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Genetics and Development Overview
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Genetics and Development Overview
Child Dev. chapter 2 and 3
Study
1
Question
What are genotypes and phenotypes?
Answer
Genotype refers to the genetic constitution of an individual, the alleles inherited from their parents that determine specific traits. Phenotype refers to the observable characteristics and traits of an individual, such as physical appearance, behavior, and biochemical properties, which result from the interaction of the genotype with the environment.
2
Question
What is the role of genotypes in variability?
Answer
Genotypes contribute to variability by providing the genetic code that defines the range of potential characteristics an individual can express. Variability arises from the combinations of alleles inherited from parents and from mutations that introduce new genetic sequences.
3
Question
Define the epigenetic view.
Answer
The epigenetic view posits that environmental factors can influence gene expression without altering the underlying DNA sequence. This perspective emphasizes the bidirectional interaction between genes and environment, where genes can be turned on or off in response to external stimuli.
4
Question
What are the bidirectional effects of genes and environment?
Answer
Bidirectional effects refer to the reciprocal interactions between genetic predispositions and environmental influences. For instance, an individual's genetic makeup can affect how they respond to environmental conditions, and those environmental conditions can, in turn, influence gene expression and phenotypic outcomes.
5
Question
What is the significance of prenatal development in understanding biological beginnings?
Answer
Prenatal development is significant as it lays the foundation for all subsequent development. This stage includes key processes such as fertilization, cell division, differentiation, and organ formation, which are critical in determining the health, capabilities, and potential challenges an individual may face later in life.
6
Question
Describe the characteristics of prenatal development.
Answer
Prenatal development is characterized by: 1. Orderly: Development follows a predictable sequence. 2. Rapid: It occurs quickly during pregnancy. 3. Cephalocaudal: Development proceeds from head to tail. 4. Proximal-distal: Development moves from the center of the body outward. 5. Critical periods: Specific times when certain developmental processes must occur.
7
Question
What is the process of conception?
Answer
Conception begins with the joining of gametes (sex cells); the egg and sperm. This process is known as fertilization, resulting in the formation of a single-cell zygote.
8
Question
What is a zygote and what does it consist of?
Answer
A zygote is the fertilized egg that results from the union of an egg and sperm. It consists of chromosomes, which are threadlike structures made of DNA containing genetic information.
9
Question
How many chromosomes are involved in the formation of a zygote?
Answer
A zygote is formed from 23 unpaired chromosomes from the mother and 23 unpaired chromosomes from the father, resulting in one complete set of 23 paired chromosomes.
10
Question
What are monozygotic twins and how do they form?
Answer
Monozygotic twins, also known as identical twins, develop from a single zygote that splits into two genetically identical replicas.
11
Question
What are dizygotic twins and how do they differ from monozygotic twins?
Answer
Dizygotic twins, or fraternal twins, develop when two separate eggs are fertilized by different sperm. They are genetically unique and only share about 50% of their genes, unlike monozygotic twins who share 100%.
12
Question
What is Down Syndrome and what causes it?
Answer
Down Syndrome is a chromosomal abnormality caused by an extra chromosome 21, resulting in 47 chromosomes instead of the typical 46. It leads to a variety of developmental and physical challenges.
13
Question
What are some common treatment options for Down Syndrome?
Answer
Treatment options for Down Syndrome may include early intervention programs, specialized education, speech therapy, occupational therapy, and medical management for associated health issues.
14
Question
What is the incidence of Down Syndrome?
Answer
Down Syndrome occurs in approximately 1 in every 700 births, making it one of the most common chromosomal abnormalities.
15
Question
What are the implications of critical periods in prenatal development?
Answer
Critical periods refer to specific times during prenatal development when certain structures develop. If adverse conditions occur during these times, it can lead to developmental disorders or abnormalities.
16
Question
What is the significance of cephalocaudal development?
Answer
Cephalocaudal development signifies that growth and motor control typically develop from the head down to the feet, indicating that infants typically gain control of their head and upper body before their legs.
17
Question
What is the significance of proximal-distal development?
Answer
Proximal-distal development indicates that growth and control move from the center of the body outward. Infants develop control of their trunk before their arms, and their hands before their fingers.
18
Question
What are the key characteristics and treatment options for mild to severe intellectual disabilities and physical abnormalities?
Answer
Treatment options include surgery, early intervention, infant stimulation, and special learning programs.
19
Question
What is the incidence rate of intellectual disabilities in births at age 20, 35, and 45?
Answer
At age 20, the incidence is 1 in 1,900 births; at age 35, it is 1 in 300 births; and at age 45, it is 1 in 30 births.
20
Question
What is Klinefelter Syndrome, and what is its genetic basis?
Answer
Klinefelter Syndrome is a condition characterized by the presence of an extra X chromosome (XXY), which causes physical abnormalities.
21
Question
What treatment options are available for Klinefelter Syndrome?
Answer
Hormone therapy is the primary treatment for Klinefelter Syndrome.
22
Question
What is the incidence of Klinefelter Syndrome in male births?
Answer
It occurs in approximately 1 in 650 male births.
23
Question
What is Fragile X Syndrome and what are its effects?
Answer
Fragile X Syndrome is caused by an abnormality in the X chromosome and can lead to intellectual disabilities, learning disabilities, or a short attention span.
24
Question
What are the treatment options for Fragile X Syndrome?
Answer
Treatment options include special education and speech and language therapy.
25
Question
Which gender is more commonly affected by Fragile X Syndrome?
Answer
Fragile X Syndrome is more common in males than in females.
26
Question
What is Turner Syndrome and its genetic characteristics?
Answer
Turner Syndrome is a condition characterized by a missing X chromosome in females (XO), leading to potential intellectual disabilities and sexual underdevelopment.
27
Question
What treatment is available for Turner Syndrome?
Answer
Hormone therapy is often used as a treatment for Turner Syndrome.
28
Question
What is the incidence rate of Turner Syndrome in female births?
Answer
Turner Syndrome occurs in approximately 1 in 2,500 female births.
29
Question
What is XXY Syndrome and what does it cause?
Answer
XXY Syndrome is characterized by an extra Y chromosome, which can result in above-average height.
30
Question
Is there any special treatment for XXY Syndrome?
Answer
There is no special treatment required for XXY Syndrome.