Psychology - Life Span - Chapter 3 - Book Work (Pt 1)

Genes are segments of molecules of deoxyribonucleic acid (DNA). DNA is the genetic material that contains the instructions for the development and functioning of all living organisms. Genes are specific sequences of DNA that encode for specific traits or characteristics. They determine the expression of traits, such as eye color, hair type, and susceptibility to certain diseases. Therefore, DNA is the correct answer as it accurately reflects the role of genes in carrying genetic information.

The correct answer is "carry the same recessive gene." In order for a child to inherit a recessive genetic disease, both parents must carry the same recessive gene. This means that both parents must have a copy of the gene, even if they do not have the disease themselves. If only one parent carries the gene, the child will not inherit the disease.

When a sperm and an ovum merge, a one-celled zygote is formed. The zygote is the initial stage of development in sexual reproduction. It contains the combined genetic material from both the sperm and the ovum, and it will undergo cell division to form an embryo. The zygote is the result of fertilization and marks the beginning of a new individual's life.

Babies born with trisomy-21 (Down syndrome) are often born to older parents. This is because the risk of having a child with Down syndrome increases with the age of the mother, especially after the age of 35. The chance of having a baby with Down syndrome is also higher for older fathers. Therefore, the likelihood of having a child with trisomy-21 is associated with advanced parental age.

When we say that a characteristic is multifactorial, it means that both genetic and environmental factors play a role in determining that characteristic. This suggests that the characteristic is not solely determined by genes or the environment alone, but rather by a combination of both. Multiple genes and environmental factors interact to influence the expression of the characteristic.

When a zygote splits, it forms two identical clusters that develop into monozygotic twins. Monozygotic twins, also known as identical twins, occur when a single fertilized egg splits into two separate embryos. These twins share the same genetic material and are typically the same sex.

The XXY chromosomal pattern is known as Klinefelter syndrome, which is a chromosomal abnormality that affects males. In this condition, males have an extra X chromosome, resulting in a total of 47 chromosomes instead of the usual 46. This can lead to various physical and developmental differences, including infertility, reduced muscle mass, and increased height.

A polygenic trait refers to a trait that is influenced by multiple genes. In order for an individual to inherit the trait, several genes must be present and contribute to its expression. This means that the trait is not controlled by a single gene, but rather by the combined effects of multiple genes. The presence of these genes increases the likelihood of inheriting the trait, but it does not necessarily mean that most people carry genes for the trait.

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 disorders are not dependent on the presence of a second mutated gene and can be passed on to offspring with a 50% chance. Examples of dominant genetic disorders include Huntington's disease and Marfan syndrome.

In females, the 23rd pair of chromosomes is XX. During fertilization, an ovum can only contribute an X chromosome to the zygote. Therefore, the correct answer is X chromosome.

Genes are segments of DNA that contain the instructions for building proteins, which are essential for the structure and function of cells. These proteins determine the characteristics and functions of different parts of the human body. Therefore, the correct answer is that genes provide the chemical instructions for a specific part of a functioning human body.

Newborns in the US are tested for phenylketonuria, a recessive genetic disorder. Phenylketonuria is a metabolic disorder that affects the body's ability to break down an amino acid called phenylalanine. If left untreated, phenylketonuria can lead to intellectual disabilities, developmental delays, and other health problems. Early detection through newborn screening allows for timely intervention and management of the condition, such as a special diet low in phenylalanine. Testing for phenylketonuria is crucial to ensure that affected infants receive the necessary treatment to prevent long-term complications.

During adulthood, genetic influences on development generally increase. This means that as individuals grow older, genetic factors have a greater impact on their development. This could be due to a variety of factors such as changes in gene expression, accumulation of genetic mutations, or the influence of genetic predispositions becoming more apparent. It suggests that genetic factors become more influential in shaping an individual's characteristics and traits as they progress through adulthood.

The correct answer is the increasing amount of time spent by children in close study of books and papers. This explanation suggests that the epidemic increase in myopia among children in Hong Kong, Singapore, and Japan is partly caused by the excessive amount of time they spend on close study, which puts strain on their eyes. This explanation is supported by the fact that myopia rates are higher in countries with a strong emphasis on education and academic achievement.