Question 1

A pregnant woman has an ultrasound to assess the progress of the twins she is expecting. Her doctor says, "From what I can see on the screen, Ms. Black, it looks as if you will have a boy and a girl." In what stage of development must the twins be?

Accepted Answer

The sex of the twins can be determined during the fetal stage, as this is when the external genitalia are developed and can be visualized via ultrasound.

Question 2

About 25 days after a conception, the brain of a baby-to-be is a tiny tube. Over time the tube grows longer and folds to form pockets that gradually evolve into structurally
Different parts. Inside the tube, neurons reproduce at an astonishing rate and then
Migrate to various locations to take on their functions. All of this happens regardless
Of the future baby's environmental circumstances. Which one of the following
Concepts best describes the nature of this early brain development?

Accepted Answer

Canalization refers to the developmental process that is genetically determined and follows a specific pattern, regardless of the external environment. This concept best describes the early brain development described, where the brain's growth and neuron migration occur in a predetermined manner, unaffected by environmental circumstances.

Question 3

Children typically have some characteristics not seen in either of their biological parents. Which one of the following is the most common source of these unique
Characteristics?

Accepted Answer

The most common source of unique characteristics in children that are not seen in their biological parents is genetic recombination, which occurs during meiosis. This process involves the crossing over of genetic material between paired chromosomes, leading to a mix of parental genes and the creation of unique genetic combinations in the offspring.

Question 4

Human cells contain 23 pairs of chromosomes. Within each pair:

Accepted Answer

Each person inherits one chromosome from each pair from their mother and the other from their father, making up the 23 pairs of chromosomes in human cells.

Question 5

Genes influence physical development most directly by:

Accepted Answer

Genes influence physical development by providing the instructions for the production of proteins, which are crucial for the structure, function, and regulation of the body's tissues and organs.

Question 6

Some physical disabilities are the result of genetic abnormalities. An example is Down syndrome, in which:

Accepted Answer

Down syndrome is caused by an extra copy of chromosome 21, leading to a total of three copies instead of the usual two. This condition is also known as trisomy 21.

Question 7

The gene for red hair is a recessive gene. Luke has red hair, but neither of his biological parents has red hair. Given this information, we can reasonably guess that:

Accepted Answer

Since red hair is a recessive trait, Luke must have inherited one red-hair gene from each parent. For him to express this trait, both of his parents must be carriers of the gene, meaning each has one red-hair gene and one non-red-hair gene.

Question 8

A tiny cluster of cells has just traveled down one of its mother's fallopian tubes and implanted itself in the mother's uterus. What word is typically used for a baby-to-be at this stage of development?

Accepted Answer

The answer of A tiny cluster of cells has just...

Question 9

Most complex psychological traits in human beings are probably shaped by:

Accepted Answer

Most complex psychological traits are influenced by multiple genes (multifactorial) and environmental factors, rather than being determined by a single gene or solely by environmental experiences.

Question 10

More than 20,000 genes make up human DNA. Of these genes, how many do all human beings have in common?

Accepted Answer

The great majority of human genes are common to all human beings, with over 99% of our DNA being identical across individuals. This shared genetic material is what makes us all human, while the small variations contribute to individual differences.

Question 11

Which one of the following best describes codominance in genes' effects on children's growth and development?

Accepted Answer

Codominance occurs when two different alleles at a gene locus are both fully expressed in the phenotype of the heterozygote, meaning both alleles influence the physical characteristic without one being dominant over the other.

Question 12

Imagine that you are a beginning teacher and learn that your new class of students will include a pair of monozygotic twins. You should expect that:

Accepted Answer

Monozygotic twins, also known as identical twins, are genetically identical because they originate from the same fertilized egg. Therefore, they often look very similar to each other, which can make it challenging for someone who is not familiar with them to tell them apart. The other options are stereotypes or misconceptions about twins that are not supported by scientific evidence.

Question 13

A small mass has been in a mother's placenta for several weeks. A small head is distinguishable from the body, and tiny buds that will become arms and legs are just beginning to sprout fingers and toes. What word is typically used for a baby-to-be at this stage of development?

Accepted Answer

At this stage of development, the term "embryo" is used. This phase occurs after the zygote stage and continues until the end of the eighth week, when the term changes to "fetus." The described characteristics, such as a distinguishable head and the beginning formation of limbs, are indicative of the embryonic stage.

Question 14

Reproductive cells (sperm in men and ova in women) are different from other human cells in that they:

Accepted Answer

Reproductive cells, also known as gametes (sperm in men and ova in women), have only half as many chromosomes as other human cells. This is because they are haploid cells, containing one set of chromosomes, ensuring that upon fertilization, the resulting zygote has the correct diploid number of chromosomes.

Question 15

Ruth has always been a rambunctious, outspoken child. She has excessively high energy levels and tendency to blurt out what she is thinking and interrupting others. What is something that is not recommended to encourage her to do?

Accepted Answer

Encouraging Ruth to follow her natural tendencies without guidance or structure might exacerbate her issues with interrupting others and blurting out thoughts, rather than helping her learn to manage her high energy and impulsiveness in socially appropriate ways. Activities like joining a drama or debate club or learning to raise her hand before speaking can provide structured outlets for her energy and teach her valuable social skills.

Question 16

Imagine that you are a preschool teacher and want to foster your students' development in a variety of domains. In which of the following areas is canalization most likely to be a significant factor in their development?

Accepted Answer

Canalization refers to the degree to which the development of a trait is buffered against environmental variability. Motor skills are highly canalized, meaning they develop in a similar way across different environments due to strong genetic influences.

Question 17

Which one of the following statements most accurately describes the effects of a particular gene on a child's development and functioning?

Accepted Answer

A gene's effects on development and functioning are influenced by a combination of genetic, environmental, and lifestyle factors, making A the most accurate description.

Question 18

A pre-school teacher who works with infants and toddlers makes sure to talk with her young students frequently. She sings nursery rhymes with them. She is taking advantage of which of the following with them?

Accepted Answer

The teacher is taking advantage of the sensitive period, a time during early childhood development when the brain is particularly receptive to acquiring specific types of knowledge and skills, such as language. Engaging in activities like talking and singing with infants and toddlers helps facilitate language development during this optimal learning window.

Question 19

Multifactorial trait refers to a situation in which a trait is influenced by:

Accepted Answer

Multifactorial traits are influenced by multiple genes, often in combination with environmental factors, rather than a single gene. This complexity contributes to the variation seen in these traits among individuals.

Question 20

Mary is pregnant with her first child and has recently had genetic testing to determine whether her baby-to-be is growing normally. Among other things, her test results indicate that the twenty-third chromosome pair of her fetus includes one X chromosome and one Y chromosome. This means that:

Accepted Answer

The presence of one X chromosome and one Y chromosome in the twenty-third chromosome pair indicates a male child, as this is the typical chromosomal pattern for males.

Quiz 4: Biological Beginnings