The Cellular and Tissue Levels of Organization Flashcards
Cells
- Smallest units that perform all vital physiological functions
- Each cells maintains Homeostasis at the cellular level
- Homeostasis at higher levels reflects combines, coordinated action of ma cells
Cells of Interest in the Human Body
-
Eukaryotic cells
- 10-100 micrometers
-
Prokaryotic cells-bacteria
- 1-10 micrometers
-
Parasites-eukaryotes
- single cells-Protista
- multicellular - fungi, insects, worms, etc…
- viruses not cells
Describe a typical human body cell
- Surrounded by an extracellular fluid, which is the fluid of the tissue
- cell membrane forms the outer membrane
- plasma membrane or plasma lemma
- Cytoplasm
- Cytosol and organelles
- Nucleus
What are the cell membrane functions.
- Physical Isolation - Extracellular and intracellular fluid composition differ (Cellular Homeostasis)
- Regulation of exchange with the environment - Semi permeable
- Controls entry of ions, nutrients
- controls exit of water, release of secretions
- Sensitivity and recognition
- Structural Support
Cell Membrane
- Phospholipid Bilayer
- Hydrophilic phosphate group on surface
- Hydrophobic fatty acid tails inside
- Fluid Mosaic Membrane
- Membrane
- cholesterol
-
Glycocalyx on extracellular surface
- Sugar groups attached to membrane lipids and membrane proteins
Functions of membrane proteins and carbohydrates
- Transport Proteins
- Chanel Proteins
- Anchoring
- Cell identity - genetically located recognition factors
- Receptors
What is the dynamic membrane of the cell
- Golgi Apparatus
- Endoplasmic Reticulum
- Sooth ER
- Rough Er
- Vesicles
- Endocytosis
Endoplasmic Reticulum (Smooth and Rough)
Smooth Endoplasmic Reticulum:
Synthesis of lipids and carbohydrates
Rough Endoplasmic Reticulum:
Synthesis of Proteins
Golgi Apparatus
Packages and process products of the RER and SER
Digestive Organelles:
Proteasomes
Digest damaged and abnormal proteins
- *Digestive Organelles:**
- *Peroxisomes**
Enzymatic breakdown of lipids and toxins
- *Digestive Organelles:**
- *Lysosomes**
Lysosomes-Vesicles with multiple types of digestive enzymes
- Digest organelles, engulfed materials for recycling
- Responsible for the lycing of injured cells
What does the Mitochondria do?
- Responsible for ATP production through aerobic respiration of small organic molecules
- site of cellular respiration - uses O2 and creates CO2 as waste
- Large number in cytoplasm of metabolically active cells that carry out aerobic metabolism
What does the nucleus do?
- 23 pairs of chromosomes storing the genetic information of the human body
- sequence of nucleotides in DNA is transcribed creating mRNA with corresponding nucleotide sequence
- mRNA exits nucleus, carrying information that is read by ribosomes to synthesize proteins
Cell Cycle and Differentiation
- All cells of a human body derive from cell divisions starting with a fertilized egg
- All somatic cells (non sex cells) contain the same genes
- Differentiation results from inactivation or activation of particular genes
- Early embryonic cells (undifferentiated) can form any type of cell
- Differentiation produces populations of specialized cells with limited capabilities