Exam 2 Flashcards
___ is a product of glycolysis, pyruvate processing, and the citric acid cycle
NADH
What is a cofactor?
an inorganic ion that reversibly interacts with an enzyme
Suppose you discovered a new amino acid. Its R-group contains only hydrogen and carbon atoms. Predict the behavior of its amino acid
It is hydrophobic
The tertiary structure of a protein is the ___.
unique three-dimensional shape of the fully folded polypeptide
A cell with a predominance of free ribosomes is most likely ____.
primarily producing proteins in the cytosol
If a solution surrounding a cell is hypertonic relative to the inside of a cell, how will water move?
It net movement of water will be out of cell via osmosis
What determines the secondary structure of a DNA molecule?
Hydrophobic interactions and hydrogen bonding
Where does the citric acid cycle occur in eukaryotes?
in the matrix of mitochondria
What contains hydrolytic enzymes?
Lysosome
The bonding of two amino acid molecules to form a larger molecule requires the ____
release of a water molecule
Steroids are considered to be lipids because they ____
are not soluble in water
As cells grow larger, there is a detriment to efficient function. How do eukaryotic cells overcome the ineffieciency?
Eukaryotic cells have organelles in the cytosol, which decreases the overall cytosolic fluid volume, allowing less room for reactions and thus increasing efficiency
What is the difference between a ribonucleotide and a deoxyribonucleotide?
Ribonucleotides have a hydroxyl group on the 2 carbon of their sugar subunit
What statement is true about NAD+?
NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle
What type of bond is directly involved in the formation of an alpha-helix?
Hydrogen bonds between amino acid residues
How do the alpha and beta forms of glucose differ?
Their ring structures differ in the location of a hydroxyl group
The evolution of eukaryotic cells most likely involved ____
endosymbiosis of an aerobic bacterium in a larger host cell-the endosymbiont evolved into mitochondria
In glycolysis, for each molecule of glucose oxidized to pyruvate
two molecules of ATP are used and four molecules of ATP are produced
One of the primary functions of RNA molecules is to ____
function in the synthesis of proteins
A glycosidic linkage is analogous to which of the following in proteins?
a peptide bond
Which plant cell organelle contains its own DNA and ribosomes?
mitochondrion
Starting with one molecule of glucose, the energy-containing products of glycolysis are ____
2 NADH, 2 pyruvate, and 2 ATP
What component of amino acid structure varies among different amino acids?
the components of the R-group
When chemical, transport, or mechanical work is done by an organism, what happens to the heat generated?
It is lost to the environment
The ____ functional group can always be found in a carbohydrate molecule
hydroxyl
What can you infer about a high-molecular-weight protein that cannot be transported into the nucleus?
It lacks a nuclear localization signal (NLS)
How does the structure of DNA allow it to be copied?
After separating the strands of a DNA double helix, each template strand can be copied to make two identical DNA molecules
Nucleic acids are polymers made up of which of the following monomers?
Nucleotides
What are polysaccharides?
Cellulose, Glycogen, amylopectin, and chitin
Most hydrophilic
Electrically charged side chains
Most hydrophobic
Nonpolar side chains
Present in a prokaryotic cell
Ribosome
Glycolysis is a series of ___ reactions that occurs in the ____ of the cells
10; cytoplasm
What are the four nitrogenous base found in RNA?
Adenine, Cytosine, Guanine, Uracil (A, C, G, U)
Which are a needed component of each monomer to make proteins?
Carboxyl group (COOH), amino functional group (NH2), and a side chain (R)
What are three attributes of mitochondria and chloroplasts that suggest they were once free-living bacteria?
They have their own small, often circular chromosomes, they produce their own ribosomes, and they replicate independently of cellular division
Which type of interaction stabilizes the alpha helix and the beta pleated sheet structures of proteins?
hydrogen bonds
Glycolysis is active when cellular energy levels are ____ the regulatory enzyme, phosphofructokinase, is ____ by ATP
low; inhibited
What are three ways monosaccharides differ from one another?
The orientations of their hydroxyl groups, the number of carbon atoms they contain, and the location of their carbonyl groupd
If you wanted to radioactively label the nucleic acids separately from the protein, you would use radioactive ____
phosphorus
Describe a reason why fats store more energy than carbohydrates
compared to carbohydrates , fatty acid chains have a higher ration of bonds with high potential energy to bonds with low potential energy
How do the secondary structures of DNA and RNA differ?
DNA consists of two nucleotide strands, and RNA consists of one that often folds on itself
Following glycolysis and the citric acid cycle, but before the electron transport chain and oxidative phosphorylation, the carbon skeleton of glucose has been broken down to CO2 with some net gain of ATP. Most of the energy from the original glucose molecule at that point in the process, however, is in the form of ________.
NADH
Which structure is the site of the synthesis of proteins that may be exported from the cell?
rough ER
Molecular zip codes direct molecules to particular destinations in the cell. How are these signals read?
They bind to receptor proteins
Redox reactions involve the gain or loss of
electrons
Lipids ____
are insoluble in water
Why is ATP an important molecule in metabolism?
It energetically couples exergonic and endergonic reactions
Under what circumstances does membrane transport require energy?
whenever a solute is moved against its electrochemical gradient
The glucose molecule has a large quantity of energy in its ____
C-H bonds
Lipids are insoluble in water because ____
they contain nonpolar C-C and C-H bonds
Which involves an increase in entropy?
hydrolysis
Which bonds are created during the formation of the primary structure of a protein?
peptide bonds
What produces and modifies polysaccharides that will be secreted?
Golgi apparatus
Which aspect of phospholipids is most important to the formation of bilayers?
they are amphipathic
What two functional groups are bound to the central carbon of every free amino acid monomer?
An amino group and a carboxyl group
