Lecture Anatomy 2 Flashcards
Robert Hooke
- The father of microscopy
- Coined term “cell” to describe the basic unit of life
Mattias schleiden and Theodore schwann
- All living things are composed of one or more cells
Hierarchy of life
- Tracing life down to the chemical level: the hierarchy of biological organization
- Ecosystem -> community -> population -> organism -> organ system -> organ -> tissue -> cell -> molecule -> atom
- Morphology of cells
o Different Sizes and shapes of cells
o Different function
o Structure determines function
- Cells differ in
o Ability to move
o Internal organization (prokaryotic versus eukaryotic (function)
o Metabolic activities (chemical reaction)
- Cells share
o Certain structural features and carry out many complicated process in basically the same way
Are the following organic molecules alive?
- Proteins, carbohydrates, lipids, and nucleic acids
o No
Cell theory
- All organisms are composed of cells and cell products
- All cells come from Previously existing cells
o Parent cell to two daughter cells (identical)
All organisms are composed of?
- Cells and cell products
Are all of the cells within an organism the same?
- No
How many distinct cell types make up the human body?
- 210
Life begins with?
- Cells
- Each cell performs all the functions necessary to sustain life
We all developed from?
- A single-celled human zygote formed by fertilization
o Smaller than a period found in your text books
- Zygote
o Eukaryotic cell formed by a fertilization event between two gametes
- Zygote develops into?
o A full blown organism with 100 trillion cells organized into complex tissues and organs
Two major categories of cells
- Prokaryotic cells and eukaryotic cells
- Difference between prokaryotic and eukaryotic cells
o Prokaryotic has no nucleus and eukaryotic has
o Prokaryotic cells:
only domains: bacteria and archea
Lacking nucleus
Simple cells
o Eukaryotic cells:
plant and animal kingdoms, including the fungi (multicellular molds and unicellular yeast
Have nucleus
What type of cells do humans have?
- Eukaryotic multicellular cells
Different cell size?
- Different function
- Complexity of what they do
Prokaryotic cells
- Consist of a single enclosed compartment that is surrounded by a plasma membrane
- Lacks a defined nucleus
- Dna is located where in prokaryotic cells?
o Nucleoid region
- What is the most numerous prokaryotes?
o Bacteria
- Bacteria
o Don’t have membrane bound compartments
o Have many proteins that are precisely localized in their aqueous interior or cytosol
- Cytosol
o The fluid in which organelles of the cell resides
Eukaryotic cells
- Contain a defined membrane-bound nucleus that is absent in prokaryotes
- Nucleus segregates the cellular DNA for the rest of the cell
Eukaryotic organisms Can be unicellular or multicellular
- Nucleus
o Command center of cell
o Contains genetic materials (RNA and DNA)
Three main parts of cells
- Plasma membrane
- The cytoplasm
- The nucleus
Plasma membrane
- Defines the extent of cell
o Inside – intracellular
o Outside – extracellular
o Interstitial fluid between cells - Separates the living cell from its nonliving surrounding
- Thing/flexible layer that separates the intracellular and extracellular compartments
What forms the plasma membrane?
- Molecule called phospholipids
- Phospholipid bilayers
- Hydrophilic head (outside cell)
- Hydrophobic tail (inside cell)
Phospholipids
- 2 fatty acid chains (tail = non polar or hydrophobic)
- A phosphate group (head = polar or hydrophilic)
Membranes consists of?
- Proteins embedded in the phospholipid bilayer
- Proteins make up 50% of membrane mass
- A fluid mosaic of lipids and proteins
Fluid mosaic
- Membrane phospholipids and proteins can drift about in the plane of the membrane
“fluid”
- Molecules can move freely within the membrane
“mosaic”
- A diversity of proteins exists within the membrane
Proteins found in plasma membrane
- Integral membrane proteins – firmly embedded
- Peripheral membrane proteins – loosely associated/not embedded
Integral membrane proteins
- Transmembrane
- Span entire width of membrane and contain both hydrophilic and hydrophobic regions
Peripheral membrane proteins
- Don’t span entire membrane
- Loosely associated with other proteins or lipid molecules
Functions of membrane
- Anchors the cells to form a common function
- Selective permeability
o Allow some substances to cross more easily than others (size or charge)
o Block passage of some substances altogether - Provides barrier against substances outside the cell
- Some act as receptor for cellular communication
- Transport
- Intercellular joining
Diffusion
- Movement of molecules from higher concentration to lower concentrating across membrane
- Tend to spread into available space
- Passive transport; no energy is needed
Facilitated diffusion
- Transport of some substances by specific transport proteins that act as selective corridors
- Traffic of some substances can only occur through transport proteins
- Glucose- require transport protein
- Passive transport
Osmosis
- (diffusion) Passive transport of water across a selectively permeable membrane from higher concentration to lower concentration
Survival of the cell depends on?
- Ability to balance water uptake and loss
Solution
- Solute and solvent
- Solute – gets dissolved
- Solvent – water does the dissolving
Isotonic solution
- Equal concentration of ions in solution and cell
Hypertonic solution
- Higher concentration of ions in solution than in cell
Hypotonic solution
- Lower concentration of ions in solution than in cell
Osmoregulation
- Control of water balance animals
Endocytosis
- Mechanism by which particles enter cells
3 forms of endocytosis
- Phagocytosis
- Pinocytosis
- Receptor-mediated endocytosis
Phagocytosis
- “cellular eating”
- Cell engulfs a particle and packages it within a food vacuole
- Most wbc
Pinocytosis
- “cellular drinking”
- Primarily used for absorption of extracellular fluids (ECF)
- Contrast to phagocytosis
o Generates very small vesicles
o Unspecific in the substances that it transports
- Receptor-mediated endocytosis
o Triggered by the binding of external molecules to membrane proteins
o Upon membrane proteins binding to certain molecules – membrane forms coted pit then pinch off to become coated vesicle (Low density lipoproteins or viruses
Exocytosis
- Mechanism that move substances (enclosed in a vesicle) out of the cell
- Vesicle migrates to plasma membrane
- Proteins from vesicle bind with membrane proteins
- Lipid layers from both membrane fuse
- Vesicle releases contents to outside of cells
Cytoplasm
- Cell-forming material
- Part of cell that lies internal to the plasma membrane and external to the nucleus
3 major elements that make up the cytoplasm
- Cytosol
- Organelles
- Inclusions
Cytosol
- Jelly-like, fluid-containing substance within the cell
- Consists of water, ions, and enzymes
- Makes up half of the volume of the cytoplasm
- Fluid In which other cytoplasmic elements are suspended
Cytoplasm contains nine types of organelles
- Mitochondria
- Ribosomes
- Lysosomes
- Cytoskeleton
- Centrioles
- Golgi apparatus
- Rough and smooth er
- Peroxisomes
Ribosomes
- Constructed of proteins and ribosome RNA
- Site of protein synthesis
- Composed of two subunits (60s and 40s) that fit together to form a functional ribosome
Type of ribosomes found in the cell:
- Free ribosomes
- Attached ribosomes
Free ribosomes
- Float in cytosol
- Make soluble proteins (function in cytosol)
Attached ribosomes
- Attached to rough ER and make membrane proteins or exported proteins
Ribosomes build all the cell’s proteins though a process
called?
- ???
- Translation
Antibiotics target the process of the?
- Ribosomes
Endoplasmic reticulum (ER)
- Network within the cytoplasm
- Extensive system of membrane-walled envelopes and tubes
Two distinct type of ER
- Rough ER
- Smooth ER
Rough ER
- Ribosomes stud the external surfaces
- Envelope stacks called cisternae
- Makes all membrane proteins and membrane
Smooth ER
- Consists of tubules in a branching network
- No ribosomes are attached
- No protein synthesis
- Store Ca(2+)
- Makes enzymes for lipid metabolism
- Including steroids
After the rough ER synthesizes a molecule it?
- Packages the molecule into transport vesicles
Golgi apparatus
- Packaging and shipping center
- Stack of 3 – 10 disk shaped membrane bound envelopes (cisternae)
- Works in partnership with ER; sorts products of rough ER at the cis end and sends them to proper destination from the trans end
Mitochondria
- Power plant of the cell
- Generates most of the cell’s energy (AT) via cellular respiration
- Enclosed by a double membrane: the inner membrane folds in forming shelf-like cristae
- Contains own DNA (maternal DNA)
Lysosome
- spherical membranous bags containing digestive enzymes, “demolition crew” that break down macromolecules