Exam #2
The actual shape of DNA is described as...
A double helix
Which statement is supported by this cladogram?
Hippopotamuses are more closely related to cows than to javelinas
What has been one effect of population growth on the physical environment?
Increased damage to coastal ecosystems
Why is meiosis important for sexual reproduction?
It allows gametes to have half the original number of chromosomes of the organism.
The graph shows the population growth of an organism over time.
The birth and death rates are equivalent
What effect might an invasive species have on the carrying capacity of an ecosystem?
The carrying capacity may decrease because there is more competition for limited resources
Sex-linked genes are located on
X or Y chromosomes
Each rung of the DNA ladder is made up of a
a pair of nitrogen bases
Each nucleotide of a DNA strand is made up of _________________________________________________.
a phosphate, a deoxyribose, and a nitrogen base
What nucleotide in DNA replication is going to be added at point 1, opposite from thymine?
adenine
Choose the factor that is unlikely to limit population growth
all are factors that limit population growth
Which of the following most likely limits a desert's carrying capacity for life?
availability of water
When does DNA replication occur?
before cell division
The purpose of mitosis is to produce
body cells
According to the finch diagram, which of the following finches is a secondary consumer?
cactus finch
DNA is copied into two new strands of DNA during a process called
replication
The purpose of meiosis is to produce
sex cells
The different finch beaks are the result of natural selection. Which of the following conditions was required for natural selection to occur in the Galápagos finches?
some genetic variation in the ancestral population
Which molecule is responsible for bringing amino acids to the ribosome to build the protein?
tRNA
An energy pyramid is used to show _____.
the amount of energy at a trophic level
Which statement describes the amount of energy passed to the hawk in the energy pyramid above?
the hawk has the least amount of energy available to it
In an experiment, a scientist encloses a mouse in a sealed terrarium. The terrarium contains sufficient water for the mouse to drink and dried seeds for food. After several hours, the mouse dies. Which statement provides the most likely explanation for the death of the mouse?
the mouse was poisoned by high carbon dioxide levels or suffocated from low oxygen levels, both problems caused by the lack of photosynthesis in the terrarium
Matter on Earth constantly cycles between the different spheres of the Earth. As matter cycles through these spheres, what effect does this have on the total amount of matter on Earth?
the total amount of matter on Earth remains constant
What did Darwin observe about finches in the Galapagos Islands?
their beaks were adaptations related to food the finches ate
Which statement below would best illustrate the concept of natural selection?
those organisms that are best adapted to the environment will survive to produce more offspring
In the RNA strand, during protein synthesis, _________________________ is replaced with uracil.
thymine
What is the purpose of protein synthesis?
to make a protein
Which RNA molecule carries amino acids?
transfer RNA
In the case of sex-linked traits, only females can be carriers.
true
What is the job of the enzyme helicase in DNA replication?
unwind and unzip the DNA molecule
What does a food web show?
what food organisms eat
What does codominance mean?
when both alleles are fully expressed
When living on the same island, which of the following finches most likely competes for food with the large insectivorous tree finch?
woodpecker finch
Which of these are the repeating units that form a DNA and an RNA molecule?
Nucleotides
Which phrase best describes the process of meiosis?
Produces haploid gametes
During which phase of meiosis does crossing over occur?
Prophase I
In protein synthesis, the end products of translation are...
Proteins
Which of the following is not part of protein synthesis?
Replication
Which of the following is an example of an abiotic factor?
Sand particle
Which of these contains both abiotic and biotic elements in a desert environment?
Scorpions and sand
Which event in meiosis increases genetic variation within a population?
Segments of chromosomes cross over
Fertilization occurs when egg and sperm unite.
True
Unlike DNA, RNA contain
Uracil
Where does transcription occur?
in the nucleus
During protein synthesis, what does mRNA do?
it delivers DNAs instructions for making proteins to the ribosome
What does transcription produce?
mRNA
Organisms near the top of the cladogram have
more traits shown on the cladogram than organisms lower on the cladogram
Where is DNA located within the cell?
nucleus
Which organelle begins to form in Phase 4 of the process in Figure 1?
nucleus
How does natural selection lead to evolution?
Helpful variations accumulate among surviving members of the species.
After meiosis you end up with ______ haploid gametes.
4
Meiosis produces
4 haploid cells
During protein synthesis, an RNA strand is transcribed from one strand of DNA. GCG TTA CCT What is the complementary RNA strand to the DNA strand shown?
CGC AAU GGA
An unfertilized egg cell has six chromosomes. After fertilization, how many chromosomes should the zygote have?
12
If the mRNA codon reads U-G-A, then the tRNA anticodon would be..
A-C-U
Which blood type is referred to as the "universal recipient" since it can receive blood types A, B, AB, and O?
AB
Which codon of the mRNA attaches to the ribosome and instructs the beginning of translation?
AUG- Methionine
Which sequence of RNA bases would pair up with a strand of DNA bases that reads TACTGCA?
AUGACGU
What is the role of the ribosome (C) during protein synthesis?
Adds the amino acid to the polypeptide chain
In what phase of meiosis do homologous chromosomes separate from their partners?
Anaphase I
When does DNA replication occur in the life of cell?
Before the process of mitosis begins
Based on the model shown, which statement correctly describes what may happen to the carbon dioxide in the atmosphere?
Carbon dioxide is used by plants in photosynthesis
Which scientist formulated the theory of evolution through natural selection?
Charles Darwin
Figure 2 illustrates genetic diversity between all four daughter cells, with no two being the same. Which component in the model helps account for creating this diversity?
Crossing-over
Transcription is _______________ and occurs ______________
DNA > RNA; nucleus
The parent cell in Figure 2 already contains double the amount of original genetic material. Which event must have occurred before the parent cell in Figure 2?
DNA replication
In his book On the Origin of Species, Charles Darwin described how species change over time. Which of the following is NOT part of his observations that describes the mechanisms of natural selection?
Disease and natural disaster will limit population growth
What is the role of DNA polymerase in DNA replication?
Dna polymerase adds complimentary free nucleotides to the original strand to make an identical copy
Which of the following questions would a scientist most likely ask to determine whether various finch populations belong to one species?
Do the various finches often mate and produce fertile offspring together?
Which best explains how energy is transferred within the energy pyramid?
Each trophic level receives a small percentage of energy from the previous level
Which of the following is not a principle of natural selection?
Evolution will occur as an organism gets older and learns more
Pedigree charts allow scientist to track traits through just one generation.
False
How is natural selection in the evolution of long necks in giraffes best explained?
Giraffes with longer necks survived because they were better suited to the environment
How would the carrying capacity of an ecosystem be affected if there were a decrease in the number of decomposers?
It would decrease due to a low amount of available nutrients for plants
Which phase of meiosis do sister chromatids line up at the equator?
Metaphase II
Which of the following best describes what carrying capacity is?
The maximum number of a population that an ecosystem can sustain
Four different nucleotides are used as building blocks of DNA. Which of the following can be used to distinguish one nucleotide from another?
The nitrogen base
Which of the following best describes what happens after RNA strands are translated?
The sequence of amino acids within a protein is determined
Which statement correctly describes how matter is conserved in Chemical Reaction 3?
The total combined number of atoms in both the reactants and the products is the same
When a red horse (RR) is crossed with a white horse (WW), the offspring are all ROAN (RW). Which of the following explains this type of inheritance?
codominance
A point on a cladogram where two lines split apart represents:
common ancestor
Which three processes occur during meiosis?
crossing over, formation of gametes, and independent
In meiosis, the replicating cell starts as a ........ cell
diploid
DNA replication results in two DNA molecules
each with one new strand and one original strand
Zero population growth occurs when the birth rate plus immigration ....... death rate plus emigration.
equals
In an energy pyramid, which way does energy flow?
from the bottom of the pyramid to the top
Which of the following is not an example of an abiotic component of an ecosystem
fungi
Darwin concluded that organisms on the Galapagos Islands
had changed over time
After meiosis I, two ......... cells are formed.
haploid
After meiosis II, four ....... cells are formed.
haploid
