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.