Biochemistry & Molecular Biology
This bond is between complementary nucleotide bases in DNA.
Hydrogen Bonds
This bond is between complementary nucleotide bases in DNA
hydrogen
In the lungs, oxygen diffuses into the blood because the partial pressure of oxygen is higher in the alveoli than in this thing.
In Mendel’s classic pea experiments, crossing two heterozygotes for a single trait produced this phenotypic ratio in the F₂ generation.
3:1
In a food chain, energy decreases at each trophic level. What is the main reason for this loss of energy?
What is energy lost as heat through metabolism and respiration?
This type of bond forms between the 3’ hydroxyl group of one nucleotide and the 5’ phosphate group of the next in a DNA strand, giving DNA its sugar-phosphate backbone.
Covalent bond
. Developing diagnostics for the Zika virus has proven to be difficult due to cross reactivity displayed by antibodies for other flaviviruses. If a person has been previously exposed to certain flaviviruses (i.e. yellow fever or West Nile virus), then he/she may have antibodies which diagnostics erroneously attribute to Zika virus exposure. The issue stems from antibodies that resulted from a prior immune response. In the classic immune response, which cells are primarily responsible for the production of antibodies?
Plasma Cells
Most nutrient absorption in humans takes place in this section of the digestive tract, which contains villi and microvilli to increase surface area.
Small intestine
A man with blood type AB and a woman with blood type O have a child. What are the possible blood types of the child?
A or B
Darwin observed differences in the beaks of finches on the Galápagos Islands. These differences arose primarily due to what evolutionary process?
Natural Selection
During DNA replication, this enzyme adds new nucleotides to the growing strand in the 5′ → 3′ direction.
These pores on the underside of leaves open and close to regulate gas exchange and water loss.
stomata
Calcium ions stored in this organelle are released during muscle contraction.
Sarcoplasmic Reticulum
A red snapdragon crossed with a white snapdragon produces pink offspring. This blending of traits in the heterozygote is called ____.
incomplete dominance
In logistic growth, population growth slows as it approaches this maximum population size that the environment can sustain.
Carrying Capacity (K)
An unnamed acid has a pKa value of 4.76. Which of the following is closest to the ratio of the concentration of its protonated to deprotonated forms in a pH environment of 6.8?
Using Henderson Hasselbach, pKa = pH + log([A-]/[AH])
Observe the seedlings growing below which have a loss of function mutation in the ethylene receptor.
The seedlings in the image are elongated and pale, with long, thin hypocotyls growing upright. The cotyledons remain small and closed, showing little to no greening. The stems appear straight rather than thickened or bent, and there is no obvious swelling or hook formation at the tip.
Which of the following statement(s) is (are) TRUE regarding this mutant’s growth response NOT being related to a triple response?
I. This mutant will not respond to the exposure of ethylene under any circumstances.
II. This mutant has a constitutive activity where it leads to the activation of kinase, which is important for the triple response.
III. This mutant has a constitutive activity where it leads to the inactivation of kinase, which is important for the triple response.
IV. If this mutant is treated with aminoethoxyvinylglycine (ethylene synthesis inhibitor), this mutant will be able to undergo triple response.
V. If this mutant is treated with aminoethoxyvinylglycine (ethylene synthesis inhibitor), this mutant will not respond to the treatment and not undergo triple response.
I. This mutant will not respond to the exposure of ethylene under any circumstances.
III. This mutant has a constitutive activity where it leads to the inactivation of kinase, which is important for the triple response.
(ethylene --> Constitutive Triple Response 1 Kinase inhibition --> EIN no phosphorylation --> downstream signalling leading to triple response)
V. If this mutant is treated with aminoethoxyvinylglycine (ethylene synthesis inhibitor), this mutant will not respond to the treatment and not undergo triple response.
Thin part of ascending loop of henle
In a dihybrid cross involving two genes that control coat color in mice, the expected F₂ ratio is not the usual 9:3:3:1. Instead, the offspring appear in a 9:4:3 ratio. This unusual ratio indicates that one gene masks the effect of the other when homozygous recessive.
recessive epistasis
In ecological succession, the first species to colonize a disturbed or newly formed area, like lichens on bare rock, are called what?
Pioneer Species
The mitochondrial enzyme ATP synthase produces ATP by using the energy from this gradient.
What is the proton (H⁺) electrochemical gradient across the inner mitochondrial membrane?
Which statement about the life cycle of the human immunodeficiency virus (HIV) is most accurate?
A. The viral glycoproteins that coat the mature virion’s lipid envelope’s outer surface are synthesized by host cell ribosomes in the cytosol.
B. The mature virus particle does not contain reverse transcriptase; the protein is translated from the RNA genome after entry into the host cell.
C. If a scientist were to extract just the viral genome from HIV virions and inject the nucleic acid into a human cell, the genome would integrate as a provirus into the host’s genome.
D. In HIV positive individuals, HIV provirus can be found latent in CD4 positive cells years after initial infection.
E. The high error rate of reverse transcriptase enables the virus to evade the host’s circulating antibodies by changing the antigenicity of its internal capsid protein.
D
Jason, a 19-year-old college student, is walking to class one day and slips on some notoriously slippery Bostonian ice, breaking his hip. Upon questioning by his doctor, he admits to feeling “slowed down” lately and experiencing frequent nausea, thirst, headaches, and muscle pain. Which organ is most likely malfunctioning?
Parathyroid
In summer squash, crossing two heterozygotes for two genes results in an F₂ ratio of 12:3:1 (white:yellow:green). What type of genetic interaction explains this deviation from Mendel’s 9:3:3:1?
What is dominant epistasis?
Darwin observed differences in the beaks of finches on the Galápagos Islands. These differences arose primarily due to what evolutionary process?
Natural Selection