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Cell Biology Lecture1Monday, June,16,2008 1

Muhammad Rafi, PS, PIEAS

The Human Cell

Lecture:2 & 3

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Cell Biology

That

branch of Biology which deals withthe

anatomy and physiology of the cell

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Organization from cell to the planet

Biosphere

Ecosystem

Community

Population

Species

Multicultural organism Organ system

Organ

Tissue

Cell

Organelle Micro and macro molecule

Atom

Subatomic particle

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Definition of the cell

The cell is the basic structuraland functional unit of life

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Cond.

Average adult person has

approximately 4*1013cells

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Types of cell

Two main categories of

the cell are

a)Somatic cell

b)Genetic cell

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Cell Biology Lecture1Monday, June,16,2008 7

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Components of the cell

The cell consists of:

a)Cell Membraneb)Cytoplasm

c) NucleusCytoplasm Cell

membrane

Nucleus

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Cell Membrane

Anatomy

Outermost boundary composed of lipids and

proteins. Small amount of carbohydrates are

also present

Function

a) Allows only selective substances to pass

through itb) Takes in materials by endocytosis

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Cytoplasm

Anatomy

Material between plasma membrane and thenucleus. Contains:

a) Cytosol largely water with dissolved protein,salts, sugars, and other solutes

b) Cytoplasmic organelles metabolic machineryof the cell

Functiona) Acts as storage house of vital chemicals

b) Site of metabolic processes like glycolysis

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Nucleus

Anatomy

Contains

a) nuclear membrane

b) chromatin networkc) nucleoplasm

Function

It controls thea) Life

b) Activities of the cell

http://www.google.com.pk/imgres?imgurl=http://content.answers.com/main/content/wp/en-commons/thumb/9/9b/350px-Diagram_human_cell_nucleus.svg.png&imgrefurl=http://www.answers.com/topic/nuclear-pore&h=98&w=120&sz=41&tbnid=PWtM5gawgSsJ:&tbnh=98&tbnw=120&prev=/images%3Fq%3Ddiagram%2Bof%2Bnucleus&hl=en&sa=X&oi=image_result&resnum=1&ct=image&cd=1

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Organelles

Endoplasmic Reticulum (ER)

Ribosomes

Golgi Bodies

Lysosomes

Peroxysomes

Centrosomes

Mitochondria

Microtubules

Microfilaments

Centrioles

Vacuoles

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Endoplasmic Reticulum

Anatomy Tubules like structure covering large portion of the

cytoplasm

Function Provide the mechanical support to the cell

ER are of two types:

1. Smooth ER: Lacks ribosomes on outer surface. Function

as lipid biosynthesis and drug detoxification.

2. Rough ER: Ribosomes stud outer surface. Function as

to manufacture proteins for incorporation into

membranes.

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Ribosomes

Tiny granular structures assembled

in the nucleolus of the nucleus from

where they are transported to the

cytoplasm via the pores in nuclear

membrane.

The factory of ribosomes is thenucleolus, while that of protein

synthesis is the ribosomes.

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Golgi Bodies

Anatomy

Flattened membranous type structure

FunctionModify the proteins and lipids by adding

carbohydrates and converting them

into glycoproteins and glycolipids

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Golgi Apparatus

Figure 3.18a

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Role of the Golgi Apparatus

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Lysosomes

Anatomy

Spherical membranous bags containing digestiveenzymes

Function Digest ingested bacteria, viruses, and toxins

Degrade nonfunctional organelles

Breakdown glycogen and release thyroid hormone

Breakdown nonuseful tissue

Breakdown bone to release Ca2+

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Peroxisomes

Anatomy

Membranous sacs containing varieties of enzymeslike oxidases and catalases

Function

Detoxify harmful or toxic substances

Neutralize dangerous free radicalsFree radicals highly reactive chemicals with

unpaired electrons (i.e., O2)

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Mitochondria

Anatomy

Rod or flattened like structure

FunctionExtracts energy from organic molecule and

packs it in ATP.

ATP Provides energy to the cell accordingthe cell demand

It is called as power house of the cell

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Mitochondria

Double membrane

structure with shelf

like cristae

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Plastid

The plastidis a major organellefound in the cellsof plantsand algae.

Plastids are the site of manufacture and storage of important chemical

compounds used by the cell. They often contain pigmentsused in

photosynthesis, and the types of pigments present can change or determine

the cell's color.

http://en.wikipedia.org/wiki/Organellehttp://en.wikipedia.org/wiki/Cell_(biology)http://en.wikipedia.org/wiki/Plantshttp://en.wikipedia.org/wiki/Algaehttp://en.wikipedia.org/wiki/Biological_pigmenthttp://en.wikipedia.org/wiki/Photosynthesishttp://en.wikipedia.org/wiki/Photosynthesishttp://en.wikipedia.org/wiki/Biological_pigmenthttp://en.wikipedia.org/wiki/Algaehttp://en.wikipedia.org/wiki/Plantshttp://en.wikipedia.org/wiki/Cell_(biology)http://en.wikipedia.org/wiki/Organelle

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MicrotubulesMicrotubules are a component of the cytoskeleton, found throughout the

cytoplasm. These tubular polymers of tubulincan grow as long as 50 micrometres,with an average length of 25 m, and are highly dynamic. The outer diameter of a

microtubule is about 25 nmwhile the inner diameter is about 12 nm. They are

found in eukaryotic cellsand are formed by the polymerization of a dimerof two

globular proteins, alpha and beta tubulin

Microtubules are very important in a number of cellular processes. They are involved in

maintaining structure of the cell and together with microfilamentsand intermediate

filaments, they form the cytoskeleton. They also make up the internal structure of cilia

and flagella.They provide platforms for intracellular transport and are involved in a

variety of cellular processes, including the movement of secretoryvesicles, organelles,and intracellular substances

http://en.wikipedia.org/wiki/Cytoskeletonhttp://en.wikipedia.org/wiki/Cytoplasmhttp://en.wikipedia.org/wiki/Tubulinhttp://en.wikipedia.org/wiki/Micrometrehttp://en.wikipedia.org/wiki/Nanometrehttp://en.wikipedia.org/wiki/Eukaryotehttp://en.wikipedia.org/wiki/Protein_dimerhttp://en.wikipedia.org/wiki/Proteinhttp://en.wikipedia.org/wiki/Tubulinhttp://en.wikipedia.org/wiki/Microfilamenthttp://en.wikipedia.org/wiki/Intermediate_filamenthttp://en.wikipedia.org/wiki/Intermediate_filamenthttp://en.wikipedia.org/wiki/Cytoskeletonhttp://en.wikipedia.org/wiki/Ciliumhttp://en.wikipedia.org/wiki/Flagellumhttp://en.wikipedia.org/wiki/Secretionhttp://en.wikipedia.org/wiki/Vesicle_(biology_and_chemistry)http://en.wikipedia.org/wiki/Organellehttp://en.wikipedia.org/wiki/Organellehttp://en.wikipedia.org/wiki/Vesicle_(biology_and_chemistry)http://en.wikipedia.org/wiki/Secretionhttp://en.wikipedia.org/wiki/Flagellumhttp://en.wikipedia.org/wiki/Ciliumhttp://en.wikipedia.org/wiki/Cytoskeletonhttp://en.wikipedia.org/wiki/Intermediate_filamenthttp://en.wikipedia.org/wiki/Intermediate_filamenthttp://en.wikipedia.org/wiki/Microfilamenthttp://en.wikipedia.org/wiki/Tubulinhttp://en.wikipedia.org/wiki/Proteinhttp://en.wikipedia.org/wiki/Protein_dimerhttp://en.wikipedia.org/wiki/Eukaryotehttp://en.wikipedia.org/wiki/Nanometrehttp://en.wikipedia.org/wiki/Micrometrehttp://en.wikipedia.org/wiki/Tubulinhttp://en.wikipedia.org/wiki/Cytoplasmhttp://en.wikipedia.org/wiki/Cytoskeleton

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Microfilaments

Microfilamentsor actin filamentsare the thinnest filaments of thecytoskeleton, a structure found in the cytoplasmof eukaryoticcells.

These linear polymersof actinsubunits are flexible and relatively strong.

Microfilaments are highly versatile, functioning in cytokinesis, amoeboid

movement, and changes in cell shape. In inducing this cell motility, one

end of the actin filament elongates while the other end contracts,presumably by myosin IImolecular motors.

http://en.wikipedia.org/wiki/Cytoskeletonhttp://en.wikipedia.org/wiki/Cytoplasmhttp://en.wikipedia.org/wiki/Eukaryotichttp://en.wikipedia.org/wiki/Cell_(biology)http://en.wikipedia.org/wiki/Biopolymerhttp://en.wikipedia.org/wiki/Actinhttp://en.wikipedia.org/wiki/Cytokinesishttp://en.wikipedia.org/wiki/Amoeboidhttp://en.wikipedia.org/wiki/Motilityhttp://en.wikipedia.org/wiki/Myosin_IIhttp://en.wikipedia.org/wiki/Myosin_IIhttp://en.wikipedia.org/wiki/Motilityhttp://en.wikipedia.org/wiki/Amoeboidhttp://en.wikipedia.org/wiki/Cytokinesishttp://en.wikipedia.org/wiki/Actinhttp://en.wikipedia.org/wiki/Biopolymerhttp://en.wikipedia.org/wiki/Cell_(biology)http://en.wikipedia.org/wiki/Eukaryotichttp://en.wikipedia.org/wiki/Cytoplasmhttp://en.wikipedia.org/wiki/Cytoskeleton

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Centriole

Centrioleis a cylindrical cell structurecomposed mainly of a protein calledtubulinthat is found in most eukaryoticcells. An associated pair ofcentrioles, surrounded by an amorphous mass of dense material, called thepericentriolar material, or PCM, makes up a compound structure called acentrosome. Most centrioles are made up of nine sets of microtubuletriplets, arranged in a cylinder.

Centrioles are involved in the organization of the mitotic spindleand in the

completion of cytokinesis.

http://en.wikipedia.org/wiki/Organellehttp://en.wikipedia.org/wiki/Tubulinhttp://en.wikipedia.org/wiki/Eukaryotichttp://en.wikipedia.org/wiki/Cell_(biology)http://en.wikipedia.org/wiki/Pericentriolar_materialhttp://en.wikipedia.org/wiki/Centrosomehttp://en.wikipedia.org/wiki/Microtubulehttp://en.wikipedia.org/wiki/Mitotic_spindlehttp://en.wikipedia.org/wiki/Cytokinesishttp://en.wikipedia.org/wiki/Cytokinesishttp://en.wikipedia.org/wiki/Mitotic_spindlehttp://en.wikipedia.org/wiki/Microtubulehttp://en.wikipedia.org/wiki/Centrosomehttp://en.wikipedia.org/wiki/Pericentriolar_materialhttp://en.wikipedia.org/wiki/Cell_(biology)http://en.wikipedia.org/wiki/Eukaryotichttp://en.wikipedia.org/wiki/Tubulinhttp://en.wikipedia.org/wiki/Organelle

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Chromosomes

Thread like structures composed of DNA andproteins

All information necessary for cell activities arepresent in chromosomes in the form of genes,which are transferred from one generation to theother generation

In one species number of chromosomes are

same and constant from generation togeneration

In man there are 46 chromosomes i.e. 23 pairs

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Cond.

22 pairs are called as autosomes while

one pair is called as sexsome

In somatic cell, no of chromosomes is

diploid (2n) while in genetic cell this no is

haploid (n)

Autosomes are responsible for body

growth while sexsomes are reserved for

sex determination

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Chromosomes

Human

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Human

Chromosomes during Mitosis

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Chromosomes, DNA & Genes

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Cell to base

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World of DNA

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