USABO Practice Flashcards

Questions and Answers

What percentage of this population is probably heterozygous for the fur color trait?

42%

What organelle is most likely malfunctioning in Pompe's disease?

lysosome

Transport of which nutrient across the intestinal epithelium is by passive diffusion?

fructose

Which two brain centers control mammalian respiration?

medulla oblongata and pons Signup and view all the answers

Match the following terms with their corresponding descriptions:

primitive = Presence of a vertebral column with respect to all vertebrates derived = Presence of a vertebral column with respect to all chordates Signup and view all the answers

What is the main explanation for the lack of a continuing abiotic origin of life on Earth today?

Our oxidizing atmosphere is not conducive to spontaneous formation of complex molecules. Signup and view all the answers

What floral pattern results from a mutation in Gene C which prevents its expression?

Sepals-Petals-Petals-Sepals Signup and view all the answers

What fraction of the F2 plants will be 27 cm in height?

56/256 Signup and view all the answers

To be functional, a linear chromosome most often contains at least?

Two telomeres, one centromere, and a large number of origins of replication. Signup and view all the answers

Which subdivision of the autonomic nervous system is most important to a zebra fleeing from a lion?

The sympathetic nervous system Signup and view all the answers

What reproductive isolating mechanism is closest to breeders keeping different dog breeds physically separate?

Ecological isolation Signup and view all the answers

What information did the genetic counselor need to claim that none of the couple's children will have the disease?

The man and the woman have mutations in different genes that result in the same migraine headache phenotype. Signup and view all the answers

How might you determine that your suspension includes glyoxysomes and peroxisomes?

Do an assay for the enzyme catalase. Signup and view all the answers

To increase pH toward normal in acidosis, how would the ventilation rate change?

Ventilation rate increases, arterial PCO2 decreases. Signup and view all the answers

What enzyme does HIV use to convert RNA to DNA?

Reverse Transcriptase Signup and view all the answers

The promoter region of a prokaryotic gene is located to the gene and is the binding site for .

5'...RNA polymerase Signup and view all the answers

Which of the following is TRUE of prokaryotes? I. Simultaneous transcription and translation II. Presence of intron sequences III. Circular DNA

I and III only Signup and view all the answers

Which amino acids would you MOST expect to find in the transmembrane region of integral transmembrane proteins?

Tryptophan Signup and view all the answers

What is the G + C content in Mycobacterium tuberculosis if 18% of the bases are adenine?

64% Signup and view all the answers

What is the proportion of carrier individuals in a population affected by an autosomally recessive inherited disorder, with a frequency of affected individuals being 1 in 4?

50% Signup and view all the answers

What cell myelinates the axon in the peripheral nervous system?

Schwann cell Signup and view all the answers

Where are the cell bodies of afferent (sensory) nerves involved in somatic reflexes located?

Dorsal root ganglion Signup and view all the answers

Rods and cones are associated with _ and _ vision, respectively.

Light/dark...Color Signup and view all the answers

Populations that are living at a density near the limit of their resources are characterized as?

K-selected Signup and view all the answers

Wild-type p53 in many types of cancer is MOST likely to be a?

Tumor suppressor Signup and view all the answers

What glycolytic product is shuttled to the mitochondria in aerobic respiration?

Pyruvate Signup and view all the answers

What process leads to the formation of three germ layers during human development?

Gastrulation Signup and view all the answers

Telomerase is responsible for _ the size of telomeres, and its function is often in carcinogenesis.

maintaining...increased Signup and view all the answers

Which of the following is NOT a mode of natural selection?

Sexual selection Signup and view all the answers

Protostomes have _ and _ types of cleavage.

spiral...determinate Signup and view all the answers

Which of the following is NOT a characteristic of all chordates?

Vertebrae Signup and view all the answers

In cardiac muscle, calcium ions can move freely between adjacent cells through which structure?

Gap junctions Signup and view all the answers

Unlike most polypeptide hormones, steroid hormones are unique in that they?

Diffuse across cell membranes Signup and view all the answers

In superoxide dismutase 1, what role does the copper ion play?

Cofactor Signup and view all the answers

What is the order of normal blood flow through the human heart?

Right atrium, right ventricle, lungs, left atrium, left ventricle, body Signup and view all the answers

What type of separation does allopatric speciation refer to?

Geographic Signup and view all the answers

Which two functional groups are always found in amino acids?

Carboxyl and amine Signup and view all the answers

What is an example of movement of ions across the membrane from higher to lower concentrations through a channel protein?

Facilitated diffusion Signup and view all the answers

Which group of plants has vascular tissue but does not produce seeds?

Ferns Signup and view all the answers

Which of the following is true for transport in xylem?

Movement through xylem depends mainly on transpiration Signup and view all the answers

Predation is considered a _ interaction, while Mutualism is considered a ___ interaction.

+/-, +/+ Signup and view all the answers

Which of the following organisms is INCORRECTLY paired with its trophic level?

Beetle - primary consumer Signup and view all the answers

Which of the following is an example of habituation?

Hydra initially contract when gently touched, but soon stop responding. Signup and view all the answers

What is the relationship between gene 'C' for color and another gene influencing color in a certain mouse?

Epistatic Signup and view all the answers

During migrations, some birds use which of the following as reference frameworks? I. The sun II. Constellations III. Earth's magnetic field

I, II, and III Signup and view all the answers

Generally, in which types of ecosystem are more species per square kilometer found?

Coral reef Signup and view all the answers

In the dark reaction (Calvin cycle) of photosynthesis, RUBP is used and PGA is formed.

Dark reaction (Calvin cycle) of photosynthesis Signup and view all the answers

Which is TRUE of the dark reaction (Calvin cycle) of photosynthesis?

True Signup and view all the answers

What is the dominant generation in the fern life cycle?

Diploid sporophyte Signup and view all the answers

How would ACTH and CRF hormone production change in a person on cortisol medication?

ACTH production would decrease, CRF production would increase Signup and view all the answers

Where would carbon particles likely be found in mice after injection?

In monocytes of the spleen Signup and view all the answers

What nutrient creates the greatest need for osmoregulation in the body?

Protein Signup and view all the answers

During translation in prokaryotes, what does the ribosome bind to?

The Shine-Dalgarno sequence Signup and view all the answers

What determines the quaternary structure of a protein?

Interactions between amino acids of different polypeptide chains Signup and view all the answers

Which of the following is NOT a function of the parasympathetic division of the nervous system?

Stimulation of the adrenal medulla Signup and view all the answers

When a growing seedling is placed in an east-facing window, where will active auxin accumulate?

West side Signup and view all the answers

Which of the following is NOT a characteristic of all mammalian species?

Placenta Signup and view all the answers

What is true regarding the lac repressor of E.coli if it is mutated so that it never binds to the operator?

The result depends on the concentration of glucose Signup and view all the answers

What type of cells are characterized by many loosely packed cells with chloroplasts?

Parenchyma Signup and view all the answers

Choose the correct statement regarding a biomass pyramid shown in an exam.

Producers reproduce quickly but are also consumed at a rapid rate Signup and view all the answers

Which would likely increase competition among voles in an area?

An increase in the reproduction rate of voles Signup and view all the answers

What genetic material does the tobacco mosaic virus contain?

RNA Signup and view all the answers

An amphipathic molecule is characterized by?

A hydrophilic end and a hydrophobic end Signup and view all the answers

What is the function of a molecular chaperone?

Bind to specific structures on the polypeptide to assist the folding of a protein Signup and view all the answers

Why is Ethidium Bromide used in electrophoresis of DNA fragments?

Makes the fragments visible under UV light Signup and view all the answers

In which geologic epoch did Homo sapiens first appear?

Pleistocene Signup and view all the answers

Which marine community would be LEAST affected by a volcanic eruption or meteor impact?

Deep sea vent community Signup and view all the answers

What is a unique feature of fertilization in angiosperms?

It is a double fusion event; one sperm fertilizes the egg, the other sperm combines with the polar or fusion nucleus Signup and view all the answers

What provides support for the plant body?

Sclerenchyma cells Signup and view all the answers

What does the Hardy-Weinberg equilibrium principle assume?

For a given trait, the frequency of dominant alleles is greater than that of recessive alleles Signup and view all the answers

Which group will produce the greatest volume of urine after different liquid intakes?

Those who drank coffee will produce the most urine, while those who drank the salt solution will produce the least Signup and view all the answers

Which protein tags proteins for degradation by proteasome activity?

Ubiquitin Signup and view all the answers

Which of the following statements is true of territorial behavior?

'Owners' defend mainly against conspecifics Signup and view all the answers

What is true about an RNA-binding membrane after gel electrophoresis?

You are trying to determine if Gene X is expressed in liver cells Signup and view all the answers

How many net NADH and ATP molecules are generated from each pyruvate molecule during pyruvate oxidation and the citric acid cycle?

3, 1 Signup and view all the answers

Which characteristic is an adaptation of temperate climatic zone plants?

Dormant buds Signup and view all the answers

Which statement is acceptable regarding plant growth?

Some plants lack secondary growth Signup and view all the answers

Why is ATP an important molecule in metabolism?

It has high-energy phosphate bonds Signup and view all the answers

In which type of cell does crossing over occur?

Gametes Signup and view all the answers

What is the frequency of the a allele in a population of 15 AA, 25 Aa, and 10 aa individuals?

0.45 Signup and view all the answers

Which groups represent a monophyletic taxon?

A, B, C, D, E, F, and G Signup and view all the answers

What is a ribozyme?

RNA molecule that functions as an enzyme Signup and view all the answers

What behavioral explanation describes the actions taken by live ants towards dead ants?

The chemical acts as a sign stimulus for a fixed action pattern Signup and view all the answers

Which of the following characteristics do vascular plants NOT share?

Development of seeds Signup and view all the answers

What is significant about the production of genetically engineered 'golden rice'?

Golden rice contains higher concentrations of β-carotene than white rice Signup and view all the answers

How many different diatom species were found in one mile of a stream in a certain investigation?

150 Signup and view all the answers

After observing a second site downstream and finding only 20 different diatom species, what can be inferred?

Organic wastes high in nitrates and phosphates entered the stream Signup and view all the answers

Study Notes

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).

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Description

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.