Cleavage: The Process of Cell Division After Fertilization

Question 1

Which of the following is the primary mechanism responsible for cell division in the early embryo called cleavage?

Accepted Answer

Mitosis

Answer

Meiosis

Answer

Cytokinesis

Answer

Endocytosis

Question 2

What is the characteristic pattern of cell division observed during early cleavage in the embryo?

Accepted Answer

Synchronous and symmetric

Answer

Asynchronous and asymmetric

Answer

Anisotropic and asynchronous

Answer

Isotropic and synchronous

Question 3

What is the significance of the first cleavage furrow created during cleavage in mammalian embryology?

Accepted Answer

It determines the plane of symmetry for subsequent cleavages.

Answer

It divides the zygote into two blastomeres.

Answer

It establishes the anterior-posterior axis.

Answer

It initiates the formation of the inner cell mass.

Question 4

Which of the following is a characteristic feature of the morula stage of embryonic development?

Accepted Answer

Solid ball of cells

Answer

Fluid-filled cavity

Answer

Differentiated cells

Answer

Extraembryonic membranes

Question 5

What is the process by which the blastocoel cavity forms within the blastocyst?

Accepted Answer

Cavitation

Answer

De-lamination

Answer

Compaction

Answer

Differentiation

Question 6

Which of the following cell layers gives rise to the embryo proper?

Accepted Answer

Inner cell mass

Answer

Trophoblast

Answer

Epiblast

Answer

Hypoblast

Question 7

What is the significance of compaction during cleavage?

Accepted Answer

Facilitates cell communication

Answer

Prevents cell adhesion

Answer

Promotes asymmetric cell division

Answer

Induces differentiation

Question 8

What is the primary function of the trophoblast layer in the blastocyst?

Accepted Answer

Facilitate implantation

Answer

Protect the embryo

Answer

Provide nourishment

Answer

Initiate gastrulation

Question 9

During human embryonic cleavage, which of the following phases does NOT occur?

Accepted Answer

Gastrula

Answer

Morula

Answer

Blastula

Answer

Blastomere

Question 10

What is the term for the fluid-filled cavity that forms within the blastocyst?

Accepted Answer

Blastocoel

Answer

Trophoblast

Answer

Inner cell mass

Answer

Zona pellucida

Question 11

Which type of cleavage results in blastomeres of equal size?

Accepted Answer

Holoblastic cleavage

Answer

Meroblastic cleavage

Answer

Radial cleavage

Answer

Spiral cleavage

Question 12

What is the primary function of cleavage furrows?

Accepted Answer

Facilitate cell division

Answer

Determine embryo size

Answer

Establish body axes

Answer

Form the amniotic cavity

Question 13

What is the main function of the zona pellucida during cleavage?

Accepted Answer

Prevent polyspermy

Answer

Provide nutrients to the embryo

Answer

Regulate cell division

Answer

Form the trophoblast layer

Question 14

What is the ultimate fate of the inner cell mass?

Accepted Answer

Embryo proper

Answer

Placenta

Answer

Amniotic sac

Answer

Umbilical cord

Question 15

Which cell adhesion molecule is crucial for regulating early cleavage stages?

Accepted Answer

E-cadherin

Answer

N-cadherin

Answer

Integrin

Answer

Fibronectin

Question 16

How do differences in the timing and direction of cell division during cleavage affect the development and lineage of embryonic cells?

Accepted Answer

Cleavage timing can lead to unequal cell sizes, influencing cell specialization.

Accepted Answer

Cleavage orientation can affect cell positioning, impacting cell-to-cell interactions.

Answer

Variations in cleavage have no impact on embryonic development.

Question 17

Which term accurately describes an embryo at the four-cell stage?

Accepted Answer

Morula

Answer

Blastocyst

Answer

Gastrula

Answer

Neurula

Question 18

What is the primary purpose of cytoplasmic determinants during cleavage?

Accepted Answer

Guiding cell fate

Answer

Controlling the rate of cleavage

Answer

Providing nutrients to the embryo

Answer

Preventing cell adhesion

Question 19

In what way does cleavage contribute to the formation of the blastocyst? (Select the best option.)

Accepted Answer

Formation of the inner cell mass and trophoblast

Answer

Establishment of the anterior-posterior axis

Answer

Generation of the germ layers

Answer

Formation of the placenta

Question 20

Which internal factor within the zygote affects the timing and pattern of cleavage divisions?

Accepted Answer

Cytoplasmic determinants

Answer

Nuclear membrane

Answer

Cell size

Question 21

During the formation of the morula from the zygote, which pattern of cleavage occurs?

Accepted Answer

Holoblastic

Answer

Meroblastic

Answer

Superficial

Answer

Discoidal

Question 22

The separation of cells during cleavage is known as:

Accepted Answer

Furrowing

Answer

Budding

Answer

Karyokinesis

Answer

Cytoplasm reduction

Question 23

The inner cell mass (ICM) of the blastocyst gives rise to which of the following?

Accepted Answer

Embryo proper

Answer

Extra-embryonic membranes

Answer

Trophoblast

Answer

Amniotic fluid

Question 24

In the cleavage stage of embryonic development, what is the primary function of cell-cell adhesion molecules?

Accepted Answer

Maintain embryo integrity by preventing blastomere separation

Answer

Provide structural support to the embryo

Answer

Facilitate nutrient and waste exchange

Question 25

Which of these is NOT a stage of cleavage in early embryonic development?

Accepted Answer

Neurula

Answer

Zygote

Answer

Morula

Answer

Blastocyst

Question 26

Which of the following is NOT a stage of cleavage in human embryonic development?

Accepted Answer

Gastrulation stage

Answer

2-cell stage

Answer

Morula stage

Answer

Blastocyst stage

Question 27

How do cleavage patterns and cell lineage relationships influence the development of distinct cell types and tissues in early embryonic development?

Accepted Answer

Cleavage patterns and cell lineage relationships determine cell location, affecting the signals they receive and their ultimate fate.

Answer

Cleavage patterns are random and do not contribute to cell fate determination.

Answer

Cell lineage relationships are solely determined by the order of cell division.

Question 28

What is the primary purpose of cleavage?

Accepted Answer

To increase the number of cells and decrease their size

Answer

To initiate gastrulation

Answer

To establish the body axis

Answer

To form the placenta

Question 29

Which cellular structure is responsible for driving cleavage?

Accepted Answer

Mitotic spindle apparatus

Answer

Microtubules

Answer

Cyclin-dependent kinases

Answer

Centrioles

Question 30

Which cell type does NOT arise from the inner cell mass of the blastocyst?

Accepted Answer

Trophoblast

Answer

Hypoblast

Answer

Primitive ectoderm

Answer

Embryoblast

Question 31

Which of the following techniques is commonly employed to study cleavage?

Accepted Answer

Time-lapse microscopy

Answer

Western blotting

Answer

Electroencephalography

Answer

Immunohistochemistry

Question 32

Elaborate on the intrinsic and extrinsic factors that influence the timing, pattern, and regularity of cleavage divisions in embryos.

Accepted Answer

Intrinsic factors encompass the amount and distribution of yolk, while extrinsic factors include temperature and ionic concentration.

Answer

Cleavage divisions always follow a regimented and symmetrical pattern.

Answer

The rate of cleavage divisions is solely dependent on the size of the zygote.

Answer

External factors do not play a role in shaping the pattern of cleavage divisions.

Question 33

Which of the following best describes the primary mechanism of cleavage in early embryonic development?

Accepted Answer

Mitotic spindle is positioned perpendicular to the previous cleavage furrow and cytokinesis occurs via cell membrane pinching

Answer

Cytokinesis occurs via cell wall formation

Answer

Meiotic spindle is positioned parallel to the previous cleavage furrow

Question 34

During the process of cleavage, the volume of the embryo:

Accepted Answer

Remains relatively constant

Answer

Decreases as cells divide

Answer

Continuously increases as cells divide

Answer

Alternately increases and decreases between cell divisions

Question 35

Which of the following is a distinctive feature of radial cleavage?

Accepted Answer

Blastomeres are arranged in a spherical pattern, giving the embryo a characteristic radial symmetry

Answer

Blastomeres are arranged in a linear pattern

Answer

Cleavage furrows are deep and extend to the vegetal pole

Answer

Yolk distribution is uneven, leading to differences in blastomere size

Question 36

Asymmetric cleavage is characterized by:

Accepted Answer

Resulting in blastomeres of unequal size and developmental potential

Answer

Occurring exclusively in mammals

Answer

Always preceding radial cleavage

Question 37

Which of the following is NOT a primary function of cleavage in early embryonic development?

Accepted Answer

Formation of the embryonic germ layers

Answer

Distribution of maternally derived factors

Answer

Increase in cell number

Answer

Establishment of cell fate

Question 38

Holoblastic cleavage is a type of cleavage commonly observed in:

Accepted Answer

Eggs with a small amount of yolk evenly distributed throughout the cytoplasm

Answer

Eggs with a large amount of yolk concentrated at one end

Answer

Eggs with a prominent polar body

Answer

Eggs with a chorion surrounding the plasma membrane

Question 39

The process of cleavage is typically initiated by:

Accepted Answer

Fertilization or parthenogenesis, depending on the species and reproductive mode

Answer

Implantation

Answer

Gastrulation

Answer

Neurulation

Question 40

Which of the following is an example of meroblastic cleavage?

Accepted Answer

Discoidal cleavage

Answer

Radial cleavage

Answer

Spiral cleavage

Answer

Holoblastic cleavage

Question 41

Which of the following is a deviation from normal cleavage patterns?

Accepted Answer

Polyspermy

Answer

Holoblastic cleavage

Answer

Meroblastic cleavage

Answer

Discoidal cleavage

Question 42

What is the primary function of the zona pellucida during cleavage?

Accepted Answer

Prevents polyspermy

Answer

Facilitates blastocyst formation

Answer

Provides structural support to the embryo

Answer

Guides sperm to the oocyte

Question 43

What is the ultimate fate of the inner cell mass?

Accepted Answer

Forms the embryo

Answer

Forms the yolk sac

Answer

Forms the amniotic sac

Answer

Forms the placenta

Question 44

Which cleavage pattern results in blastomeres with significant yolk content?

Accepted Answer

Meroblastic discoidal

Answer

Holoblastic equal

Answer

Holoblastic superficial

Answer

Meroblastic superficial

Question 45

Cleavage directly transforms the zygote into a:

Accepted Answer

Morula

Answer

Gastrula

Answer

Blastocyst

Answer

Fetus

Question 46

Which of the following is NOT a characteristic of cleavage?

Accepted Answer

It involves significant cell growth between divisions.

Answer

It reduces the cytoplasmic volume per cell.

Answer

It increases the surface area of the embryo.

Answer

It increases the number of cells in the embryo.

Question 47

The inner cell mass of the blastocyst contributes to the formation of the:

Accepted Answer

Embryo proper

Answer

Placenta

Answer

Blastocoele

Answer

Trophoblast

Question 48

The primary function of the trophoblast layer in the blastocyst is:

Accepted Answer

Implantation into the uterine wall

Answer

Differentiation into the three primary germ layers

Answer

Regulation of early cleavage divisions

Answer

Formation of the embryonic germ layers

Question 49

Compaction, a crucial step in blastocyst formation, is primarily mediated by:

Accepted Answer

E-cadherins

Answer

Immunoglobulins

Answer

Selectins

Answer

Integrins

Question 50

Which of the following characteristics does NOT apply to cleavage?

Accepted Answer

It is a random process.

Answer

It is typically rapid and synchronous.

Answer

It contributes to the formation of a blastocyst.

Question 51

During the first cleavage division of the zygote, what is the plane of the cleavage furrow called?

Accepted Answer

Meridional plane

Answer

Equatorial plane

Answer

Latitudinal plane

Answer

Radial plane

Question 52

Which type of cleavage results in the formation of an inner cell mass enclosed by an outer trophoblast layer?

Accepted Answer

Holoblastic cleavage

Answer

Superficial cleavage

Answer

Meroblastic cleavage

Answer

Radial cleavage

Question 53

What is the primary function of the polar bodies formed during cleavage?

Accepted Answer

To discard excess genetic material from the zygote.

Answer

To provide nourishment for the developing embryo.

Answer

To contribute genetic material to the blastocyst.

Question 54

Which factors can potentially influence the rate of cleavage?

Accepted Answer

Oxygen concentration, pH, and temperature.

Answer

Gestational age

Answer

Maternal age

Question 55

What cellular process is primarily responsible for driving cleavage?

Accepted Answer

Cytokinesis

Answer

Meiosis

Answer

DNA replication

Answer

Mitosis

Question 56

Which of the following is NOT a potential consequence of abnormal cleavage?

Accepted Answer

Increased likelihood of multiple pregnancies.

Answer

Developmental defects

Answer

Reduced implantation success

Answer

Ectopic pregnancy

Question 57

Approximately how long does the cleavage stage typically last in humans?

Accepted Answer

3-4 days

Answer

5-6 days

Answer

1-2 days

Question 58

Which research technique is commonly used to observe and study cleavage in the laboratory?

Accepted Answer

Time-lapse microscopy

Answer

Flow cytometry

Answer

Electroencephalography

Question 59

In the context of assisted reproductive technologies (ART), what is a significant use of cleavage observations?

Accepted Answer

Assessing embryo quality and viability

Answer

Preventing multiple pregnancies

Answer

Determining the genetic sex of the embryo