Biology 100 Test 2
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True or False: All normal diploid cells in the human body have a complete set of DNA.
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True
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False
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Biology 100 TEST 2 assesses knowledge on cell biology and genetics, focusing on DNA structure, chromosome behavior during cell division, and gene regulation. It tests understanding of fundamental genetic processes, crucial for students specializing in biological sciences.
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- 2.
When a cell is not dividing, chromosomes are uncoiled into long, thin molecules of DNA and proteins called:
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Chromatids
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Chromatin
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Chlorophyll
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Genes
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Enzymes
Correct Answer
A. ChromatinExplanation
When a cell is not dividing, the chromosomes are uncoiled into long, thin molecules of DNA and proteins called chromatin. Chromatin is the relaxed form of DNA that allows for gene expression and other cellular processes to occur. It is important for the regulation of gene activity and is responsible for the overall structure and organization of the genetic material within the cell nucleus.Rate this question:
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- 3.
Which of the following statement is false ?
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The genetic makeup of an organism constitutes its genotype.
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An allele that is always fully expressed is referred to as recessive.
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An organism with two different alleles for a single trait is said to be heterozygous for that trait
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Alleles are alternative forms of a gene.
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The expressed physical traits of an organism are called its phenotype.
Correct Answer
A. An allele that is always fully expressed is referred to as recessive.Explanation
The statement "An allele that is always fully expressed is referred to as recessive" is false. In genetics, an allele that is always fully expressed is referred to as dominant, not recessive. Recessive alleles are only expressed when an organism has two copies of that allele.Rate this question:
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- 4.
The phase during meiosis when the sister chromatids separate and move to opposite sides of the cell is
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Telophase I
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Anaphase II
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Prophase II
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Metaphase I
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Metaphase II
Correct Answer
A. Anaphase IIExplanation
During anaphase II of meiosis, the sister chromatids separate and move to opposite sides of the cell. This is the phase where the genetic material is divided equally between the daughter cells. In telophase I, the chromosomes decondense and the nuclear envelope reforms. Prophase II is the phase where the nuclear envelope breaks down and the spindle apparatus forms. Metaphase I is the phase where the homologous pairs of chromosomes align at the equator of the cell. Metaphase II is the phase where the individual chromosomes align at the equator of the cell.Rate this question:
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- 5.
Which of the following statements about gene regulation is false?
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It plays an important role in proper development.
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Many cancers begin because of problems associated with gene regulation.
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Although complex, researchers have an excellent understanding of gene regulation.
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It is the process that controls gene expression.
Correct Answer
A. Although complex, researchers have an excellent understanding of gene regulation. -
- 6.
The phase during mitosis when the chromosomes line up along the midline of the cell is
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Telophase
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Anaphase
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Prophase
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Metaphase
Correct Answer
A. ProphaseExplanation
During prophase, the chromosomes condense and become visible. They also line up along the midline of the cell, forming a structure called the metaphase plate. This is the phase when the nuclear envelope breaks down and the spindle fibers start to form. Telophase is the phase when the chromosomes move to opposite ends of the cell, anaphase is the phase when the chromosomes separate and move to opposite poles, and metaphase is the phase when the chromosomes are fully aligned along the metaphase plate.Rate this question:
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- 7.
Which of the following occurs/occur during Interphase of the Cell Cycle? Choose the best answer
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The cell grows
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A copy of DNA is made (DNA duplicates)
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The cell cytoplasm divides
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All of the above are correct
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A and B are correct, but not C
Correct Answer
A. A and B are correct, but not CExplanation
During Interphase of the Cell Cycle, the cell grows and a copy of DNA is made (DNA duplicates). However, the cell cytoplasm does not divide during Interphase.Rate this question:
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- 8.
Which of the following terms refers to a change in the nucleotide sequence of DNA?
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Translation
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Non-disjunction
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Pteiotropy
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Mutation
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Replication
Correct Answer
A. MutationExplanation
A mutation refers to a change in the nucleotide sequence of DNA. This can occur due to various factors such as errors during DNA replication or exposure to certain environmental factors. Mutations can lead to genetic variations and can have significant impacts on an organism's traits and functions. Translation, non-disjunction, pteiotropy, and replication are not related to changes in the nucleotide sequence of DNA.Rate this question:
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- 9.
The centromere is
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A molecule necessary to make copies of a gene.
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The point where sister chromatids are attached together.
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A structure where proteins are assembled together.
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An enzyme that unzips a DNA molecule.
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None of the above.
Correct Answer
A. The point where sister chromatids are attached together.Explanation
The centromere is the point where sister chromatids are attached together. During cell division, the sister chromatids separate and move to opposite poles of the cell, and the centromere plays a crucial role in ensuring the proper distribution of genetic material to the daughter cells. It acts as an attachment site for proteins that help in the movement and segregation of chromosomes. This process ensures that each daughter cell receives a complete set of chromosomes. Therefore, the centromere is not a molecule necessary to make copies of a gene, a structure where proteins are assembled together, or an enzyme that unzips a DNA molecule.Rate this question:
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- 10.
Which of the following statements about single trait, multiple gene inheritance is false?
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It occurs when many genes influence one characteristic.
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It tends to affect males much more than females.
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It produces phenotypes that tend to vary along a continuum.
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It works when the effects of many genes add together to produce a particular phenotype.
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It is also called polygenic inheritance.
Correct Answer
A. It tends to affect males much more than females.Explanation
Single trait, multiple gene inheritance occurs when many genes influence one characteristic. It produces phenotypes that tend to vary along a continuum. It works when the effects of many genes add together to produce a particular phenotype. It is also called polygenic inheritance. However, it does not tend to affect males much more than females.Rate this question:
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- 11.
Which of the following is NOT necessarily true of pairs of homologous chromosomes?
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They separate from each other during Meiosis I.
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They segregate independent of each other during gamete formation.
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They carry the same alleles.
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They carry the same genes.
Correct Answer
A. They carry the same alleles.Explanation
Pairs of homologous chromosomes do not necessarily carry the same alleles. Homologous chromosomes are similar in size and carry genes for the same traits, but they can have different versions of those genes, known as alleles. This genetic variation allows for diversity and the possibility of different traits being expressed in offspring.Rate this question:
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- 12.
Which of the following statements about promoter sequences and terminator sequences is false?
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Proper reading of these sequences relies on molecules of tRNA.
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Every gene is designated by these sequences.
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They are nucleotide sequences that either start or stop transcription at that location on the molecule of DNA
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They lie on either side of a coding sequence along a molecule of DNA.
Correct Answer
A. Proper reading of these sequences relies on molecules of tRNA.Explanation
Promoter sequences and terminator sequences are nucleotide sequences that either start or stop transcription at a specific location on the DNA molecule. They are not directly involved in the reading of these sequences by molecules of tRNA. Instead, tRNA molecules are responsible for carrying amino acids and matching them to the appropriate codons on the mRNA during translation. Therefore, the statement that proper reading of these sequences relies on molecules of tRNA is false.Rate this question:
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- 13.
How many sex chromosomes are in a human gamete?
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4
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3
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2
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1
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0
Correct Answer
A. 1Explanation
A human gamete, such as a sperm or an egg, contains only one sex chromosome. This is because during the process of meiosis, the cells that give rise to gametes undergo a special division where the number of chromosomes is halved. In the case of sex chromosomes, males have one X and one Y chromosome, while females have two X chromosomes. Therefore, a human gamete can either have an X chromosome (if it is an egg) or a Y chromosome (if it is a sperm), determining the sex of the offspring when it combines with another gamete during fertilization.Rate this question:
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- 14.
Choose the proper pair of words to fill in the blanks in this statement: A codon consists of three _____, and codes for one ____.
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Nucleotides...... protein
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Nucteotides.... . .amino acid
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Polypeptides.... . .amino acid
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Amino acids...... protein
Correct Answer
A. Nucteotides.... . .amino acidExplanation
A codon is a sequence of three nucleotides, which are the building blocks of DNA and RNA. These nucleotides determine the sequence of amino acids in a protein. Therefore, the correct pair of words to fill in the blanks is "nucleotides" and "amino acid".Rate this question:
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- 15.
At the beginning of the mitosis, each chromosome of a eukaryotic cell consists of a pair of identical structures called:
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Sister chromosomes
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Sister chromatids
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DNA transcripts
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Nucleotides
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Chromatin
Correct Answer
A. Sister chromatidsExplanation
At the beginning of mitosis, each chromosome of a eukaryotic cell consists of a pair of identical structures called sister chromatids. Sister chromatids are formed during DNA replication, where the DNA is duplicated and each copy remains attached to the other at a region called the centromere. These sister chromatids are held together until they separate during the later stages of mitosis, ensuring that each daughter cell receives an identical copy of the genetic material.Rate this question:
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- 16.
Which of the following statements about cell division is false?
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Cell division is how old or damaged cells are replaced.
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Cell division is the process that enables organisms to grow.
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Cell division only occurs in cells of that produce eggs and sperm.
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Ell division is the process during which the DNA is copied and the cell is split into two daughter cells.
Correct Answer
A. Cell division only occurs in cells of that produce eggs and sperm.Explanation
The given statement that "Cell division only occurs in cells that produce eggs and sperm" is false. Cell division is a fundamental process that occurs in all types of cells, not just in cells that produce eggs and sperm. Cell division is necessary for growth, repair, and maintenance of tissues in multicellular organisms. It involves the replication of DNA and the division of the cell into two daughter cells.Rate this question:
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- 17.
Which of the following statements about a gene is false?
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It is a particular sequence of nucleotides found in a particular location along the molecule of DNA.
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It can exist in alternative forms.
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It contains the directions for the manufacture of a particular protein.
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It is always expressed in the individual who has it.
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It is copied during transcription.
Correct Answer
A. It is always expressed in the individual who has it.Explanation
A gene is not always expressed in the individual who has it. Gene expression is regulated by various factors such as environmental conditions, cellular signals, and the presence of specific regulatory proteins. Some genes may be expressed only under certain circumstances or in specific tissues, while others may be completely silent or inactive. Therefore, it is incorrect to assume that a gene is always expressed in the individual who possesses it.Rate this question:
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- 18.
The genetic information carried by a DNA molecule lies in
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The sequence of the different nucleotides along the length of the molecule.
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The sequence of amino^acids that run along its backbone.
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He type of sugars it possesses.
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The total number of nucleotides it contains.
Correct Answer
A. The sequence of the different nucleotides along the length of the molecule.Explanation
The genetic information carried by a DNA molecule lies in the sequence of the different nucleotides along the length of the molecule. This is because the order of the nucleotides, which are adenine (A), thymine (T), cytosine (C), and guanine (G), determines the genetic code. The specific sequence of nucleotides forms genes, which are the instructions for building proteins. These proteins then carry out various functions in the cell, ultimately determining the traits and characteristics of an organism. Therefore, the sequence of nucleotides is crucial for transmitting genetic information.Rate this question:
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- 19.
The non-sex chromosomes are called
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Chromatin
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Chromatids
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Autosomes
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Gametes
Correct Answer
A. AutosomesExplanation
Autosomes are the non-sex chromosomes in an organism. These chromosomes are responsible for determining the traits and characteristics other than the sex of an individual. Unlike sex chromosomes, which determine the sex of an individual, autosomes are present in both males and females and carry genetic information related to various bodily functions and traits. Therefore, autosomes are the correct answer as they accurately represent the non-sex chromosomes.Rate this question:
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- 20.
Stem cells are
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Useful for understanding the process of DNA replication.
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A type of cell found only in plants.
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Unspecialized, undifferentiated cells.
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Important for directing natural selection.
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None of the above
Correct Answer
A. Unspecialized, undifferentiated cells.Explanation
The correct answer is "Unspecialized, undifferentiated cells." Stem cells are a type of cells that are not yet specialized or differentiated into specific cell types. They have the potential to develop into different types of cells in the body and are important for various biological processes such as growth, development, and repair. Stem cells can be found in both plants and animals, and they are not specifically related to DNA replication or natural selection.Rate this question:
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- 21.
Egg and sperm cells are called
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Clones.
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Hybrids.
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Gametes.
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Somatic cells.
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Stem cells.
Correct Answer
A. Gametes.Explanation
Egg and sperm cells are called gametes. Gametes are specialized reproductive cells that are involved in sexual reproduction. They are responsible for carrying the genetic information from the parents to the offspring. Clones refer to genetically identical organisms, hybrids are the offspring of two different species, somatic cells are non-reproductive cells, and stem cells are undifferentiated cells with the potential to develop into different cell types.Rate this question:
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- 22.
Imagine that flower color in a rose species is controlled by a single gene. You mate a rose homozygous for red flowers with a rose homozygous for white flowers and get numerous offspring, all of which have pink flowers. This pattern of color expression is most likely to be an example of
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Codominance
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Polygenic inheritance
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Crossing over
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Incomplete dominance
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Complete dominance
Correct Answer
A. Incomplete dominanceExplanation
The pattern of color expression in the offspring, where all of them have pink flowers, suggests that neither the red nor the white allele is completely dominant over the other. In incomplete dominance, the heterozygous offspring exhibit a phenotype that is intermediate between the two homozygous phenotypes. In this case, the pink flowers in the offspring indicate that the red and white alleles are both expressed, resulting in a blend of the two colors. Therefore, incomplete dominance is the most likely explanation for this pattern of color expression.Rate this question:
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- 23.
Given the nucfeotide sequence: ATAACCCGAT; which is the correct sequence of nucleotides needed to complete replication of a DNA molecule?
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TUTTGGGCTU
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ATAACCCGAT
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CGCCAAATCG
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TATTGGGCTA
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UAUUGGGCUA
Correct Answer
A. TATTGGGCTAExplanation
The given nucleotide sequence is ATAACCCGAT. To complete replication of a DNA molecule, the complementary strand needs to be formed. The complementary strand is formed by pairing adenine (A) with thymine (T) and cytosine (C) with guanine (G). Therefore, the correct sequence of nucleotides needed to complete replication would be TATTGGGCTA, where T pairs with A, A pairs with T, G pairs with C, and C pairs with G.Rate this question:
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- 24.
Use the information from the following paragraph to answer questions 24 and 25. A woman has been, unsuccessfully, trying to conceive for several years. At a fertility clinic, they discover that she has blocked fallopian tubes. Using modem technologies, some of her eggs are removed, fertilized with her husband's sperm, and implanted into her uterus. The procedure is successful, but the couple discovers that their new son is color-blind and has blood type O. The woman claims that the child can't be theirs since she has blood type A and her husband has type B. Also, neither parent is color-blind, although one grandparent (the woman's father) is also color-blind. As a genetic counselor, you would explain to the parents that :
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The baby is theirs, since the blood types of parents have no relation to their children's blood types.
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The eggs must have been accidentally switched, since the baby's blood type has to match one of his parents.
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Each parent could have contributed one recessive allele, resulting in type O blood.
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The eggs must have been accidentally switched, since a type A parent and a type B parent can have any type children except O.
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It is possible for the baby to have type O blood, since type O is inherited through a dominant allele.
Correct Answer
A. Each parent could have contributed one recessive allele, resulting in type O blood.Explanation
The correct answer is that each parent could have contributed one recessive allele, resulting in type O blood. This explanation is based on the understanding of blood types and inheritance. In the case of the couple, the woman has blood type A and the man has blood type B. Both blood types are dominant, but the recessive allele for type O blood can be inherited from both parents. Therefore, it is possible for the baby to have type O blood even if both parents have different blood types.Rate this question:
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- 25.
In regard to the baby's color blindness, you explain that
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Color blindness often appears randomly, even if neither parent is color-blind.
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Since color blindness is recessive, both parents can pass it on, even if neither is color-blind.
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the baby's father must have a recessive allele for color blindness.
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Since color blindness is sex-linked, a son can inherit color blindness if his mother carries the recessive color blindness allele.
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The eggs must have been accidentally switched, since males inherit sex-linked traits only from their fathers.
Correct Answer
A. Since color blindness is sex-linked, a son can inherit color blindness if his mother carries the recessive color blindness allele.Explanation
Color blindness is a sex-linked trait, meaning it is carried on the X chromosome. Since males have one X chromosome inherited from their mother, they can inherit color blindness if their mother carries the recessive color blindness allele. This is because males only need one copy of the recessive allele to express the trait. Therefore, if the mother carries the recessive color blindness allele, she can pass it on to her son, resulting in color blindness.Rate this question:
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