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Explore the characteristics, differences, and functions of prokaryotic and eukaryotic cells, organelles, and how size and shape impact cell activities. Dive into details on common and unique organelles in plant and animal cells.
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A Tour of the Cell Chapter 6
You Must Know • 3 diff. prokaryotic and eukaryotic cells. • Common organelles (Plant/Animal) • Unique organelles (Plant/Animal) • Organelles > Cell Function • Size and Shape affect rate of nutrient/waste
TuesdayDecember 1st Agenda: Checklist for Chapter 6 Due Thursday Videos: • Introduction to Cells
WednesdayDecember 2, 2015 Agenda: 1. Surface area to volume demonstration 2. Checklist for Chapter 6 Due Tmrw Videos: • Cell Size
Surface Area to Volume Ratios • Need a large surface area to accommodate for growing demands of cell – energy, nutrients, wastes, gasses • More cells vs. Larger cells Alveoli of the lungs
Cells must be small to maintain a large surface area to volume ratio • Large S.A. allows rates of chemical exchange between cell and environment
Practice Problem Simple cuboidalepithethial cells line the ducts of certain human exocrine glands. Various materials are transported into and out of the cell by diffusion. What would be the volume of the larger cell in um3? SA Formula: 6 x S2 Volume: S3 S = length of side 10 um 20 um
Surface Area Example (Animal): Small Intestine: highly folded surface to increase absorption of nutrients • Villi: finger-like projections on SI wall • Microvilli: projections on each cell
Surface Area Example (Plant): Root hairs: extensions of root epidermal cells; increase surface area for absorbing water and minerals
Thursday – December 3rd Agenda: Ch 6 Check for Understanding Microscope Lab
Chapter 6Check for Understanding • What are the 2 main types of cells? Which Domains do they consist of? • List 3 ways that eukaryotes differ from prokaryotes.
Special Note: Archaea and bacteria generally lack internal membranes and organelles and have a cell wall.
2 Types of Cells: • Prokaryotes: Domain Bacteria & Archaea • Eukaryotes (Domain Eukarya): Protists, Fungi, Plants, Animals
CommonalitiesProkaryote and Eukaryote • Plasma Membrane • Ribosomes (Not membrane bound in P) • DNA: • Prokaryote: Region, Circular Chromosome • Eukaryote: Nucleus, Linear Chromosome
SummaryProkaryote Vs. Eukaryote • “before”“kernel” • No nucleus, DNA in a nucleoid • Cytosol • No organelles other than ribosomes • Small size • Primitive • i.e. Bacteria & Archaea • 1-10 um • “true”“kernel” • Has nucleus and nuclear envelope • Cytosol • Membrane-bound organelles with specialized structure/function • Much larger in size • More complex • i.e. plant/animal cell • 1-100 um
Chapter 6Check for Understanding Compare and contrast Animal vs. Plant Cells
Endosymbiont theory • Mitochondria & chloroplasts share similar origin • These prokaryotic cells engulfed by ancestral eukaryotic cells • Evidence: • Double-membrane structure • Have own ribosomes & DNA • Reproduce independently within cell
For the AP Exam Know the function of the cytoskeleton. Not needed. Specifics on structure & function of: • Microtubules • Microfilaments • Intermediate filaments
For the AP Exam NOT NEEDED FOR THE EXAM…. • Plasmodesmata • Gap junctions • Tight junctions • Desmosomes
Microscope Activity Partner
Friday December 4th Agenda: Organelles Review Chapter 7 Checklist – Due Monday Warmup Worksheet Chapter 6 Part 1
Organelles What is the function of an organelle? Why does the cell compartmentalize?
What are some commonalities between the nucleus, mitochondria and chloroplast?
Mitochondria • Function: site of cellular respiration • Double membrane: outer and inner membrane • Cristae: folds of inner membrane; contains enzymes for ATP production; increased surface area to ATP made • Matrix: fluid-filled inner compartment
Chloroplasts • Function: site of photosynthesis • Double membrane • Thylakoid disks in stacks (grana); stroma (fluid) • Contains chlorophylls (pigments) for capturing sunlight energy
Other types of plastids • Amyloplastids: colorless plastids that store starch in roots and tubers • Chromoplasts: Store colored pigments for fruits and flowers Tubers are various types of modified plant structures that are enlarged to store nutrients. Used to survive the winter or dry months, to provide energy and nutrients, and a means of asexual reproduction.
What is the relationship between the nucleus and the endomembrane system?
Nucleus • Function: control center of cell • Contains DNA (code for making proteins) • Surrounded by double membrane (nuclear envelope) • Continuous with the rough ER • Supported by protein filament network called nuclear lamina • Nuclear pores: control what enters/leaves nucleus Inside of the nucleus – • Nuclear matrix – internal support , protein framework • Chromatin: complex of DNA + proteins; makes up chromosomes • Nucleolus: region where ribosomal subunits are formed • Prokaryote: Nucleoid Region- dense region
Nucleus • Contains DNA • Function: control center of cell • Surrounded by double membrane (nuclear envelope) • Continuous with the rough ER • Nuclear pores: control what enters/leaves nucleus • Chromatin: complex of DNA + proteins; makes up chromosomes • Nucleolus: region where ribosomal subunits are formed
Ribosomes • Function: protein synthesis • Composed of rRNA + protein • Large subunit + small subunit • Types: • Free ribosomes: float in cytosol, produce proteins used within cell • Bound ribosomes: attached to ER, make proteins for export from cell
Nuclear Envelope ER Golgi Lysosomes Vesicles Vacuoles Plasma Membrane Regulates protein traffic & performs metabolic functions in the cell Endomembrane System:
Endoplasmic Reticulum (ER)“Within the cytoplasm” - “Little net” • Rough ER: ribosomes on surface Function: package proteins for secretion, send transport vesicles to Golgi, make replacement membrane • Smooth ER: no ribosomes on surface Function: synthesize lipids, metabolize carbs, detox drugs & poisons, store Ca2+
What types of lipids are synthesized in the smooth ER? Where (in the human body) would we find a lot of SER for this purpose?
What type of body cells would have a high number of Smooth ER for detoxification?
Barbiturates – CNS DepressantsAnxiety, Seizures and Sleep Disorders Example: Alcohol • Induce the proliferation (growth of production) of smooth ER and it’s detoxification enzymes (increase the rate) • In turn, this increases your tolerance • Can also decrease effectiveness to drugs you need – like antibiotics
Golgi Apparatus Function: synthesis & packaging of materials (small molecules) for transport (in vesicles); produce lysosomes Series of flattened membrane sacs (cisternae) • Cis face: receives vesicles • Trans face: ships vesicles
Lysosomes • Function: intracellular digestion; recycle cell’s materials; digestion in prokaryotes • Containshydrolytic enzymes Apoptosis
What happens if a lysosome accidentallyruptures in the cell?What is the name of the lysosomal disorder where individuals lack the enzyme needed to breakdown lipids?
Peroxisomes • Functions: break down fatty acids for the mitochondria; detox alcohol • Contain catalase, Involves production of hydrogen peroxide (H2O2)
Vacuoles • Function: storage of materials (food, water, minerals, pigments, poisons) • Eg. food vacuoles, contractile vacuoles (pump) • Plants: large central vacuole -- stores water, ions Turgid