UNIT 1: THE CELL
Hans and Zacharias Janssen
(father and son), late 16th century
- Dutch spectacle makers, inventors
of the first microscope...
Robert Hooke (1635-1702)
- observed cork under the
microscope

- used the word CELLS for the first
time, to describe the t...
Anton van Leeuwenhoek (1632-1723)
- Dutch cloth merchant.
- “father of microbiology: he used a
simple microscope to observ...
Robert Brown (1773-1858)
- he discovered the cell nucleus,
in plant cells.
Matthias Jakob Schleiden
(1804-1881)
- German botanist.
- Observed plants under the
microscope, and concluded:

“All plant...
Friedrich Theodor Schwann
1810-1882)
- German physiologist and anatomist.
- He studied animal tissues under the microscope...
Rudolf Carl Virchow (1821-1902)
- German doctor and pathologist.
- He studied cell reproduction and
concluded:
“All cells ...
The CELL THEORY is the result of the discoveries
of Schleiden, Schwann and Virchow, and consists
on 3 principles:





...
Santiago Ramón y Cajal
(1852-1934)
- Spanish doctor, who
studied the Nervous System
- He proved that neurons were independ...
Levels of Organization of the Living Beings
The Elements of Life:
Bulk Elements:
C H O N
P

They form aprox. 99% of living matter
They are found in ALL living things
...
Elements in the living beings:
The Molecules of Life (Biomolecules):
Inorganic:

WATER
MINERALS

(common to non-living and
living matter)

CARBOHYDRATES
...
WATER:
Most abundant molecule in the cells.
Important biological functions:
“Universal Solvent”
Substance exchange between...
MINERALS:
Present in two forms:
Precipitated (solid): bones, shells, etc.

Ions (dissolved): regulating several cellular
p...
CARBOHYDRATES (I):
- Formed by C, H and O:
- Three main types:

Cn(H2O)n

MONOSACCHARIDES

DISACCHARIDES

Sweet and solubl...
CARBOHYDRATES (II):
POLYSACCHARIDES
Not sweet, not soluble
Many molecules of monosaccharides

ENERGY
STORAGE
PLANTS

ANIMA...
LIPIDS (I):
All of them formed by C, H and O.
Some of them contain N and P.
None of them are soluble in water.
Triglicerid...
LIPIDS (II):
Fatty Acids:
long chains of C, H and O

Triglicerids (fats and oils):
3 fatty acid chains attached to a glyce...
LIPIDS (III):
Waxes:

Protect the leaves and fruits in plants, and skin, hair and feathers in
animals. (structural)

Terpe...
PROTEINS (I):
Formed by C, H, O, N (and S)
Long chains (polymers) of basic
units (monomers) called AMINO
ACIDS
There are 2...
PROTEINS (II):
Functions:
Structural: cell membranes, cell organelles.
Catalytic: enzymes make possible cell reactions.
Tr...
NUCLEIC ACIDS (I):
- Formed by C, H, O, N and P.
- They are chains (polymers) of basic units
(monomers) called nucleotides...
NUCLEIC ACIDS (II):
DNA (DeoxyriboNucleic
Acid)
- carries the hereditary
information of the cell
RNA (RiboNucleic Acid)
- takes the information in the
DNA and helps to make
proteins with it
Parts of a Compound Light Microscope
Prokaryotic cell
No nucleus
Circular DNA floating in the cytoplasm
No membranous organelles
Ribosomes
Mesosomes
Cell wall ...
Eukaryotic Cell: Plant Cell
Eukaryotic Cell: Animal Cell
Viruses
Not cells
DNA or RNA + protein capsid
Some have an envelope
Obligatory parasites of animals,
Bacteriophage

Influe...
Cell Membrane
A phospholipid bilayer with
proteins.
Isolates the cell and controls the
substance exchange with the
medium....
Nucleus
Controls the cell activity.
Double membrane, with pores.
Nucleoplasm.
Nucleolus (RNA+proteins): where
ribosomes ar...
Cell Wall
Only present in plant cells.
It covers and protects the cell membrane.
It gives the cell a fixed shape.
Formed b...
Mitochondria

Double membrane (outer and inner
The inner membrane forms cristae.
The inner space (matrix) contains
DNA and...
Chloroplasts
Only present in plant cells.
Like mitochondria, they have a double
membrane (outer and inner).
Like mitochond...
Endoplasmic Reticulum
System of membranes that
extend over the cytoplasm.
Two types:
ROUGH ER: with ribosomes
attached. Pr...
Golgi Apparatus (or Complex)
Composed of membranous flat sacs piled
up forming stacks.
It modifies the substances that rec...
Vacuoles
Vesicles that store substances.
Plant cells usually have 1 or 2 big vacuoles.
Animal cells have many small vacuol...
Ribosomes
Present in all types of cells (prokaryotic and eukaryotic)
Composed of RNA and proteins. Produced in the nucleol...
Cytoskeleton
Only present in animal cells.
Composed of protein filaments of two types:
Microfilaments
Microtubules

Functi...
Centrosome
Only present in animal cells.
Composed of two centrioles,
one perpendicular to the other.
It organizes the cyto...
Cillia and Flagella
Only found in animal cells (unicellular or multicellular organisms).
Extensions of the cell membrane t...
Transport through
the Cell Membrane
Cells need to exchage substances with their environment, in order to get
materials for nutrition and remove wastes.
This e...
Passive Transport (I): DIFFUSION
Small molecules like gases (O2, CO2), water, nutrients move through
the cell membrane fro...
Passive Transport (II): FACILITATED DIFFUSION
Some molecules need the help of a carrier, a protein in the cell
membrane, t...
Passive Transport (III): OSMOSIS
Special term used for the diffusion of water through a semi-permeable cell
membrane (= on...
ACTIVE TRANSPORT
Movement occurs against the concentration
gradient (from low to high concentration)
A carrier protein in ...
ENDOCYTOSIS / EXOCYTOSIS
Transport of large particles through the cell membrane, using vesicles.
and requiring energy.
EXO...
Unit1 the cell
Unit1 the cell
Unit1 the cell
Unit1 the cell
Unit1 the cell
Unit1 the cell
Unit1 the cell
Unit1 the cell
Unit1 the cell
Unit1 the cell
Unit1 the cell
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Unit1 the cell

  1. 1. UNIT 1: THE CELL
  2. 2. Hans and Zacharias Janssen (father and son), late 16th century - Dutch spectacle makers, inventors of the first microscope (simple, and compound). - Also associated with the invention of the first telescope. simple (single-lens) microscope
  3. 3. Robert Hooke (1635-1702) - observed cork under the microscope - used the word CELLS for the first time, to describe the tiny, empty chambers he saw.
  4. 4. Anton van Leeuwenhoek (1632-1723) - Dutch cloth merchant. - “father of microbiology: he used a simple microscope to observe pond water... and discoverd a whole new world of living microorganisms! - he was the first one to observe living cells, among them: bacteria, sperm cells, blood cells, protozoa...
  5. 5. Robert Brown (1773-1858) - he discovered the cell nucleus, in plant cells.
  6. 6. Matthias Jakob Schleiden (1804-1881) - German botanist. - Observed plants under the microscope, and concluded: “All plants are made of cells” (1838)
  7. 7. Friedrich Theodor Schwann 1810-1882) - German physiologist and anatomist. - He studied animal tissues under the microscope, and concluded: “All animals are made of cells” (1839)
  8. 8. Rudolf Carl Virchow (1821-1902) - German doctor and pathologist. - He studied cell reproduction and concluded: “All cells come from pre-existing cells” (1858) Louis Pasteur refuted one year later for good the “Spontaneus Generation”
  9. 9. The CELL THEORY is the result of the discoveries of Schleiden, Schwann and Virchow, and consists on 3 principles:    ALL ORGANISMS ARE MADE OF CELLS THE CELL IS THE BASIC UNIT OF LIFE IN ALL LIVING THINGS (structural and functional unit) ALL CELLS COME FROM THE DIVISION OF PRE-EXISTING CELLS
  10. 10. Santiago Ramón y Cajal (1852-1934) - Spanish doctor, who studied the Nervous System - He proved that neurons were independent cells, which finally confirmed the Cell Theory. - He was awarded the Nobel Prize in Physiology and Medicine
  11. 11. Levels of Organization of the Living Beings
  12. 12. The Elements of Life: Bulk Elements: C H O N P They form aprox. 99% of living matter They are found in ALL living things S Trace Elements: Ca Na K Cl Fe Cu F I Zn They form <1% of living matter (if <0.1% they are called oligo-elements Some of them are common to all living beings, some others are specific
  13. 13. Elements in the living beings:
  14. 14. The Molecules of Life (Biomolecules): Inorganic: WATER MINERALS (common to non-living and living matter) CARBOHYDRATES LIPIDS (only in living matter they all contain C) Organic: PROTEINS NUCLEIC ACIDS
  15. 15. WATER: Most abundant molecule in the cells. Important biological functions: “Universal Solvent” Substance exchange between cell/medium, transport, removal. Temperature buffer: moderates the temperature changes in the cell
  16. 16. MINERALS: Present in two forms: Precipitated (solid): bones, shells, etc. Ions (dissolved): regulating several cellular processes
  17. 17. CARBOHYDRATES (I): - Formed by C, H and O: - Three main types: Cn(H2O)n MONOSACCHARIDES DISACCHARIDES Sweet and soluble Only one molecule: 1: 2: 1 Sweet and soluble SUGARS Two molecules of monosaccharides Sucrose ENERGETIC Ribose Glucose Lactose
  18. 18. CARBOHYDRATES (II): POLYSACCHARIDES Not sweet, not soluble Many molecules of monosaccharides ENERGY STORAGE PLANTS ANIMALS STRUCTURAL Starch Cellulose Glycogen Chitin
  19. 19. LIPIDS (I): All of them formed by C, H and O. Some of them contain N and P. None of them are soluble in water. Triglicerids (fats, oils) Phospholipids Types of lipids Contain FATTY ACIDS Waxes Terpens Steroids Do NOT contain FATTY ACIDS
  20. 20. LIPIDS (II): Fatty Acids: long chains of C, H and O Triglicerids (fats and oils): 3 fatty acid chains attached to a glycerol molecule They store energy. Phospholipids: They contain P. They constitute the cell membranes (structural) .
  21. 21. LIPIDS (III): Waxes: Protect the leaves and fruits in plants, and skin, hair and feathers in animals. (structural) Terpenes: - Aromatic oils and pigments in plants. - Some vitamins: A,E and K are terpenes. Steroids: - Some vitamins: D (regulatory) - Some hormones: sex hormones (testosterone, estrogens) and other hormones (cortisone, aldosterone) - Biliar acids - Cholesterol (structural)
  22. 22. PROTEINS (I): Formed by C, H, O, N (and S) Long chains (polymers) of basic units (monomers) called AMINO ACIDS There are 20 types of amino acids. Proteins are different depending on their sequence (order) Proteins are folded in space. Their function depends on this tridimensional structure.
  23. 23. PROTEINS (II): Functions: Structural: cell membranes, cell organelles. Catalytic: enzymes make possible cell reactions. Transportation of oxygen (hemoglobin) and other substances. Regulatory: some hormones are proteins (insulin) Muscular contraction: actin, myosin Defense: some proteins belong to the IS: antibodies (energetic)
  24. 24. NUCLEIC ACIDS (I): - Formed by C, H, O, N and P. - They are chains (polymers) of basic units (monomers) called nucleotides. nucleotide polinucleotide
  25. 25. NUCLEIC ACIDS (II): DNA (DeoxyriboNucleic Acid) - carries the hereditary information of the cell
  26. 26. RNA (RiboNucleic Acid) - takes the information in the DNA and helps to make proteins with it
  27. 27. Parts of a Compound Light Microscope
  28. 28. Prokaryotic cell No nucleus Circular DNA floating in the cytoplasm No membranous organelles Ribosomes Mesosomes Cell wall covering the Cell Memebrane Capsule Flagellum
  29. 29. Eukaryotic Cell: Plant Cell
  30. 30. Eukaryotic Cell: Animal Cell
  31. 31. Viruses Not cells DNA or RNA + protein capsid Some have an envelope Obligatory parasites of animals, Bacteriophage Influenza plants or bacteria. TMV
  32. 32. Cell Membrane A phospholipid bilayer with proteins. Isolates the cell and controls the substance exchange with the medium. Cytoplasm Content of the cell: Cytosol (liquid): water and soluble substances. Cell Organelles
  33. 33. Nucleus Controls the cell activity. Double membrane, with pores. Nucleoplasm. Nucleolus (RNA+proteins): where ribosomes are formed. Chromatin (DNA+proteins) transforms into chromosomes when the cell is going to divide.
  34. 34. Cell Wall Only present in plant cells. It covers and protects the cell membrane. It gives the cell a fixed shape. Formed by a matrix of cellulose molecules.
  35. 35. Mitochondria Double membrane (outer and inner The inner membrane forms cristae. The inner space (matrix) contains DNA and ribosomes! They produce energy in a metabolic process called cellular respiration.
  36. 36. Chloroplasts Only present in plant cells. Like mitochondria, they have a double membrane (outer and inner). Like mitochondria, they have DNA and ribosomes. The inner membrane forms a system of sacs piled up forming structures called thylakoids. The stacks of thylakoids are called grana. The space inside the inner membrane is called stroma. They contain pigments like chlorophyll, that make photosynthesis possible.
  37. 37. Endoplasmic Reticulum System of membranes that extend over the cytoplasm. Two types: ROUGH ER: with ribosomes attached. Produces, stores and trasnports proteins SMOOTH ER: no ribosomes. Produces, stores and transports lipids.
  38. 38. Golgi Apparatus (or Complex) Composed of membranous flat sacs piled up forming stacks. It modifies the substances that receives from the ER, and secrets them outside the cell. Lysosomes Vesicles formed in the Golgi Complex. They contain digestive enzymes that break down large molecules or cell organelles. If they broke, the cell would be destroyed by them.
  39. 39. Vacuoles Vesicles that store substances. Plant cells usually have 1 or 2 big vacuoles. Animal cells have many small vacuoles.
  40. 40. Ribosomes Present in all types of cells (prokaryotic and eukaryotic) Composed of RNA and proteins. Produced in the nucleolus. Not membranous. May be floating free in the cytoplasm or attached to the RER They synthesize (=produce) proteins.
  41. 41. Cytoskeleton Only present in animal cells. Composed of protein filaments of two types: Microfilaments Microtubules Functions: Helps the cell to divide (mitosis) Contraction Cell movement (form pseudopodia) Transport inside the cytoplasm. Form the centriols, cillia and flagella.
  42. 42. Centrosome Only present in animal cells. Composed of two centrioles, one perpendicular to the other. It organizes the cytoskeleton and helps the cell to divide (mitotic spindle)
  43. 43. Cillia and Flagella Only found in animal cells (unicellular or multicellular organisms). Extensions of the cell membrane that are able to move. They have the same structure, but cillia are shorter and more numerous than flagella. They allow the cells to move (protozoa, sperm cells...); they also help the cell to capture nutrients from the environment, and move the liquids on the surface of the cells (respiratory epithelia)
  44. 44. Transport through the Cell Membrane
  45. 45. Cells need to exchage substances with their environment, in order to get materials for nutrition and remove wastes. This exchage can be: PASSIVE: ACTIVE: does NOT require ENERGY down a gradient (high to low) requires ENERGY up a gradient (low to high)
  46. 46. Passive Transport (I): DIFFUSION Small molecules like gases (O2, CO2), water, nutrients move through the cell membrane from the area of higher concentration to the area of lower concentration, until the gradient disappears (concentration equals) Permeable to the solute
  47. 47. Passive Transport (II): FACILITATED DIFFUSION Some molecules need the help of a carrier, a protein in the cell membrane, to enter or exit the cell.
  48. 48. Passive Transport (III): OSMOSIS Special term used for the diffusion of water through a semi-permeable cell membrane (= only allows the solvent -water – to go through it) Water moves frome the HYPOTONIC solution to the HYPERTONIC solution. Semi-permeable membrane
  49. 49. ACTIVE TRANSPORT Movement occurs against the concentration gradient (from low to high concentration) A carrier protein in the membrane is required, as well as energy.
  50. 50. ENDOCYTOSIS / EXOCYTOSIS Transport of large particles through the cell membrane, using vesicles. and requiring energy. EXOCYTOSIS: waste products are placed in vesicles that then fuse with the cell membrane, releasing their contents outside the cell. ENDOCYTOSIS: the cell membrane engulfs a large molecule outside the cell and releases it inside. There are two types of endocytosis: PHAGOCYTOSIS: the cell takes solid food particles. PINOCYTOSIS: the cell takes nutrients dissolved in fluids.

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