A compound contains hydroxyl groups as its predominant functional group. What is true of this compound?
It should dissolve in water
A chemist wishes to make an organic molecule less acidic. What functional group should be added to the molecule?
From its atomic number of 15, it is possible to predict that the phosphorus atom has?
15 protons and 15 electrons
which macromolecular structure plays an essential role in hydrogen bonds?
alpha helix, protein tertiary structure, cellulose
polymerization of which macromolecular structures does not involve dehydration synthesis?
the attraction of phospholipid molecules to form a bilayer involves?
exclusion of water from the bilayer structure
which eukaryotic cell structure is characterized by two biological membranes?
nucleus and mitochondria
chloride ion channels are membrane structure that either are or include what in their structure?
the movement of potassium into an animal cell requires?
an energy source such as ATP or a proton gradient
if a cell is placed in pure water, why does it take up water?
water is able to leak across plasma membrane. the higher solute concentration of dissolved molecules inside a cell causes water to move into the cell by osmosis
the mechanism in which the end product of a metabolic pathway inhibits an earlier step in the pathway is known as?
if you know the change in free energy of a reaction. what does this value tell you?
whether is proceeds from left to right
what is the activation energy of a reaction?
the energy to which reaction intermediates must be brought before a reaction can proceed
why do two of the first three steps of glycolysis require ATP?
in both reactions a phosphate is added to glucose. addition of two phosphate groups make glucose unstable so it splits in two parts
for each glucose molecule metabolized in glycolysis , how many acetyl Co-A molecules are produced?
what is the immediate energy source that through coupling permits the synthesis to happen in cells?
hydrogen ion gradient across the inner mitochondrial membrane
hemoglobin is a blood protein that is made of four polypeptide chains. What is the term used to describe the protein structure created when multiple polypeptide subunits bind together
Macromolecules are polymers. If the monomers are nucleotides, what class of macromolecules are we talking about?
A cell has the following molecules and structures: enzymes, DNA, ribosomes, plasma membrane, and mitochondria. It could be a cell from:
a plant or an animal
where are ribosomes found in eukaryotic cells?
cytosol, rough endoplasmic reticulum, mitochondria, and chloroplasts
where in a eukaryotic cell are proteins destined for lysosomes synthesized?
rough endoplasmic reticulum
Which type of organelle is primarily involved in the synthesis of oils, phospholipids, and steroids?
smooth endoplasmic reticulum
What distinguishes facilitated transport across a cell membrane from active transport?
Active transport requires the expenditure of chemical free energy, facilitated transport does not.
A series of enzymes catalyze the reaction X-->Y--> Z--> A. In the metabolic chain, product A binds to the active site of the enzyme that converts X to Y. This binding decreases the activity of the enzyme. Substance A functions as
a competitive inhibitor
Imagine a chemical reaction A --> B with a ΔG = -2kcal/mole. What can be done to change the reaction so that B --> A will actually happen?
add more reagent B
In a coupled reaction the positive ΔG of one partial reaction is overcome by the negative ΔG of another partial reaction. When the second half-reaction is ATP --> ADP + Pi, there is normally a reaction intermediate. What is the nature of this intermediate?
a phosphate group covalently bound to another organic molecule
in cellular biochemistry, what does an allosteric activator do?
binds to a regulatory site causing an allosteric enzyme to change its shape from inactive to active form
How many carbon atoms are fed into the citric acid cycle as a result of the oxidation of one molecule of pyruvate?
One of the end products of oxidative phorylation is ATP. The process is rather complicated. Where does the energy come from that is used to combine phosphate with ADP in mitochondria?
the combination of electrons from glucose with oxygen