cell organelles1

8/13/2019 Cell Organelles1

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BIOLOGY

FGS 0044

MR. KHAIRUL HAFEZAD BIN ABDULLAH

CENTRE FOR FOUNDATION STUDIES

MANAGEMENT AND SCIENCE UNIVERSITY


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Cell Theory (History)

1665 - Robert Hooke first described and namecellulae.

- Anton van Leeuwenhoek discovered single-

celled organisms, called it as animalcules.1838 - Matthias Schleiden make a conclusion that cell as

a units of life.

- developed the first statement of cell theory allplants are aggregates of fully individualized,independent, separate beings, namely cellsthemselves.

1839 - Theodor Schwann reported that animal tissuesalso consist of individual cells.


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Cell theory (Ideas)

1. All living things consists of cells

2. All cells come from other cells.

3. Cells are the smallest living things, the basic units of

organization of all organisms.

4. The ability of cells to divide to form new cells is the basis

for all reproduction and for the growth and repair of

multicellular organisms.

5. All cells are enclosed by membrane.

6. Every cells, at some stage, in its life contains DNA.

7. Two major kind of cells are prokaryote and eukaryote.


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Prokaryotic and Eukaryotic cells

Prokaryotic :

o a type of cell lacking a membrane bound nucleus and other

membrane

o found only in bacteria and cyanobacteria

Eukaryotic :

o a type of cell that has a membrane-bound nucleus, membrane

organelles and chromosomes in which the DNA is associated

with proteins.


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Comparison of prokaryotic and eukaryotic cells

Characteristics Prokaryotic cells Eukaryotic cells

Group of organisms

where such cells are

found

Bacteria and cyanobacteria Algae, fungi, protozoa, plants

and animals

Range of size Usually extremely small, 0.5-

10um in diameter

Usually larger cells, 10-100um

in diameter

Plasma membrane Present Present

Microtubules &

microfilaments

None, except in certain

spirochetes

Present

Chromosomes No chromosomes, only a single

ring-shaped circular DNA

molecule;

Linear DNA associated with

protein histone; usually exists in

pairs in somatic cells.


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Nucleolus None Present

Nucleus No distinct nucleus A distinct membrane-bound

nucleus

Nuclear division No mitosis @ meiosis occurs Mitosis and/ or meiosis occurs

Membrane-boundorganelles

Usually none. If present, verysimple

Many organelles, bound bydouble & single membrane

Photosynthesis

apparatus

Chlorophyll (if present) is not

contained in chloroplast

Chlorophyll (if present) is

contained in chloroplast


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Chapter 1: Cell structures and organelles

BIOLOGY (SGSF 0044)

CENTRE FOR FOUNDATION STUDIES


Ribosomes Protein synthesized in small

ribosomes

Protein synthesized in large

ribosomes

Centrioles None Present in animal cells

Flagella Flagella (if present) lack internal

9+2 fibril arrangement

Flagella have 9+2 internal

fibril arrangement

Cell wall Present, contain mucopeptides

(peptidoglycan)

Present in plants and fungi,

contains cellulose

Capsule Present in some prokaryotic cells None


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Cell Ultrastructure

Cell is visualized/digambarkan/dibayangkan as/sebagai a tiny

three-dimensional sac/pundi/kantung consisting/yg terdiri drpd

of three main parts:

i. Cell membrane (and cell wall if it is a plant cell)ii. Cytoplasm(inclusive/sampai dgn/termasuk of cytosol

and membranous organelles

suspended/menggantungkan/menutup in it).

iii. Nucleus Cell membrane (and cell wall in the plant cell) is the outer

layer of the cell.

Cytoplasm- jelly-like substance contained/terdapat within/di

dlm/dalam/dgn/diantara/dari the plasma membrane.


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Cell ultrastructure

made-up of two parts: cytosol (cytoplasmic solution) and cell

organelles.

cytosol - semi-fluid portion of the cytoplasm (cooloidal

solution). most of proteins in cytosol exhibit properties of enzymes.

cell organellescarry out specific functions within the cell.

all cell organelles, apart from nucleuspart of cytoplasm.

organelles such as nucleus, endoplasmic reticulum,mitochondria, plastids and Golgi apparatus: membranous

organelles.

Other organelles such as ribosomes and centrioles: non-

membranous organelles.


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Activity 1

Draw a typical structure of Plantand Animal Cells. You must labelyour diagram.


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Compare and ContrastPlant cells & Animal Cells:

Cytoplasm

Cell

Membrane

LARGE

vacuoles

Chloroplast

Cell Wall

Rectangle

shaped

Small

Vacuoles or

NONE.

*Centrioles &

Lysosomes

Round

shaped

Nucleus &

NuclearMembrane

PlantCells AnimalCells


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Cell Wall

most bacteria encased by strong cell wall composed ofpeptidoglycan(carbohydrate)- only for prokaryotic

plants, fungi, protists also have cell wall but made from differentmaterials (cellulose or chitin).

based on their cell walls, bacteria can be classify asa) Gram-positive - thick, single layered cell wall (produced

purple color after staining).

b) Gram-negative- multilayered cell wall (exhibit red colorafter staining).

functions: i. protects the cellii. maintain shape

iii. prevent excessive uptake of water


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Cell wall

disease causing bacteria secrete jellylike protective capsule ofpolysaccharide around the cell.

some bacteria have flagellum/flagella (long, threadlike

structures attached to the surface of cell for locomotion andfeeding).

eukaryotic cells are more complicated, all organelles are incompartment.

plant cells have large membrane-bounded sac called central

vacuole (stores proteins, pigments, waste materials). animal & plant cell contains vesicles (stores and transport a

variety of materials).

inside nucleus, DNA is in packaged called chromosomes.

all eukaryotic cells supported by cytoskeleton.


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Cell membrane

Fluid Mosaic Model

- composed of lipids and globular protein

- biologists thought the protein covered the inner and outer

surfaces of the phospholipids bilayer like a coat of paint

- 1935, Davson-Danielli model suggested that membrane as a

sandwich; phospholipids bilayer between two layers of

globular protein.

- this theory was not logic because membrane proteins are not

very soluble in water.

- 1972, S. Singer & G. Nicolson proposed a new simple model;

the globular proteins are inserted into the lipid bilayer.


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Cell membrane

Fluid Mosaic Model


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Cell membrane

Fluid Mosaic Model

- phospholipid bilayer

a. contain tryglyseride

b. move literally in a membranec. hydrophilic heads of the phospholipids are in contact with

water

d. hydrophobic tails are in contact with each other and remote

from water- protein mosaic

a. mixed with lipid bilayer

b. there are 2 major populations of membrane proteins


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Cell membrane

c. integral proteins penetrate far enough into the membrane for

their hydrophobic regions to surrounded by the hydrocarbon

tails of lipids

d. peripheral proteins are not embedded in the lipid bilayer atall; they are appendages attached to the surface of the

membrane

- cholesterola. wedged between phospholipid molecules in the plasma

membranes of animals, help stabilize membrane stability.


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Cell membrane

Components of cell membrane

Component Composition Function

Phospholipid

membrane

Phospholipid

molecules

Provides permeability barrier, matrix for protein

Transmembrane

proteins

Carriers Active and passive transport of molecules across

membranes

Channels Passively transport molecules across membrane

Receptors Transmit information into cell.

Interior proteinnetwork

Spectrins Determine shape of cell

Clathrins Anchor certain proteins to specific sites

Cell surface

markers

Glycoproteins self- recognition

Glycolipid Tissue recognition


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Cell nucleus

The cell nucleus is the brain of eukaryotic cellsand a remarkable

organelle because it forms the package for our genes and their

controlling factors. It functions to:

Store genes on chromosomes

Organize genes into chromosomes to allow cell division.

Transport regulatory factors & gene products via nuclear

pores

Produce messages (messenger Ribonucleic acid or mRNA)that

code for proteins

Produce ribosomes in the nucleolus

Organize the uncoiling of DNA to replicate key genes


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Cell nucleus


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METHODS OF RESEARCH


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MICROSCOPE

LIGHT MICROSCOPE ELECTRON MICROSCOPE

Use light that is focused in

specimen

Light is focused by glass condenser

Ability to differentiate for two close

object : resolution

Resolution for light microscope

:0.2-0.25 m

Magnifying power : 100-1500 x

For specimen : must be very thin

layer, dehydrate and coloured

Use beam of electrons instead of light

specimen must be ultrathinTwo kind of electron microscope;

a) Transmission electron microscope

(TEM)

b) Scanning electron microscope

(SEM)


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ELECTRON MICROSCOPE

Transmission Electron Microscope

(TEM)

Scanning Electron Microscope

(SEM)

The electrons used to visualize thespecimens are transmitted through

material

capable of resolving objects only 0.2

nanometer apart ( just twice the

diameter of hydrogen atom )

SEM beams the electrons onto the

surface of the specimen from a fine

probe that passes rapidly back and

forth.

Image can be viewed and photograph


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SPECIMEN PROCESSING FOR ELECTRON MICROSCOPE

Fixing in osmic acid

Dehydrated and placed in embedding agent

Sections are bombarded with heavy metal ions such as gold, platinum, lead,

to produce better contrast

Sections floated on water and taken up by touching then with copper grid

Cut (ultrathin) using microtome


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CENTRIFUGATION

Dividing the cell into its parts (or fractions) is called cellfractionation andis achieved by the processofcentrifugation using acentrifuge.

A centrifuge is a device which can spin tubes contain liquid

suspensions at a very high speed.

The effect is to exert a force on the contents of the tubesimilar to, but much greated that of gravity

Different cell organelles have different weights ; this allowthem to be separated into cell fractions by centrifugating thesuspension at different speeds and different lengths of time


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CHROMATOGRAPHY

Use to separate tiny quantities of components ofmixtures in very small samples , and then to identifythem or use the isolated components for furtherinvestigations.

Ideal to separate amino acids, proteins, andphotosynthetic pigments

The mixture carried by a chromatography solvent(mobile phase) is made to flow through a porouschromatography medium (stationary phase) whichrestricts the movement of molecules

Molecular size, solubility and adhesion effects thespeeds of the molecules to pass through the medium


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TISSUE

- covers outside of the body

- lines organ and cavities within the body

- the cells a riveted together by tight junction

- this tight packing enables the epithelium to

function as a barrier protecting against

mechanical


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Epithelium tissue

-Tissue - a group of cells with a common

structure and function. Different types of

tissues have different structures that areespecially suited to their function

- 4 main categories: epithelial, connective,

nervous and muscle tissue.


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Epithelium tissue

- a group of cells with a common structure

and function. Different types of tissues have

different structures that are especially suited

to their function

- 4 main categories: epithelial, connective,

nervous and muscle tissue.

- 2 criteria for classifying epithelia:

i. the number of cell layers

ii. shape of cells on the free surface


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Epithelium tissue

i) Number of cell layers

- simple single layers of cells

- stratified multiple layers of cells

- pseudo stratified single layered, but

appears multiple because the cell vary in

length


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Epithelium tissue


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Epithelium tissue

- the structure of epithelial tissue fits itsfunction

1. Simple squamus - thin and leaky

f(x) - exchange of materials by

diffusion

where??- blood vessels, air sacs of

lungs


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Epithelium tissue

2. stratified regenerate rapidly. The new

squamus cells are pushed to the free

surface as replacement for

cell that are continually sloughoff

f(x) - change new cells

where?? - surfaces subject to abrasion,such as the outer skin and

lining of the esophagus, anus

and vagina


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Epithelium tissue

3. columnar - having cells with relatively large

cytoplasmic volume

f(x) - secretion or active absorption ofsubstance is an important function

where?? intestines simple columnar

nasal passages pseudostratifiedciliated columnar

inner surfaces of urinary bladder

stratified columnar


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Epithelium tissue

4. Cuboidal - specialized for secretion

f(x) - secretion

where?? - kidneys tubules, many glands,

(thyroid, salivary)


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Connective tissue

f(x): to bind and support other tissues

- have a sparse population of cells scattered

through and extracellular matrix

- the matrix generally consists of a web of fibers

embedded in a uniform foundation that may be

liquid, jellylike or solid- Three kind of connective tissue fibers made of

protein: collagenous fibers, elastic fibers,

reticular fibers


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Connective tissue

iii. Reticular fibers

- very thin and branched

- compose of collagen

- continuous with collagenous fibers

- form a tightly woven fabric that joinsconnective tissue to adjacent tissues


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Connective tissue

the major types of connective tissue in vertebrate

- loose connective tissue

- adipose tissue

- fibrous connective tissue

- cartilage

- bone

- blood


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Connective tissue

i. loose connective tissue

- the most widespread connective tissue

- binds epithelia to underlying tissues andfunctions as packing material, holding organ in

place

- has all three types of fiber: collagenous,elastic and reticular

- two types of cell predominates: the fibroblasts

and macrophage


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Connective tissue

fibroblasts : secrete the protein ingredient

of extracellular fibers

macrophage : engulfing bacteria and thedebris of dead cells by

phagocytosis


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Connective tissue

ii. adipose tissue

- specialized form of loose connective tissue

that stores fat in adipose cells distributed

throughout its matrix

f(x): pads and insulate the body and stores fuel

molecules

- heredity, exercise and the amount of fat weeat can affect the amount of fat our adipose cell

stored


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Connective tissue

iii. fibrous connective tissue

- is dense due to its large numbers of

collagenous fibers

- the fibers are, organized into parallel bundles,an arrangement that maximizes non-elastic

strength

- can be found in tendon and ligamentstendon : attach muscle to bone

ligament : join bones together at joints


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Connective tissue

iv. Cartilage

- has an abundance of collagenous fibers

embedded in a rubbery matrix made of a

substance called chondroitin sulfate (a protein carbohydrate complex)

- strong yet flexible support material

eg.: shark skeletons, nose, ears, ring ofwindpipes, caps on the end of some bones


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Connective tissue

v. bone

- a mineralized connective tissue

- bone forming cell is called osteoblast

- osteoblast deposit a matrix of collagen, but

they also release Ca2+, Mg and phosphate ion,

which chemically combine and harden within

the matrix into the mineral hydroxyapatite


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Connective tissue

vi. blood

- although different from other connective

tissue, but it does have an extensive

extracellular matrix

- the matrix called plasma, consist of water, salt

and dissolved protein

- two types of blood cells: erythrocytes,

leukocytes

- cell fragments: platlet


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Nervous tissue

- senses stimuli and transmits signal from onepart of the animal to another

- functional unit: neuron (nerve cell)

- f(x): transmit signal called nerve impulses

- Consists of cell body and two or more

extension called dendrits and axon

dendrits : transmit impulses from their tipstoward the rest of the neuron

axon : transmit impulses toward anotherneuron or toward and effectors


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Muscle tissue

- composed of muscle fibers that are capable of

contracting when stimulated by nerve impulse

- In muscle fibers: large number of microfilamentmade of the contractile proteins action and

myosin

- 3 types: skeletal muscle, cardiac muscle andsmooth muscle


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Muscle tissue

skeletal : for voluntary movement of the body

cardiac : branched contractile wall of the heart

smooth : lacks striation, in the wall of digestivetract, bladder, arteries and other

internal organ for involuntary body

activities


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Activity 2

Construct a mind-map to simplify allthe information of four major type oftissues.

cell organelles1

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