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This molecule is on the surface or within a cell that recognizes and binds with specific molecules, producing an effect in the cell.
What is a ligand?
It is a molecule that travels through the protein channel into the cell that lands on an intracellular receptor OR onto a membrane's protein receptor
What is a gated channel?
These channels may or may not open to their specific ions as a result of changes in channel shape
This is a membrane protein that use a source of free energy such as ATP or light to drive transport of ions or molecules. It is an example of active transport.
What kind of active transport is symport? What does it do?
- Secondary active transport: it uses a downhill movement of one particle to transport another particle against its concentration gradient.]
What is secondary or indirect active transport?
It uses the downhill flow of an ion to pump some other molecule or ion against its gradient.
What kind of transport are antiports? what does it do?
- secondary active transport: it moves 2 or more different particles across the cellular membrane in opposite directions. It moves one particle down its concentration gradient and uses the energy generated from that process to move another particle up its concetration gradient.
This part of the cell memrane can be found on bacterium. It is on the surface which helps molecules to contribute to cell-cell recognition, commnication, and intracellular adhesion.
This type of cell junction is tightly stiched seams between cells. It comletely encircles each cell, preventing movement of material between the cell.
This type of cell junction have protein attachments between adjacent cells. Inside the plasma membrane, it bears a disk-shaped structure from which protein fibers extend into the cytoplasm.
What is the benefit of desmosomes and where can they be found?
they weld together tissues that undergo considerable stress. they can be found on the skin and heart muscle.
This type of cell junction are narrow tunnels between cells that consist of proteins called connexons. It allows only the passage of ions and small molecules.
Other than allowing small ions to pass through, what else do gap junctions allow?
Allows communication between cells through the exchange of materials or the ransmission of eletrical impulses
a, b, c?
- a) desmosome
- b) tight junction
- c) gap juntion
What six things influence RATE of diffusion?
- 1. concetration gradient
- 2. size of molecules involved (mass)
- 3. distance the molecule has to travel
- 4. Temperature
- 5. solubility of the molecule
- 6. surface area of the membrane over which the molecule can work
What is facilitated diffusion? (3 parts)
- 1. it is a type of passive transport
- 2. it is dependent on single transport protein carries
- 3. the solutes move from regions of higher to lower concentration
What is the difference between normal diffusion and facilitated diffusion?F
- - Facilitated diffusion is when polar or charged molecules cross the cell membrane through a transmembrane channel protein
- - Regular diffuson is when small, non-polar molecules cross the cell membrane directly through the lipid bilayer.
What is crenation?
It is the shrinkage of a cell that occurs when a cell is placed in a concentrated salt solution (hypertonic)
This type of transport is an active process in which materials move in and out of the cell enclosed as vesicles, formed from the cell membrane or fused with it. What is it also known as?
Vesicular transport, also known as BULK TRANSPORT, which move proteins, polysacch, and maromolecules
This is a type of active bulk transport, where materials are exported out of the cell via secretory vesicles. What organelle use this trnansport? What is primary function?
Exocytosis: done in the golgi and is important in expulsion of waste materials and secretion of enzymes and hormones.
What is endocytosis and what are its 3 parts?
- Bulk transport that uses ATP:
- 1. phagocytosis
- 2. pinocytosis
- 3. receptor-mediated endocytosis
What is transepithelial transport?
it occurs through or across an epithelium
How can channels be "gated?"
though ligands, voltage and mechanical
What kind of transport are carriers?
A facilitated, passive type of transport. the rate decreases as concentration gradient goes down.
What are the 3 types of passive transport?
- 1. diffusion: going from high -> low concentration
- 2. facilitated diffusion
- 3. osmosis
What is primary active transport?
Uses a membrane channel that acts as a pump by using ATP.
What is secondary active transport?
Secondary active transport, is transport of molecules across the cell membrane utilizing energy in other forms than ATP. This energy comes from the electrochemical gradient created by pumping ions out of the cell. This Co-Transport can be either via antiport or symport.
Cells that are electrically connected together use what kind of cell junction? (tight, gap, desmosomes)
True or False: Exogenous ligands are made inside the body
False: Endogenous ligands are made inside the body
What is the type of transport called that takes molecules, like sugar from food in our small intestine into capillaries?
What kind of transport does transepthelial xport use? How is glucose transferred? which parts need energy and don't need energy?
- secondary active transport: glucose will be brought in through symports with sodium
- - sodium is pumpe out of the cell using ATP through primary AT.
- - once the glucose enters the epithelial cell initially from the small intesetine, it is transferred out the other side of the cell using facilitated diffusion.
- - no energy is required here because the concentration gradient of glucose is higher outside the cell.
This is called a "programmed" cell death. Why is it important?
Apotosis: important so a cell's digestive enzymes do not attack other healthy cells
T or F: Cilia increases surface area for absorption and move to push up mucus
False: cilia are motile to push up mucus.
Where can stereocilia be found?
reprodutive tract and inner ear
What is the name of the protein that pull on the microfilaments on the clia to make it sway back and forth?
Where in the cell does glycolysis occur? Does it require oxygen?
In the cytosol, no O2 required
What are the products of glycolysis?
2 pyruvate (3-carbon), 2 net ATP, and 2 NADH
What happens if cellular respiration ends right after glycolysis? what is another result if it ended with other organisms?
Anaerobic respiration: a build up of lactic acid occurs. In other organisms, ethanol is made instead of lactic acid.
What are the products from 1 kreb cycle turn? How many CO2s are made after 2 spins?
- 3 NADH, 1 FADH, ATP, 2CO2.
- 6 CO2s: 2 to make acetylCoA and 4 during kreb cycle products.
Why is oxygen essential to cellular respiration? What end product is it made into?
It is the electron acceptor for the hydrogen ions when it comes back into the membrane. It becomes H2O.
What is glulconeogenesis?
When the body makes its own new glucose
What is the structure of plasma membranes?
- Plasma membranes have a bilayer phosphilipid:
- a polar head and two nonpolar fatty acid chain tails.
What is the importance of phosphilpids in a water environment for plasma cell membranes?
- The polar ends of a phospholipid is hydrophilic, meaning itt can interact with water molecules.
- The hydrophobic FA tails will not mix ith water.
What is the importance of cholesterol in plasma membranes?
It contributes to both fluidity and stability of the membrane. Tucked between the phospholipid molecules, they prevent the fatty acid chains from packing together and crystallizing.
What are peripheral proteins?
Polar molecule proteins that do not penetrate the membrane, they stud only the oute or more commonly the inner surface.
What are integral proteins? What are they also called?
- Proteins embedded in the lipid bilayer, with most extending through the entire thickness of the membrane.
- Also called transmembrane proteins.