Cell and Its Life

8/7/2019 Cell and Its Life

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PBL Group 9 :

Adani Nur Imanina

Adeli Caryabudi

Ary Agustanti

Beatrice Intan Kasih

Fatimah R. Gita I.

Muhammad Luthfi

Olivia Elton H.

Pritami Arista

Riyan Adiputra Lukardi

Vanessa Honey Sumardi

Yulita





Cell is the smallest unit of all kind of living organism

that performs physiologycal function and acts as

the building blocks.



1. A cell is the basic structural and functional unit of living organisms.

2. the activity of an organism depends on both the individual and

collective activities of its cells.

3. according to the principal of complementarity, the biochemical

activities of cells are dictated by the specific subcellular structuresof cells.

4. Continuity of life has a cellular basic.



` 1. Obtaining food (nutrients) and oxygen (O2) from the environment

` 2.Performing chemical reactions that use nutrients and O2 to provide energy for the

cells

` 3.Eliminating to the cell¶s surrounding environment carbon dioxide (CO2) and other

by-products, or wastes, produced during these chemical reactions.

` 4.Synthesizing proteins and other components needed for cell structure, for growth,and for carrying out particular cell functions.

` 5.Controlling to a large extent the exchange of materials between the cell and its

surrounding environment.

` 6.Moving materials from one part of the cell to another in carrying out cell activities

` 7.Being sensitive and responsive to changes in the surrounding environment.

`

8.In the case of most cells, reproducing.`



The different substances that make up the cell are collectively called protoplasmwhich Is composed mainly from five basic substances:

` Water : principal fluid medium, present in most cells, except the fat cells

` Ions : most important: K,Mg,PO3,SO4,CO3 and Na,Cl,Ca; provide inorganicchemicals for cellular reaction and essential for operation of some cellular controlmechanism

` Proteins : Divided into:a. Structural Proteins (present mainly in form of ling filaments of

polymers from individual protein molecules. Ex: forming

microtubules)

b. Functional Proteins (composed of combinations of a few

molecules in tubular-globular for. Ex. Enzymes)

`

Lipid : Several types of substances that grouped together because their commonproperty of being soluble in fat solvents. Essentials for the forming of phospholipids, cholesterol, and triglycerides

` Carbohydrates : Has little structural function, plays more as a part of glycoprotein;major role in the nutrition of the cells; present surrounding extracellular fluid andreadily available to the cell; stores in cells in form of glycogen



` Plasma Membrane

` Cytoplasma

` Nucleus





�

Membrane Proteindouble layer lipid hydrophobic (phosphate)(phospholipid bilayer) hydrophilic ( fatty acid)

� Membrane Protein :6 types:1. channels : form a passageway through membrane plasma (water &

smaal solutes2. carrier : bind solutes and transport them across the plasma membrane3. Receptor proteins : sensitive to presence of extracellular molecules4. enzymes : integral or pheripherial proteins ± to catalyze reactions5. identifier : glycoproteins ± immune system6. anchoring proteins : supporting filaments in cytoplasm

` Membrane Carbohydrateattached with : - lipid glycolipid

- protein glycoprotein



Membranous Organelles

1. Endoplasmic ReticulumRough ER ± synthesizes and releases protein into the lumen

Smooth ER ± packages and sends molecules from the ER to

the Golgi complex by vesicular transport

2. Golgi complex ± processes raw material transported from the ER

into finished products then sorts and directs them to their destinations 3. Lysosomes ± destroys

unwanted material in the cell

4. Peroxisomes ± detoxifies

waste

5. Mitochondria ± energy

organelle; major site of ATPproduction; contains

enzymes for citric acid cycle,

protein electron transport

system, and ATP synthase



Non-membranous Organelles

1. Ribosome ± conducts protein synthesis2. Vaults ± cellular transport from nucleus to cytoplasm

3. Centrioles ± forms the mitotic spindle during division



Cytosol Cytoskeleton

1. Intermediary metabolism

enzymes ± facilitates intracellular

reactions2. Transport, secretory and

endocytic vesicles ± transport

and/or store products being

moved within, out of, or into the

cell

3. Inclusions ± stores excess

nutrients (in the form of: fat

droplets in the adipose tissue,

glycogen in liver and muscle cells)

1. Microtubules ± maintains cell

shape and coordinates cell

movement; highways for transportof secretory vesicles in cells; main

structural and functional component

of cilia and flagella; forms mitotic

spindle during cell division

2. Microfilaments ± cellular

contractile system; mechanicalstiffener for microvilli

3. Intermediate fillaments ± resists

mechanical stress



� Controls cell¶s activities

� Three parts :

1. Nucleus envelope ± double membrane

is pierced by many nucleus pore which allow

exchange between the nucleus and cytoplasm

2. Nucleoli ± composed of ribosomal RNA and

proteins, as the site of ribosome subunit manufacture3. Chromatin ± composed of DNA and histone protein



Characteristic Prokaryot Eukaryot

Size of Cell Typically 0.2-2.0 m m indiameter

Typically 10-100 m m indiameter

Nuclear Body a. The nuclear body is not

bounded by a nuclear

membrane .

b. It usually contains one

circular chromosome

composed of deoxyribonucleic acid (DNA)

associated with histone-like

proteins.

c. There is no nucleolus.

d. The nuclear body is called

a nucleoid

a. The nuclear body is

bounded by a nuclear

membrane having pores

connecting it with the

endoplasmic reticulum

b. It contains one or morepaired, linear chromosomes

composed of

deoxyribonucleic acid (DNA)

associated with histone

proteins

c. A nucleolus is present.

d. The nuclear body is called

a nucleusCell division a. The cell usually divides by

binary fission. There is no

mitosis.

b. Prokaryotic cells are

haploid. Meiosis is not

needed.

a. The nucleus divides by

mitosis

b. Haploid (1N) sex cells in

diploid or 2N organisms are

produced through meiosis




Plasma Membrane a. The cytoplasmic membrane is afluid phospholipid bilayer usuallylacking sterols . Many bacteria docontain sterol-like molecules called

hopanoids.b.The membrane is incapable of endocytosis and exocytosis.

a. The cytoplasmic membrane is afluid phospholipid bilayer containingsterols.b. The membrane is capable of

endocytosis (phagocytosis andpinocytosis) and exocytosis

Cytoplasmic structure a. The ribosomes are composed of a50S and a 30S subunit forming an70S ribosomeb. Internal membrane-boundorganelles such as mitochondria,endoplasmic reticulum, Golgi

apparatus, vacuoles, and lysosomesare absentb. There are no chloroplasts.Photosynthesis usually takes place in

infoldings or extensions derived fromthe cytoplasmic membrane.c. There is no mitosis and no mitoticspindle.d. They may contains only actin-like

proteins that, along with the cell wall,contribute to cell shape.

a. The ribosomes are composed of a60S and a 40S subunit forming an80S ribosome.b. Internal membrane-boundorganelles such as mitochondria,endoplasmic reticulum, Golgi

apparatus , vacuoles, and lysosomesare presentc. Chloroplasts serve as organellesfor photosynthesis.

d. A mitotic spindle involved in mitosisis present during cell division.e. A cytoskeleton is present. Itcontains microtubules, actinmicofilaments, and intermediate

filaments. These collectively play arole in giving shape to cells, allowingfor cell movement, movement of organelles within the cell andendocytosis, and cell division.




Respiratory enzymes and

electron transport chain

The electron transport system is

located in the cytoplasmic

membrane.

The electron transport system is

located in the inner membrane

of the mitochondria.

Cell wall a. With few exceptions,

members of the domain

Bacteria have cell walls

composed of peptidoglycan

b. Members of the domain

Archae have cell walls

composed of protein, a complex

carbohydrate, or unique

molecules resembling but not

the same as peptidoglycan.

a. Plant cells, algae, and fungi

have cell walls, usually

composed of cellulose or chitin.

Eukaryotic cell walls are never

composed of peptidoglycan

b. Animal cells and protozoans

lack cell walls

Locomotor organelles Many prokaryotes have flagella,

each composed of a single,

rotating fibril and usually not

surrounded by a membrane.

There are no cilia.

Eukaryotic cells may have

flagella or cilia. Flagella and cilia

are organelles involved in

locomotion and in eukaryotic

cells consist of a distinct

arrangement of slidingmicrotubules surrounded by a

membrane.





Paracrine signaling: Sender cell secretes local

regulator molecule which is an element that

affects cell that's close to it. Example: growth

factor in animals. Nerve system in animals: nerve cells generates

chemical signals (neurotransmitter) diffused to

target cell that is adjacent, and then the electric

signal triggers neurotransmitter moleculesecretion to the synapsis.



Hormonal signaling / endocrine signaling:

specialsed cell releases hormone molecules into

veins in circulation system -> the hormone flows

to the target in other body part.



Adhering junction: spreads inside the body, mostly

in skin, heart, muscle, and uterus



Tight junction: In epithelial tissue layer,

impermeable, prevents leaks



Gap junction: it is a gap between cells connected

by small channels called connexon, passage way

for water soluble substances



Cells adhesion allows group of cell unifies andform tissue and organ.

Extracell matrix works as biological glue. Secreted

by local cells.3 main protein fibers:

- colagen: forms cable-like fibers or layer thatgenerates tensil power (resistence againstlongitudinal stress)

- elastin: elastic, located in lungs

- fibronectine: supports cell adhesion and keepscells in place















` Anabolism: the buildup, or synthesis, of larger organicmolecules from the small organic molecular subunit

` Catabolism: the breakdown, or degradation, of large,energy-rich molecules within cells, example:

- Lipid metabolism- Protein metabolism

- Carbohydrate metabolism :1. Glicolysis

2. Citric acid cycle / Krebs cycle

3. Electron transport chain







` NADH + ½ O + H NAD + HO

approximate number of ATP molecules per reduced

coenzyme for this formula is equal with 3ATP

FADH + ½ O FAD + HOapproximate number of ATP molecules per reduced

coenzyme for this formula is equal with 2ATP

Note: Glycolisis takes place in the cell sap, while Krebs

Cycle and Electron Transport occur inside

mithochondria





` Transcription

` Translation



`

the transcription of mRNA from a DNA gene inthe nucleus.

` At some other prior time, the various other

types of RNA have been synthesized using the

appropriate DNA.` The RNAm migrate from the nucleus into the

cytoplasm.



` The mRNA joins to the small ribosomal unit at

the 5' untranslated region. This binds to a special

binding site on the small ribosomal subunit. The

large ribosomal subunit has 3 binding sites, E, P,

and A.

� The large ribosomal subunit attaches to the smallsubunit such that the first codon is aligned at the

P binding site.

� A tRNA carrrying the amino acid methionine

attaches to the start codon (AUG) on themessaenger RNA. This inititates elongation.



` Attachment of first amino acid carrying tRNA to A

binding site.` Peptide bond formation between the met and the

amino acid carried at the A binding site.` Ribosome moves in the 3' direction down the

messenger RNA by three bases or one codon shiftingthe tRNA and polypeptide chain to the P Binding site.The A binding site is open and a vacant tRNA is inthe E binding site.

` tRNA ejected from the E binding site.` Continue until stop codon encountered.` Old tRNA ejected from the E Binding site



` The polypeptide chain is at the P site. The

stop codon at the A site.` A Release factor protein binds to the stop

codon at the A binding site.

` Release factor protein initiates separation of

polypeptide chain` Separation of translation machinary.

Polypeptide chain may go to cytoplasm for further processing.





` The cell¶s adaptation activity is related tohomeostasis. Homeostasis is the specialized

activities of the cells that make up the bodysystems are aimed at maintaining homeostasis, adynamic steady state of the constituents in the

internal fluid environment.` Homeostasis is essential for the survival of each

cell, and each cell, through its specializedactivities, contributes as part of a body system to

the maintenance of the internal environmentshared by all cells.



To maintain normal function, cell has ability to adapt

to environmental changes.

There are 2 types of adaptation:

1.Physiological metabolic adaptation

2. Physiological structural adaptation



1. Physiological metabolic

adaptationIt represent fine regulation of metabolic function at abiochemical level, not reflected in easily detectablechanges in structure.

for example:` during periods of fasting, fatty acids are mobilized

from adipose tissue to supply energy

` during periods of calcium lack, calsium is mobilizedfrom bone matrix by activity of osteoclast.



2. Physiological structural

adaptationit caused by a change in the normal pattern

of growth and accompanied by easily

detectable structural changes.

Divided into 3 broad types:

` Increased cellular activity

` Decreased cellular activity` Alteration of cell morphology



` Hyperplasia ± increase in the number of cells in a

tissue caused by increased cell division.

found i n:tissues that have capacity for cell division.

example :

if serum calsium abnormally low, the parathyroidglands increase the number of parahormone-

secreting cells.



` Hypertrophy ± increase in the size of existing

cells, accompanied by increase in their functional

activity.

found i n:

Tissues which are unable to divide, like in skeletal

and cardiac muscle.

example :

For athletes, skeletal muscle fibers increase in sizein response to exercise and increased metabolic

demands.





`

Involusion ± decrease in the size of cells in atissue caused by increased in the catabolism

example :

the size of thymus are dramatically reduced after

puberty, and the organ is primarily replacedwith fat



Metaplasia ± replacement of one type of fully

differentiated type. It is a substution and not a true

transformation.

example:

` In urinary bladder, the normal transitional

epithelium may be replaced by squamous

epithelium in response to chronic irritation bybladder calculi or infection.





G1

S

G2

G0

Protein

synthesis

DNAreplication,

synthesis of

histones

Normal cell

functions plus cell

growth,duplication of

organelles, protein

synthesis

Specialized cell function /

Differentiation



` G1 phase. Metabolic changes prepare the cell for division. At a certain point - the restriction point - thecell is committed to division and moves into the Sphase.

` S phase. DNA synthesis replicates the geneticmaterial. Each chromosome now consists of two sister chromatids.

` G2 phase. Metabolic changes assemble thecytoplasmic materials necessary for mitosis andcytokinesis.

` M phase. A nuclear division (mitosis : prophase,metaphase, anaphase, telophase) followed by a celldivision (cytokinesis).



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Cell and Its Life