Mastering Biology 1 questions Flashcards
Large amounts of DNA typically wrap around large proteins called ________; this forms the ________ structure of DNA.
Histones; tertiary
What is primarily responsible for the functional versatility observed in RNA?
Single-stranded RNA molecules will fold into different shapes based on interactions between their own bases.
What is responsible for the increased stability of DNA compared to RNA?
DNA is a more stable molecule because it lacks a hydroxyl group on the 2’ carbon.
Which of the following best describes tertiary structure of RNA?
A single nucleotide strand where multiple “stem and loop” structure begin to interact
How do the α and β forms of glucose differ?
Their ring structures differ in the location of a hydroxyl group.
A molecule with the chemical formula C6H12O6 is probably a _____.
monosaccharide
What type of bond is formed between two sugars in a disaccharide?
Glycosidic linkage
Predict how the structure of cellulose would change if all of the β
-1,4-glycosidic linkages were changed to α
-1,4-glycosidic linkages.
The α
-glucose residues would all be oriented the same, and the molecule would coil into a helix.
1,4-glycosidic linkages
They’re found in starch and form helical structures
Which of the following polysaccharides contains peptide bonds?
Peptidoglycan is a structural polysaccharide found in bacterial cell walls. The sugars are modified with amino acids that can form peptide bonds to covalently link adjacent strands.
What are the primary functions of carbohydrates in cells?
cell identity, energy storage, raw material source for synthesis, and structure
How do carbohydrates contain and/or display information for cells?
Carbohydrates contain and display information at the cell surface.
If you hold a salty cracker in your mouth long enough, it will begin to taste sweet. What is responsible for this change in taste?
Amylase is a critical enzyme that initiates the breakdown of starch into glucose, which provides a sweet taste.
Starch
Food, basically energy source to humans that is broken down into glucose
Lipids that contain a high number of double bonds in their fatty acid chains will ________.
likely be liquid at room temperature
Integral membrane proteins are anchored in lipid bilayers. Which of the following groups of amino acid residues would likely be found in the portion that crosses the lipid bilayer?
Nonpolar groups because the interior of the membrane is nonpolar
he presence of cholesterol in the plasma membranes of some animal cells _____.
enables the membranes to stay fluid when cell temperature drops
Which of the following is the best explanation for why cholesterol decreases the permeability of biological membranes?
Because cholesterol is amphipathic, it fits in between the phospholipids and blocks diffusion through the membrane.
If a solution surrounding a cell is hypertonic relative to the inside of the cell, how will water move?
It will move out of the cell via osmosis.
Ions diffuse across membranes through specific ion channels down ________.
their electrochemical gradients
Which of the following structural features is common to cellulose, chitin, and peptidoglycan?
They can all form bonds between polymer chains that create parallel strands.
Which of the following is NOT a potential function of proteins?
Energy storage that can be easily digested and metabolized
Starch and cellulose ________.
are polymers of glucose
A strong acid like HCl _____.
dissociates completely in an aqueous solution
Which of the following best describes protein shape?
Proteins may fluctuate between inactive and active forms, where portions of the protein are disordered.
placed in a solution with a high concentration of potassium and no sodium. How would the cellular sodium-potassium pump function in this environment?
It would continue using ATP to pump sodium out of the cell and potassium into the cell.
What is/are the variable structure(s) of a nucleotide?
the sugar and the base
If you mechanically shook a mixture of phospholipids and water, what would you expect to see when you observe the solution using an electron microscope?
Some lipids will have formed tiny vesicles filled with water.
What are the primary functions of carbohydrates in cells?
Cell identity, energy storage, raw material source for synthesis, and structure
Structurally, nucleotides are similar to what energy-rich molecule?
ATP
What determines the primary structure of a DNA molecule?
Deoxyribonucleotide sequence
What type of bond is directly involved in the formation of an α-helix?
Hydrogen bonds between amino acid residues
Which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly?
CO2 because it is a small nonpolar molecule.
In terms of structure, how do channel proteins differ from carrier proteins?
Channel proteins are pores that are either open or closed to allow transport across, while carrier proteins have to change conformation to ensure molecules move from one side of the membrane to the other.
Enzymes that readily break starch apart cannot hydrolyze the glycosidic linkages found in cellulose. Why is this logical?
The geometry of the bonds is different, and the shapes of enzyme active sites are highly specific.
What are the primary functions of carbohydrates in cells?
cell identity, energy storage, raw material source for synthesis, and structure
Which of the following is TRUE regarding how cholesterol affects the fluidity and permeability of biological membranes?
At low temperatures, cholesterol increases membrane fluidity and permeability by reducing the extent to which phospholipids pack tightly together.
Which of the following is the best explanation for why cholesterol decreases the permeability of biological membranes?
Because cholesterol is amphipathic, it fits in between the phospholipids and blocks diffusion through the membrane.
What is primarily responsible for the functional versatility observed in RNA?
Single-stranded RNA molecules will fold into different shapes based on interactions between their own bases.
The partial negative charge at one end of a water molecule is attracted to the partial positive charge of another water molecule. What is this attraction called?
a hydrogen bond
lipids that contain a high number of double bonds in their fatty acid chains will ________.
likely be liquid at room temperature
Which of the following polysaccharides contains peptide bonds?
Peptidoglycan is a structural polysaccharide found in bacterial cell walls. The sugars are modified with amino acids that can form peptide bonds to covalently link adjacent strands.
In a nucleic acid polymer, the bonds that help to hold double-stranded regions together occur between what parts of the nucleotide monomers?
View Available Hint(s)
Across the two DNA strands, three hydrogen bonds form between GC base pairs and two hydrogen bonds form between AT base pairs.
What do molecules have that make them soluble in water
Molecules that contain hydroxyl or Carboxyl are the most soluble in water
Molecules that contain Hydrocarbons are insoluble because its nonpolar
Spontaneous reactions
Reaction that proceeds without an input of external energy
what every organic molecules contain
a carbon
Why ionic molecules dissolve and dissociate in water
Water is formed by a polar covalent bond
What forms a triple bond
N2 is a triple bond
What has the lowest concentration of protons
Low concentration of protons would have a high pH and would be a base. A high concentration of protons would have a low pH and be an acid.
All the systems
Open system
Can exchange energy with the environment
Can exchange matter with environment
Closed system
Can exchange energy with environment
Cannot exchange matter with environment
Isolated system
Cannot exchange neither energy or matter with environment
What’s necessary for an atom to particpate in the formation of a double covalent bond
The participating atoms must have two or more unpaired electrons
What are substrates also known as
Reactants
When did life become possible
Self-replicating molecule
Protein’s quaternary structure
produced by combinations of two or more polypeptides.
Linear of amino acids in a protein helps determine which level of protein structure
All of the levels of protein structure
Infectious disease-causing agents caused by protein misfolding are called
Prions
Why do R groups that consist solely of carbon and hydrogen atoms rarely participate in chemical reactions
This is because they’re nonpolar and don’t interact with water well
Important function of proteins in organisms
Impart mobility to entire cells and molecules within cells
What part of the protein structure will destroy the tertiary structure
A chemical that breaks disulfide bonds
Secondary structure
Hydrogen bonding between complementary bases
Where does the energy for the polymerization of nucleotides come from
hydrolysis of phosphate groups from nucleoside triphophates
Thymine and Uracil structure
Double bonded to Oxygen but Thymine is also contains Ch3, which uracil does not
What piece of evidence was critical in proposing the RNA world theory
Discovery of ribozymes
What does the nitrogen in the nitrogenous base bond too
The 1’ carbon of sugar
Experiments in Bartel’s laboratory tried to generate ribozymes that could perform what functions
RNA replication and ribonucleotide production
Glycoproteins
cell-cell recognition
Predominant form of glucose dissolved in an aqeuous solution
Ring formation
What polysaccharide has a modified monosaccharide
Chitin
