DEN 1114 Lecture 2Professor Maria-Elena Bilello

http://www.youtube.com/watch?v=1B4F2V0_yYg

   

Cell Smallest living unit of organization: Epithelial cell, neuron, myofiber,

chondrocyte, fibroblast, erythrocyte, macrophage. sperm

Tissue Collection of similarly specialized cells: Epithelium, nervous tissue, muscle,

cartilage, bone, blood

Organ Independent body part formed from tissues: Skin, brain, heart, liver

System

Organs functioning together: Central nerous system, respiratory system,

immune system, cardiovascular system

:

Criteria for LifeReproduction Ability to replicate ones self (going from one to two)

Growth Ability to increase in size

Metabolism The process by which substances are produced, maintained and destroyed and energy is produced Anabolism - put particles together (synthesis) from smaller ones (constructive metabolism)Catabolism – Complex molecules are broken down into simpler one and release energy(Destructive metabolism).

Assimilation The conversion of absorbed food into the substance of the body

Excretion Ability to eliminate

respiration Total process of conveying O2 to tissues & cells and the oxidation process whereby CO2 & H2O are given off.

Irritability Ability to respond to a stimulus

Conductivity Ability to transmit that stimulus

Homeostasis Ability to work together to maintain equilibrium (harmony)

http://www.youtube.com/watch?v=NiiLS_ovLwM&feature=related

Cell contains:Cell membraneCytoplasmOrganelles Cellular inclusions

http://www.youtube.com/watch?v=NiiLS_ovLwM&feature=related

Lipids diffusion regulator (barrier)

Only allows substancessoluble in lipid to pass

through the membrane.

Proteins Structural

reinforcement - stabilize cell membrane

Receptor – hormones

neurotransmitters immunoglobulins (antibodies)

Types of proteins: Transmembrane proteins

(transport materials through bi-layer) Surface membrane proteins

(receptors AB & hormones)http://www.youtube.com/watch?v=GW0lqf4Fqpg&feature=related

Semi-fluid portion Between liquid & gel (75-90%)

Contains - IonsMolecules - Amino Acids

Sugars - glucose & fructose

Cytoskeleton System of support

Contains – microfilaments intermediate filaments microtubulesThese create stability and compartmentalize the cytoplasm.

Chemical messages from the cytoplasm & membrane (the cellular environmental) influence gene activity.

http://www.youtube.com/watch?v=kud4qUhsCxg&feature=related

Major Organelles:Nucleus

MitochondriaRibosomes

Endoplasmic ReticulumGolgi Complex

LysosomesCytoskeleton

http://www.youtube.com/watch?v=1IqsE8CVTms&feature=related

Nucleus‘Command Central’

Contains: DNA – deoxyribonucleic acid RNA - ribonucleic acid Nucleolus

DNA & RNA – Memory Bank (genetic coding)control all functions of the cell

COMPONENTS:NUCLEOPLASM: in the form of chromatin contains DNA - Chief nucleic acid– linked into chromosomes

NUCLEOLUS:PRODUCES - rRNA (ribosomal RNA) - nucleotides of the 2 other types of RNA*IMPORTANT for PROTEIN SYNTHESIS (No Nucleolus – No Protein Synthesis)

NUCLEAR ENVELOP - double-layered Membrane which may be pierced by nuclear pores.

NUCLEAR PORES – communicates between the nucleoplasm and the outer cytoplasm

•http://www.youtube.com/watch?v=lTHY430ohJI

DNA GENETIC INFORMATION

RNA TRANSLATES DNA-

CARRIES THE TRANSLATION TO THE SITE OF PROTEIN

SYNTHESISDeoxyribonucleic acid

Adenine cytosine Guanine thymine Chromatin – ‘loose’ DNA

when no division is occurring (just strands)http://www.youtube.com/watch?

v=qy8dk5iS1f0&feature=related

Besides hereditary activity,DNA directs synthesis of

manyenzymes, proteins and

secretory products

TYPES OF RNA:mRNA – Messenger RNAcomplementary copies of segments of DNA

tRNA – Transfer RNA molecules that bind to & transport amino acids units for protein systhesisrRNA – Ribosomal RNA

http://www.youtube.com/watch?v=1fiJupfbSpg&feature=related

Energy Production (Conversion) – ATP Cristae – folds inside mitochondria

Cristae – contain enzymes on surface to aid in cell metabolism

cell function depends on the amount (increase # mitochondria = increased cellular

activity)Increase # cristae = more active cell

* Cardiac muscle and the liver contain the most mitochondria.

http://www.youtube.com/watch?v=TgJt4KgKQJI&feature=related

Made in the Nucleolus from rRNA & protein molecules and assembled in the cytoplasm

Found: free in cytoplasm (bound to membranes)

within mitochondria attached to mRNA molecule bound to rough endoplasmic reticulum outer nuclear membrane

Sequences protein chains Within ribosomes – free amino acids are being joined together

in accordance with the order specified by the mRNA transcript

Network of parallel membrane-bound channels

and folds which is continuous (connects) with

nuclear envelope.Functions: modifies, stores, segregates

and transports proteinsSmooth Endoplasmic Reticulum (SER)

Rough Endoplasmic Reticulum (RER)

Free of Ribosomes

Smooth – lipid/fat synthesis

Ribosomes on outer surface

Rough – protein synthesis

Composed of stacks of 3 to 20 flattened, smooth-membraned vesicular sacs – parallel to each other

Fuses with vesicles of protein molecules (hormones, enzymes, secretory products) from RER

Protein molecules are further modified concentrated and packaged.

Packaging – wraps larger #’s of molecules into a single membranous vesicle (using merocrine secretion)

Prepares proteins for export by EXOCYTOSIS Produces lysosomes – a separate organellehttp://www.youtube.com/watch?v=bD4z27ASN1M&feature=related

Function –Digestion Intracellular & Extracellular

Vesicle – develops and pinches off Golgi complex

Enzymes of the lysosomes are produced on RER, transported for

packaging to Golgi complex

lyses – to digest - breaks down particles (good & bad – foreign particles)during phagocytosisAutolysis – self destructionCaused by:Powerful hydrolytic enzymes and digestive enzymes

•Main hydrolytic enzyme - hyaluronidase

* All cells – except red blood cells (RBC) have digestive activityhttp://www.youtube.com/watch?v=E3Zfgtkv-ik

Function: Significant role in reproduction - cell division (mitosis)

Aids in spindle formation Oval-shaped organelle Always located near nucleus Contains: Centrioles - pair of cylindrical

structures*Without self-replicating centriole-

centrosome unit , animal cells cannot reproduce

http://www.youtube.com/watch?v=N0JCD3ofyIM

Function: Support - a 3-dimensional

System that gives stabilityCompartmentalizes thecytoplasm for movement

of moleculesComponents:

Microfilaments, Intermediate filamentsMicrotubules

(these consists of specialized proteins)

Microfilaments: Delicate, thread-like, not

hollow Maintain cell shape Transport intracellular

materials

Microtubules: Slender, hollow, tubular Assist microfilaments Framework for cilia,

flagella, centrioles

Intermediate filaments: Thicker, thread-likeExamples: Tonofilaments – role in

intercellular junctions Keratin –found in calloused

epithelial tissueshttp://www.youtube.com/watch?v=5rqbmLiSkpk&feature=related

Inert (not active) substances that are produced in the cell to be used later -

transient.Vacuoles – spaces/cavities in the cytoplasm Are released from storage by the cell as needed water Lipids and glycogen can be decomposed for

energy from inclusions. Melanin (a pigment) stored as inclusion in skin

cells and oral mucosa. Residual bodies such as old lysosomes & their

digested material.

Fills the spaces between cells in a tissue

Serves as barrier Serves as a medium for the exchange

of gases & metabolic substances. Produced by the cells. Colorless, shapeless and transparent.

• Tissue Fluid (interstitial fluid)– Dissolves, mixes, transports substance and

carries out chemical reactions. (contains small amount of plasma proteins)– Diffuses through capillary walls from plasma of

blood.– Returns into blood as lymph by osmosis via the

lymphatic system

The amount of tissue fluid varies.Excess tissue fluid = EDEMA

DESMOSOME CELL TO CELL - IS DISC-SHAPED

HEMIDESMOSOMECELL TO NON-CELLULAR

SUBSTANCE

as in upper layers of skin as in gingival epithelium & tooth surface

Attachment device - attachment plaque in the cell & tonofiliments

http://www.youtube.com/watch?v=XdaUthOUvIo&feature=related

Hemidesmosomes as mechanism for attaching the epithelium to

connective tissue such as in the oral mucosa by way of the basement membrane

Desmosomes as mechanism for attaching upper

layers of the skin

http://www.youtube.com/watch?v=W0HQt1MTrAc&feature=related