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Bacteria on us oh no • http://www.scientificamerican.com/arti

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The inner life of the cell

Full narrated version

Objective 1.2 Ultrastructure of cells

Understanding (Statement objectives) ● Prokaryotes have a simple cell structure without compartments.● Eukaryotes have a compartmentalized cell structure.● Prokaryotes divide by binary fission.● Electron microscopes have a much higher resolution than light microscopes.

Applications● Describe the structure and function of organelles within exocrine gland cells of the pancreas.● Describe the structure and function of the organelles within palisade mesophyll of the leaf.

Nature of science● Developments in scientific research follow improvements in apparatus: Describe how the invention of electron microscopes led to greater understanding of cell structure.

Skills● Draw and label a diagram of the ultrastructure of prokaryotic cells based on electron micrographs.

○ Drawings of prokaryotic cells should show the cell wall, pili and flagella, and plasma membrane enclosing cytoplasm that contains 70S ribosomes and a nucleoid with naked DNA.

● Draw and label a diagram of the ultrastructure of eukaryotic cells based on electron micrographs.○ Drawings of eukaryotic cells should show a plasma membrane enclosing cytoplasm that contains 80S ribosomes and a nucleus, mitochondria and other membrane-

bound organelles are present in the cytoplasm. Some eukaryotic cells have a cell wall.● Interpret of electron micrographs to identify organelles and deduce the function of specialized cells.● Compare eukaryotic and prokaryotic cells.

○ Naked DNA versus DNA associated with proteins○ DNA in cytoplasm versus DNA enclosed in a nuclear envelope○ No mitochondria versus mitochondria○ 70S versus 80S ribosomes○ Eukaryotic cells have internal membranes that compartmentalize their functions.

● State three differences between plant and animal cells.

EukaryotesLife with a nucleus

Image: Hela Cell nuclei via http://en.wikipedia.org/wiki/File:HeLa_cells_stained_with_Hoechst_33258.jpg

Objective 1.2 Ultrastructure of cells

Understanding (Statement objectives) ● Prokaryotes have a simple cell structure without compartments.● Eukaryotes have a compartmentalized cell structure.● Prokaryotes divide by binary fission.● Electron microscopes have a much higher resolution than light microscopes.

Applications● Describe the structure and function of organelles within exocrine gland cells of the pancreas.● Describe the structure and function of the organelles within palisade mesophyll of the leaf.

Nature of science● Developments in scientific research follow improvements in apparatus: Describe how the invention of electron microscopes led to greater understanding of cell structure.

Skills● Draw and label a diagram of the ultrastructure of prokaryotic cells based on electron micrographs.

○ Drawings of prokaryotic cells should show the cell wall, pili and flagella, and plasma membrane enclosing cytoplasm that contains 70S ribosomes and a nucleoid with naked DNA.

● Draw and label a diagram of the ultrastructure of eukaryotic cells based on electron micrographs.○ Drawings of eukaryotic cells should show a plasma membrane enclosing cytoplasm that contains 80S ribosomes and a nucleus, mitochondria and other membrane-

bound organelles are present in the cytoplasm. Some eukaryotic cells have a cell wall.● Interpret of electron micrographs to identify organelles and deduce the function of specialized cells.● Compare eukaryotic and prokaryotic cells.

○ Naked DNA versus DNA associated with proteins○ DNA in cytoplasm versus DNA enclosed in a nuclear envelope○ No mitochondria versus mitochondria○ 70S versus 80S ribosomes○ Eukaryotic cells have internal membranes that compartmentalize their functions.

● State three differences between plant and animal cells.

Eukaryotic vs. Prokaryotic Cells

Prokaryotic Cells Eukaryotic Cells

DNA in ring form without protein

DNA with proteins: chromosomes/chromatin

DNA free in cytoplasm (nucleoid region)

DNA enclosed within a nuclear envelope (nucleus)

No mitochondria Mitochondria

70s ribosomes 80s ribosomes

No membrane bound organelles

Membrane bound organelles

Animal Cells

Objective 1.2 Ultrastructure of cells

Understanding (Statement objectives) ● Prokaryotes have a simple cell structure without compartments.● Eukaryotes have a compartmentalized cell structure.● Prokaryotes divide by binary fission.● Electron microscopes have a much higher resolution than light microscopes.

Applications● Describe the structure and function of organelles within exocrine gland cells of the pancreas.● Describe the structure and function of the organelles within palisade mesophyll of the leaf.

Nature of science● Developments in scientific research follow improvements in apparatus: Describe how the invention of electron microscopes led to greater understanding of cell structure.

Skills● Draw and label a diagram of the ultrastructure of prokaryotic cells based on electron micrographs.

○ Drawings of prokaryotic cells should show the cell wall, pili and flagella, and plasma membrane enclosing cytoplasm that contains 70S ribosomes and a nucleoid with naked DNA.

● Draw and label a diagram of the ultrastructure of eukaryotic cells based on electron micrographs.○ Drawings of eukaryotic cells should show a plasma membrane enclosing cytoplasm that contains 80S ribosomes and a nucleus, mitochondria and other membrane-

bound organelles are present in the cytoplasm. Some eukaryotic cells have a cell wall.● Interpret of electron micrographs to identify organelles and deduce the function of specialized cells.● Compare eukaryotic and prokaryotic cells.

○ Naked DNA versus DNA associated with proteins○ DNA in cytoplasm versus DNA enclosed in a nuclear envelope○ No mitochondria versus mitochondria○ 70S versus 80S ribosomes○ Eukaryotic cells have internal membranes that compartmentalize their functions.

● State three differences between plant and animal cells.

EUKARYOTIC CELLS

NUCLEUS

Nucleus• Structure:

• Double membrane, continuous with ER

• Contains DNA and proteins

• DNA wound around proteins organized into chromosomes

• Perforated by pores

• Nucleolus inside

• Function:

• DNA is code for proteins, genetic information

• Nucleolus made up of ribosomal RNA, which makes up the ribosomes where protein synthesis happens

• Pores allow mRNA and rRNA to leave nucleus

RIBOSOMES

Ribosomes• Structure:

• Made of rRNA and protein

• Small and large subunits

• Some are attached to endomembranous system, some are free

• Function

• Site of protein synthesis

• Proteins made on bound ribosomes are secreted outside the cell

• Proteins made on free ribosomes are used inside the cell.

ENDOMEMBRANE SYSTEM

Endoplasmic reticulum

Endoplasmic Reticulum• Smooth ER has no

ribosomes, has enzymes embedded in the membrane

• Rough ER has ribosomes

• Smooth ER: synthesis of lipids, metabolism of carbohydrates, detoxification of drugs and poisons.

• Stores Ca++ in muscle cells

• Rough ER: synthesis of proteins and glycoproteins

• Makes membrane proteins and phospholipids that makes up its own membrane

Golgi Apparatus

Golgi apparatus• Structure:

• Flattened, membranous sacs called cisterns

• Function:

• Proteins and phospholipids are modified

• Products leave in vesicles, these can go to other places in the cell or to the membrane for secretion.

• Products are tagged chemically so they go to the correct places

Lysosome

lysosome• Structure:

• Membranous sac with digestive enzymes

• Only in animal cells

• Functions:

• Intracellular digestion of macromolecules

• Recycling of damaged organelles called autophagy

Everyone should have a favorite organelle :)

Mitochondria• Structure: more detail when we

learn about respiration• Function: cellular

respiration

Why I am obsessed with my mitochondrial function

Vacuoles• Similar to lysosomes,

have hydrolytic enzymes

• Present in plant and fungi, protista

• Functions:

• Food vacuoles store food

• Contractile vacuoles in protists control water and salts

• Plants have central vacuole that gives internal support, stores organic molecules, pigments, poisons

PlantCells

chloroplast• Structure: more detail when we

learn about photosynthesis

• Function - Photosynthesis

Animal Cell vs. Plant Cell

Feature Animal PlantCell wall Not present Present- composed

of cellulose

Carbohydrate storage

Glycogen Starch

Chloroplast Not present Present in plant cells that

photosynthesize

Vacuole Small if present at all

Large, fluid filled vacuoles

Centrioles Centrioles within a small centrosome

area

No centrioles

TOK Thought• We observe the world around us by looking at what we can see

• Is there any difference between something you observe with your 5 senses vs. something you need technology to assist with (ex- looking through a microscope)

• real cells

Grab a whiteboard…quick quiz :)1) A cell has cytoplasm, a cell wall, naked DNA and ribosomes. Based on this

information, what type of cell could this be?A. A cell from a pine treeB. A grasshopper cellC. A human red blood cellD. A bacterium

2) Prokaryotic cells lack a truea) ribosomeb) mesosome c) cytoplasmd) nucleus

Quick quiz….

Identify the labeled structures in this liver cell TEM image.

Source: http://www.udel.edu/biology/Wags/histopage/empage/empage.htm

Calculate: • The magnification of the image• The maximum diameter of the nucleus

Identify the labeled structures in this liver cell TEM image.

Source: http://www.udel.edu/biology/Wags/histopage/empage/empage.htm

Calculate: • The magnification of the image• The maximum diameter of the nucleus

nucleusrough er

vesicles

ribosome

plasma membrane

golgi apparatus

Scale bar measures 33mmActual = Measured/magnificationMag = 16,500xDiameter measures 85mmActual = 5.15 µm

What you’ll see under your microscope

• This is what your drawings should look like!

Today’s :ab