A&P 1 Chapter 3 [Part1] (Lecture) [The Cell, Part 1] Flashcards
*6 Types of Membrane Proteins
1) Anchoring 2) Recognition 3) Enzymes 4) Receptor 5) Carrier 6) Channels
*Anchoring Proteins
Attachment (adhesion) Membrane to cytoskeleton Membrane to glycocalyx Two cell membranes to each other
*Recognition Proteins
Identification Allow immune system to identify self (friend) from nonself (foe)
*Enzymes
Integral or Peripheral Brush border -Lactase -Sucrase -Maltase -Peptidases
*Receptor Proteins
Communication Bind to specific substances/substrates Hormone receptors Neurotransmitter receptor (Ligand binds with receptor proteins)
*Carrier Proteins
Transport Amino Acid Carriers Glucose carriers
*Channels
Allow/disallow passage of ions, other substances Na+ channels K+ channels Ca2+ Channels Aquaporins (water channels) [recently discovered]
Functions of the Plasma Membrane
1) Physical isolation 2) Exchange regulation 3) Environmental sensitivity 4) Structural support
Physical Isolation
“Barrier” between extracellular fluid and interstitial fluid Interstitial fluid is also known as the cytoplasm
Exchange Regulation
Controls what enters and exits the cells Selectively permeable
Environmental Sensitivity
Detects what chemicals are present in the ECF (Extracellular Fluid) Ex: Amino Acids, Carbohydrates, Hormones, & Neurotransmitters
Structural Support
Attached to structures on inside and outside of cell Inside: Cytoskeleton Outside: Glycocalex
*Components of the Plasma Membrane
Phospholipid bi-layer (Phospholipids & Cholesterol) Proteins (Integral & Peripheral) Glycolic Substances (Glycoproteins & Glycolipids)
*Cholesterol
Stiffness and support
*Diffusion
Movement of solutes from an area of high concentration to an area of low concentration. (Down the concentration gradient) Faster: Distance is shorter, Molecule size is smaller, Temp is higher, & Gradient size is larger Simple Diffusion: Lipid soluble materials, NO transport proteins Facilitated Diffusion: Small, water-soluble protein; Transport protein needed
*Facilitated Diffusion
Channels -ions Carriers -Amino Acid -Monosaccharides
*Osmosis
Movement of water (solvent) across a semi-permeable membrane. Water follows solute. Between phospholipids (Slower); Through aquaporins (faster)
Osmotic Pressure
Force of water moving through semi-permeable membrane. Hydrostatic pressure: force of fluid against the membrane.
*Osmolarity v. Tonicity
Osmolarity: Total amount of solute present in a solution. How much “stuff” is in the water. Tinicity: Effect of a solution on the movement of water. Where the “stuff” makes the water go.
*Lysis
When a cell bursts
*Crenation
When a cell shrivels
*Isotonic
An isotonic solution has the same solute concentration as the cytosol. There is no concentration gradient to drive osmosis, so there is no net movement of water into or out of a cell in an isotonic solution. (CELLS STAY THE SAME)
*Hypotonic
A hypotonic solution has a lower solute concentration than the cytosol. A cell placed in a hypotonic solution will gain water by osmosis and may swell and burst. (CELLS SWELL)
*Hypertonic
A hypertonic solution has a higher solute concentration than the cytosol. A cell in a hypertonic environment will lose water by osmosis and shrivel or CRENATE, because water will be drawn toward the more concentrated solution. (CELLS SHRINK)
*Cytoskeleton
Network of fibers throughout cytoplasm.
Smallest to Largest:
- Microfilaments
- Intermediate Filaments
- Microtubules
*Microtubules
- Thickest cytoskeletal layer
- Hollow rods made of protein
- Functions
- Structural support
- Anchor organelles
- Organelle rail system
- Organelle component
- Centrioles
- Cilia
- Spindle apparatus
- Structural support
*Centrosomes
Microtubule organizing system.
Home to centrioles
*Centrioles
- Composed of nine microtubule triplets
- Function
- Involved in formation of spindle apparatus
- If cell lacks centrioles, it cannot replicate
*Microfilaments
- Thinnest cytoskeletal fiber
- Solid rods made of two twisted strands of actin molecules
- Functions
- Mechanical strength
- Cell Shape Change
- Pseudophobia
- Muscle cell contraction
- Interact with thick (myosin) filaments
- Connect
- Plasma membrane to cytoskeleton
- *Cell to cell
- *Organelle component
- Microvilli
- Terminal Web
*Microvilli
- Short extensions of plasma membrane
- Increase surface area for absorption
- Stiffened and anchored by microfilaments to terminal web of skeleton
*Terminal Web
- Membrane skeleton
- Layer of microfilaments beneath exposed surface of cells that form linings
- Intestinal lining
- Skin
- Provides support
*Intermediate Filaments
- Medium-sized syroskeleton fiber
- Tightly coiled filaments made of keratin-like proteins
- Functions
- Strength & shape
- Stabilizes organelle position
- Stabilizes cell position
*Nonmembranous Organelles
- Cytoskeleton
- Microvilli
- Centrioles
- Cilia
- Ribosomes
- Proteasomes
*Membranous Organelles
- Endoplasmic Reticulum
- Golgi Apparatus
- Lysosomes
- Peroxisomes
- Mitchondria
- Nucleus
*Ribosomes
- Two subunits
- Large (S70)
- Small (S30)
- Each subunit
- Ribosomal Protein
- Ribosomal RNA
- Function
- Protein synthesis
*Proteasomes
- Barrell-shaped complexes
- Found in cytoplasm and nucleus
- Function
- Breaks down unneeded proteins
*Endoplasmic Reticulum (ER)
- Network of membranous tubules and sacs (cisternae)
- Rough ER
- Has ribosomes embedded
- Smooth ER
- No ribosomes
*Smooth Endoplasmic Reticulum
Functions:
- Synthesis
- Membrane lipids
- Phospholipids
- Cholesterol
- Steroid hormones
- Membrane lipids
- Synthesis & Storage
- Glycerides
- Fat Cells
- Liver Cells
- Glycogen
- Muscle Cells
- Liver Cells
- Glycerides
*Rough Endoplasmic Reticulum
Functions:
- Assists ribosomes in protein and glycoprotein synthesis
- Proteins enter RER
- Assume secondary and tertiary structure
- Packaged for transport vessicles and sent to the golgi apparatus for further processing
*Golgi Apparatus
- Structure:
- Stacks of flattened membranes (cisternae) containing chambers.
- Function:
- Storage, alteration, and packaging of synthesized products
*Lysosomes
- Digestion and recycling of membranous vesicles and organelles
- Digestion of materials
- Autolysis (digests cell)
*Peroxisomes
- Vesicles containing several enzymes (including peroxidase)
- Breaks down toxic substances and long fatty acid chains
- Found in all cells
- Especially in liver and kidney cells
*Mitochondrion
- Power house of the cell
- Produces ATP through cellular respiration
- Outer membrane
- Intermembrane space
- Inner membrane
- cristae
- Matrix
*Cilia
- Long, slender extensions of the cell membrane
- Function
- Move materials across surface of the cell
- Composed of nine microtuble pairs surrounding a central pair (9+2)
- Basal body
- Anchor for the cilia beneath cell membranes
*Passive Transport
No energy needed. Goes with the concentration gradient.
- Simple Diffusion
- Facilitated Diffusion (Carrier-mediated transport)
- Osmosis
*Active Transport
Energy needed. Goes against concentration gradient.
- Primary Active (Carrier-mediated transport)
- Secondary Active (Carrier-mediated transport)
- Vesicular
*Carrier-mediated transport
Uses a protein (carrier or channel)
- Facilitated Diffusion
- Primary Active Transport
- Secondary Active Transport
*Facilitated Diffusion
(Passive). Goes with concentration gradient
*Primary Active Transport
Goes against the concentration gradient
*Secondary Active Transport
One way is with the concentration gradient and the other way is against the concentration gradient.
*Vesicular Transport
Vesicles (transport trucks) (Endocytosis & Exocytosis)
- Endocytosis
- Pinocytosis- drinking
- Phagocytosis- eating
- Receptor-Mediated Endocytosis- receptor proteins (ligands)
