All of the following statements are specific to the critical periods of cell division EXCEPT

Mitosis is a process where a single cell divides into two identical daughter cells (cell division).

• During mitosis one cell divides once to form two identical cells.
• The major purpose of mitosis is for growth and to replace worn out cells.
• If not corrected in time, mistakes made during mitosis can result in changes in the DNA that can potentially lead to genetic disorders.

Mitosis is divided into five phases:

1. Interphase:

• The DNA in the cell is copied in preparation for cell division, this results in two identical full sets of chromosomes.
• Outside of the nucleus are two centrosomes, each containing a pair of centrioles, these structures are critical for the process of cell division.
• During interphase, microtubules extend from these centrosomes.

2. Prophase:

• The chromosomes condense into X-shaped structures that can be easily seen under a microscope.
• Each chromosome is composed of two sister chromatids, containing identical genetic information.
• The chromosomes pair up so that both copies of chromosome 1 are together, both copies of chromosome 2 are together, and so on.
• At the end of prophase the membrane around the nucleus in the cell dissolves away releasing the chromosomes.
• The mitotic spindle, consisting of the microtubules and other proteins, extends across the cell between the centrioles as they move to opposite poles of the cell.

3. Metaphase:

• The chromosomes line up neatly end-to-end along the centre (equator) of the cell.
• The centrioles are now at opposite poles of the cell with the mitotic spindle fibres extending from them.
• The mitotic spindle fibres attach to each of the sister chromatids.

4. Anaphase:

• The sister chromatids are then pulled apart by the mitotic spindle which pulls one chromatid to one pole and the other chromatid to the opposite pole.

5. Telophase:

• At each pole of the cell a full set of chromosomes gather together.
• A membrane forms around each set of chromosomes to create two new nuclei.
• The single cell then pinches in the middle to form two separate daughter cells each containing a full set of chromosomes within a nucleus. This process is known as cytokinesis.

Illustration showing the five stages of mitosis.
Image credit: Genome Research Limited

This page was last updated on 2021-07-21

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Note: Select an answer for each question, then click the “Evaluate Quiz” button at the bottom of the page to check your answers.

1. Neural development begins with rapid division of nerve cells in a process called

   a. synaptogenesis.
   b. cell migration.
   c. differentiation.
   d. neurogenesis.
   

2. During neural development, the nervous system generates more cells than it ultimately needs. Over half of the extra cells

   a. die though a natural process before birth.
   b. are stored in the cortex to replace damaged neurons later.
   c. are integrated into the circulatory system.
   d. develop into cell masses that house the neurotransmitters.
   

3. In the final stages of synaptogenesis, neurons

   a. differentiate into cerebral cells.
   b. grow dendrites and axons.
   c. undergo synapse rearrangement.
   d. die as a result of natural aging.
   

4. Any substance that can potentially harm the fetus during birth is called a

   a. teratogen.
   b. pollutant.
   c. plasticity factor.
   d. cell death agent.
   

5. Vision researchers have shown that a person will fail to develop visual perception abilities if light does not stimulate the eye early in development. This is evidence of _______ during development.

   a. synaptic pruning
   b. plasticity
   c. sensitive periods
   d. cell migration
   

6. Which statement regarding brain development is true?

   a. Adult brains are better able to recover from injury than children’s brains.
   b. Young children’s brains do not experience synapse rearrangement.
   c. The final stage of plasticity occurs during the adolescent years.
   d. Children’s brains are much more plastic than adults’ brains.
   

7. Two reflexes that help an infant receive nourishment are the _______ reflex, or the turning of the head in response to a brush of the cheek, and the _______ reflex, primarily for intake of breast milk.

   a. grasping; sucking
   b. rooting; grasping
   c. sucking; rooting
   d. rooting; sucking
   

8. Which of the following demonstrates the concept of habituation?

   a. A toddler repeats an activity in the same way multiple times.
   b. An infant shows a preference for viewing a single object over multiple objects.
   c. A baby stares into her mother’s eyes while breast feeding.
   d. A baby glances at a familiar stuffed animal, then stares at a new one.
   

9. Piaget’s theory of development has been referred to as _______ because in his view, children adapt to the world by actively building and organizing their experiences.

   a. constructivism
   b. postconventional
   c. egocentrism
   d. psychosocial
   

10. When a child learns new information about the world that fits with her schema, it is called _______. When a child learns new information that requires her to change her schema, it is called _______.

    a. assimilation; accommodation
    b. association; assimilation
    c. accommodation; assimilation
    d. accommodation; association
    

11. Lila is 18 months old and is no longer surprised when her mother hides her ball, only to reveal it again in a different position in front of her. What cognitive milestone is Lila displaying?

    a. Concrete operations
    b. Object recognition
    c. Conservation
    d. Object permanence
    

12. Preoperational children are often described as _______ because they do not understand that different people can have different points of view.

    a. logical
    b. egocentric
    c. constructivist
    d. preconventional
    

13. The procedure by which researchers test whether a child has developed a theory of mind is called the

    a. strange situation task.
    b. conservation test.
    c. preferential looking task.
    d. Sally and Anne test.
    

14. At about eight months of age, as a part of normal attachment development, infants begin to show

    a. rooting reflexes.
    b. avoidant attachment.
    c. stranger anxiety.
    d. ambivalent attachment.
    

15. Gerard’s mother has noticed that he becomes very upset when she leaves for work in the morning. When she gets home, he is resistant to her attempts to bond with him. Gerard is displaying

    a. disorganized attachment.
    b. ambivalent attachment.
    c. secure attachment.
    d. avoidant attachment.
    

16. All of the following are female secondary sex characteristics except

    a. wide hips.
    b. breast development.
    c. soft skin.
    d. ovaries.
    

17. Which developmental milestone characterizes menarche?

    a. The onset of menstruation
    b. An enhanced sex drive
    c. The first signs of puberty
    d. Thinning hair
    

18. Thinning of the top layer of the cortex in adolescence is a good indicator of the neurodevelopmental process called

    a. synapse rearrangement.
    b. demyelination.
    c. differentiation.
    d. cell death.
    

19. Kohlberg constructed his theory of moral reasoning by asking people to decide how a fictional character, Heinz, should respond to a moral dilemma. Kohlberg was most interested in the

    a. number of times people changed their minds while deciding.
    b. reasoning by which people reached their decisions.
    c. degree of empathy in the decision-making process.
    d. degree of justice in the decision-making process.
    

20. A child finds a five-dollar bill beside her teacher’s desk. Which scenario describes the application of preconventional moral reasoning?

    a. The child wants her teacher to like her, so she gives him the money.
    b. The child knows that stealing is wrong, so she leaves the money where she found it.
    c. The child is afraid she’ll get in trouble if she takes the money, so she gives it to her teacher.
    d. The child knows it is wrong to keep the money, but she slips it into her pocket, anyway.
    

21. Which theory outlines a series of stages that occur throughout the lifespan and involve tension between conflicting ways of interacting with others?

    a. Freud’s psychosexual theory
    b. Erikson’s psychosocial theory
    c. Piaget’s constructivist theory
    d. Bowlby’s attachment theory
    

22. According to Erikson’s theory of psychosocial development, which question best corresponds with an adolescent’s search for identity?

    a. What activities am I good at, compared to other people?
    b. Which adults can I trust, and which are not trustworthy?
    c. How can I fit in socially with the people around me?
    d. What rules can I break without getting caught?
    

23. Which statement is consistent with research on cognitive processing and aging?

    a. Older people typically respond faster than younger people in memory experiments.
    b. Fluid intelligence develops and improves from adolescence through old age.
    c. Memory decline in older people is the result of an enlargement of the hippocampus.
    d. Crystallized intelligence continues to grow throughout the aging process.
    

24. A 70-year-old woman who is given a touch-screen tablet becomes hopelessly frustrated when she tries to use it. Which of the following best explains her lack of success?

    a. A decline in crystallized intelligence makes it difficult for her to apply previous knowledge to a new situation.
    b. A decline in fluid intelligence keeps her from reasoning abstractly when confronted with an unfamiliar object.
    c. The similarity between her laptop computer and the tablet causes confusion between crystallized and fluid intelligence.
    d. The unfamiliarity of the tablet’s technology causes a breakdown of her crystallized intelligence.
    

25. Alzheimer’s disease is dementia that is caused by

    a. normal slowing of cognition due to rapid aging of the frontal cortex.
    b. random cell death primarily in the temporal lobe.
    c. the build-up of amyloid in and outside of acetylcholine neurons.
    d. diets high in fat, which cause the slow disintegration of brain cells.
    

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