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ABCTE ALL Biology Plus PDF Questions
And Answers (Guaranteed A+)
Why are human muscle and bone cells different?
A They contain different sets of genes.
B They contain different sets of operons.
C Different genes are switched on or off.
D Similar genes produce different proteins in different cells. - Answer✔C is the correct answer.
Only 2-5 percent of the genes in a specialized cell are activated. Choice A is incorrect because all
of the gene sets are the same. Choice B is incorrect because eukaryotic cells are not known to
contain operons. Choice D is incorrect because each specific gene produces a specific protein,
unless the mRNA is damaged or reshuffled.
How many genes are estimated to be in a human cell?
A 250
B 2,500
C 25,000
D 250,000 - Answer✔C is the correct answer. Latest research shows that human cells have about
25,000 active genes.
Choices A and B are too low. Choice D is too high.
There is about 1,000 times as much DNA in a human cell as in an E. coli cell, but only about 10-
20 times
as many genes. How can this be?
A A human cell has more non-coding DNA.
B The DNA packaging is much more complex in a prokaryotic cell.
C Most of the genes in a human cell are turned off.
D E. coli is less able to respond to its environment than humans. - Answer✔A is the correct
answer. Most of the human DNA strand consists of non-coding introns. Choice B is
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incorrect because DNA packaging is simpler in a prokaryotic cell. Choice C is incorrect;
although the genes in specialized cells may be inactivated, they are still present. Choice D is
incorrect because E.
coli is able to respond readily to its environment.
Where in the cell does gene transcription take place?
A Mitochondria
B Cytoplasm
C Ribosome
D Nucleus - Answer✔D Nucleus
Which of the following is the primary method of regulating gene expression in eukaryotes?
A Controlling transcription of a gene
B Controlling translation of mRNA into protein
C Degrading proteins in the cytoplasm
D Making mRNA molecules more unstable - Answer✔A is the correct answer. Regulation of
gene expression is accomplished through changing the rate of transcription. Choices B, C, and D
are methods of lesser importance.
In recombinant DNA experiments, substance X is used to cut pieces of DNA, and substance Y
joins these
segments to form recombinant DNA. Which of the following choices correctly pairs these two
substances?
A restriction enzyme—DNA ligase
B plasmid—restriction enzyme
C plasmid—DNA ligase
D DNA ligase—restriction enzyme - Answer✔A is the correct answer. Choices B and C are
incorrect because a plasmid is the structure in a bacterial cell into which the DNA is inserted.
Choice D has the correct two substances, but in the wrong order.
Which of the following describes a nucleic acid probe?
A It inserts genes into a host cell.
B It synthesizes DNA for cloning.
C It cuts DNA into fragments.
D It finds a particular nucleotide sequence. - Answer✔D is the correct answer. Nucleotide probes
are used to locate specific nucleotide sequences. Choice A is a description of the function of the
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enzyme ligase. Choice B is a description of a process. Choice C is a description of a restriction
enzyme.
Archaeologists excavated a human femur and succeeded in extracting a tiny amount of DNA
from the
bone. Which of the following would be the best first step in analyzing the DNA found?
A Perform gel electrophoresis to analyze the DNA.
B Fragment the DNA with restriction enzymes.
C Use the polymerase chain reaction to amplify the DNA.
D Use a nucleic acid probe to identify nucleotide sequences. - Answer✔C is the correct answer.
The polymerase chain reaction amplifies the DNA segments. Choice A is
incorrect because there may be insufficient DNA to analyze. Choice B is incorrect because
fragmenting the small amount of DNA would not be productive. Choice D is useful only for
identifying particular
sequences.
Which tissue type contains few cells?
A Muscle
B Nervous
C Epithelial
D Connective - Answer✔The correct answer is D; connective tissue is a matrix of collagenous
fibers. Muscle, nervous, and epithelial tissues have many more cells than connective tissue.
What distinguishes Parazoa from Eumatazoa?
A Presence of body cavities
B Presence of bilateral symmetry
C Absence of true tissue
D Presence of coelom - Answer✔The correct answer is C. Parazoa, such as sponges, have
differentiated cells but they are not organized into tissues. Choices A and D are the same, which
is what distinguishes the coelomates. Choice B is a description of the Deuterostomes.
Which of the following statements explains why animals possess homologous structures?
A They are doomed to extinction.
B They evolved from a common ancestor.
C They have increased genetic diversity.
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D They are examples of convergent evolution. - Answer✔B is the correct answer. Homologous
structures are an indication of common ancestry. Choice A is incorrect because homologous
structures do not indicate extinction. Choice C is incorrect because organisms with homologous
structures are genetically similar. Choice D is incorrect because convergent evolution produces
analogous structures.
A hollow sphere of cells during embryonic development is called a
A zygote.
B amniotic sac.
C ovum.
D blastula. - Answer✔The correct answer is D. A zygote is a cell resulting from fertilization. The
amniotic sac consists of two
membranes that hold the embryo, then fetus. An ovum is an egg—a female sex cell or gamete.
During which trimester does organogenesis occur?
A First
B Second
C Third
D Fourth - Answer✔A is the correct answer. The first trimester is characterized by development
of rudimentary forms of all adult structures.
Choice B is the trimester of growth.
Choice C is the trimester of rapid growth.
Choice D is incorrect because there is no fourth trimester.
Which of the following organisms has all its cells directly in contact with the external
environment?
A Hydra
B Earthworm
C Oak Tree
D Amoeba - Answer✔The correct answer is D. The cells of choices A, B, and C are not all in
direct contact with the external
environment.
Which of the following organisms has a closed circulatory system?
A Arthropod
B Mollusk
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ABCTE ALL Biology Plus PDF Questions
And Answers (Guaranteed A+)
Why are human muscle and bone cells different?
A They contain different sets of genes.
B They contain different sets of operons.
C Different genes are switched on or off.
D Similar genes produce different proteins in different cells. - Answer✔C is the correct answer.
Only 2-5 percent of the genes in a specialized cell are activated. Choice A is incorrect because all
of the gene sets are the same. Choice B is incorrect because eukaryotic cells are not known to
contain operons. Choice D is incorrect because each specific gene produces a specific protein,
unless the mRNA is damaged or reshuffled.
How many genes are estimated to be in a human cell?
A 250
B 2,500
C 25,000
D 250,000 - Answer✔C is the correct answer. Latest research shows that human cells have about
25,000 active genes.
Choices A and B are too low. Choice D is too high.
There is about 1,000 times as much DNA in a human cell as in an E. coli cell, but only about 10-
20 times
as many genes. How can this be?
A A human cell has more non-coding DNA.
B The DNA packaging is much more complex in a prokaryotic cell.
C Most of the genes in a human cell are turned off.
D E. coli is less able to respond to its environment than humans. - Answer✔A is the correct
answer. Most of the human DNA strand consists of non-coding introns. Choice B is
1|Page
, ©EVERLY 2024/2025 ALL RIGHTS RESERVED.
incorrect because DNA packaging is simpler in a prokaryotic cell. Choice C is incorrect;
although the genes in specialized cells may be inactivated, they are still present. Choice D is
incorrect because E.
coli is able to respond readily to its environment.
Where in the cell does gene transcription take place?
A Mitochondria
B Cytoplasm
C Ribosome
D Nucleus - Answer✔D Nucleus
Which of the following is the primary method of regulating gene expression in eukaryotes?
A Controlling transcription of a gene
B Controlling translation of mRNA into protein
C Degrading proteins in the cytoplasm
D Making mRNA molecules more unstable - Answer✔A is the correct answer. Regulation of
gene expression is accomplished through changing the rate of transcription. Choices B, C, and D
are methods of lesser importance.
In recombinant DNA experiments, substance X is used to cut pieces of DNA, and substance Y
joins these
segments to form recombinant DNA. Which of the following choices correctly pairs these two
substances?
A restriction enzyme—DNA ligase
B plasmid—restriction enzyme
C plasmid—DNA ligase
D DNA ligase—restriction enzyme - Answer✔A is the correct answer. Choices B and C are
incorrect because a plasmid is the structure in a bacterial cell into which the DNA is inserted.
Choice D has the correct two substances, but in the wrong order.
Which of the following describes a nucleic acid probe?
A It inserts genes into a host cell.
B It synthesizes DNA for cloning.
C It cuts DNA into fragments.
D It finds a particular nucleotide sequence. - Answer✔D is the correct answer. Nucleotide probes
are used to locate specific nucleotide sequences. Choice A is a description of the function of the
2|Page
, ©EVERLY 2024/2025 ALL RIGHTS RESERVED.
enzyme ligase. Choice B is a description of a process. Choice C is a description of a restriction
enzyme.
Archaeologists excavated a human femur and succeeded in extracting a tiny amount of DNA
from the
bone. Which of the following would be the best first step in analyzing the DNA found?
A Perform gel electrophoresis to analyze the DNA.
B Fragment the DNA with restriction enzymes.
C Use the polymerase chain reaction to amplify the DNA.
D Use a nucleic acid probe to identify nucleotide sequences. - Answer✔C is the correct answer.
The polymerase chain reaction amplifies the DNA segments. Choice A is
incorrect because there may be insufficient DNA to analyze. Choice B is incorrect because
fragmenting the small amount of DNA would not be productive. Choice D is useful only for
identifying particular
sequences.
Which tissue type contains few cells?
A Muscle
B Nervous
C Epithelial
D Connective - Answer✔The correct answer is D; connective tissue is a matrix of collagenous
fibers. Muscle, nervous, and epithelial tissues have many more cells than connective tissue.
What distinguishes Parazoa from Eumatazoa?
A Presence of body cavities
B Presence of bilateral symmetry
C Absence of true tissue
D Presence of coelom - Answer✔The correct answer is C. Parazoa, such as sponges, have
differentiated cells but they are not organized into tissues. Choices A and D are the same, which
is what distinguishes the coelomates. Choice B is a description of the Deuterostomes.
Which of the following statements explains why animals possess homologous structures?
A They are doomed to extinction.
B They evolved from a common ancestor.
C They have increased genetic diversity.
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D They are examples of convergent evolution. - Answer✔B is the correct answer. Homologous
structures are an indication of common ancestry. Choice A is incorrect because homologous
structures do not indicate extinction. Choice C is incorrect because organisms with homologous
structures are genetically similar. Choice D is incorrect because convergent evolution produces
analogous structures.
A hollow sphere of cells during embryonic development is called a
A zygote.
B amniotic sac.
C ovum.
D blastula. - Answer✔The correct answer is D. A zygote is a cell resulting from fertilization. The
amniotic sac consists of two
membranes that hold the embryo, then fetus. An ovum is an egg—a female sex cell or gamete.
During which trimester does organogenesis occur?
A First
B Second
C Third
D Fourth - Answer✔A is the correct answer. The first trimester is characterized by development
of rudimentary forms of all adult structures.
Choice B is the trimester of growth.
Choice C is the trimester of rapid growth.
Choice D is incorrect because there is no fourth trimester.
Which of the following organisms has all its cells directly in contact with the external
environment?
A Hydra
B Earthworm
C Oak Tree
D Amoeba - Answer✔The correct answer is D. The cells of choices A, B, and C are not all in
direct contact with the external
environment.
Which of the following organisms has a closed circulatory system?
A Arthropod
B Mollusk
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