal cells• Possess many organelles• Much larger than prokaryotic cells

Protozoan

Prokaryote vs. Eukaryote

• Pro = No nucleus

• Eu = Yes, there is a nucleus

Representative Animal Cell

Representative Plant Cell

Organelles

• In eukaryotic cells

• Cellular machinery

• Different functions

Cell Membrane

• All cells• Protects the inside of a cell from the outside• Made of proteins and lipids called

phospholids

Phospholipids

Protein

Movement Across the Plasma Membrane

• Some things move freely in and out of the cell• Some things are blocked and need proteins to

help them cross the membrane

Cell Walls

• Found in plants, fungi, & many protists• Surrounds plasma membrane• Gives shape and support

Cell Wall Differences• Stiff structure• Protects from viruses and other

harmful organisms• Has holes that connect cell

membranes between cells

Cytoplasm

• Fluid inside the cell• Mostly water and salts• Cytoskeleton

– Proteins that are the framework of a cell– Like a skeleton or web of stick-like proteins– Gives shape– Helps the cell move

Cell Appendages

• Help with movement– Flagella – tail-like and whips back and forth– Cilia – fine-hairs that move the cell or

molecules around it

Nucleus

• Control center of cell• Usually largest

organelle• Double membrane• Contains

– Chromosomes

– Nucleolus

Nuclear Envelope

• Separates nucleus from rest of cell

• Double membrane

• Has pores

Nucleolus

• Dark Spot in nucleus

• Forms ribosomes, organelle that makes proteins

DNA

• Hereditary material

• Chromosomes– tightly wound DNA

• Humans have 23 pairs

Endoplasmic Reticulum

• Helps move substances within cells

• Network of interconnected membranes

• Two types– Rough endoplasmic reticulum– Smooth endoplasmic reticulum

Rough Endoplasmic Reticulum

• Ribosome are attached

• Spreads throughout the cell

• The site of protein production

Ribosome• Attached to the rough ER

– Make proteins– Attached to rough ER or free floating– Not surrounded my a membrane– There are many in a cell

Smooth Endoplasmic Reticulum

• No attached ribosomes

• Makes lipids such as cholesterol– Carbohydrates– Lipids

Golgi Apparatus

• Involved in synthesis of plant cell wall

• Packaging & shipping station of cell

Golgi Apparatus Function

1. Prepares proteins for their jobs

2. Packages proteins into vesicles

Vesicles

• Many inside the cell• After a protein is modified in the Golgi Apparatus

a vesicle pinches off containing the proteins• Transport substances• Tiny balls of membrane

Lysosome

• Specialized Vesicle

• Full of enzymes, proteins that break down and recycle cell components like old proteins

• Tiny membrane ball

• Many

Vacuoles

• Membrane bound storage sacs

• Plant cells have one large one

• Animal cells have many small ones

• Contents – Water– Food– wastes

Energy Processing Organelles

• Release & store energy

• Types – Mitochondria

(release energy) – Chloroplasts

(store energy)

Mitochondria

• Hundreds sometimes thousands

• Bound by double membrane

Mitochondria

• Break down fuel molecules (cellular respiration)

– Glucose– Fatty acids

• Release energy– ATP

ATP

• Adenosine triphosphate

• High-energy molecule

• Fuel for cellular processes

Chloroplasts

• In plant cells

• Membrane bound

• Uses light to make glucose from CO2 and H2O

Photosynthesis

• Takes place in the chloroplast

• Makes cellular food – glucose

Review of Eukaryotic Cells

Review of Eukaryotic Cells

Cell Transport

Cells Have Large Surface Area-to-Volume Ratio

Molecule Movement & Cells

• Passive Transport

• Active Transport

• Endocytosis

(phagocytosis & pinocytosis)

• Exocytosis

Passive Transport

• No energy required

• Move due to gradient– differences in concentration, pressure, charge

• Move to equalize gradient– High moves toward low

Types of Passive Transport

1. Diffusion

2. Osmosis

3. Facilitated diffusion

Diffusion

• Molecules move to equalize concentration

Osmosis

• Special form of diffusion

• Fluid flows from lower solute concentration

• Often involves movement of water– Into cell– Out of cell

Solution Differences & Cells• solvent + solute = solution

• Hypotonic– Solutes in cell more than outside– Outside solvent will flow into cell

• Isotonic– Solutes equal inside & out of cell

• Hypertonic– Solutes greater outside cell– Fluid will flow out of cell

Facilitated Diffusion

• Differentially permeable membrane

• Channels (are specific) help molecule or ions enter or leave the cell

• Channels usually are transport proteins (aquaporins facilitate the movement of

water)• No energy is used

Process of Facilitated Transport

• Protein binds with molecule

• Shape of protein changes

• Molecule moves across membrane

Active Transport

• Molecular movement

• Requires energy (against gradient)

• Example is sodium-potassium pump

Endocytosis

• Movement of large material– Particles– Organisms – Large molecules

• Movement is into cells

• Types of endocytosis– bulk-phase (nonspecific)– receptor-mediated (specific)

Process of Endocytosis

• Plasma membrane surrounds material

• Edges of membrane meet

• Membranes fuse to form vesicle

Forms of Endocytosis

• Phagocytosis – cell eating

• Pinocytosis – cell drinking

Exocytosis

• Reverse of endocytosis

• Cell discharges material

Exocytosis

• Vesicle moves to cell surface

• Membrane of vesicle fuses

• Materials expelled

End Chapter 5