Physiology 3140A Lecture Notes - Lecture 2: Cell Membrane, Myelin, Nervous Tissue
2 May 2018
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Cell Physiology Lecture 2
Integrating Cells into Tissues
September 11 2017
Similarities of Cells
- At one point contain DNA or still do
- Require Energy
- Function as biochemical factories
- Enclosed in a plasma membrane
Cells contain DNA
- Cells need DNA to function- instructions for life
o contained in a highly ordered fashion, easy access to specific portions of DNA for cellular
use
o How to make protein and when to make it, encode when the protein is to be degraded
- Which cells do not contain DNA?
o RBCs (erythrocytes), cells in upper layer of skin, mature hair cells, things on the way out that
are dying (mostly the skin)
- The cell spends a lot of energy organizing and packing DNA so it fits into the nucleus and easily
accessible
- Sugar backbone of DNA is a perfect structure:
o Flexible, allows bending, is water loving (on the outside), bases are hydrophobic (in the
center) double stranded in a stacked fashion
Cells Require Energy
- Replication of DNA (high-fidelity)
- Separation of DNA for replication
- Production of RNA and proteins
- Signal propagation through phosphorylation – tyrosine, threonine, serine kinases
- A lot of energy derived from the cell is through the breakdown of glucose and combination of water
- Energy in the form of ATP
o ATP is chemical energy – MAJOR SOURCE
- Cells can generate electrochemical energy by moving ions to build up on one side of the membrane to
power other machines (e.g. sodium, hydrogen gradients)
Cells Function as Biochemical Factor
- All cells will utilize the same subset of molecules to derive all of their needs and carry out specific
programmed functions
- Requirement for ATP
o ATP as precursor for DNA and RNA
o ATP in the form of energy
Cells are Enclosed in Plasma Membranes
- Selective barrier
o Molecules needed to enter the cell?
▪ Glucose
▪ Nutrients
▪ Proteins
find more resources at oneclass.com
find more resources at oneclass.com
▪ Amino acids
▪ Many can not pass the plasma membrane
o Molecules needed to exit the cell?
▪ Protein cell needs to secrete
▪ Waste products – ex. urea what you don’t want in the cell
▪ Also selected!
- PM is a dynamic structure that is physiologically active
o Ensures what needs to leave stays out, what needs to go in stays in
Cell Differences
- Variability of Cell Shape
o Depending on their function
o Large part of cell that keeps its shape is the cytoskeleton
▪ Intermediate filaments, microtubules, etc.
- Organelle Number
o Mitochondria – active has more than a cell that does not
- Expression of genome- ability or inability to express
o All the cells have the same DNA but different cells express certain genes
o Different parts of the DNA will be accessible in different cells
- Membrane Protein Composition
o Ex. Neuron has myelin sheath
Tissue Types
- Nervous tissue
o Mental activity, sensory input and integration, regulates muscles and glands, homeostasis
o Brain, spinal cord
- Muscular tissue
o Contraction; movement and support
o Skeletal muscle, cardiac muscle, smooth muscle
- Connective tissue
o Supportive role in tissues and organs; energy storage e.g. nutritional support for epithelium),
protection of organs, tissue repair, structure
o 2 main classes:
▪ Fat based connective tissue
• Energy stored, protection of organs
▪ Collagen based connective tissue
• Tissue repair and structure
• Bones, teeth, cartilage, tendons, dermis in the skin
- Epithelial tissue
o Lines surfaces and cavities; section, absorption, protection etc.
o Lining of gut and mouth, skin, where you are continuous with extracellular area, blood vessel
cells, alveoli, gut lining, epidermis, etc.
- Blood
o Regulates nutrient and oxygen transport, metabolic waste, immune system
o White blood cells, red blood cells, platelets
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
At one point contain dna or still do. Which cells do not contain dna: rbcs (erythrocytes), cells in upper layer of skin, mature hair cells, things on the way out that are dying (mostly the skin) The cell spends a lot of energy organizing and packing dna so it fits into the nucleus and easily accessible. Sugar backbone of dna is a perfect structure: flexible, allows bending, is water loving (on the outside), bases are hydrophobic (in the center) double stranded in a stacked fashion. A lot of energy derived from the cell is through the breakdown of glucose and combination of water. Signal propagation through phosphorylation tyrosine, threonine, serine kinases: atp is chemical energy major source. Cells can generate electrochemical energy by moving ions to build up on one side of the membrane to power other machines (e. g. sodium, hydrogen gradients)
