Lesson 6 - The Cell Flashcards
Homeostasis
Keeping internal environment constant despite a change in external environment
Where is Homeostasis control centre? What does it do?
Controlled in the hypothalamus which is the bodies control centre. Receives input and controls hormones
What do we need to keep constant in the body
Nutrients/ wastes
Oxygen and CO2 levels
pH
Water/electrolytes
Temperature
Blood volume and pressure
Circadian Rhythms
The physical, mental, and behavioral changes an organism experiences over a 24-hour cycle. Light and dark have biggest affect
Homeostasis Process
Internal or external change
-Body attempt to correct
Successful correction
-homeostasis reestablished
failure to adjust
-death or illness
Feedback loops
Negative feedback loop: Response in which the effects of a reaction slow or stop that reaction
Error occurs results in disease, over compensation or competing regulators
Positive feedback loop: occurs to increase the change or output. Response reinforces stimulus, snowball affect
Levels of organization
Chemical
-molecules
cells
-basic unit of life
Tissue
-4 types
Organ
Body system
organism
Cell subdivided into three part
Plasma (cell) membrane
Cytoplasm
-cytosal
-organelles
Nucleus
-chromosomes
-genes
Cell shapes
cells will vary in size and contain different organelles based on function
Nucleus
Cell replication and repair
Usually 1 per cell
Ribosomes
-make proteins
-either free or attached
- Free, makes proteins for the cell
Endoplasmic reticulum (ER)
Smooth ER
-calcium storage
- detoxification
- steroid production
Rough ER
-Ribosomes attached
- Makes organelle
- protein product for export
Golgi complex
Repackages RER proteins into vesicles to leave cell
Peroxisomes
Oxidative Enzymes
-Metabolism
-Detoxify various waste products
Lysosomes
Sac of digestive enzymes
Used for repair and removal of foreign matter
Proteosomes
Large portion complexes
-Protein digesting enzymes
With age, maybe unable to normally remove proteins
Cytoskeleton
Complex protein network
-acts as “bone and muscle” of cell
Three distinct elements
-mircotubles
-microfilaments
-intermediate filaments
Function of the three distinct elements of Cytoskeleton
Mircotubles
-transport secretory vesicles
-form mitotic spindle during cell division
Mircofilaments
- contractile systems
- muscle
- mechanical stiffeners
Intermediate filaments
-Help resist mechanical stress
-hair, skin
Cilia and Flagella
Cilia
- directional movement of particles
Flagella
- on moving cell
Mitochondria
Powerhouse of the cell and energy organelle
-site of ATP production
- Enzymes for TCA cycle and ETC
Cellular diversity
Adult has roughly 100 trillion cells
- roughly 200 types of cells
- variety of shapes and sizes
-differing lifespans
-organize into complex tissues and organs
Specialized function of cell is according to:
shape of cell and is arrangement of organelles
Aging and cells
As we age:
-our cells gradually deteriorate
-number of body cells goes down
-they lose integrity of extra cellular components
Development aspect of cells (theory)
Aging effecting
Free radical theory
-damage from byproducts of cellular metabolism
- radicals build up and damages essential molecules of cells
Mitochondria theory:
-decrease in production of energy weakens cells
Genetic theory:
- proposes that aging is programmed within genes
-with each replication of DNA, nucleotides are lost
-Telemeres “end caps” on chromosomes
