Exam 2 Flashcards
What is Osmosis?
The movement of water from a region of lower solute to a region of higher solute.
Ex: egg in vinegar
What is passive transport?
Transport across the membrane that does not require energy
What is a hypotonic solution?
A solution with fewer solutes than the cell. Water rushes in. Cell may burst
What is isotonic solution?
A solution that has the same concentration of particles as the cell.
What is a hypertonic solution?
A solution with greater solutes than a cell. Water rushes out. Cell shrivels up.
What are plant cells and why?
Hypertonic because of their membrane
What is turgor pressure and name an example.
Water entering the cell creates a pressure on the inside of the cell.
Ex: Venus Fly Trap
What are aquaporins?
Channels that allow water to pass through the membrane
What is important to remember about channels?
They are selective due to the carboxyl groups and nitrogen’s at the pores
What is conductance?
The rapid movement of ions across a membrane
What happens when charged ions cross the membrane?
An electrical current forms (Conductance)
What is the Voltage- Gated Channel?
Confirmation depends on differences in ion concentrations on the 2 side of the membrane
ex: potassium channel
What is the Ligand-Gated Channel?
Conformation depending on binding of a specific factor that induces opening
Ex: GABA receptor
What is Mechano- gated Channels?
Stretching or tension lead to opening
ex: hair cell of the ear
What is Light- gated Channels?
Light opens the channel
ex:
What is a light microscope?
Standard microscope, utilizes full spectrum visible “White Light”
There is a light source at bottom
How can you optimize images with a light microscope?
By filtering wavelengths of light
What is florescent microscopy?
Uses higher energy light to visualize samples
What is laser microscopy?
Type of microscopy where the whole sample is illuminated, but the light can be manipulated to only a portion of the sample to get rid of depth of field. Several pictures are taken at different parts of the sample where light is illuminated.
What types of microscopy fall under laser microscopy?
Confocal
Two Photon
Light Sheet
What is different about two photon microscopy?
Two light sources are used to get the electron to jump to the next level
What is special about light sheet microscopy?
Used to watch cells inside an embryo grow and divide into the organism
What is super resolution used for?
Cleans out all the light that is not in focus to see very, very clear images
What is the transmission electron microcopy and what can you see with it.
Type of microscopy used to look at organelles within a cell ex: tissue sections. Requires labeling with metals like osmium
What is the scanning electron microscope and what can you see with it?
Used to look at the outer surface of the organism
ex: insect eye, T4 Phage
What is the atomic force microscope and what can be seen with it?
Used to see bonds between two molecules. Insane magnification
What is cytology?
Study of organelles, structure, and how they interact
What does “Cells are not isolated Entities” mean?
Cell are packed in together, held together, communicating
What is the epidermis in skin cells?
Epithelial Cells
What is the dermis of skin cells?
Connective Tissue
What is the glycocalyx?
Outside of the membrane, made up of glycoproteins and glycolipids
Why are glycoproteins important?
They act as cell signaling
What is the extracellular matrix?
An organized network of material, that are present outside, but in the immediate proximity to the plasma membrane
What is the purpose of the extracellular matrix?
- Hold cells together
- Regulates the function and survivability of cells
- Provides chemical and physical signals for the cell through direct interactions with integral membrane proteins
What is the basement membrane?
The 2nd part of the ECM
Surrounds some cells
Not everywhere in the body but mainly in neurons, muscles, and fats
How does the basement membrane function in epithelial cells?
It acts as a barrier to keep liquids in the cells
What is collagen?
- A glycoprotein found only in the ECM
- Most abundant protein in human tissue
- Highly stable (ex: found in dinosaurs)
- Consists of 3 polypeptide chains in a triple helix
- 27 distinct types of collagen
What is Type I Collagen?
Osteogenisis Imperfecta (happens when collagen is taken away) bone become highly brittle
What is Type II Collagen?
Dwarfism, Ehlers- Danlow Syndrome, fibrous of the liver or lung (happens when collagen is taken away)
What is Type IV Collagen?
Alport syndrome (Kidney disease of the basement membrane?
What is Fibronectin?
Molecule made up of several protein domains used for protein binding
Glycoprotein in the ECM. Binds to integrin
What is the function of Fibronectin?
Located in the basement membranes of various tissues and provides a selective path for migration. Important in cell differentiation, cell adhesion, growth, and migration
ex: neural crest pathway
What is Laminin?
Major constituent of the basement membrane
Laminin lost= lost of fetus (very important)
Important in muscle development– could cause Muscular Dystrophy
ECM Dynamics
- can be stressed under tension
- constantly being remodeled
What is Integrin?
Proteins that function to integrate the ECM with the intracellular environment
How does Integrin work?
The heterodimer identity determine the ECM component that it binds to
What are homodimers?
Two identical polypeptide chains coming together
What is Talin?
Changes cytoplasmic tail spacing thus opening the proper binding sites up
What is inappropriate clotting?
Thrombosis
What is Outside- In signaling?
ECM binding leads to receptor clustering
ex: cytoskeleton can form (signaling scaffold)
How can Outside- In signaling affect cells?
Can alter cell shape directly or lead to changes at the transcriptional level
How do we study ECM interactions?
In vitro
What is the focal adhesion complex?
Reorganization of the cytoskeleton to from a different structure (More so In Vitro)
Which 4 proteins are involved in cell-cell interactions and cell adhesion?
Integrins
Selectins
Immunoglobulin
Cadherins
What are Selectins?
Glycoproteins
Require calcium to properly function
Roles of Selectins.
Mediate cell capture in the blood vessel (COME BACK)
The Immunoglobulin Superfamily
Calcium independent cell adhesion
Cadherins
- Calcium dependent glycoproteins
- Homphillic interactions bring cells together during development
Types of Cadherins
come back
What are tight junctions?
Junctions used in cells to keep stuff separated
ex: intestinal bacteria, epithelial cells
What are gap junctions?
Direct cytoplasm connection between cells mediated by connexions (cytoplasmic flow between two cells)
ex: heart cells
What is the central dogma?
DNA —> mRNA—-> protein
What happens in the bio synthetic pathway?
- Proteins are translated by the ribosome in the endoplasmic reticulum
- They are folded, processed, and packaged for transport
- Packaged proteins are moved to the Golgi Apparatus where they are further modified ex: glycosylation
- Proteins are then packaged further and sent to various destinations in the cell
What is the secretory pathway?
Proteins are packaged in the golgi apparatus and sent into the extracellular matrix
What is consecutive secretion?
Vesicles are transported and secreted in a continual manner
What is regulated secretion?
Vesicles are made and destroyed, they are released upon the appropriate stimuli
What are secretory granules?
Large densely packed vesicles that are stored by the plasma membrane and await release
What is a mutation and what is it used for?
Mutations are used to “break the cell”. It is a change at the DNA level that alters protein functions or possibly eliminates function
What is RNAi and what it is used for?
Used to “break cells”. They work by inhibiting the translation of RNA by strericly hindering translation or degrading RNA
What does the endoplasmic reticulum do?
It is a network of highly dynamic membranes that fill much of the cytoplasm in a cell
What does the smooth ER do?
- Synthesizes steroid hormones
2. Detoxifies liver
What does the rough ER do?
A protein synthesizer. 1/3 of proteins synthesized on the ER.
Who won the 1999 Nobel Prize for developing and proving the signal hypothesis?
Gunter Blobel
What are signal peptides?
They tell the proteins where they are suppose to end up
Where are signal peptides?
Encoded in the protein
What is glycosylation?
Glycotransferases are enzymes added to proteins so the protein can leave the ER
What is the Unfolded Protein Response?
Misfolded or improperly glycosylated proteins are ejected from the ER.. Degraded by a molecular machine called the proteosome
Who discovered the Golgi Apparatus?
Camillo Golgi, he won the nobel prize in 1906 in his kitchen laboratory
What is the Cis Golgi?
Sort whether a protein need to go back to the ER or proceed through the Golgi
What is the trans golgi network?
The sorting station that puts proteins in vesicles and ships them to their proper location
What does the golgi matrix do?
Disassembles are reassembles the golgi during cell division
What are COPII vesicles?
Coated vesicles that move from the ER to the TGN
What are Clathrin - Coated Vesicles?
Move materials from the TGN to the lysosome, endosome, or plant vacuole
What are the characteristics of lysosomes?
- Only in animal cells
- Functions as the digestive organelle
- Enzymes inside the lysosome that keep the pH low,
What is autophagy?
Catabolic mechanism that involves cell degradation of nonfunctional or un-needed cellular components
- the regulated destruction of a cells organelles by lysosomes
How does autophagy work?
- The organelles is surrounded by a double membrane to make a vesicle called the autophagosome
- Come back
What does the vacuole do?
- Storage of macromolecules
- Storage of toxins/waste
- Similar to lysosomes, has ATPase
