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What characterizes a prokaryotic cell?
presence of a nucleus with no DNA
lack of ribosomes
having a cell wall without a cell membrane
lack of a membrane-enclosed nucleus
presence of mitochondria
Which of the following is NOT considered a weak molecular interaction?
van der Waals interactions
ionic bond in the presence of water
Acid rain has lowered the pH of a particular lake to 3.0. The hydrogen ion concentration of the lake is
A cation always has:
more protons than neutrons
more electrons than protons
equal numbers of protons and electrons
more protons than electrons
Nucleotides are important in
All of the preceding
energy production and utilization
transmission of hereditary information
nucleic acid organization
Water is able to form hydrogen bonds because
the oxygen atom in water molecules is weakly negative
the hydrogen in water molecules is weakly positive
All of the above are correct
the water molecule is polar
The unique sequence of amino acids in a polypetide:
quaternary structure of a protein
primary structure of a protein
tertiary structure of a protein
secondary structure of a protein
An enzyme accelerates a metabolic reaction by
making the substrate molecule more stable
pushing the reaction away from equilibrium
altering the overall free-energy change for the reaction
lowering the activation energy
Which of the following organelles is common to plant and animal cells?
wall made of cellulose
Which of the following components is present in prokaryotic cell?
On which of the following features do most plant and animal cells differ?
structure of nucleus
primary energy source
active transport mechanisms
If a sexually reproducing species has a chromosome number of 2n=16, then:
it is diploid with 32 chromosomes
its gametes contain 16 chromosomes
it received 8 chromosomes from the egg and 8 chromosomes from the sperm
it has 16 different pairs of chromosomes
A biochemist isolated and purified molecules needed for replication. When DNA was added, replication occurred but the DNA molecules were defective. Each consisted of a normal DNA strand with many DNA segments a few hundred nucleotides long. What has the biochemist left out of the mixture?
A microbiologist found that some bacteria infected by phages had developed the capacity to make a particular amino acid that they did not make before. The new capacity probably reflects
Which of the following is not true of a codon? A codon
is a basic unit of genetic code
never codes for more than one amino acid
may code for the same amino acid as another codon
extends from a tRNA molecule
The cells of the liver are distinct from cells of the spleen because they
have different chromosomes
use different genetic codes
express different genes
have unique ribosomes
contain different genes
Which of the following techniques would you use to produce a great number of DNA copies?
polymerase chain reaction
All of the following compounds are required at some stage of photosynthesis EXCEPT
Which of the following would never contribute to genetic variation within a bacterial population?
The final electron acceptor of the electron transport chain that functions in oxidative phosphorylation is
During human gestation, organogenesis occurs
in the first trimester
during the blastocyst
during the embryo
while the embryo is in the oviduct
in the second trimester
Organogenesis begins with the development of the
neural tube (brain & spinal chord)
Programmed cell death occurs normally in the development of the nervous and immune systems. This is termed
Mammals are distinguished from other vertebrates by the presence of
an amniote egg
a four chambered heart
hair and mammary glands
As humans diverged from other primates, which of the following most likely appeared first?
the development of culture
an enlarged brain
an erect stance
The major endothermic (warm blooded) vertebrates include the
mammals and birds
birds and reptiles
Which of the following enzymes acts first during digestion?
In which of the following blood vessels would you expect to find the most nutrients?
hepatic portal vein
posterior vena cava
renal portal vein
The various metabolic exchanges occur in
Pulse is a direct measure of
Compared to interstitial fluid that bathes active muscle cells, blood reaching these cells in arteries has a
higher partial pressure of O2
lower osmotic pressure of CO2
higher partial pressure of CO2
Humoral immunity is mediated primarily by
HIV compromises the immune system primarily by infecting _______ cells
Fertilization of human eggs most often takes place in the
oviduct (fallopian tube)
The nitrogenous waste generated by an animal is best correlated with the animals _______ metabolism.
nucleic acid and lipid
protein and nucleic acid
The concept that recognizes that the internal environment is maintained at an optimal level is termed
The functional units of the kidney control blood composition through
all of the preceding
The coordination of movement is mediated by the
The largest and most complex part of the human brain is the
Of the following components of the nervous system, which is the most inclusive?
central nervous system
Which scientific name is presented correctly?
A single bacterium existing in an environment with unlimited resources and no competition would
___________ capacity is the maximum number of individuals of a species an environment can support.
none of the preceding
Which of the following compounds is the most common compound in the bacterial cell wall?
A mycelium consists of
cellular slime molds
Genes that regulate development are conserved. This means that they
have evolved large differences among multicellular organisms
none of the above
have changed very little over the course of evolution
are always turned on
During translation, polypeptide chain elongation requires the __________ enzymatic activity
Which of the following processes occurs in the cytoplasm of a eukaryotic cell?
DNA replication and translation
translation and transcription
By executing a test cross, the genotype of an organism that expresses a dominant trait can be determined by
crossing the organism with a heterozygous dominant organism
crossing the organism with a homozygous dominant organism
crossing the organism with a homozygous recessive organism
observing the phenotype of the progeny from any cross
observing the genotype of the progeny from any cross
Ribosomes are a collection of __________ that are needed for ____________.
proteins and rNAs; translation
small proteins; translation
proteins and tRNAs; transcription
proteins and mRNAs; translation
mRNAs and tRNAs; translation
The genetic code is degenerate because
amino acids may have more than one codon
each codon codes for only one amino acid
both A &B
neither A nor B
Epistasis refers to
group of genes that are close together
the equal interaction of two genes so that a new phenotype is produced
the expression of two genes in the same individual
the linear order of genes on a chromosome
the expression of one gene making the expression of another
FOR QUESTIONS 54, 55, 56 & 57 BASE RESPONSE ON THE FOLLOWING INFORMATION
In a species of tropical bird, wing feather coloration is controlled by the action of 6 loci: R, D, G, Y, A and B, alleles R and r, D and d, etc. Complete dominance occurs at each locus.
The R and D loci exhibit additive gene action: R__ D__ bird have dark red wings; rrdd birds have pink wings; and all other genotypic combinations at these loci result in birds with pale red wings.
The G locus is dominantly epistatic to the R and D loci; G__ birds exhibit green wing coloration. The Y locus is recessively epistatic to the R,D and G loci; yy birds have yellow wings. The A and B loci control pigment production and are recessively epistatic to the color loci; aa and/or bb birds have white wings [i.e. dominance is required at both loci for pigment production].
RrDdGgYyAaBb x rrddggYYAaBb
(just click "okay bih" in answer options)
tell me something good *song tune*
From the mating above, what proportion of the progeny would be expected to exhibit the paternal phenotype?
From the mating above, what proportion of the progeny would be expected to exhibit the maternal phenotype?
An inbred pale red wing female is mated with a white male. The F1 (subscript 1) progeny are mated among themselves. What is the largest proportion of the F2 (subscript 2) progeny that would be expected to exhibit green wing feathers?
(I didn't have the answer for this one and I'm way too sleepy to figure it out)
I DONT KNOW
A green winged female is mated with a yellow winged male. What is the largest proportion of their progeny that would be expected to exhibit pale red wings?
Which phrase regarding a Mendelian monohybrid cross is incorrect? It
demonstrates independent assortment
demonstrates segregation of only one pair of alleles
gives two phenotypic classes
gives three phenotypic classes
Which statement about chromosome number is incorrect?
each type of chromosome is represented twice in a diploid cell
gametes usually contain only one set of chromosomes, referred to as haploid
a human somatic cell has one pair of sex chromosomes
sister chromatids of a chromosome are genetically identical and constitute a homologous pair
During meiosis, when are homologous pairs of chromosomes separated?
no answer is correct
What is the pattern of inheritance for a rare recessive allele?
very affected person has an affected parent
affected parents do not produce affected children
unaffected parents can produce children who are affected
unaffected mothers have affected sons and daughters who are carriers
There are 46 chromosomes in a human diploid cell. How many autosomes are present in an egg cell?
_________ is the term for an allele that has more than one distinguishable phenotypic effect.
Experiments conducted by Meselson and Stahl demonstrated that DNA replication is
Nucleotides are composed of:
ribose sugar ad phosphates
ribose sugars and nitrogenous bases
nitrogenous bases and phosphates
both b and c
Which of the following is a normal human female?
For double helical DNA (This is Chargaff's Rule):
A+T/G+C always approximates 1.0
A+T/G+C always approximates 0.5
A+G/T+C always approximates 1.0
A+G/T+C always approximates 1.5
A human somatic cell contains _____ chromosomes.
DNA makes DNA
DNA makes RNA
RNA makes a polypetide chain
RNA makes DNA
Which of the following processes occurs in the cytoplasm of the eukaryotic cell?
DNA replication translation
Which of the following series represents alleles:
In the human body, gametes are produced by
During replication in E. coli, DNA is maintained as single-stranded molecules at replication fork by:
The problem of replication on the lagging strand is solved by DNA through the use of
the unwinding enzyme, helicase
DNA polymerase I synthesis new molecules of DNA in:
a 3' to 5' direction
a 5' to 3' direction
both a and b
The two strands of double helical DNA are held together by
The genotypic ratio in a cross between a homozygous recessive and a heterozygous (aa x Aa) is:
Processing of primary transcripts results in
smRNPs are involved in:
posttranslation modification of proteins
What is the difference between DNA and a chromosome:
chromosomes contain DNA within their structure
DNA often incorporate a chromosome into its mass
chromosomes fill the nucleus while DNA is in the nuclear membrane
they are essentially the same
A couple who are both carriers for the gene for cystic fibrosis have two children who have cystic fibrosis. What is the possibility that their next child will have cystic fibrosis?
If factor "a" is lethal in the homozygous condition, "aa", then how many offsprings out of every 16 will survive from the cross AsBb x AaBb?
Given the parents AABBCc x AabbCc, assume simple dominance and independent assortment. What proportion of the progeny will be expected to phenotypically resemble the first parent?
What role do herbivores (organisms that eat plants) play in the energetics of ecosystems?
Which gas is most abundant in earth's current atmosphere?
occurs in anerobic conditions
converts nitrogen gas to ammonia
converts nitrate to nitrate
is carried out by Rhizobium bacteria
Most of the earth's carbon is found in:
tree trunks and living biomass
A female African elephant produces a single offspring at interval levels of several years, caring for her young for an extended period before reproducing again. The elephant's reproductive life history is referred to as:
Offspring from a sexual union contribute only one-half as much to the evolutionary fitness of either parent as asexually produced offspring. This relative reduction in fitness is called:
the Red Queen hypothesis
the cost of meiosis
Desert shrubs competing for scarce supplies of water are likely to show which dipersion pattern?
When predators and their prey exhibit cyclic population oscillations, the typical pattern is:
predator number increases after prey number increases
prey number increases after predator number increases
both predator and prey cycles are nearly identical (synchronous peaks)
no predictable relationship between predator and prey population sizes
Hummingbirds will chase away other birds that attempt to visit backyard feeders. This interaction is an example of:
The relationship between plants and their insect pollinators is best described as:
Which of the following nutrient elements typically limits primary production in fresh water?
Which of the following ecosystems has a level of production similar to a tropical rain forest?
Mycorrhizal fungi aid in supplying what critical element to plant roots?
Production of large sized offspring is most likely linked to:
high competition among juveniles
wind dispersal of offspring
production of large numbers of offspring
increased survivorship of parents
The predominant sexual system in flowering plants is:
When a population grows according to the logistic model, what is the value of "r' when the population numbers are stable?
r = 0
r = K
r = N
r = 1/2 K
All of the following are plant secondary compounds used for defense against herbivores EXCEPT:
Keystone predators can increase species diversity in a community because:
they eat most kinds of species
they allow species to live outside of their ecological range
they prevent prey from eating each other
they may prevent a superior competitor from becoming dominant
The first few years of succession on an abandoned agricultural field are characterized by a community of:
annual and biennial herbaceous plants
perennial herbaceous plants
The largest single source of anthropogenic (human-caused) increase in atmospheric carbon dioxide:
burning fossil fuel