Studied by 8 peopleHow does water enter the cell membrane?
Some water molecules don’t need proteins to enter the cell but they may need help due to the huge amount of water trying to enter the cells
The water gets this help due to a specific type of transport protein known as aquaporin
What is the fluid mosaic model?
model used to describe a membrane’s structure(diverse protein molecules suspended in fluid phospholipid bilayer)
in other words it describes the fluidity of the cel membrane
What does the plasma membrane allow?
selective permeability(lets certain things in and out of the cell)
What molecules have an easier time going through the cell membrane?
Smaller not charged molecules easily travel through the membrane
Meanwhile, bigger,charged molecules have a hard time to pass through membrane and need special protein to pass through
What do transport molecules do?
allow specific ions/molecules to enter or exit the cell
What is a channel transport protein?
This protein is one that allows the solute molecule into the cell and requires no energy to do so as it is “down hill/going with the gradient”
What is an active transport protein?
This protein is one that allows solute molecules to enter the cell by going “uphill/against the gradient” by requiring energy (ATP)
What is an enzyme?
certain membrane proteins that carry out sequential reactions as well as modify one molecule through an interaction and create a new product
What are attachment proteins?
attach to the extracellular matrix and cytoskeleton
help support the membrane(attach from outer side of the membrane with the ECM to the inner side of the membrane with the cytoskeleton)
can coordinate external and internal changes
Receptor Proteins
signaling molecules bind to receptor proteins
these receptor proteins then relay the message by activating other molecules inside the cell
Junction Proteins
form intercellular junctions that attach adjacent cells
in other words they attach together to form tissue
Glycoprotein
serve as ID tags (recognize self from non-self)
may be recognize by membrane proteins of other cells
What is the overview of cell signaling?
Give an overview for signal transduction pathways.
What does the cell membrane of cells look like and what are the different parts that compose them?
What is the general term “transport” in cells mean?
allows passage of substances across cell membranes
What does passive transport generally mean?
Transporting molecules into the cell by going “with the gradient” and not using energy
What does active transport generally mean?
the use of transporting molecules out of the cell by going against the gradient and using energy
What are the gradients movement ways for active and passive transport?
Active: Low to High
Passive: High to Low
What are the different types of passive transport
Diffusion: molecules go from high to low concentration
Facilitated Diffusion: molecules go from high to low concentration with the help of certain proteins
Osmosis: diffusion of water from higher to lower concentrations across a selectively permeable membrane
What is diffusion and its goal?
tendency of particles to spread out evenly in an available space
its goal is to find equilibrium among the same type of molecules
Describe the U-tube experiment and what is signifies.
In this experiment the amount of solute is uneven on both sides of the tube as a membrane is permeable to water but not the solute
Due to this the water will cross the membrane and move down its own concentration gradient until the solute concentration on both sides is equal
What is tonicity?
term that describes the agility of a surrounding solution to cause a cell to gain or lose water in order to reach equilibrium
What is a hypertonic solution and what is its effect on cells?
causes cells to shrink and is a solution with high solute levels
What is a hypotonic solution and what is its effect on cells?
Plant cells= Turgid(normal)
Animal Cells=swelling till burst
Solution with low solute levels
What is an isotonic solution and what is its effect on cells?
animal cells=normal
plant cells=flaccid
solution with equal solute levels
What types of substances early diffuse across a cell membrane?
hydrophobic/nonpolar
What types of substances need help moving across membranes?
hydrophillic/polar substances need help moving across the membrane with specific transport proteins
this is known as facilitated diffusion
What is the general rule of thumb for transport proteins?
greater the number of transport proteins for a particular solute in a membrane, the faster the solute’s rate of diffusion
What is the importance of aquaporin?
allows for the rapid diffusion of water into and out of certain cells as it is a channel protein
What happens in active transport?
a cell must expend ATP energy to move solutes against concentration gradient
What are the two mechanisms to move large molecules across membranes?
Exocytosis
Endocytosis
What is exocytosis?
used to export bulky molecules such as proteins or polysaccharides
What is endocytosis?
used to take in large molecules
What happens in both endocytosis and exocytosis?
material is transported after it is packaged within a vesicle that fuses with the membrane
What are the three kinds of endocytosis?
Phagocytosis
Receptor-mediated endocytosis
Pinocytosis
Phagocytosis
engulfment of a food practice by the cell wrapping cell membrane around it and forming a vacuole
Receptor-mediated endocytosis
uses membrane receptors for specific solutes
Pinocytosis
engulfment of small particles suspended in extracellular fluid
Energy
Ability to do work
Kinetic Energy
Energy of motion
What does kinetic energy require?
Requires ATP via cellular respiration made via mitochondria
What are the two forms of kinetic energy?
thermal(heat) energy and light energy
What is potential energy?
Energy stored in the location or structure of matter
Chemical Energy
Type of potential energy that is available for release in a chemical reaction
What is an example of chemical energy?
The process of breaking down glucose to make ATP via cellular respiration
What can light be used to do?
Harness the power of photosynthesis
What is thermodynamics?
Study of energy transformations
What is system in terms of thermodynamics?
Matter under study
What is surroundings in terms of thermodynamics?
Everything outside of the study
What is a closed system?
Isolated from its surroundings like a liquid in a thermos
What is an open system?
Energy and matter can be transferred between system and surroundings
What type of system are organisms?
Open systems since they absorb light in organic molecules and release heat and metabolic waste
What is the first law of thermodynamics?
states that energy can be transferred and transformed, in other words “Energy is neither created nor destroyed”
What is the second law of thermodynamics?
states that every energy transformation must make the universe more disordered or entropy (quantity used as a measure of disorder, or randomness)
What is an exergonic reaction?
Releases energy
Exergonic Reactions
Huge amount of reactions into small amount of products with a side product of ATP
What are examples of exergonic reactions?
Hydrolysis(breaks down polymers to monomers and release energy) and Cellular Respiration
What are endergonic reactions ?
require energy and yield products rich in potential energy
What is an example of an endergonic reaction?
Photosynthesis
What does motabolism do?
encompasses all of a cell’s chemical reactions- a mix of both exergonic and endergonic.
How does ATP power cellular work?
transfer of a phosphate group from ATP forming ADP and P is involved in chemical, transport, and mechanical work
How exactly does the hydrolysis process work?
The process breaks down the bond between the second and third phosphates and releases energy therefore it is exergonic/ endergonic
What are the three kinds of work does a cell do?
1)Chemical: driving endergonic reactions such as the synthesis of polymers from monomers.
Transport: pumping substances across membranes against the direction of spontaneous movement
Mechanical: beating of cilia, contraction of muscle cells, and movement of chromosomes
What is dephosphorelation and phosphorylation?
Removing phosphate and adding phosphate
Describe the ATP to ADP+P cycle
What are enzymes?
protein catalysts that decrease the activation energy needed to begin a reaction
What must a substrate do?
Fit specifically into an enzyme’s active site
What is activation energy?
amount of energy necessary to push the reactants over an energy barrier
What is the transition state
summit the molecules are at an unstable point
What is delta G?
The difference between free energy of the products and the free energy of the reactants
How do enzymes work?
Speed reactions by lowering activation energy and can be reached even at moderate temperatures
Describe the catalactic cycle of an enzyme
What is a competitive inhibitor?
competes with the substrate for the active site.
What is a non competitive inhibitor?
alters an enzyme’s function by changing its shape
What is feedback inhibition?
helps regulate metabolism
Product of reaction is the inhibitor
What are some uses for enzyme inhibitors?
Enzyme inhibitors have also been developed as
pesticides, deadly poisons for chemical warfare, and Beneficiary drugs
What are cofactors?
non protein helpers for catalytic activities
They may be organic or inorganic
They bind to the enzyme permanently or reversibly
Some inorganic cofactors include zinc, iron, and copper
What are coenzymes?
Are organic cofactors that include vitamins or molecules derived from vitamins
Note
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