cell division 2

Question 1

A genetic disorder caused by trisomy 21, where an individual has three copies of chromosome 21 instead of two, leading to distinct physical features, intellectual disability, and health issues.

Answer 1

Down syndrome

Question 2

Threadlike structures within the nucleus that carry genetic material in the form of DNA.

Answer 2

Chromosomes

Question 3

A type of cell division that results in two daughter cells with the same number of chromosomes as the original cell.

Answer 3

Mitosis

Question 4

A two-stage cell division process that reduces the chromosome number by half to form gametes.

Answer 4

Meiosis

Question 5

The union of haploid gametes to form a diploid zygote.

Answer 5

Fertilization

Question 6

Cells that have two complete sets of chromosomes, one from each parent.

Answer 6

Diploid (2n)

Question 7

Cells with only one set of chromosomes, such as gametes.

Answer 7

Haploid (n)

Question 8

Identical copies of a chromosome joined at the centromere.

Answer 8

Sister chromatids

Question 9

The region of a chromosome where sister chromatids are attached.

Answer 9

Centromere

Question 10

A visual representation of an individual’s complete set of chromosomes arranged by size and shape.

Answer 10

Karyotype

Question 11

The repeating sequence of cell growth and division.

Answer 11

Cell cycle

Question 12

The first phase of interphase, where the cell grows and prepares for DNA replication.

Answer 12

G1 phase

Question 13

The phase of interphase where DNA synthesis and chromosome duplication occurs.

Answer 13

S phase

Question 14

the final phase of interphase where the cell prepares for mitosis.

Answer 14

G2 phase

Question 15

The first stage of mitosis when chromosomes condense, and the mitotic spindle begins to form.

Answer 15

Prophase

Question 16

The stage of mitosis when chromosomes align at the metaphase plate.

Answer 16

Metaphase

Question 17

The stage of mitosis when sister chromatids separate and move toward opposite poles.

Answer 17

Anaphase

Question 18

The final stage of mitosis when nuclear envelopes re-form around the separated chromosomes.

Answer 18

Telophase

Question 19

The division of the cytoplasm to form two separate daughter cells.

Answer 19

Cytokinesis

Question 20

Control mechanisms in the cell cycle that ensure proper division and prevent errors.

Answer 20

Checkpoints

Question 21

The failure of chromosomes to separate properly during meiosis, leading to aneuploidy.

Answer 21

Nondisjunction

Question 22

A condition where cells have an abnormal number of chromosomes, such as trisomy 21 (Down syndrome).

Answer 22

Aneuploidy

Question 23

The pairing of homologous chromosomes during prophase I of meiosis.

Answer 23

Synapsis

Question 24

The exchange of genetic material between homologous chromosomes during meiosis, increasing genetic diversity.

Answer 24

Crossing-over

Question 25

The random distribution of homologous chromosomes during metaphase I of meiosis.

Answer 25

Independent assortment

Question 26

Meiosis I, where homologous chromosomes separate, reducing chromosome number by half.

Answer 26

Reductional division

Question 27

Meiosis II, where sister chromatids separate, similar to mitosis.

Answer 27

Equational division

Question 28

What is the main difference between mitosis and meiosis?

Answer 28

Mitosis produces two identical diploid daughter cells, while meiosis produces four genetically unique haploid gametes.

Question 29

Why does Down syndrome occur?

Answer 29

It results from trisomy 21, where an individual has an extra copy of chromosome 21.

Question 30

What is the function of a centromere?

Answer 30

It is the attachment point for sister chromatids and spindle fibers during cell division.

Question 31

What happens during prophase I of meiosis?

Answer 31

Homologous chromosomes pair up, and crossing-over occurs to exchange genetic material.

Question 32

What is the importance of independent assortment?

Answer 32

It increases genetic diversity by randomly distributing maternal and paternal chromosomes in gametes.

Question 33

How is genetic variation introduced in meiosis?

Answer 33

Through crossing-over in prophase I and independent assortment in metaphase I.

Question 34

What are the major checkpoints in the cell cycle?

Answer 34

The G1 checkpoint (before DNA replication), the G2 checkpoint (before mitosis), and the M checkpoint (during mitosis).

Question 35

How does cytokinesis differ in plant and animal cells?

Answer 35

In animal cells, a cleavage furrow forms, while in plant cells, a cell plate forms to divide the cell.

Question 36

What is nondisjunction, and why is it significant?

Answer 36

It is the failure of chromosomes to separate properly during meiosis, leading to disorders like Down syndrome.

Question 37

The process of exchanging genetic material between homologous chromosomes, leading to new allele combinations.

Answer 37

Recombination

Question 38

A multinucleate cell that results from incomplete cytokinesis, common in some animal embryos.

Answer 38

Syncytium

Question 39

A multinucleate plant tissue, such as coconut milk, formed by repeated nuclear divisions without cytokinesis.

Answer 39

Coenocyte

Question 40

Microtubules that extend from centrosomes and help position the spindle apparatus.

Answer 40

Polar microtubules

Question 41

Microtubules that radiate outward from the centrosomes toward the cell's periphery.

Answer 41

Astral microtubules

Question 42

A protein structure at the centromere where spindle fibers attach to pull chromatids apart.

Answer 42

Kinetochore

Question 43

An imaginary plane where chromosomes align during metaphase.

Answer 43

Metaphase plate

Question 44

Proteins that hold sister chromatids together until anaphase.

Answer 44

Cohesins