Post on 21-Apr-2018
Unit 2: Cells Mr. Nagel
Meade High School
Warm Up
• Construct diagrams of: – E. Coli – Animal Cell (Liver) – Plant Cell
– Indicate which are present in each:
• Cell wall, plasma membrane, cytoplasm, pili, flagella, ribosomes, nucleoid, rough ER, golgi apparatus, mitochondrion, nucleus.
IB Syllabus Statements • 2.3.4
– Compare prokaryotic and eukaryotic cells. • 2.2.4
– State that prokaryotic cells divide by binary fission. • 2.2.1
– Draw and label a diagram of the ultrastructure of Escherichia coli (E. coli) as an example of a prokaryote.
• 2.2.2 – Annotate the diagram from 2.2.1 with the functions of each named structure.
• 2.2.3 – Identify structures from 2.2.1 in electron micrographs of E. coli.
• 2.3.1 – Draw and label a diagram of the ultrastructure of a liver cell as an example of an animal cell.
• 2.3.2 – Annotate the diagram from 2.3.1 with the functions of each named structure.
• 2.3.3 – Identify structures from 2.3.1 in electron micrographs of liver cells.
• 2.3.5 – State three differences between plant and animal cells.
• 2.1.7 – State that multicellular organisms show emergent properties.
• http://click4biology.info/c4b/2/cell2.htm
Prokaryotes v. Eukaryotes • HW: Compare and Contrast with a partner
– Common structures – How do they reproduce?
• Binary Fission v. Mitosis
Prokaryotic Cell (E. Coli)
Individual Cells are Either:
• “Round” – i.e.: staphylococcus
• “Spirial”
– i.e. Spirillum
• “Rod Shaped” – i.e. Anthrax
Prokaryotes in Pictorial Form
Up Close and Personal… Cell Membrane -Controls passage of materials in and out of cell -Can be infolded (called a mesosome) Cytoplasm -Fluid space where metabolism takes place Ribosome -Freely floating site of protein synthesis NO membrane bound organelles!
Some Prokaryotes have a cell wall…
• Gives shape, support and protection to the plasma membrane and cytoplasm of the cell.
• Made of peptidoglycan* (protein-sugar molecules).
*different than plant cell walls, which
are made of cellulose
Flagellum and Pili • Some bacteria have one or more Flagellum. (motility)
• Pili are short fibers found on some bacteria. (cling)
Capsules • A special mucus-like protective coating
found on some disease-producing bacteria.
Gram+ and Gram-
• Gram-positive bacteria: – Stain purple – Have a very thick cell wall
(because of lots of peptidoglycan).
• Gram –negative bacteria: – Stain pink – Cell walls only contain a
few layers of peptidoglycan – Many are pathogenic,
meaning they can cause disease in a host organism.
Eukaryotes (Plants and Animals)
• Discuss with someone next to you differences between plant and animal cells. (Minimum 3)
Eukarytoic Cell (Animal)
Liver Cell
Ultrastructure of a liver cell. 1:Nucleolus; 2:Chromatin; 3:Dense Chromatin; 4:Nuclear Pores; 5:Mitochondria; 6:Rough ER; 7:Ribosomes; 8:Golgi Apparatus; 9:Smooth ER;10:Peroxisomes; 11:Lysosomes; 12:Bile Capillary; 13:Desmosomes; 14:Microvilli.
-Nucleolus: Ribosome synthesis -Golgi: Cis Trans
Eukaryotic Cell (Plant)
Onion Cell
Emergent Properties
• Quite simply, “The whole is greater than the sum of its parts.” – Imagine a mouse trap.
• In studying the spring, woodblock, and cheese, you don’t necessarily SEE a design for a mousetrap.
• Placing the items together allows for a whole new level of use for these parts.
– Applies to multicellular organisms.
Research
• Individually or in pairs, select an organelle. – Construct a 6-8 sentence paragraph about:
• Structure • Function • Eukaryotic (plant, animal) or Prokaryotic or both • Catalogue any subgroups that may be a part
– Ex: Plastids Chloroplast, chromoplast, amyloplast
• What would happen to a cell without it?
Warm Up
• State the cell theory (three parts).
• Which increases faster as a cell expands: Surface Area or Volume? – What does this mean in terms of the
survivability of larger cells?
• Which type of microscope would be best for observing the internal structure of a bacteria?
Webquest
• Cells and Organelles
IB Syllabus Statements • 2.3.6
– Outline two roles of extracellular components. • 2.4.1
– Draw and label a diagram to show the structure of membranes. • 2.4.2
– Explain how the hydrophobic and hydrophilic properties of phospholipids help to maintain the structure of cell membranes. • 2.4.3
– List the functions of membrane proteins. • 2.4.4
– Define diffusion and osmosis. • 2.4.5
– Explain passive transport across membranes by simple diffusion and facilitated diffusion. • 2.4.6
– Explain the role of protein pumps and ATP in active transport across membranes. • 2.4.7
– Explain how vesicles are used to transport materials within a cell between the rough endoplasmic reticulum, Golgi apparatus and plasma membrane.
• 2.4.8 – Describe how the fluidity of the membrane allows it to change shape, break and re-form during endocytosis and exocytosis.
• 2.5.1 – Outline the stages in the cell cycle, including interphase (G1, S, G2), mitosis and cytokinesis.
• 2.5.2 – State that tumours (cancers) are the result of uncontrolled cell division and that these can occur in any organ or tissue.
• 2.5.3 – State that interphase is an active period in the life of a cell when many metabolic reactions occur, including protein synthesis, DNA replication
and an increase in the number of mitochondria and/or chloroplasts. • 2.5.4
– Describe the events that occur in the four phases of mitosis (prophase, metaphase, anaphase and telophase). • 2.5.5
– Explain how mitosis produces two genetically identical nuclei. • 2.5.6
– State that growth, embryonic development, tissue repair and asexual reproduction involve mitosis. • 2.1.8
– Explain that cells in multicellular organisms differentiate to carry out specialized functions by expressing some of their genes but not others. • 2.1.9
– State that stem cells retain the capacity to divide and have the ability to differentiate along different pathways. • 2.1.10
– Outline one therapeutic use of stem cells.
• http://click4biology.info/c4b/2/cell2.htm
Lipid Bilayer • What is the Extracellular Matrix?
– Support, Adhesion, and Movement – Hydrophilic vs. Hydrophobic
• Fluidic vs. Viscous (unsaturated vs. saturated HC tails) • Lateral movement common; layer flip-flop rare • http://www.johnkyrk.com/cellmembrane.html
– Membrane Proteins (Support/Transport)
Diffusion and Osmosis
• Diffusion – Molecules moving from higher
to lower concentration – Osmosis is the diffusion of
water molecules
• Turgor Pressure – Water pushing against cell
membrane from inside
Passive and Active Transport
• Passive (no Energy) – Simple Diffusion – Facilitated Diffusion
• Protein structure helps molecule travel across
– Gated Channels • Separate stimulus
opens/closes ‘tunnel’
• Active (ATP) • Electrogenic pump (H+) • Sucrose-H+ cotransport • Na (out) / K (in) pump
•Exocytosis •Secretion of proteins
•Endocytosis •Internalization of materials
•Phagocytosis (food) •Pinocytosis (fluids) •Receptor-Mediated endocytosis
Transport: Vesicles
Consider…
• How does your skin know to grow cells when you get cut, but does not grow when you are undamaged?
• Do your cells split on a regular basis? How often? What would be the purpose?
• Could you define the ‘events’ in the life of a cell?
Cell Cycle • Interphase
– G1, S, and G2 • G = Gap • S = Synthesis
– Mass production! • Cancer cells
– What do you think goes wrong?
• CDKs (cyclin dependent kinases) ex: p57
• Perfect reproduction (two identical nuclei)
• Growth, embryonic development, tissue repair, asexual reproduction
• P.M.A.T.
Mitosis
Name That Phase…
Cell Cycle Project
• How long does a typical cell spend in each phase of Mitosis/Cell Cycle?
• Let’s consider an onion root tip cell… – http://www.biology.arizona.edu/cell_bio/activiti
es/cell_cycle/cell_cycle.html
Warm Up
• What macromolecules are part of the extracellular matrix?
• What two molecules can pass through the lipid bilayer unhindered?
• Plant cells prefer ___tonic conditions, whereas animal cells prefer ___tonic conditions.
• The phase of the cell cycle in which DNA is replicated is ___phase.
Cell Cycle Project
• How long does a typical cell spend in each phase of Mitosis/Cell Cycle?
• Let’s consider an onion root tip cell… – The average cycle duration is 24 hours.
Interphase Prophase Metaphase Anaphase Telophase TOTAL
Quantity 36
Percent 100%
Time 24 hrs
Interesting Thoughts…
• In the human body, the rate of mitosis is believed to be 25 million cells produced every second!
• That comes out to 2 trillion cells per day!
• Cells that divide rapidly – Skin, Epithelial,
Bone Marrow • Cells that must be
stimulated to divide – Liver
• Cells that do not divide – Nerve, Muscle
Circle Map – Stem Cells
• Cells in multicellular organisms differentiate to carry out specialized functions by expressing some of their genes but not others.
• Stem cells retain the capacity to divide and have the ability to differentiate along different pathways. There are a variety of levels.
• There are numerous therapeutic applications of stem cells – both currently in use and theorized.
Stem Cells and Specialization
Warm-up
• Outline the stages in the cell cycle.
• Outline the events of the four phases of Mitosis.
• What life processes are evidenced by Mitosis?
Warm-up
• State three differences between plant and animal cells.
• Define Diffusion and Osmosis.
• How can/could stem cells be used therapeutically?