USABO Practice Flashcards

HIV and Enzymes

• Reverse Transcriptase is the enzyme HIV uses to convert its RNA into DNA.

Genetics Terminology

• In prokaryotes, the promoter region is located at the 5' end of the gene and serves as a binding site for RNA polymerase.
• Prokaryotes exhibit simultaneous transcription and translation and possess circular DNA, but do not have intron sequences.

Membrane Proteins

• Integral transmembrane proteins likely contain hydrophobic amino acids such as Tryptophan in their transmembrane regions.

Bacterial Genomics

• Mycobacterium tuberculosis has a G + C content of 64% if 18% of its bases are adenine.

Inheritance Patterns

• In a population at Hardy-Weinberg equilibrium with an autosomal recessive disorder frequency of 1 in 4, the proportion of carrier individuals is 50%.

Neural Conduction

• Schwann cells are responsible for myelinating axons in the peripheral nervous system, which increases action potential conduction velocity.

Sensory Nerves

• The cell bodies of afferent (sensory) nerves involved in somatic reflexes are located in the dorsal root ganglion.

Vision

• Rods are associated with light/dark vision, while cones are linked to color vision.

Population Ecology

• K-selected species are typically found in populations living at densities near resource limits.

Cancer Biology

• The p53 gene functions as a tumor suppressor, and its loss is common in various cancers.

Cellular Respiration

• Pyruvate is the glycolytic product that is shuttled to the mitochondria during aerobic respiration.

Developmental Biology

• Gastrulation is the process that leads to the formation of the three germ layers in human development.

Telomeres and Carcinogenesis

• Telomerase maintains telomere size and its function can increase during carcinogenesis.

Natural Selection

• Sexual selection is not considered a mode of natural selection.

Developmental Biology

• Protostomes exhibit spiral and determinate types of cleavage.

Chordates

• Not all chordates possess vertebrae; this is not a universal characteristic.

Cardiac Muscle Physiology

• Calcium ions in cardiac muscle move freely through gap junctions between adjacent cells.

Hormonal Differences

• Unlike most polypeptide hormones, steroid hormones can diffuse across cell membranes.

Enzymatic Activity

• In superoxide dismutase 1, copper functions as a cofactor essential for enzyme activity.

Blood Circulation

• The normal flow of blood through the heart follows this path: right atrium, right ventricle, lungs, left atrium, left ventricle, body.

Speciation

• Allopatric speciation occurs due to geographic separation.

Amino Acid Structure

• Amino acids always contain both a carboxyl group and an amine group.

Membrane Transport

• Facilitated diffusion describes the movement of ions across membranes from high to low concentrations through channel proteins.

Plant Classification

• Ferns are vascular plants that do not produce seeds, unlike mosses and gymnosperms.

Xylem Function

• The movement of water and nutrients in xylem primarily relies on transpiration.

Interaction Types

• Predation is a -/+ interaction while mutualism is a +/+ interaction.

Trophic Levels

• The trophic level assignment of a beetle as a secondary consumer can be incorrect.

Behavioral Ecology

• Habituation is exemplified by Hydra that initially respond to touch but eventually stop.

Genetic Interactions

• Epistasis occurs when one gene affects the expression of another gene; as in the black and brown color genes in mice.

Migration in Birds

• Birds migrate using various reference frameworks including the sun, constellations, and Earth's magnetic field.

Biodiversity and Ecosystem

• Coral reefs generally host more species per square kilometer compared to other ecosystems.

Photosynthesis

• In the dark reaction (Calvin cycle), RUBP is utilized and PGA is formed, using carbon dioxide.

Plant Life Cycle

• The diploid sporophyte generation is dominant in the life cycle of ferns.

Hormonal Regulation

• In conditions of cortisol medication, ACTH levels typically decrease while CRF levels may increase.

Immune System and Blood

• After injecting carbon particles into mice, the highest concentration is expected in monocytes of the spleen.

Kidneys and Osmoregulation

• Diets high in protein create a greater need for osmoregulation by the kidneys.

Translation in Prokaryotes

• During prokaryotic translation, the ribosome binds to the Shine-Dalgarno sequence.

Protein Structure

• The quaternary structure of a protein involves interactions between the amino acids of different polypeptide chains.

Nervous System

• Functions not attributable to the parasympathetic division include stimulation of the adrenal medulla.

Plant Growth Direction

• Active auxin accumulates on the west side of a seedling placed in an east-facing window.

Mammalian Characteristics

• Not all mammalian species possess a placenta.

Gene Regulation

• Mutation of the lac repressor in E. coli affecting operator binding results in dependence on glucose concentration.

Plant Tissues

• Parenchyma cells in leaves are characterized by loosely packed structure and contain many chloroplasts.

Population Ecology

• Rapid reproduction of voles would increase competition among the population in a given area.

Virus Properties

• Tobacco mosaic virus retains properties of the original virus when mixed with proteins from another virus.

Molecular Characterization

• Amphipathic molecules feature distinct hydrophilic and hydrophobic regions.

Protein Folding

• Molecular chaperones assist in the proper folding of proteins via binding to their specific structures.

DNA Techniques

• Ethidium Bromide is used in DNA electrophoresis for visualizing fragments under UV light.

Geological Epochs

• Homo sapiens first appeared during the Pleistocene epoch.

Resilience of Marine Communities

• Deep sea vent communities are least affected by significant atmospheric debris reducing sunlight.

Angiosperm Fertilization

• Fertilization in angiosperms involves a double fusion event, one sperm fertilizes the egg, and another fuses with polar nuclei.

Plant Structure

• Sclerenchyma cells primarily provide structural support for plants.

Hardy-Weinberg Assumptions

• The Hardy-Weinberg principle does not assume that the frequency of dominant alleles exceeds recessive alleles.

Physiology and Urine Volume

• Coffee consumption leads to increased urine production compared to saline solutions or regular water.

Protein Degradation

• Ubiquitin tags proteins for degradation by the proteasome.

Territorial Behavior

• Territorial "owners" mainly defend their territory against members of the same species (conspecifics).

Gene Expression Experimentation

• A hybridization experiment with RNA extracts can help determine if a specific gene is expressed in liver cells.

Metabolic Pathways

• Inhibition of succinate dehydrogenase affects ATP and NADH generation during cellular respiration.

Plant Adaptations

• Dormant buds are a notable adaptation in temperate climate plants.

Flowering Responses

• Long-day plants can flower even with interruptions of darkness by short light periods.

Second Messenger Concept

• Magnesium ions do not function as second messengers in cellular signaling.

Calvin Cycle Dynamics

• The reduction phase of the Calvin cycle mirrors the energy payoff phase of glycolysis in reverse.

Ecosystem Production

• Ecosystems ranked by average net primary production: open ocean, savanna, temperate forest, tropical rainforest.

Parental Investment

• In mammals, higher parental investment by females is due to their typical K-selected reproductive strategy.

Plant Reproductive Structures

• The megagametophyte is integral to the egg-producing structures in plants.

Vaccine Boosters

• Booster vaccinations enhance blood antibody levels and increase effector cell populations.

Genetic Probability

• In a cross of gray mice, the probability of offspring not having white fur is 3 out of 4.

Aquatic Zones

• The limnetic zone in lakes contains the highest concentration of phytoplankton.

Oxygen Affinity Differences

• Myoglobin exhibits a greater affinity for oxygen compared to hemoglobin.

Photosynthesis Limiting Factors

• Oxygen production in photosynthesis can become limited by light intensity and CO2 concentration at different stages.

Evolution Complexity

• Monocots being secondary flowering plants indicates that evolutionary pathways may not ascend from simple forms to more complex ones.

Growth Rate Calculations

• In a deer population, the birth-to-death ratio can determine the population growth rate ( r ) of 0.09 based on recorded births and deaths.

Kidney Failure Symptoms

• Kidney failure often results in elevated salt concentrations in the blood due to impaired regulation.

Diatom Distribution

• Variability in diatom species diversity indicates the effect of organic waste input into streams.

Plant Growth Patterns

• Variability in growth forms in plants can include the absence of secondary growth in some species.

ATP's Role in Metabolism

• ATP plays a crucial role in metabolism owing to its high-energy phosphate bonds that facilitate energy transfer.

Genetic Variation Mechanism

• Crossing over contributes to genetic diversity during gamete production by exchanging segments between homologous chromosomes.

Allele Frequency Calculation

• In a population, the frequency of allele "a" can be calculated using the Hardy-Weinberg equation yielding a value of 0.45.

Cladistics and Taxonomy

• Monophyletic groups in cladistics include all descendants from a### Plant Height Genetic Crosses
• Two strains of the same species have a mean height of 24 cm.
• F1 generation from crossing these strains also exhibits a height of 24 cm.
• F2 generation shows a diverse range of heights, predominantly resembling P1 and F1.
• Approximately 0.4% of F2 plants are only 12 cm tall, while another 0.4% are 36 cm tall.
• The fraction of F2 plants that are 27 cm tall is 56/256.

Genetic Considerations

• Each allele contributes equally to the plant height phenotype.
• This variation indicates polygenic inheritance where multiple genes affect a single trait.

Chromosome Structure

• A functional linear chromosome must contain:
  • At least two telomeres.
  • One centromere.
  • Numerous origins of replication to support DNA replication.

Autonomic Nervous System Function

• The sympathetic nervous system is critical for immediate responses, such as a zebra fleeing from a lion, providing 'fight or flight' responses.

Reproductive Isolation Mechanisms

• Breeders keeping different dog breeds physically separated during heat mimics ecological isolation, preventing crossbreeding.

Genetic Counseling in Recessive Diseases

• Genetic counselors can assure no children will inherit a recessive disease if both parents have mutations in different genes that lead to the same condition phenotype.

Isolating Cellular Organelles

• Differential centrifugation can separate organelles like glyoxysomes and peroxisomes.
• Validation of the organelle presence in the suspension can be done by performing an assay for the enzyme catalase.

Acid-Base Balance and Ventilation

• In case of acidosis, to normalize pH, the ventilation rate should increase, resulting in a decrease in arterial PCO2 (partial pressure of carbon dioxide).

Test your knowledge on key biology concepts with these USABO practice flashcards. Focus on enzymes, gene structures, and prokaryotic characteristics to enhance your understanding of molecular biology. Perfect for students preparing for the USABO competition.