Studied by 17 peoplepartial opposite charges on molecules come close enough to attract each other.
A hydrogen bond occurs when
the oxygen atom in one molecule and a hydrogen atom in another molecule.
In a group of water molecules, hydrogen bonds form between
a weak interaction between two molecules because they involve polarity, or polar interactions.
A hydrogen bond is
an aqueous solution
A typical soda contains sugar, flavorings, coloring agents, and carbon dioxide that have been dissolved in water. Soda is therefore
Polar solvents, because their molecules have a positive and a negative pole, are excellent solvents for ions and for other polar materials.
The most widely effective solvent for organisms is a material that is
are polar.
Sodium chloride (NaCl) dissolves in water because water molecules
ice floats. Ice is LESS dense than water.
Because the molecules of water are farther apart in ice than in liquid water,
Cohesion and Adhesion (helps a plant by countering the pull of gravity as the water moves up from the roots.
What property of water makes it move upward from the roots of plants?
the attraction between 2 SAME particles
Cohesion
the attraction between 2 DIFFERENT particles
Adhesion
Peanut oil, a plant product, contains unsaturated fats, which contain one or more double bonds.
Double bonds are present in the majority of the fats of which of the following foods?
Oils and other fats that do not dissolve in water-based solutions
What is hydrophobic?
unsaturated
A fatty acid containing at least one double bond is called
adding hydrogens (unsaturated fats have been synthetically converted to saturated fats by the addition of hydrogen.)
Manufacturers make vegetable oils solid or semisolid by
fewer double bonds
How do "partially hydrogenated vegetable oils" differ from unmodified vegetable oils?
Both are important components of cell membranes.
What do phospholipids and cholesterol have in common?
phospholipids
The lipids that form the main structural component of cell membranes are
Lipids
Cholesterol belongs to which class of molecules?
Each person has a unique set of carbohydrate chains attached to his or her plasma membranes.
Frequently, transplanted organs are rejected by the recipient's body. How is this reaction related to plasma membranes?
proteins
What is the primary component of membranes that gives membranes cell-specific properties?
cholesterol molecules
Fluidity of an animal cell plasma membrane is enhanced by
so that the nonpolar parts of two lipids point toward each other
The lipids in a cell membrane are arranged
chemical species in which the distribution of electrons between the covalently bonded atoms is not even.
polar molecule
would stay together but in a reverse orientation, with their tails projecting outward
In an oil-based, nonpolar environment, phospholipids would arrange themselves so that they
form spontaneously in aqueous environments
When considering the formation of membranes, they
the direction of the oxygen concentration gradient
What controls the net direction of molecules, such as oxygen, involved in passive transport?
diffusion
The movement of atoms, ions, or molecules from a region of higher concentration to regions of lower concentration is called
the difference in water concentration across a selectively permeable membrane
What really drives osmosis?
he movement of water molecules from a solution with a high concentration of water molecules to a solution with a lower concentration of water molecules, through a cell's partially permeable membrane.
What is Osmosis?
actively pump water back into their cells to counter its loss due to osmosis
Utah's Great Salt Lake has an average salinity seven times higher than that of the oceans. Very few multicellular organisms live in this harsh environment. An example is the brine shrimp, which must devote a large portion of its metabolic energy to osmoregulation. These brine shrimp must
remain standing upright
When placed in a hypotonic environment, where the solute concentration is below that of the cell, a houseplant will
a hypertonic sucrose solution
The concentration of solutes in a red blood cell is about 2%. Sucrose cannot pass through the membrane, but water and urea can. Osmosis would cause red blood cells to shrink the most when immersed in which of the following solutions?
9
The host hands you three different amino acids, four different sugars, and two different ions. Then the host shouts, "How many different proteins does the cell need to move these molecules across the plasma membrane using facilitated transport?"
Facilitated diffusion of solutes occurs through protein pores in the membrane.
Which of these statements describes what occurs in facilitated diffusion?
Active transport moves solutes against their concentration gradient; facilitated diffusion moves substances down their concentration gradient.
Which of the following is an accurate comparison of active transport and facilitated diffusion?
Active transport requires the expenditure of cellular energy, and facilitated diffusion does not.
Which of the following is a difference between active transport and facilitated diffusion?
the concentration of the solute is lower inside the cell than outside it
The transport of molecules of a particular solute from inside an animal cell across the cell membrane to the extracellular fluid always requires energy when
Microbes are engulfed into the macrophage via phagocytosis.
Macrophages are white blood cells that roam the body searching for invading microbes. Inside macrophage vacuoles these invaders are destroyed. How do the microbes get inside the macrophages?
endocytosis
A nursing infant is able to obtain disease-fighting antibodies, which are large protein molecules, from its mother's milk. These molecules probably enter the cells lining the baby's digestive tract via
A cell engulfs a particle by wrapping pseudopodia around it and packaging it within a vacuole.
Which statement best describes phagocytosis?
any external solution that has a high solute concentration and low water concentrations. water molecules will move OUT of the cell
Hypertonic
Water molecules move INTO the cell and it may expand or even burst. (more water than the solute)
Hypotonic
the cell volume WON'T change (equal)
Isotonic
Turgid (hypotonic. the cell wall protects it from bursting)
What osmoregulation do plants, prokaryotes, and fungi prefer to be in?
the cells shrivel
What happens to cells in hypertonic enviroments?
diffusion of water across a cell membrane
Osmosis
Water will cross the membrane, moving down its own concentration gradient until the solute concentration is equal on both sides.
What will happen if a membrane is permeable to water but not to the solutes that separates two solutions with different concentrations of a solute?
describes the ability of a solution to cause a cell to gain or lose water (depends on the concentration of a solute on both sides of the membrane)
tonicity
The cell wall exerts pressure.
What does a plant cell do to prevent itself from bursting in a hypotonic environment?
Exocytosis and Endocytosis
What forms of cell transportation transport large molecules across membranes?
exports bulky molecules such as proteins and polysaccarides.
Exocytosis
a large molecule made of many smaller monosaccharides. Monosaccharides are simple sugars, like glucose.
polysaccharide
used to impart substances useful to the livelihood of the cell
Endocytosis
material to be transported is packaged within a vesicle that joins the membrane
How does endocytosis transport substances?
engulfment of a particle by wrapping the cell membrane around it
Phagocytosis
fluids are taken into small vesicles
pinocytosis
a space within the cytoplasm of a cell
Vesicle
Polar or charged substances move across the cell membrane with the help of a transport protein (facilitated diffusion).
How do polar or charged substances cross membranes?
A bilayer of phospholipids with embedded and attached proteins in a s structure called fluid mosaic.
What are cell membranes composed of?
helps stabilize membranes at warmer temperatures and keeps membrane fluid at longer temperatures
What is the role of cholesterol in animal cells?
maintain cell shape, may exhibit selective permeability, may attach adjacent cells to one another
What do cell membrane proteins do?
They are attached to the water of the environment and the internal part of the cell
What are hydrophilic heads attached to?
In the center of the bilayer.
Where do hydrophobic tails bind?
an oily organic compound insoluble in water but soluble in organic solvents; essential structural component of living cells
Lipid
Note
Flashcard