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Membranes are a fluid mosaic of __________ and ___________
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Membranes are a ________ _________ of phospholipids and proteins.
fluid mosaic
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What is it called a fluid mosaic?
- mosaic b/c there are proteins embedded in the phospholipids
- - fluid because the proteins can move around in the phospholipids
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Many phospholipids are made from _______ ________ _______ that have kinks in their tail
unsaturated fatty acids
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The kinking from unsaturated fatty acids prevents:
the phospholipids from packing too tightly together, keeping the membrane fluid.
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In animal cells, ______ is also wedged into the bilayer to help keep it liquid at lower temperatures.
cholesterol
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Some _________ in the membrane serve as identification tags that are specifically recognized by membrane proteins of other cell
glycoproteins
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- cell-cell recognition enables cells of the ________ _________ to recognize and reject foreign cells, such as infectious bacteria
immune system
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Biological membranes exhibit __________ _______: property that allows some substances to cross more easily than others.
selective permeability
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Two types of molecules in selective permeability:
- - Nonpolar molecules (carbon dioxide and oxygen) cross easily.
- - Polar molecules (glucose and other sugars) do not cross easily
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Transport across a membrane can be _______or ______
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Passive transport does not require:
energy; solutes move with concentration gradient
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Active transport requires:
energy; solutes move against concentration gradient.
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_______ is the process in which particles spread out evenly in an available space
Diffusion
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What is Diffusion?
Diffusion is the process in which particles spread out evenly in an available space
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Particles diffuse down their:
concentration gradient
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Simple diffusion across a cell membrane is:
passive transport.
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________ is the diffusion of water across a membrane down its concentration gradient
Osmosis
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Osmosis is:
the diffusion of water across a membrane down its concentration gradient
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________ _______ between cells and their surroundings is crucial to organisms.
Water balance
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Many organisms are able to maintain water balance within their cells by a process called ________, a processs that prevents excessive uptake or excessive loss of water
osmoregulation
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osmoregulation is?
Many organisms are able to maintain water balance within their cells by a process called osmoregulation, a processs that prevents excessive uptake or excessive loss of water
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_______ is a term that describes the ability of a solution surrounding a cell to cause that cell to gain or lose water
Tonicity
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Tonicity is:
a term that describes the ability of a solution surrounding a cell to cause that cell to gain or lose water
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_______ concentration of solute is the same on both sides
Isotonic
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Isotonic is:
conentration. of solute is the same on both side
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_______ conentration.of solute is higher outside the cell
Hypertonic
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Hypertonic is:
concentration of solute is higher outside the cell
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________ concentration of solute is higher inside the cell
Hypotonic
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Hypotonic is:
concentration of solute is higher inside the cell
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Passive transport can occur with or without ______ _______
transport proteins
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Many substances that are necessary for viability of the cell do not freely ________across the membrane
diffuse
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Substances that are necessary for viability of the cell do not freely diffuse across the membrane.They require the help of specific transport proteins that assist in ___________ _________, a type of passive transport that does not require energy.
facilitated diffusion
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facilitated diffusion is:
a type of passive transport that does not require energy.
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Some proteins in facilitated diffusion function by becoming a _______ _______ for passage
hydrophilic tunnel
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The transport protein is __________for the substrate, which can be sugars, amino acids, ions, and water (aquaporins)
specific
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Transport across a membrane can be _______ or ________describe each:
- Passive transport does not require energy; solutes move with concentration gradient.
- Active transport requires energy; solutes move against concentration gradient
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Active transport requires the expenditure of energy in the form of_________
ATP
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Active trasport alters the shape of the membrane protein through _______ using ATP
phosphorylation
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Active trasports 4 steps are:
1) Solute attaches to a specific binding site on the transport protein.
2) ATP transfers 1 phosphate group to the transport protein.
3) Transport protein changes shape and the solute is released on the other side of the membrane
.4) Phosphate group detaches and transport protein returns to original shape.
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Active transports 4 steps:
1) Solute attaches to a specific binding site on the _______ _________.
2) _______ transfers 1 _______ _________ to the transport protein.
3) ______ ________ changes shape and the solute is released on the other side of the membrane.
4) _____ ________ detaches and________ _______ returns to original shape.
1. transport protein
2. ATP, phosphate group
3. Transport protein
4. Phosphate group, transport protein
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________ and ___________ transport large molecules across membranes
Exocytosis, endocytosis
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________ is used to export bulky molecules, such as proteins or polysaccharides
Exocytosis
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Exocytosis is used:
to export bulky molecules, such as proteins or polysaccharides
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_________ is used to import substances necessary for the cell.
Endocytosis
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Endocytosis is used:
to import substances necessary for the cell.
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In Exosytosis and Endocytosis, material to be transported is packaged within a ________ that fuses with the membrane
vesicle
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Exocytosis: Transport vesicle filled with _______ buds from __________ ________, fuses with ________ ________, and contents spill out of the cell
macromolecules, Golgi aparatus, plasma membrane
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Endocytosis: ________ is engulfment of a particle by wrapping cell membrane around it, forming a vacuole.
Phagocytosis
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Phagocytosis is:
Endocytosis Example: Phagocytosis is engulfment of a particle by wrapping cell membrane around it, forming a vacuole.
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Endocytosis/Phagocytosis: ______ + digestive enzymes buds from _____ ________, fuses with food vacuole and enzymatically breaks down (digests) the food
Lysosome, rough ER
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Cells are small ______ _______. Thousands of _______reactions result in maintenance of the cell, manufacture of cellular parts, and replication.
chemical factories, chemical
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___________ is the capacity to perform work/ re-arrange matter
Energy
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_______ is accomplished when an object is moved against an opposing force
Work
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2 types of energy
Potential energy is stored energy; energy that matter possesses b/c of its location or arrangement. i.e. water behind a damMolecules possess potential energy b/c of the arrangement of their atoms.
Chemical energy is potential energy available for release in chemical reactions.
Kinetic energy is the energy of motion. i.e. water flowing over a dam
Heat, or thermal energy, is kinetic energy associated with the random movement of atoms.
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2 laws govern energy transformations in organisms.
Thermodynamics is the study of energy transformations.
The first law of thermodynamics is that all energy in the universe is constant.
- a.k.a. Law of Conservation: energy can be transferred and transformed but cannot be created or destroyed.
The second law of thermodynamics is that energy conversions increase the disorder of the universe b/c during every transfer or transformation of energy, some energy becomes unavailable to do work
Entropy is the measure of disorder, or randomness.
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Chemical reactions either _______or ______energy
release, store
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A chemical reaction that releases energy (that is stored in covalent bonds) is an ________ _______
exergonic reaction
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exergonic reaction is:
A chemical reaction that releases energy (that is stored in covalent bonds) is an exergonic reaction
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A chemical reaction that requires an input of energy an _______ _______; yields products rich in potential energy (stored in covalent bonds of the products)
endergonic reaction
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endergonic reaction is:
A chemical reaction that requires an input of energy an endergonicreaction; yields products rich in potential energy (stored in covalent bonds of the products)
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All of the thousands of combined endergonic and exergonic chemical reactions produced by a living organism is called ___________.
metabolism
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metabolism is:
All of the thousands of combined endergonic and exergonic chemical reactions produced by a living organism is called metabolism.
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A _________ ________ is a series of chemical reactions that either break down a complex molecule or build up a complex molecule
metabolic pathway
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To accomplish work, a cell uses exergonic processes to drive endergonicprocesses = ___________ _______
energy coupling
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________ shuttles chemical energy and drives cellular work.
ATP
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ATP stands for:
adenosine triphosphate, is the energy currency of cells
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ATP is composed of:
- 3 phosphate groups
- 5-Carbon sugar - ribose
- Nitrogenous base - adenine
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ATP is a _______ __________ of energy for the cell.- When energy is released in an exergonic reaction, such as breakdown of glucose, the energy is used in an endergonic reaction to generate ATP
renewable source
exergonic
endergonic
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____________ of ATP releases energy by transferring its third phosphate to some other molecule = phosphorylation.
Hydrolysis
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