Exam 2

Which of the following is most similar in structure in ATP? -A steroid with phosphate groups attached -The sodium/potassium pump -A phospholipid -A triglyceride -a nucleotide

A nucleotide

Which of the following statements are true with regard to this animation -Both sodium and potassium ions are transported against their concentration gradients -Potassium ions are transported down their concentration gradient -The cell is not expending energy -The cell does not extend ATP -Sodium ions are transported down their concentration gradient

Both sodium and potassium ions are transported against their concentration gradients -Both ions are transported from where their concentration is low to where their concentration is high, and the cell expends energy in the form of ATP to do it

Which transport proteins are fueled by ATP? -Na+ channels on nerve cells that open during an action potential -K+ channels on nerve cells that open during an AP -Ca2+ transporters that move Ca2+ from the SR pouch to the cytosol to trigger muscle contraction -Ca2+ transporters that move Ca2+ from the cytosol to the SR pouch during muscle relaxation -the aquaporin protein that facilitates diffusion of water

Ca2+ transporters that move Ca2+ from the cytosol to the SR pouch during muscle relaxation ATP fuels transport proteins that build gradients. Facilitated diffusion utilizes a gradient but does not build a gradient. Both Na+ and K+ channels open up like floodgates and utilize Na+ or K+ gradients to facilitate diffusion. Muscle contraction involves a Ca2+ channel that opens like a floodgate and lets Ca2+ rush out of the SR pouch into the cytosol by facilitated diffusion utilizing the Ca2+ gradient built by the Ca2+ pump on the SR membrane that actively pumps Ca2+ from the cytosol into the SR pouch

What type of reaction breaks the bonds that join the phosphate groups in an ATP molecule? -Dehydration synthesis -Anabolism -Hydrolysis -Dehydration decomposition -Entropic

Hydrolysis Involves breaking bonds with the addition of water

Predict where hydrophobic amino acids are found in the sodium-potassium pump: -In the binding site for Na+ -In the binding site for K+ -In the pump's portion in contact with water inside the cell -In the pump's portion in contact with water outside of the cell -In the outer middle regions of the protein in contact with the membrane's fatty acid tails

In the outer middle regions of the protein in contact with the membrane's fatty acid tails

Which movement does not require a protein? First exclude all movements that do require a protein -hydrophilic glucose molecule moving along its concentration gradient -O2 moving from high to low concentration -H2O moving from high to low concentration -Na+ moving from low to high concentration -Hydrophilic glucose moving against its concentration gradient

O2 moving from high to low concentration

What specific membrane structures serve to build gradients? -cholesterol -the lipid bilayer -proteins on the membrane surface -proteins that span the membrane -aquaporins

Proteins that span the membrane

What powers transport proteins that build gradients across a membrane? -the substance that is moved -addition of a phosphate group to the transport protein -addition of a C-H group (that can be burned with oxygen to release energy) to the transport protein -the amino acids of the transport protein -once cannot answer this question without knowing if the transported substance is hydrophilic or hydrophobic

addition of a phosphate group to the transport protein Building a gradient with the help of a transport protein is fueled by transfer of an energized phosphate group from ATP to the transport protein, like in the case of the sodium/potassium pump or the calcium pump. Let's double-check the other options. Do I need to know if the transported substance is hydrophilic or hydrophobic? No; building a gradient always requires energy. Neither the substance that is moved nor the amino acids of the transport protein can provide the energy for building a gradient. C-H groups in fuels like gas contain energy that can be released by burning with oxygen but cannot be used to power transport proteins

What do all transport proteins found in the cell membrane have in common? They -allow only specific types of molecule to pass through -all utilize a gradient to move substances -always build a gradient -must be proteins located on the membrane surface, but not spanning the membrane -all require cellular energy in he form of ATP

allow only specific types of molecule to pass through -Transport proteins must span the membrane to allow substances to pass all the way from one side of the membrane to the other. Transport proteins only allow molecules with specific properties (solubility, shape, and size) to go through their inner channel; this is how cells are able to control what comes in and goes out. Some transport proteins serve in facilitated diffusion utilizing a gradient and require no additional energy input from the cell. Other transport proteins build a gradient by active transport and require energy input from ATP

Which statement correctly completes the following statement? Exclude the 4 incorrect options. Omega-3 polyunsaturated fatty acids -can be synthesized in the human body from scratch -are necessary to allow shape changes in the sodium-potassium -promote membrane stability at high temp -have more C-H bonds than saturated fatty acids with the same number of C atoms -have fewer C=C bonds than monounsaturated fatty acids

are necessary to allow shape changes in the sodium-potassium -Omega-3 polyunsaturated fatty acids are very fluid and thereby support the shape changes of the sodium-potassium pump. Double-check the other options. Since omega-3 fatty acids cannot be synthesized in the human body without an omega-3 fatty acid, they have to be consumed with the diet. Omega-3 fatty acids are polyunsaturated and contain more C=C bonds and fewer C-H bonds than either monounsaturated fatty acids or saturated acids with the same number of carbon atoms. The additional kinks in polyunsaturated fatty acids cause membranes to be less stable at higher temp

Compare the sodium/potassium pump with the barrel-shaped protein (LDL) that carries cholesterol through the blood stream. The pump is ___ on the inside; LDL is ____ on the outside -hydrophilic, hydrophilic -hydrophobic,hydrophilic -hydrophilic,hydrophobic -hydrophobic, hydrophobic

hydrophilic, hydrophilic The sodium/potassium pump's inner channel must be hydrophilic to be able to allow the charged substances Na+ and K+ to move through it. The LDL protein must be hydrophilic on the outside to be able to interact with water molecules with their partial electrical charges and dissolve in the water-based blood fluid

Complete the sentence: The phosphorylation of ADP to ATP -does not require energy -is powered by an outside energy source -is driven by muscle movement -is driven by active transport of sodium or potassium -is driven by the movement of vesicles

is powered by an outside energy source

An example of mechanical work is ____; and example of transport work is ____ -movement of a vesicle by a motor protein; building a K+ gradient across a membrane -movement of a vesicle by a motor protein; utilizing a Ca2+ gradient -movement of a muscle fibers; movement of a vesicle by a motor protein -building a Na+ gradient; building a K= gradient -building a Ca2+ gradient; utilizing a Ca2+ gradient

movement of a vesicle by a motor protein; building a K+ gradient across a membrane

A squirrel eating nuts breaks down nut __ into their three components: fatty acids, glycerol, and phosphate monomers. Some or all of these building blocks could contribute to the formation of ___ by the squirrel -fats; lipids, and ATP -triglycerides; fats and phospholipids -phospholipids; fats, phospholipids, and ATP -fats; proteins and fats

phospholipids; fats, phospholipids, and ATP The 3 components listed in the question prompt are the components of phospholipids. These components (fatty acids, glycerol, and phosphate monomers) can contribute to the formation of several substances:fats(using fatty acids and glycerol), phospholipids (using all 3 components listed), and ATP (using only the phosphate monomers).

Which will be attracted to a negatively charged region of a protein -The O atom in the water molecule -a phosphate group -the H atom in a C-H bond -Cl- -the H atom in the water molecule

the H atom in the water molecule Opposite charges attract each other by electrical attraction between positive and negative charges. All negative poles or charges are attracted to positive poles or positive charges, 1. Oxygen as the negative pole of water molecule, 2. a negatively charged phosphate group, and 3. Cl-. The C-H bond has no partial electrical charges and its H is neither attracted nor repelled. Hydrogen as the positive pole of the water molecule is attracted to negative charges