2.3 Appreciating the Uniqueness of the Cell
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Transcript of 2.3 Appreciating the Uniqueness of the Cell
Chapter 2 : Cell Structure & Cell Organisation
INTERNAL ENVIRONMENT
INTERNAL ENVIRONMENT
environment inside the organisms, i.e. fluid surrounding the cells
External Environment
physical place where it lives in and where it interacts with other
organisms
Tissue Fluid / Interstitial Fluid
• Fluid surrounding the cells
Tissue Fluid / Interstitial Fluid
• Fills the narrow spaces between the cells
• bathes the cells• keeps the cells
functioning normally
Formation of interstitial fluid
FACTORS AFFECTING INTERNAL ENVIRONMENT
Temperature
Osmotic pressure
pH value
Glucose level 37⁰C
≈ 7.4
90mg per 100 cm-3
Maintenance Optimal Temperature
Temperature is maintained at 37ºC
Too High DENATURE
Too LowINACTIVE
Maintenance of Optimal pH
pH of human tissue fluid is 7.4
If the pH changes, enzymes will be denatured and lose the ability to function
HOMEOSTASIS
HOMEOSTASIS
Maintenance of a steady state in the internal environment
The steady state is the optimum level for all body functions
Organ systems interact with one another to maintain a stable internal environment
HOMEOSTASIS MAINTAINED :
BLOOD PH TEMPERATURE
OSMOTIC PRESSURE BLOOD GLUCOSE
integumentary, nervous and endocrine system nervous & endocrine system
endocrine system, kidney & ADH hormone endocrine system, glucagon & insulin
normal condition normal condition
Receptor detects stimulus & start corrective mechanism
Receptor detects stimulus & start corrective mechanism
Stimulus (above normal)
Stimulus (below normal)
Negative feedback
Negative feedback
Glucose Level
Osmoregulation
pH
• Above / below pH 7.4• Involves the following systems:
a) Respiratory systemb) Excretory systemc) Circulatory system
• Maintain optimal pH by monitoring the concentrations of ions & salts in the blood
THE UNIQUENESS OF THE CELL
Organelle missing Predicted state of the cell
Nucleus •All cell activities stop•Cell does not live long•The cell dies
Mitochondrion • No energy for cell activities• The cell dies
Ribosome • Cell is unable to synthesise enzymes (proteins)• Cell growth stops• Cell is unable to repair itself• Finally, the cell dies
Endoplasmic reticulum (RER & SER)
• Less enzymes produced• Synthesis and transport of proteins & glycerol stop
Golgi Body • Proteins produced become defective• Cell is unable to produce certain types of proteins