Themes of Biology
Chemistry and Carbon
Water
Carbohydrates and Lipids
Proteins and nucleic acids
100
In an experiment testing the effects of different fertilizers on plant growth, what is the independent variable?
The type of fertilizer. Plant growth is the dependent variable.
100
Which type of bonds does carbon form?
Carbon always forms 4 covalent bonds
100
Which atom in a water molecule carries a partial negative charge?
The oxygen atom is partially negative because it has a high electronegativity which leads it to hog electrons. The Hydrogen atoms carry a partial positive charge.
100
Which molecule is an essential component of animal cell membranes and the precursor to steroid hormones?
Cholesterol
100
What is the complementary strand that would bind to the following DNA molecule?
ATCATG
TAGTAC
T always bind to A
C always binds to G
200
In a clinical trial testing the efficacy of a new diabetes drug, what is the proper negative control group?
A placebo group is the proper negative control group. This group receives a similar pill that does not contain the drug to control for the placebo effect.
200
What term describes electrons in an atom's outermost electron shell?
Valence electrons.
The number of valence electrons determines an atoms properties.
200
A solution changes from pH 7 to pH 6. How has its H⁺ concentration changed?
It has increased 10 fold (10 times higher)
200
What polysaccharide do animals use to store glucose?
Glycogen.
Cells store excess glucose glycogen. A long, branched polymer of glucose.
200
What part of an amino acid differs between the 20 amino acids in the body?
The amino acid side chain (R-group)
300
Which of the following cells contain mitochondria?
Bacterium
Archaea
Neuron
Neuron.
Neurons exist is animals which are eukaryotic organisms. Only eukaryotic organisms contain organelles.
300
Adding a hydroxyl group to a molecules will have what effect on the properties of that molecule.
It will add polarity to the molecule.
If the molecule is small, it will have a larger impact than if the molecule is large.
300
Why do Na+ ions rush into the cell when channels are opened?
A concentration gradient is created keeping the concentration of dissolved Na+ higher outside the cell compared to inside.
300
Why can LDL and HDL transport cholesterol through blood even though cholesterol is hydrophobic?
They are transported in lipoproteins with hydrophilic shells and hydrophobic interiors.
300
Which amino acid forms disulfide bonds to help hold a protein together? What type of bond is this?
Cysteine forms covalent disulfide bonds with other cysteins.
400
Two unrelated plant species living in separate deserts independently evolve thick stems that store water. If their common ancestor lacked this trait, what is the best explanation?
Similar selective pressures of a dry environment led to each species developing a similar feature. This is known as convergent evolution
400
Two atoms have identical numbers of electrons but different numbers of protons. Could they be the same element?
NO.
Number of protons define the element. These atoms will have different charges.
400
Two cells contain identical solute concentrations internally. Cell A is placed in hypertonic solution and Cell B in hypotonic solution. Which cell will shrink?
Cell A will shrink. The water will rush out of the cell to attempt to balance the salt concentrations.
Cell B will swell because water will rush into the cell.
400
A patient has unusually few functional LDL receptors on liver cells. Predict what happens to their blood LDL concentration.
LDL increases because the liver cannot remove LDL particles efficiently.
This can lead to increased risk for cardiovascular disease.
400
A protein found in the blood contains several nonpolar amino acids. Where would you expect these amino acids to be located when the protein is folded?
In the interior of the protein, shielded from water.
500
A scientist hypothesizes that high temperature kills yeast. Yeast grown at 40°C show greater death than yeast at 25°C, but the 40°C cultures also produced twice as much ethanol. What change would make the experiment capable of testing the hypothesis?
Balance the amount of ethanol in the cultures.
In this experiment, amount of ethanol in the cultures is a confounding variable
500
If a strong acid is added to a tube of water and a tube of blood, which will end up with a lower pH?
The water will end up with a lower pH because blood contains a buffer which makes it resistant to pH changes.
500
Will the following molecule interact with water?
NO. This is a non-polar hydrocarbon molecule that will not interact with water.
500
After eating a carb-heavy meal, blood glucose rises. Several hours later, it begins falling. Describe the two-hormone system that prevents blood glucose from remaining extremely high or falling too low.
High glucose stimulates insulin, promoting glucose uptake and storage as glycogen; as glucose falls, glucagon promotes liver glycogen breakdown and glucose release.
500
An antagonist is a drug that binds to a receptor but does not trigger its downstream function. Explain how an antagonist can prevent the normal signaling molecule from activating the receptor.
It blocks normal molecule from binding to the receptor.
With the drug blocking the binding site, the normal molecule can no longer bind and activate the downstream function.