Heredity And Environment Unit Exam
You can use your chapter three study guide and your birth defect notes on this test - no textbooks!
Questions and Answers
- 1.
In the male, the twenty-third pair of chromosomes is designated_______; in the female, this pair is designated_______.
- A.
XX; XY
- B.
XY; XX
- C.
XO; XXY
- D.
XXY; XO
Correct Answer
B. XY; XXExplanation
In humans, the twenty-third pair of chromosomes determines the sex of an individual. In males, this pair is designated as XY, where X represents a sex chromosome inherited from the mother and Y represents a sex chromosome inherited from the father. In females, this pair is designated as XX, where both sex chromosomes are inherited from the mother.Rate this question:
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- 2.
When a zygote splits, the two identical, independent clusters that develop become:
- A.
Dizygotic twins
- B.
Monzygotic twins
- C.
Fraternal twins
- D.
Trizygotic twins
Correct Answer
B. Monzygotic twinsExplanation
When a zygote splits, it forms two identical clusters that develop into monzygotic twins. Monzygotic twins, also known as identical twins, are formed when a single fertilized egg splits into two separate embryos. These twins share the same genetic material and are typically of the same sex.Rate this question:
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- 3.
In scientific research, the best way to separate the effects of genes and the environment is to study:
- A.
Dizygotic twins
- B.
Adopted children and their biological parents
- C.
Adopted children and their adoptive parents
- D.
Monozygotic twins raised in different environments
Correct Answer
D. Monozygotic twins raised in different environmentsExplanation
To separate the effects of genes and the environment, it is important to study individuals who have identical genetic makeup but are exposed to different environmental factors. Monozygotic twins, also known as identical twins, share the same genes as they are formed from a single fertilized egg that splits into two. By studying monozygotic twins raised in different environments, researchers can compare the impact of genes on their similarities and differences while controlling for environmental influences. This allows for a clearer understanding of the relative contributions of genes and the environment in shaping individual traits and behaviors.Rate this question:
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- 4.
Most of the known genetic disorders are:
- A.
Dominant
- B.
Recessive
- C.
Seriously disabling
- D.
Sex-linked
Correct Answer
A. DominantExplanation
Most of the known genetic disorders are dominant. This means that if an individual inherits a single copy of the mutated gene from one parent, they will develop the disorder. Dominant genetic disorders are often caused by mutations in genes that provide instructions for producing proteins necessary for normal cell function. These mutations can result in a wide range of disorders, such as Huntington's disease and Marfan syndrome. In contrast, recessive genetic disorders require the inheritance of two copies of the mutated gene, one from each parent, in order for the disorder to manifest.Rate this question:
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- 5.
Genes are segments of molecules of:
- A.
Genotype
- B.
Deoxyribonucleic acid (DNA)
- C.
Karyotype
- D.
Phenotype
Correct Answer
B. Deoxyribonucleic acid (DNA)Explanation
Genes are segments of molecules that carry genetic information and are responsible for the expression of traits. DNA, or deoxyribonucleic acid, is the molecule that contains the genetic instructions for the development and functioning of all living organisms. It is composed of nucleotides and is organized into structures called genes. Therefore, the correct answer is Deoxyribonucleic acid (DNA).Rate this question:
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- 6.
The potential for genetic diversity is humans is so great because:
- A.
There are approximately 8 million possible combinations of chromosomes
- B.
When the sperm and ovum unite, genetic combinations not present in either parent can be formed
- C.
Just before a chromosome pair divides during the formation of gametes, genes cross over, producing recombinations
- D.
All of the above reasons
Correct Answer
D. All of the above reasonsExplanation
The potential for genetic diversity in humans is so great because there are approximately 8 million possible combinations of chromosomes. Additionally, when the sperm and ovum unite, genetic combinations not present in either parent can be formed. Furthermore, just before a chromosome pair divides during the formation of gametes, genes cross over, producing recombinations. Therefore, all of these reasons contribute to the significant genetic diversity observed in humans.Rate this question:
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- 7.
Polygenic complexity is most apparent in _______ characteristics.
- A.
Physical
- B.
Psychological
- C.
Recessive gene
- D.
Dominant gene
Correct Answer
B. PsychologicalExplanation
Polygenic complexity refers to the phenomenon where a trait or characteristic is influenced by multiple genes. In the case of psychological characteristics, such as intelligence or personality traits, it is believed that they are influenced by the interaction of multiple genes. This means that the expression of these traits is not determined by a single gene, but rather the combined effect of many genes. Therefore, psychological characteristics exhibit polygenic complexity.Rate this question:
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- 8.
Babies born with trisomy-21 (Down syndrome) are often
- A.
Born to older parents
- B.
Unusually aggressive
- C.
Abnormally tall by adolescence
- D.
Blind
Correct Answer
A. Born to older parentsExplanation
Trisomy-21, also known as Down syndrome, is a genetic disorder caused by the presence of an extra copy of chromosome 21. Advanced maternal age, typically older than 35, is a known risk factor for having a baby with Down syndrome. The likelihood of having a baby with Down syndrome increases with the age of the mother. Therefore, babies born with trisomy-21 are often born to older parents. The other options, such as being unusually aggressive, abnormally tall by adolescence, or blind, are not necessarily associated with Down syndrome.Rate this question:
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- 9.
Some genetic diseases are recessive, so the child cannot inherit the condition unless both parents
- A.
Have Kleinfelter syndrome
- B.
Carry the same recessive gene
- C.
Have XO chromosome
- D.
Have the disease
Correct Answer
B. Carry the same recessive geneExplanation
The correct answer is "Carry the same recessive gene." This is because recessive genetic diseases require both parents to carry the same recessive gene in order for the child to inherit the condition. If only one parent carries the gene, the child will not inherit the disease.Rate this question:
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- 10.
Dizygotic twins result when:
- A.
A single egg is fertilized by a sperm and then splits
- B.
A single egg is fertilized by two different sperm
- C.
Two eggs are fertilized by two different sperm
- D.
Either a single egg is fertilized by one sperm or two eggs are fertilized by two different sperm
Correct Answer
C. Two eggs are fertilized by two different spermExplanation
Dizygotic twins, also known as fraternal twins, occur when two eggs are fertilized by two different sperm. This means that each twin has its own placenta and amniotic sac. Dizygotic twins can be of the same or different genders and can have different physical characteristics, just like any other siblings. This is in contrast to monozygotic twins, which result from a single fertilized egg that splits into two embryos.Rate this question:
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- 11.
Molecules of DNA that in humans are organized into twenty-three complementary pairs are called:
- A.
Zygotes
- B.
Genes
- C.
Chromosomes
- D.
Ova
Correct Answer
C. ChromosomesExplanation
Chromosomes are the correct answer because they are the molecules of DNA that are organized into twenty-three complementary pairs in humans. Each chromosome contains many genes, which are segments of DNA that code for specific traits. Chromosomes are found in the nucleus of cells and are responsible for carrying genetic information from one generation to the next.Rate this question:
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- 12.
If an ovum is fertilized by a sperm bearing a Y chromosome:
- A.
A female will develop
- B.
Cell division will result
- C.
A male will develop
- D.
Spontaneous abortion will occur
Correct Answer
C. A male will developExplanation
If an ovum is fertilized by a sperm bearing a Y chromosome, a male will develop. This is because the presence of a Y chromosome determines the development of male characteristics. The Y chromosome contains genes that are responsible for the development of male sex organs and secondary sexual characteristics. Therefore, when the sperm carries a Y chromosome, it will contribute the necessary genetic information for the development of a male fetus.Rate this question:
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- 13.
Most human traits are...
- A.
Polygenic
- B.
Multifactorial
- C.
Determined by dominant-recessive patterns
- D.
Both a. and b.
Correct Answer
D. Both a. and b.Explanation
Most human traits are polygenic, meaning they are influenced by multiple genes. They are also multifactorial, meaning they are influenced by both genetic and environmental factors. Therefore, the correct answer is both a. and b.Rate this question:
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- 14.
The genes that influence height and skin color interact according to the _______ pattern.
- A.
Nonadditive
- B.
Additive
- C.
Dominant-recessive
- D.
X-linked
Correct Answer
B. AdditiveExplanation
The term "additive" refers to the pattern in which the genes that influence height and skin color interact. In an additive pattern, the effects of different genes are combined in a cumulative manner, meaning that the more genes involved, the greater the effect on the trait. This is in contrast to a nonadditive pattern, where the effects of different genes do not combine in a cumulative manner. Therefore, the correct answer is "Additive".Rate this question:
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- 15.
X-linked recessive genes explain why some traits seem to be passed from
- A.
Mother to son
- B.
Father to son
- C.
Mother to daughter
- D.
Father to daughter
Correct Answer
A. Mother to sonExplanation
X-linked recessive genes explain why some traits seem to be passed from mother to son. This is because males have one X chromosome and one Y chromosome, while females have two X chromosomes. If a mother carries a recessive gene on one of her X chromosomes, she can pass it on to her son. Since the son only has one X chromosome, he will express the trait if the gene is recessive. However, if the father carries the recessive gene, he can only pass it on to his daughter, as she will inherit one of his X chromosomes.Rate this question:
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- 16.
According the text, the effects of environment on genetic inheritance include
- A.
Direct effects, such as nutrition, climate, and medical care
- B.
Indirect effects, such as the individual’s broad economic, political, and cultural context
- C.
Irreversible effects, such as those due to brain injury
- D.
Everything that can interact with the person’s genetic inheritance at every point in life
Correct Answer
D. Everything that can interact with the person’s genetic inheritance at every point in lifeExplanation
The effects of environment on genetic inheritance include everything that can interact with the person's genetic inheritance at every point in life. This means that not only direct effects such as nutrition, climate, and medical care, and indirect effects such as the individual's broad economic, political, and cultural context, but also irreversible effects such as those due to brain injury can influence genetic inheritance. It suggests that any factor or condition that can interact with an individual's genes throughout their lifespan can potentially impact their genetic inheritance.Rate this question:
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- 17.
The personality trait of inhibition (shyness) seems to be partly genetic. A child who inherits the genes for shyness will be shy
- A.
Under most circumstances
- B.
Only if shyness is the dominant gene
- C.
If the environment does not encourage greater sociability
- D.
If he or she is raised by biological rather than adoptive parents
Correct Answer
C. If the environment does not encourage greater sociabilityExplanation
The correct answer is "If the environment does not encourage greater sociability." This suggests that even if a child inherits the genes for shyness, the environment they are raised in can play a significant role in whether or not they actually exhibit shyness. If the child is not encouraged or exposed to situations that promote sociability, they may be more likely to exhibit shyness. This implies that environmental factors can have a significant impact on the expression of the genetic trait of shyness.Rate this question:
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- 18.
Laurie and Brad, who both have a history of alcoholism in their families, are concerned that the child they hope to have will inherit a genetic predisposition to alcoholism. Based on information presented in the text, what advice should you offer them?
- A.
“Stop worrying, alcoholism is only weakly genetic.”
- B.
“It is almost certain that your child will become alcoholic.”
- C.
“Social influences, such as the family and peer environment, play a critical role in determining whether alcoholism is expressed.”
- D.
“Wait to have children until you are both middle aged, in order to see if the two of you become alcoholic.”
Correct Answer
C. “Social influences, such as the family and peer environment, play a critical role in determining whether alcoholism is expressed.”Explanation
The correct answer suggests that while there may be a genetic predisposition to alcoholism, social influences such as the family and peer environment also play a critical role in determining whether alcoholism is expressed. This means that even if the child inherits a genetic predisposition, their environment and the choices they make can greatly influence whether they develop alcoholism or not. Therefore, Laurie and Brad should focus on creating a supportive and healthy environment for their future child rather than worrying excessively about the genetic factor alone.Rate this question:
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- 19.
Genetically, Claude’s potential height is 6’0. Because he did not receive a balanced diet, however, he grew to only 5’9”. Claude’s actual height is an example of a
- A.
Phenotype
- B.
Genotype
- C.
Dominant gene
- D.
Recessive gene
Correct Answer
A. PhenotypeExplanation
Claude's potential height is determined by his genotype, which is the genetic makeup he inherited from his parents. However, his actual height is influenced by environmental factors such as his diet. The fact that Claude grew to only 5'9" instead of his potential height of 6'0" indicates that his actual height is a result of the interaction between his genotype and the environment, which is known as his phenotype. Phenotype refers to the observable characteristics or traits of an organism, which are influenced by both genetic and environmental factors.Rate this question:
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- 20.
Winona inherited a gene from her mother that, regardless of her father’s contribution to her genotype, will be expressed in her phenotype. Evidently, the gene Winona received from her mother is a(n) _______ gene
- A.
X-linked
- B.
Dominant
- C.
Recessive
- D.
Polygenic
Correct Answer
B. DominantExplanation
Winona inherited a gene from her mother that will be expressed in her phenotype regardless of her father's contribution. This suggests that the gene is dominant, meaning that its presence will override any other gene in determining the phenotype.Rate this question:
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- 21.
The female will determine the sex of the child.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
The statement suggests that the female will determine the sex of the child. However, this is incorrect. The sex of the child is determined by the male's sperm, which carries either an X or Y chromosome. If the sperm carries an X chromosome, the child will be female, and if it carries a Y chromosome, the child will be male. Therefore, it is the male who determines the sex of the child, not the female.Rate this question:
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- 22.
Sickle cell anemia involves abnormal blood cells
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Sickle cell anemia is a genetic disorder that affects the shape of red blood cells. In this condition, the red blood cells become crescent-shaped or sickle-shaped instead of their normal round shape. These abnormal blood cells can cause various complications as they can get stuck in blood vessels, leading to reduced oxygen supply to different parts of the body. Therefore, the statement "Sickle cell anemia involves abnormal blood cells" is true.Rate this question:
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- 23.
The only cure for club foot is surgery when the child is first born
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Surgery is not the only cure for club foot. While surgery may be necessary in some cases, there are other treatment options available as well. Non-surgical methods such as stretching exercises, casting, and bracing can also be effective in correcting club foot. Therefore, the statement that surgery is the only cure for club foot is false.Rate this question:
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- 24.
The birth defect Turner Syndrome is the lack of the 2nd X chromosome and only occurs in females
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Turner Syndrome is a genetic disorder that affects females. It occurs when one of the sex chromosomes (X or Y) is missing or partially missing. In the case of Turner Syndrome, females are born with only one X chromosome instead of the usual two. This condition can lead to various physical and developmental abnormalities, including short stature, infertility, and heart defects. Therefore, the statement that Turner Syndrome is the lack of the 2nd X chromosome and only occurs in females is true.Rate this question:
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- 25.
Congenital heart defects occur when the heart forms abnormally after the baby is born.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Congenital heart defects occur when the heart forms abnormally before the baby is born.Rate this question:
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- 26.
Tourette children often display tics that can be abrupt and repeated movement
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Tourette children often display tics that can be abrupt and repeated movements. This means that they may exhibit sudden and repetitive movements, such as blinking, twitching, or jerking. These tics can be involuntary and difficult to control. Therefore, the statement "True" is the correct answer as it accurately reflects the characteristic behaviors of Tourette children.Rate this question:
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- 27.
An incomplete formed spinal cord, which cause partial paralysis is known as...
- A.
Down Syndrome
- B.
Spina Bifida
- C.
Cystic Fibrosis
- D.
PKU
Correct Answer
B. Spina BifidaExplanation
Spina Bifida is the correct answer because it is a condition characterized by an incomplete formation of the spinal cord. This incomplete development can lead to various degrees of paralysis, ranging from mild to severe. Down Syndrome, Cystic Fibrosis, and PKU are unrelated conditions and do not involve the incomplete formation of the spinal cord.Rate this question:
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- 28.
Choose one of the following birth defect Spina Bifida or Cystic Fibrosis and explain the following: v Explain the disease v How it impacts a child’s life What are the treatments
- 29.
Do you think a genetic counselor should tell a couple whether or not they should have children? Why or why not?
- 30.
Imagine you are an adopted child who has received no information about your biological parents. From you observable characteristics what could you determine about your biological parents? Explain your reasoning.
- 31.
Name five prenatal hazards:
- 32.
Which is more serious and which is more common: dominant genetic disorders or recessive geneteic disorders?
- 33.
How can environent influence genetic physical traits, such as height, and psychological traits, such as shyness?
- 34.
What would you do if you knew you were the carrier of a gene for a serious disease?
- 35.
"Once there was a king, who had a beautiful, large pure diamond. There was no other diamond like it in the world. One day, it became deeply scratched. The king called his best diamond cutters, “I’ll promise you a great reward if you can remove the imperfection from my jewel.” But they could not. The king was very upset. Many months later, a man came to the king. He promised to make the diamond even more beautiful than it ever had been. Impressed by the man’s confidence, the king consented. He watched as the man engraved an exquisite rosebud around the blemish and used the scratch to make its stem". Why can this story be equated with birth defects? Why should people focus of the abilities of the person?
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