OSAT - Biological Science

Ionic bonds

occurs when one atom transfers electrons to another

Stored fat molecules can be used to produce more ATP per gram than glucose molecules because fat molecules are what?

they are highly reduced with only C-C and C-H bonds

The process by which water is moved from a plant's roots to its leaves depends on the

attraction between a hydrogen atom of one water molecule and the oxygen atom of another

The high specific heat capacity of water best explains how water

insulates aquatic organisms in the winter under a layer of ice

During an enzyme mediated reaction, a regulatory molecule binds to a secondary site on the enzyme and changes the conformation of the enzyme's active site. Which of the following processes best describes this interaction

allosteric regulation

Feedback inhibition

Is a cellular control mechanism in which an enzyme's activity is inhibited by the enzyme's end product. This mechanism allows cells to regulate how much of an enzyme's end product is produced.

competitive inhibition

phenomenon in which a substrate molecule is prevented from binding to the active site of an enzyme by a molecule

allosteric regulation

a form of noncompetitive inhibition that slows down enzymatic activity by binding to an allosteric site

students creating ball-and-stick models of biologically important molecules use white balls to represent hydrogen atoms, red balls for oxygen atoms, and black balls for carbon atoms. Short, flexible pieces of plastic are used for bonds between the atoms. What type of biomolecules could be represented most easily using these materials?

carbohydrates

A cross section of an object under an electron microscope is found to contain a single loop of chromosomal DNA, ribosomes, and a cell membrane. This object is most likely a

bacterium

Which of the following structures is most important with regard to increasing the surface area of the chloroplast for the absorption of light energy

thylakoid stacks

Absorption of nutrients in the human small intestine is facilitated by cells that would most likely exhibit which of the following specialized characteristics?

brush border of microvilli

the inside of a cell has high concentrations of sodium (NA+) ions and low concentrations of chloride (Cl-) and potassium (K+) ions. The solution in which the cell sits has a high concentration of chloride and potassium ions and low concentrations of sodium ions. The outside of the cell has a positive charge relative to the inside of the cell. If the membrane is equally permeable to all of the ions, both the concentration gradient and the force of the electric charge will tend to move

potassium into the cell

Communication between cells in the nervous system differs from cell communication involving the endocrine system because communication between cells in the nervous system:

relies on ligands that are quickly degraded

The phase of the cell cycle where DNA replication takes place.

S phase

This is the first gap phase where the cell grows and prepares itself for DNA replication

G1 phase

This is the phase where the cell divides its duplicated chromosomes. By the end of this phase, the DNA content returns to normal

M phase

This is the second gap, where the cell grows further and prepares for mitosis.

G2 Phase

In humans, the unregulated cell division that may result in cancer is the result of problems with the checkpoint at the end of the following phases of the cell cycle

G2

Compared to that of other heterotrophs, the manner in which multicellular fungi obtain and utilize energy is unique because fungi

digest matter externally before ingesting it.

Which of the following substances is the initial source of energy for most of the microorganisms inhabiting a deep-sea ecosystem?

hydrogen sulfide

which of the following substances is primarily responsible for an increase in mass associated with the growth of a seed into a tree

carbon dioxide taken in by leaves

What is the difference between aerobic and anaerobic respiration

aerobic respiration is more efficient and yields more energy of ATP than anaerobic respiration

A characteristic of chloroplasts and mitochondria related to their function in living organisms is that both of these cell organelle types

have double membranes that facilitate in oxidative phosphorylation

A researcher studying algae growing in fish tank increases the light intensity available to the algae for a period of 5 days. What is the likely outcome?

increased production of carbohydrates

When chlorophyll molecule absorbs the energy from a photon of light, there is an effect of an increase in the potential energy of which of the following particles?

electrons

When desert lizards bask in the sun, they demonstrate that ectothermic organisms need to

maintain a stable internal environment

Spider crabs conform to the minor changes in salinity in their environment by gaining losing water. This contrasts with the strategy of pacific salmon, which actively regulate the solutes in their blood. Compared with the spider crab strategy, the pacific salmon's strategy is most likely associated with which of the following parameters.

greater expenditures of energy

In green plants, the exchange of water and gases with the surrounding environment is directly facilitates by which structure

stoma

The narrow structure of the human cervical canal allows for the cervix to perform which of the following functions

directing sperm into the uterus

Models of optimal foraging behavior predict that individual members of a species will increase the distance traveled and the amount of time spent foraging when the

population density of the foraging species is high

In seeded vascular plants, the sporophyte phase of the repro cycle is dominant and the gametophyte is greatly reduced. What best describes the evolutionary advantage of this arrangement compared to that of seedless vascular plants?

The gametophyte can be protected from the environment and nourished within the sporophyte

As part of an engineering design unit focusing on the human body, students use easily obtained materials to create a protype of a filter that removes objects from water. This prototype models what function in which organ?

kidneys

commensal relationship

a relationship between individuals of two species in which one species obtains food or other benefits from the other without either harming or benefiting the other species

what condition distinguishes a tropical rainforest from a hardwood forest

Most nutrients are held in vegetation and forest litter

density-independent factors

refer to any influences on a population's birth or death rates, regardless of the population density. They are typically a physical factor of the environment, unrelated to the size of the population in question(common density independent factors, such as temperature, natural disasters, and the level of oxygen in the atmosphere.)

K-selected species

species whose populations fluctuate at or near the carrying capacity (K) of the environment in which they reside.

Type I survivorship curves

a curve displayed on a semilogarithmic scale that tracks organisms that tend to live long lives

Boom-and-bust populations

These are dramatic flucuation in population. occur when the population growth of one species is closely tied to a limiting factor that may be expended. (fluctuation of predators and prey affecting the population of other species)

Density-dependent factors

any force that affects the size of a population of living things in response to the density of the population (Some of the common examples are the availability of food, parasitism, predation, disease, and migration)

quadret method

important method by which organisms in a certain proportion (sample) of the habitat are counted directly. It is used to estimate population abundance (number), density, frequency and distributions. The quadrat method has been widely used in plant studies.

Compared to terrestrial area undergoing primary succession, a terrestrial area that is going through secondary succession following the abandonment of an agricultural field is usually characterized by

existence of nutrient-rich soil

An invasive species, such as the zebra mussel, impacts the biodiversity of an aquatic ecosystem because

lacks natural predators

In a forest ecosystem, the conversion of organic matter to inorganic matter for use by autotrophs would be carried out by which of the following organisms?

bacteria

The relationship between energy and matter in an ecosystem is reflected by which of the following patterns among its inhabitants?

the producer level that has the greatest biomass

the primary reason that generalist predators are more likely to survive an environmental disturbance than are specialist predators dependent on a single prey species is that generalist predators have a

wider range of potential food sources

As a group, chemoautotrophic bacteria share ability to

use inorganic compounds as a source of relatively high-energy electrons

A science teacher builds a compost pile out of dried sheep manure, shredded leaves, grass clippings, kitchen waste, and water. Each component is weighed before it is placed in the pile and the pile's volume record. Students regularly turn and mix the pile and add water. After six weeks, the pile has become compost and is reweighed and its volume calculated. The pile is shown to have decreased significantly in both weight and volume

release of carbon as carbon dioxide during the process of bacterial respiration

release of sulfur dioxide into the atmosphere contributes most directly to which of the following environmental problems

acid precipitation

The rapid growth of algae in a suburban lake has resulted in a die-off of fish and other aquatic organisms. Which of the following factors most likely contributed to this phenomenon

a runoff of fertilizer used on nearby lawns

An environmental advantage associated with the use of genetically modified agricultural crops is that these plants

require less use of pesticides

Wildlife biologists have proposed and developed wildlife corridors b/w different populations of wolves primarily to help prevent what?

inbreeding within isolated populations of wolves

The green revolution was a worldwide confluence of research, development, and transfers of technology that saved hundreds of millions of people from starvation from the 1940s through the 1970s. The primary component of this agricultural revolution was the development of

high-yielding varieties of cereal grains

Bioremediation is a process in which organisms metabolize toxic substances and produce less harmful byproducts. In consideration of laboratory safety, this method of cleaning up environmental contamination would best be modeled by investigation of the

variables that affect respiration in yeast using sugar as a carbon source

An increase in the rate of sea level rise is primarily caused by an increase in

ocean temps

The following sequence is ranking genetic material in order from smallest to largest

nucleotide --> DNA --> gene --> chromosome

deletions and duplications of genetic material in sister chromatids are most likely caused by which of the following types of alteration to chromosomal structure

translocations

inversions

occurs when part of your chromosome breaks off and then reattaches, but sometimes pieces along the edges are lost

nondisjunction

when chromosomes do not separate properly during cell division

What event occurs during translation process in eukaryotic cells?

tRNA molecules bind to both amino acids and mRNA transcripts

In the bacterium Escherichia coli, tryptophan molecules inhibit the synthesis of amino acid tryptophan by blocking gene transcription as a result of

activating a repressor protein that binds to the operator

The development of which of the following components of genetic engineering was key in enabling scientists to successfully insert the human gener for insulin into bacteria

DNA restriction analysis

Which of the following steps of transgenic crop engineering would require the use of polymerase chain reaction (PCR)

producing multiple copies of the gene

Examination of an individuals karyotype pattern provides evidence of errors in which of the following levels of genetic material

chromosome

incomplete dominance

when a dominant allele does not completely mask the effects of a recessive allele, and the organism shows a blending of both alleles

Codominance

a form of inheritance where two alleles of the same gene are expressed roughly equal amounts in an organism

sex-linked trait

an observable characteristic of an organism that is influenced by the genes on the chromosomes that determine the organism's sex

Historically, tall pea plants were crossed with short pea plants and the resulting F1 generation plants were all tall. When these F1 generation plants were crossed, however, 75% of these F2 offspring were tall plants and 25% were short. These experiments provided support for the idea that

certain traits appear to mask other trait

compared to other patterns of inheritance, a characteristic of traits inherited by mitochondrial inheritance is that

only bio mothers can pass the trait to their offspring

Most cases of Down syndrome are caused by

chromosomal nondisjunction's during meiosis

A geneticist would use a testcross in order to determine

given organism is homozygous or heterozygous for a trait

Which phenomenon was discovered well after On the Origin of Species was published and is also vitally important to the process of natural selection

mutation

Which of the following statements best describes speciation as viewed in the punctuated equilibrium model of evolution compared with the gradualism model

speciation is assumed to occur much more rapidly in the punctuated equilibrium model

The reproduce structures of grasses often lack pedals and fragrances and exhibit long, protruding anthers and feathery stigma. These adaptations facilitate pollination by what mechanism

wind

Which of the following situations would likely result in sympatric speciation

fruit flies occupying a tropical rain forest use different courtship behaviors to attract potential mates

In a population of spring peepers, female frogs tend to mate with males that have the loudest mating calls . As a result, the number of males with loud calls becomes more abundant. In this population, allelic frequency is affected by what processes

sexual selection

Character divergence occurs when two similar species overlap in part of their ranges. Bc of competititon b/w the species in the overlapping area, the populations in each species diverge in some characteristics, as compared to populations in areas where overlap does not occur. This is called what

Directional selection

Disruptive selection

Disruptive selection is a mode of natural selection where the two extreme phenotypes are favored over the intermediate ones. (Fish populations where both small and large individuals have advantages over medium-sized individuals.)

behavioral isolation

occurs when a subset of a particular species slowly undergoes changes in its behavior ordinarily due to traveling to different geographical regions.

What discoveries in he field of molecular systematics has been most responsible for the widespread acceptance of the three-domain classification scheme at the expense of the classical five-kingdom scheme

genetic diversity in prokaryotes that is much greater than previously thought

Researchers are examining the rate of speciation of cave spiders in different chambers of a cave. They are trying to examine how fast an ancient cave flooded, creating the several unconnected chambers that the spiders now inhabit. In their study, the scientists are making what assumption?

Long periods of geographical isolation will create more genetically distinct spider species

The colony behaviors of social insects, the laws of classical mechanics, and weather patterns are examples of which of what characteristics of complex natural systems

emergent properties

Each number in a Fibonacci sequence is the sum of the two previous numbers. Which of the following natural phenomena has been described using Fibonacci sequence

The arrangement of leaves on a stem, such that the arrangement minimizes the degree to which they shade each other.

During the time that Charles Darwin was developing his ideas on "descent with modification," which later became better known as Darwin's theory of evolution, his views were most strongly supported by

Alfred Russel Wallace's work on the geographic distribution of species

A population of frogs undergoes a dramatic increase during an unseasonably hot summer. A scientist carefully designs and performs an experiment to test the hypothesis that they higher average water temp that have been observed are causing female frogs to lay more eggs than usual. If the data do not support the hypothesis, what is the most appropriate next step for scientist to take?

considering other factors that might affect population size and formulating a new hypothesis

In the classroom a physical model would be most helpful in illustrating what biological concept?

the structure of DNA molecule

Two bird species regularly visit feeders for sunflower seeds during the winter. For a month, several students take turns watching the feeding station from 6:30 to 7:30 every morning and recording their observations. They find that whenever individuals of one species arrive at the feeder, individuals of the other species leave. The students conclude that competition for food between the species is an important factor in their ecological relationship. The students; conclusion described in the passage would be strengthen by adding which of the following elements?

observing the feeding behaviors of both species under natural conditions

To remove pigments from the leaves of a plant, wilted leaves from the plant are placed in a flask of alcohol. The alcohol must be heated just to its boiling point to remove pigments from the leaves. Which of the following is the most appropriate procedure for heating the alcohol and the leaves?

putting the flask in a water bath and slowly heating the alcohol to the boiling point using a hot plate.

The functioning of a compound light microscope is based on which of the following physical phenomena

Light is refracted when it passes from one medium to another.

Nucleotides are components of the compounds that are directly responsible for which of the following functions in biological systems

storing genetic information

Researchers studying enzyme-catalyzed systems in the lab use buffered solutions in order to

limit changes in enzyme activity that might otherwise occur as a result of changes in pH

which of the following cell organelles are found in both prokaryotic and eukaryotic cells?

ribosomes

Energy production in prokaryotic cells differs from that in eukaryotic cells, because in prokaryotes

the entire cell acts as its own mitochondrion

which of the following structures is present in animal cells but not plant cells

lysosomes

the inside of a cell has high concentrations of sodium (NA+) and low concentrations of chloride (Cl-) and potassium (K+) ions. The solution in which the cell sits has high concentrations of chloride and potassium ions and a low concentration of sodium ions. The outside of the cell has a positive charge relative to the inside of the cell. If the membrane is equally permeable to all of the ions, both the concentration gradient and the force of the elctric charge will tend to move

potassium into the cell

In germinating seeds, increased production of ATP is positively correlated with what factor

increased temp

which of the following processes is most responsible for providing the phenotypic variation that makes evolution possible

sexual reproduction

The multinucleate nature of skeletal muscle cells during vertebrate's development is a direct consequence of

their formation from the fusion of many different cells.

a point mutation involving the insertion of a single nucleotide pair is usually more damaging to the production of proteins than is a substitution. That is bc, unlike a substitution, an insertion always:

disrupts the coding of a triplet by altering the triplet grouping and causing the improper grouping of all downstream triplets.

Communication b/w cells in the nervous system differs from cell communication involving endocrine system because communication between cells in the nervous system

relies on ligands that are quickly degraded.