Test: Human Development - 1 - MCAT MCQ

The reflex described in option D is called the Babinski reflex, which is a neonatal reflex. When the sole of a baby's foot is stroked, the baby's toes fan out and the big toe moves upward while the other toes spread apart. This reflex is typically present in infants and disappears as the nervous system matures. It is considered a normal response in newborns but may indicate an abnormality if it persists beyond the expected age range. The other options, A, B, and C, describe neonatal reflexes that are commonly observed in newborn babies.

Fetal alcohol syndrome (FAS) is a birth defect that is caused by maternal consumption of alcohol during pregnancy. When a pregnant woman drinks alcohol, it can pass through the placenta and reach the developing fetus, causing damage to the developing organs and systems. FAS is characterized by a range of physical, behavioral, and cognitive abnormalities, including growth deficiencies, facial abnormalities, intellectual disabilities, and behavioral problems.

Option A, polycystic kidney disease, is a genetic disorder that is inherited and not directly associated with teratogenic substances during pregnancy. Option C, autism spectrum disorder, is a neurodevelopmental disorder with a complex etiology involving genetic and environmental factors, but it is not specifically linked to teratogenic substance exposure. Option D, phenylketonuria (PKU), is a genetic disorder characterized by the inability to break down an amino acid called phenylalanine. It is not caused by exposure to teratogenic substances during pregnancy.

In a cross-sectional study design, data is collected from different individuals at a single point in time. In this scenario, the researcher recruits children from different age groups and compares their cognitive test results. By examining children of different ages at the same time, the researcher can observe potential age-related differences in executive function development. This design allows for a quick and efficient assessment of the relationship between age and cognitive performance.

Option B, case study design, involves in-depth analysis of a single individual or a small group of individuals. It is not applicable in this scenario as the researcher is interested in comparing children from different age groups.

Option C, longitudinal design, involves collecting data from the same individuals over an extended period of time. It would require following the same group of children and assessing their executive function development over multiple time points. This is not the design described in the scenario.

Option D, experimental design, involves manipulating variables and comparing groups to assess cause-and-effect relationships. The scenario does not mention any manipulation of variables or comparison between different treatment groups, so this design is not applicable.

Klinefelter syndrome is a chromosomal disorder that occurs in males and is characterized by the presence of an additional X chromosome, resulting in an XXY genotype. Typically, males have one X and one Y chromosome (XY genotype), but individuals with Klinefelter syndrome have an extra X chromosome. This condition can lead to various physical, hormonal, and developmental differences, including reduced fertility, taller stature, gynecomastia (enlarged breasts), and potential learning and behavioral difficulties.

Option A, Turner syndrome, is a chromosomal disorder that affects females and is characterized by the absence of one X chromosome, resulting in an X0 genotype.

Option B, Down syndrome, is caused by the presence of an extra copy of chromosome 21 (trisomy 21), resulting in a total of three copies of chromosome 21.

Option C, Trisomy X, is a chromosomal disorder that affects females and is characterized by the presence of an extra X chromosome, resulting in a XXX genotype.

Therefore, the correct answer is D. Klinefelter syndrome is associated with an XXY genotype.

During embryonic development, the blastocyst undergoes gastrulation, a process in which the three primary germ layers form. These germ layers give rise to different tissues and organs in the body. The mesoderm is one of these germ layers and is responsible for the development of various structures, including muscles, bones, connective tissues, blood vessels, and the cardiovascular system.

Option B, ectoderm, gives rise to structures such as the nervous system, skin, hair, and nails.

Option C, endoderm, is involved in the development of the gastrointestinal tract, respiratory system, liver, and pancreas.

Option D, blastopore, is a structure formed during gastrulation but is not specifically associated with muscular development. The blastopore is the opening that forms in the early embryo and eventually develops into either the mouth or the anus, depending on the organism.

Therefore, the correct answer is A. Mesoderm is the germ layer associated with muscular development.

Gross motor skills involve the movement and coordination of large muscle groups in the body. They typically involve activities that require whole-body movements or the use of larger muscle groups. Throwing a ball requires the coordination and movement of multiple muscle groups, such as the arms, shoulders, and legs, to propel the ball forward.

Option A, picking up a spoon, is an example of a fine motor skill as it involves precise hand movements and coordination.

Option B, stirring cake batter, can be considered a fine motor skill as it requires precise hand movements and coordination to mix the ingredients.

Option C, painting with fingers, can be classified as a fine motor skill as it involves precise finger movements and hand-eye coordination.

Therefore, the correct answer is D. Throwing a ball is an example of a gross motor skill.

Axon myelination, which is the process of forming a protective covering called myelin around nerve fibers, begins during the second trimester of prenatal development. This is a crucial stage of neurological development when the brain and nervous system undergo rapid growth and maturation. Myelination continues throughout infancy and childhood, gradually improving the speed and efficiency of nerve signal transmission.

Option A, third trimester, is not the correct answer because myelination typically begins earlier, during the second trimester.

Option C, first trimester, is not the correct answer because myelination does not occur during this early stage of prenatal development.

Option D, year one, is not the correct answer because myelination begins during prenatal development, specifically in the second trimester, and continues into infancy. It is an ongoing process that extends beyond the first year of life.

Therefore, the correct answer is B. Axon myelination begins during the second trimester of development.

Piaget's stages of cognitive development are sequential and progress in the following order: Sensorimotor (birth to 2 years), Preoperational (2 to 7 years), Concrete Operational (7 to 11 years), and Formal Operational (11 years and beyond). Each stage is characterized by distinct cognitive abilities and ways of thinking.

Primary sex characteristics refer to the development and maturation of reproductive organs and structures directly involved in sexual reproduction. This includes the onset of puberty, the growth and maturation of the reproductive organs (such as the testes and ovaries), and the development of secondary sexual characteristics (such as the growth of pubic hair and changes in breast size).

Imprinting is a process observed in some animal species, where newborns form strong and rapid attachments to specific objects or individuals shortly after birth. It is believed to be an instinctual behavior that promotes survival and social bonding. While imprinting is less prominent in human development compared to some animal species, it can still play a role in early social bonding and attachment.