Cellular Biology and Adaptation Flashcards
8 Specialized Functions of a Cell
- Movement
- Conductivity
- Metabolic Absorption
- Secretion
- Excretion
- Respiration
- Reproduction
- Communication
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Movement
- Muscle cells can generate forces that produce motion
- Cardiac, muscle, and blood vessel contraction
- White blood cells (WBC’s) are able to travel to the site of the infection through this function
Conductivity
- The capacity of living cells to transmit a wave of electrical disturbance from one point to another within the body
- Occurs as a response to a stimulus manifested by waves of excitation, an electrical potential that passes along the surface of the cell to reach other parts
- Occurs due to the presence of ions and mobile polar molecules within the system
- Chief function of the nerve cells
- Present in nerve cells and the electrical conduction system of the heart
Metabolic Absorption
- A function of the cell that allows all cells to take in and use nutrients and other substances from their surroundings
- Occurs in the intestine and renal tubules
Secretion
- A process by which substances are produced and discharged from a cell, gland or organ for a particular function in the organism or for excretion
- Certain cells can synthesize new substances from substances they absorb and then secrete the new substances to serve as needed elsewhere
- Ex) Hormone producing cells; Pancreas; Sex Organs; Pituitary Trophiv Hormones
Excretion
- All cells can rid themselves of waste products resulting from the metabolic breakdown of nutrients
- Lysosomes within cells contain enzymes that break down or digest large molecules, turning them into waste products that are released from the cell
- Occurs in the renal tubules
Respiration
- The process by which cells break down glucose to release the energy they contain in order to power other chemical processes
- Aerobic or Anaerobic
Cellular (Aerobic) Respiration/Oxidation
- The process that releases energy by breaking down glucose in the presence of oxygen, producing carbon dioxide, water and energy
- Occurs in mitochondria
Fermentation (Anaerobic) Respiration
- The chemical process by which molecules such as glucose are broken down without the presence of oxygen
- Regenerates NAD+ so glycolysis can continue
- Can lead to the build up of toxins due to lack of O2
Reproduction
- Process by which cells duplicate their contents and then divide to yield multiple cells with similar, if not duplicate contents
- Not all cells are capable of continuous division (Nerve, muscle, and retina cells can not regenerate)
- Tissue growth occurs as cells enlarge and divide themselves
- Even without growth, tissue maintenance requires that new cells be produced to replace cells that are lost normally through cellular death
Cell Cycle
G1, S, G2, M
Can last 12-24 hours
Mitosis
Cell division that results in two daughter cells that each have same number and kind of chromosomes as the parent
Prophase
first appearance of chromosomes
* Each chromosome has 2 identical halves called chromatids
Metaphase
Chromosome line up in the middle of the cell and chromosomes are arranged in an orderly fashion
Anaphase
Chromosomes pulled to opposite sides of the cell
Telophase
New nuclear membrane forms around each group of 46 chromosomes, forming 2 identical diploid daughter cells from the original cell
Communication
*The ability of the cell to receive, process and transmit signals with its environment and with itself
* Vital for cells to survive as a society of cells
* Allows for maintenance of a dynamic steady state —> homeostasis (Feedback loops)
Feedback Loope
a biological occurrence wherein the output of a system amplifies the system (positive) or inhibits the system (negative)
Plasma membrane
- A selectively permeable phospholipid bilayer forming the boundary of the cells
- functions include cell-to-cell recognition, cellular mobility and the maintenance of the cellular shape
Plasma Membrane (Structure Importance)
- Critical to normal function of the cell
- Important element in the hormone activity
- important element in pharma logic action
- Structure allows for selective transport of substances between cell and environment
- Allows for cell to cell recognition
- Promotes cell mobility
Plasma Membrane Structure
- Determined by the lipid bilayer
Plasma Membrane Lipids
- Include phospholipid, glycolipids, and cholesterol
- Maintain membrane integrity
- Each lipid molecule is said to be polar or amp hips this, which means that one part is hydrophobic & another part is hydrophilic
Plasma Membrane Proteins
- Membrane functions are determined largely by proteins
- Key components of energy transduction, converting chemical energy into electrical energy, or electrical energy into either mechanical energy or synthesis of ATP
- May float or become embedded
Plasma Membrane Proteins Functions
- Cell adhesion molecules (CAMs) or proteins that allow cells to hook together and form attachments of the cytoskeleton for maintaining cellular shape
Cell Adhesion Molecules (CAMs)
- Proteins found on surface of most cells that aid in binding the cell to the extra cellular matrix or to other cells
- Allow cells to hook together
Integral Membrane Protein
A protein embedded in the lipid bilayer of a cell. Typically cell surface receptors, channels, or pumps
Peripheral Membrane Protein
- A protein that is associated with the plasma membrane of a cell, but that is not embedded in the lipid bilayer
- Reside on the surface of the membrance
- Bound to integral protein
- Typically associate with embedded proteins through hydrogen bonding or electrostatic interactions
Plasma Membrane Fludity
- Affected by cholesterol content
- At low temperature= Gel like
- At high temperature = Liquid
Cells Link Together by
- Cell adhesion molecules in the cell’s plasma membrane
- The extra cellular matrix (Hells cells from and mesh)
- Specialized cell junctions
Cell Junctions
- Connections between cells rhat hold the cells together as a unit
- Contact points between the plasma membranes of tissue cells
- Allow small molecules to pass from cell to cell
Desmosomes
- Anchoring junctions that prevent cells from being pulled apart
- Hold cells together like a system of braces
Tight Junctions
- Membranes of neighboring cells are pressed together, preventing leakage of extracellular fluid
- Barriers to diffusion (Nephron)
GAP junctions
- Provide cytoplasmic channels between adjacent animal cells
- Allow small ions and molecules to pass directly from inside one cell to another
Nucleus
- Responsible for growth and reproduction
- The largest membrane-bound organelle
- Center of the cell
Nucleolus
- A small dense structure composed largely of RNA
- Found inside the nucleus and produces ribosomes
- Cell repository of RNA
- Most of the processing of RNA occurs here
Caveolae
- Cave like indentations in the plasma membrane
- Repository/storage site for receptors
- Route of cellular transport
- Initator of signals
Lysosomes
- Sac like structures that contain enzymes for digesting most cellular substances to their basic. form
- Cellular injury leads to the release of digestive enzymes (hydroplanes that cause cellular self-destruction
- A new function is signaling hubs of sophisticated network for cellular adaptation
- Protected from other cellular structures by membranes
