cells cytologists welcome. the micro and the macro world antony van leeuwenhoek (1632-1723)
TRANSCRIPT
Cells
Cytologists Welcome
The Micro and the Macro WorldAntony van Leeuwenhoek (1632-1723)
Size variation
Cell
Size
rangeMost Cells
Cell Biology• 1665 - Robert Hooke - cork cells
Hooke was reminded of the small rooms or “cells” in a monastery.
Cell Biology
1805 - Lorenz Ohen - cell theory– All living things originate from, and are made of cells– Spontaneous Generation debunked
1835 - Matthias Schleiden – Botanist–& Theodor Schwann – Zoologist
- Schleiden - all plants are made of cells and the cell is the basic unit of tissue function
- Schwann - all animals are composed of cells
1859-Rudolf Virchow - “Ommia cellula e cellula”– “All cells come from cells”
Cell Theory
All living things are composed of cellsNew cells are produced from preexisting cells.Cells are the basic units of structure and function in living things
What happens on the Macro Level happens on the Micro Level
CellsProkaryotes
Cells that have genetic material that is not contained in the nucleus,No membrane bound organellesAll bacteria
EukaryotesContain a nucleus in which their genetic material is separated from the rest of the cell, Membrane bound organellesMost life forms
Archaean Mixture of prokaryotic & eukaryotic characteristics, with some unique properties
Kingdom Archaea The archaea very much
resemble bacteria, so much so that they were once thought to be a weird group of bacteria. However, by studying archaeal cells on a molecular level, scientists have now come to think that these "weird bacteria" actually are a separate category of life altogether. In fact, in some ways, archaea are more like you than they are like bacteria!
Archeaens Distinctives -ExtremophilesMany archaeans thrive in conditions that would kill other creatures: boiling water, super-salty pools,
sulfur-spewing volcanic vents, acidic water and deep in Antarctic ice. These types of archaea are often
labeled "extremophiles," meaning creatures that love extreme conditions.
Prokaryotic Cell
Cell membrane
Cell membrane
Cytoplasm
Cytoplasm
Nucleus
Organelles
Eukaryotic Cell
General Archaean Structure
Plant Cell
Nuclearenvelope
Ribosome(attached)
Ribosome(free)
Smooth endoplasmicreticulum
Nucleus
Rough endoplasmic reticulum
Nucleolus
Golgi apparatus
Mitochondrion
Cell wall
CellMembrane
Chloroplast
Vacuole
Organelle – specialized organs, “little organs”
Animal Cell
Centrioles
NucleolusNucleus
Nuclearenvelope
Rough endoplasmic reticulum
Golgi apparatus
Smooth endoplasmicreticulum
Mitochondrion
CellMembrane
Ribosome(free)
Ribosome(attached)
Prokaryotes Eukaryotes
Cell membraneContain DNA
NucleusEndoplasmic reticulum
Golgi apparatusLysosomesVacuoles
MitochondriaCytoskeleton
Animal Cells Plant Cells
Centrioles
Cell membraneRibosomes
NucleusEndoplasmic reticulum
Golgi apparatusLysosomesVacuoles
MitochondriaCytoskeleton
Cell WallChloroplasts
Organelles in Plant & Animal Cells
Nucleus – contains nearly all the cells DNA with coded
instructions for making proteins and other important molecules.Nuclear envelope – surround nucleus, composed of two membranes, allow materials to move in and out of the nucleus
Organelles in Plants & Animal Cells
Chromatin – DNA bound to protein, material you can see in the nucleusChromosomes – condensed chromatin, contains genetic information that is passed from one generation to the nextNucleolus – where assembly of ribosomes begins
Organelles in Plants & Animal Cells
Ribosomes – make proteinsEndoplasmic reticulum – assemble lipids of the cell membrane, along with proteins and other materials that are exported from the cellRough ER – contains ribosomes on the outside of the ERSmooth ER – ribosomes are not found of the surface of the ER
Organelles in Plants & Animal Cells
Golgi apparatus – modify, sort and package proteins and other materials from the ER for storage in the cell or secretion outside the cell, the “UPS guys” of the cell
Organelles in Plants & Animal Cells
Lysosome – digestion or breakdown of lipids carbohydrates and proteins into small molecules that can be used by the rest of the cell.Vacuoles – store materials such as water, salts, proteins, and carbohydrates.Mitochondria – powerhouse of the cell, contain own DNA, endosymbiotic theory, possible descendent of ancient prokaryotes
Organelles in Plants & Animal Cells
Cytoskeleton – support the cell, involved in maintaining shape and involved in movementMicrofilament – threadlike structures made of protein called actin, framework of cell, help with movementMicrotubules – hollow structures made up of protein, maintain cell shape, important in cell division help build projections from the cell surface such as cilia, flagella
Cell membrane
ER
microtubule
microfilament
ribosomes
mitochondria
Organelle in Plants Only
Chloroplasts – captures the suns energy from sunlight and convert it to chemical energy in a process called photosynthesis
Organelle in Animals Only
Centrioles – microtubules that aid in cell division
Outsideof cell
Insideof cell(cytoplasm)
Cellmembrane
Proteins
Proteinchannel Lipid bilayer
Carbohydratechains
Structure of the Cell Membrane
Cell membrane – regulates what enters and leaves the cell, lipid bilayer, mosaic of different molecules
Cell Wall
Cell Wall - in plants only, provides protection and support for the cell
Plants v. Animal Cells
PLANTSChloroplastsLarge vacuolesCell wallNo centrioleDoes not usually have lysosomes
ANIMALSNo chloroplastsSmaller vacuolesNo cell wallCentrioleLysosomes
HighConcentration
LowConcentration
CellMembrane
Glucosemolecules
Proteinchannel
Diffusion Through Cell Boundaries
Diffusion – particles tend to move from an area where they are more concentrated to an area where they are less concentrated until they reach equilibrium, no energy required
Osmosis
Osmosis – diffusion of water through a selectively permeable membrane
Facilitated Diffusion
Facilitated Diffusion movement of specific molecules across cell membranes through protein channels, does not require energy, only if there is a higher concentration of a particular molecule on one side than the other side
Molecule tobe carried
Moleculebeing carried
Energy
Active transport - requires energy, low concentration to high concentration
• Endocytosis
• Phagocytosis
• Pinocytosis
• Exocytosis
Active Transport
Phagocytosis
Cell Specialization
Cell Specialization – cells throughout an organism can develop in different ways to perform different tasks.
Unspecialized Cells – cells must perform all of the tasks needed for survival
Muscle cell Smooth muscle tissue Stomach Digestive system
Levels of Organization
Atom – Molecule - Organelle – Cell –Tissue – Organ – Organ
System - Organism
ExamplesNervous, digestive
Brain, stomach
nerves, muscle
neuron, smooth muscle cell
Organelles, nucleus
Water, sugar, fat
Oxygen, carbon
Proton, electron
Cell Size
Surface Area (length x width x 6)
Volume (length x width x height)
Ratio of Surface Area to Volume
Ratio of Surface Area to Volume in Cells
Section 10-1
Limits to Cell Growth – cannot move nutrients and waste through the cell, “DNA overload”
Enzymes • a protein that does a special job
• lock and key theory, specific fit
• effected by temp. pH concentration…
• Can build or break down molecules
• Catalyze reactions
Catalyst – speeds up the rate of a chemical reaction
Chapter 9
The Cell Cycle and Cellular Reproduction
includes
is divided into is divided into
Concept MapCell Cycle
M phase (Mitosis)
Interphase
G1 phase S phase ProphaseG2 phase Metaphase TelophaseAnaphase
During Interphase (S phase), each chromosome is replicated, consisting of two identical “sisters” or sister chromatids. Centromere attaches the sister chromatids.
M phase
G2 phase
S phase
G1 phase
The Cell Cycle
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Mitosis and Cytokinesis
Interphase – cell grows and replicates its DNA and centrioles
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Mitosis and Cytokinesis
Prophase – chromatin condenses in to the chromosomes, centrioles separate, spindle forms, nuclear envelope disappears
plant
animal
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Mitosis and Cytokinesis
Metaphase – chromosomes line up in the center of the cell, each chromosome is connected at the centromere to the spindle fiber.
plant
Asters
Spindle fibers
animal
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Mitosis and Cytokinesis
Anaphase – sister chromatids separate into individual chromosomes and are moved apart
plant
animal
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Mitosis and Cytokinesis
Telophase – chromosomes gather at opposite ends of the cell, two nuclear envelopes will form.
plant
animal
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Mitosis and Cytokinesis
Cytokinesis – the cytoplasm pinches in half, each daughter cell has duplicate chromosomes.
Control of Cell Division
Cells have contact inhibition, they will continue growing until in contact with other cells.
A sample of cytoplasm is removed from a cell in mitosis.
The sample is injected into a second cell in G2
of interphase.
As a result, the second cell enters mitosis.
Effect of Cycling
Cyclins – regulate the timing of the cell cycle in eularyotic cells along with internal and external regulators
RESULT: Caused non-dividing cells to divide
Cancer
Definition / Causes– Cancer is the uncontrolled growth of cells– Changes in a cells’ DNA can lead to unrestrained
cell reproduction– Cells are produce a growth factor and never stops
dividing OR– Cells do not produce a suppressor protein and it
never stops dividing
Cancer
Normal vs. Cancerous)
nonoRounded, globular
CancerCell
yesyesFlattened,monolayer
NormalCell
Contact inhibition
Anchorage dependent
Shape of cell
Cancer
Tumors - 2 types
1. Benign - slow growing, noninvasive, no metastasis
2. Malignant - rapid growth, invasive, metastatic
Cancer Research ?’s
What is the common & proper name for this cancer?What is the cause of this cancer?What are the effects of this cancer? – Micro – What is happening at the cellular level?– Macro – What symptoms does the patient experience?
What treatments are available?What is the typical outcome / prognosis?
Stem Cell Research
Stem Cell Research
What Are Stem Cells?
• Stem Cells are unspecialized, which means that they do not have a specific function.
• They are cells that are capable of dividing and renewing themselves for long periods.
• Stem Cells can give rise to specialized cells. In other words, these cells can be given a specific function.
Embryonic Stem Cells
• Embryonic stem cells are derived from embryos. In other words, they come from embryos that develop eggs that have been fertilized.
• These stem cells have the ability to transform themselves into any other type of cell in the body.
• Five days after fertilization, the human embryo becomes a blastocyst, a hollow sphere of about 100 cells. The cells in the inner sphere go on to form the tissues in the body, which are the embryonic stem cells.
Adult Stem Cells• Adult stem cells is one type of stem cell. They are
unspecialized cells found among functional cells in a tissue or organ like the brain, skin and liver.
• The primary role of adult stem cells are to maintain and repair the tissue, which they are found.
• The origin of adult stem cells are unknown in mature tissues.
• In adults, however, there are a very small amount of stem cells in each tissue.
Unspecialized Adult Stem Cells
Differences Between Adult and Embryonic Stem Cells
• Embryonic stem cells had two important qualities: they can become almost anything in the body and can be grown in culture in an unlimited quantity.
• Even though the embryonic stem cell can transform to more cells, they are rejected more. Also, they are more likely to become cancerous.
• Adult stem cells has limitations to what they can transform to and they don’t transform as quickly as embryonic stem cells. They are difficult to grow in quantity and worries about genetic abnormalities due to radiation exposure.
• The biggest advantage of adult stem cells is that they are rarely rejected by patients and they aren’t as controversial as embryonic stem cells.
Why Are They Important?
• Potential is enormous because they can help us to understand more about the development of the human body.
• They have the ability to restore any type of cell and could help cure Parkinson’s and Diabetes.
• They hold the promise of the complete regeneration of the human body.
Embryonic Stem Cell
Importance Of Stem Cells
• Human stem cells could be used to test new drugs because they can specialize them and try drugs on different types of cells.
• They can regenerate cells and issues by being directed to differentiate the cells into specific types.
• They can revolutionize the way we cure diseases.
Stem Cell Potentials
• Totipotent cells are cells that have the ability to become any kind of specialized cell.
• Pluripotent stem cells are cells that have the potential to become other kinds of specialized cells, but mostly becomes the cell it derives from.
• Committed stem cells are cells that can’t become a different kind of specialized cell. Does what it is first made out to be.
• This measures the potential of a stem cell.
Controversy?Pro
• Stem cell research has the potential to help cure diseases that were never thought possible.
• Most embryonic stem cells are from embryos that were obtain from fertilization clinics.
• Have consent from donors to use embryos and it is legal to proceed with stem cell research.
• Adult stem cells can be extracted without harm.
• People will not have to wait for organ donors
Con• Stem cell research can lead
to cloning because embryos are needed. An event in Northeast U.S. sparked the idea of cloning.
• Can cause an increase in abortions and isn’t moral standards.
• Extracting stem cells from embryos kills the cell/ doesn’t develop.
• Considered murder when embryos are destroyed.
• May cause genetic abnormalities or cause cancer in patients that are in need of help.
Specialized Cells• When unspecialized stem cells give rise to specialized cells, the
process is called differentiation. This is triggered by signals inside and outside stem cells. Internal signals are controlled by the cell’s genes and external signals are controlled by chemicals secreted by other cells or other molecules in the environment.
• Adult stem cells tend to generate the types of tissues they reside in, but there have been rare cases in adult stem cells where a cell from one tissue can form different cells for different tissues. This phenomenon is called plasticity.
• If stem cells are grown in certain conditions, they can remain unspecialized cells, however, if the cells are allowed to clump together, they can specialize spontaneously. To generate specific types of specialized cells, scientists try to control the differentiation of stem cells (mostly embryonic). Scientists have established “recipes” to create specific cell types. Main problem is that they can’t reliably direct differentiation of embryonic stem cells.