3. Basics of Cytology

Basics of cytologyBIOLOGY OF THE CELL ...Life begins with cells

Progenitor cells2

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One creator ... One Grand Designer5

The Cell6

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 Schwannall organisms are composed of one or more cells (basic unit of life); cells arise from pre-existing cells

Diversity and Commonality7

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

organisms Internal organization

Prokaryotic Eukaryotic

Diversity and Commonality8

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

Camembert.

Diversity and Commonality9

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 Commonality10

Blood cells Erythrocytes Leukocytes Thrombocytes

Diversity and Commonality11

Large single cells: fossilized dinosaur eggs

Diversity and Commonality12

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 Commonality13

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 Commonality14

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 Commonality15

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 Commonality16

What is a cell?1. Degree of organization1. 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 parts1. 2. 3. Cytoplasmic /plasma membrane Nuclear region Cytoplasm

Prokaryotic cellCytoplasmic 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 cellCytoplasmic membrane

Selective Semi-permeable Bi-lipid

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

Prokaryotic cellNuclear Region Genetic material DNA Called nucleoid (not bound by a membrane)

Eukaryotic cellNuclear Region Genetic material DNA Membrane-bound

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

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

Prokaryotic cellAdditional structures Cell wall Capsule; Glycocalyx; Slime layer; S layer Fimbriae and Pili Flagella Axial filaments Endospore

Prokaryotic vs. Eukaryotic27

Prokaryotic vs. Eukaryotic28

Prokaryotic vs. Eukaryotic29

Prokaryotic vs. Eukaryotic30

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Phospholipid bilayer32

Molecules of Cells33

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Mitosis40

Prophase - chromatin condenses, nucleoli

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

Mitosis41

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.

Mitosis42

Metaphase - chromosomes line up, single file, on the

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

Mitosis43

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.

Mitosis44

Telophase - daughter nuclei begin to form, DNA

begins to "de-condense".

Meiosis45

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!)

Meiosis46

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)

Meiosis47

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.

Meiosis48

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!!

Meiosis49

Prophase II - chromatin condenses, nucleoli

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

Meiosis50

Metaphase II - chromosomes line up, single file, on

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

Meiosis51

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.

Meiosis52

Telophase II - daughter nuclei begin to form, DNA

begins to "de-condense".

Comparison53

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