3. Basics Of Cytology

Basics of cytology BIOLOGY OF THE CELL ...Life begins with cells

Progenitor cells 2

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One creator ... One Grand Designer 5

The Cell 6

Fundamental / Basic subunit of life First verified by Robert Hooke by examining a CORK  Cellulae (Latin for small rooms) Cell theory 

By Matthias Schleiden and Theodor Schwann “all organisms are composed of one or more cells (basic unit of life); cells arise from pre-existing cells”

Diversity and Commonality 7

Morphology Ability to move Stability of structures Metabolic activities and requirements Multicellularity vs. Colony formation in unicellular

organisms Internal organization  

Prokaryotic Eukaryotic

Diversity and Commonality 8

Eubacteria (with rapidly dividing cells) Lactococcus lactis Used to produce cheese such as Roquefort, Brie, and

Camembert.

Diversity and Commonality 9

A mass of archaebacteria Methanosarcina produce their energy by converting carbon dioxide

and hydrogen gas to methane Some species that live in the rumen of cattle give rise to >150 liters of methane gas/day

Diversity and Commonality 10

Blood cells  Erythrocytes  Leukocytes  Thrombocytes

Diversity and Commonality 11

Large single cells: fossilized dinosaur eggs

Diversity and Commonality 12

A colonial single-celled green alga Volvox aureus The large spheres are made up of many individual

cells, visible as blue or green dots The yellow masses inside are daughter colonies, each made up of many cells

Diversity and Commonality 13

Purkinje neuron of the cerebellum Can form more than a hundred thousand connections

with other cells through the branched network of dendrites Made visible by introduction of a fluorescent protein Cell body is the bulb at the bottom

Diversity and Commonality 14

Cells can form an epithelial sheet, (slice through

intestine shown here. Each finger-like tower of cells) A villus, contains many cells in a continuous sheet

Diversity and Commonality 15

Plant cells are fixed firmly in place in vascular plants supported by a rigid cellulose skeleton Spaces between the cells are joined into tubes for

transport of water and food.

Diversity and Commonality 16

What is a cell? 1.

Degree of organization 1. 2.

Multicellular Unicellular

2. Ability to exchange materials with their surroundings 3. Ability to transform energy 4. Ability to grow 5. Ability to reproduce independent progeny (offspring)

Basic parts 1. 2. 3.

Cytoplasmic /plasma membrane Nuclear region Cytoplasm

Prokaryotic cell Cytoplasmic membrane   

Selective Semi-permeable Bi-lipid



Functions: ETC DNA synthesis & Cellular reproduction Secretion of intracellular enzymes Nutrient transport (simple diffusion, osmosis, active transport) Cell wall synthesis Chemotaxis

Eukaryotic cell Cytoplasmic membrane   

Selective Semi-permeable Bi-lipid



Functions: Secretion of intracellular enzymes Nutrient transport (simple diffusion, osmosis, active transport) Cell wall synthesis Chemotaxis Endocytosis

Prokaryotic cell Nuclear Region  Genetic material  DNA  Called “nucleoid” (not bound by a membrane)

Eukaryotic cell Nuclear Region  Genetic material  DNA  Membrane-bound

Prokaryotic cell Cytoplasm  Everything contained within the cytoplasmic membrane except the nuclear region  Contains ribosomes & sometimes plasmids  No membrane bound organelles  Contains inclusions/inclusion granules

Eukaryotic cell Cytoplasm  Everything contained within the cytoplasmic membrane except the nuclear region  Contains ribosomes  Membrane bound organelles: Mitochondria Chloroplasts Endoplasmic reticulum Golgi membranes / apparatus Cytoskeleton

Prokaryotic cell Additional structures  Cell wall  Capsule; Glycocalyx; Slime layer; S layer  Fimbriae and Pili  Flagella  Axial filaments  Endospore

Prokaryotic vs. Eukaryotic 27

Prokaryotic vs. Eukaryotic 28

Prokaryotic vs. Eukaryotic 29

Prokaryotic vs. Eukaryotic 30

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Phospholipid bilayer 32

Molecules of Cells 33

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Mitosis 40

Prophase - chromatin condenses, nucleoli

disappear, sister chromatids are visible, spindle begins to form as centrosomes move away from one another.

Mitosis 41

Prometaphase - nuclear envelope fragments,

spindle increases in size and spread, microtubules from one side of the spindle attach to the kinetochore of one of the sister chromatids, while microtubules from the other side of the spindle attach to the kinetochore of the othe sister chromatid.

Mitosis 42

Metaphase - chromosomes line up, single file, on the

metaphase plate (an imaginary line in the middle of the cell)

Mitosis 43

Anaphase - sister chromatids uncouple and pull

apart, one sister chromatid (now called a full-fledged "chromosome"!) moves towards one side ("pole") of the cell, while the other sister chromatid moves towards the other side. Microtubules attached to the kinetochores of each chromosome shorten, thereby pulling the chromosomes poleward. Microtubules that are NOT attached to kinetochores lengthen, thereby elongating the cell.

Mitosis 44

Telophase - daughter nuclei begin to form, DNA

begins to "de-condense".

Meiosis 45

Prophase I - chromatin condenses, nucleoli

disappear, sister chromatids are visible, spindle begins to form as centrosomes move away from one another. Homologous chromosomes synapse(come together) to form a tetrad (XX) andcrossing over(fragments of homologous chromosomes switch places - so the homologue that originated in an individual's mother now has portions of the father's chomosome attached, and vice versa!)

Meiosis 46

Metaphase I - chromosomes line up, AS TETRADS

(homologous chromosomes line up as PAIRS rather than in single file as occurred in mitosis), on the metaphase plate (an imaginary line in the middle of the cell)

Meiosis 47

Anaphase I - homologous chromosomes pull apart

but sister chromatids remain attached, one homologous chromosome moves towards one side ("pole") of the cell, while the other homologue moves towards the other side. Microtubules attached to the kinetochores of each chromosome shorten, thereby pulling the chromosomes poleward. Microtubules that are NOT attached to kinetochores lengthen, thereby elongating the cell.

Meiosis 48

Telophase I - daughter nuclei begin to form. Note

that now, the two daughter cells have HALF the number of chromosomes as the original parent cell!!

Meiosis 49

Prophase II - chromatin condenses, nucleoli

disappear, sister chromatids are visible, spindle begins to form as centrosomes move away from one another.

Meiosis 50

Metaphase II - chromosomes line up, single file, on

the metaphase plate (an imaginary line in the middle of the cell)

Meiosis 51

Anaphase II - sister chromatids uncouple and pull

apart, one sister chromatid (now called a full-fledged "chromosome"!) moves towards one side ("pole") of the cell, while the other sister chromatid moves towards the other side. Microtubules attached to the kinetochores of each chromosome shorten, thereby pulling the chromosomes poleward. Microtubules that are NOT attached to kinetochores lengthen, thereby elongating the cell.

Meiosis 52

Telophase II - daughter nuclei begin to form, DNA

begins to "de-condense".

Comparison 53

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