Cell Division

Question 1

mitotic phase

Answer 1

mitotic phase of the cell cycle involves a pair
of related processes: mitosis and cytokinesis

Question 2

mitosis

Answer 2

division of the nucleus that results
in two identical nuclei (assuming no errors)

Question 3

cytokinesis

Answer 3

division of the cytoplasm that
results in two daughter cells (usually occurs
in conjunction with mitosis but not always)

Question 4

prophase: mitosis

Answer 4

the first stage of cell division, before metaphase, during which the chromosomes become visible as paired chromatids and the nuclear envelope disappears. the first prophase of meiosis includes the reduction division

Question 5

prometaphase: mitosis

Answer 5

stage of eukaryotic cell division that falls between prophase and metaphase. during prophase, the cell ’s chromosomes have condensed and the cell’s centrosome, or microtubule organizing center, has divided and moved to opposite sides of the cell

Question 6

metaphase: mitosis

Answer 6

the second stage of cell division, between prophase and anaphase, during which the chromosomes become attached to the spindle fibers

Question 7

anaphase: mitosis

Answer 7

the stage of meiotic or mitotic cell division in which the chromosomes move away from one another to opposite poles of the spindle

Question 8

telophase: mitosis

Answer 8

the final phase of cell division, between anaphase and interphase, in which the chromatids or chromosomes move to opposite ends of the cell and two nuclei are formed

Question 9

mitotic division

Answer 9

several checkpoints
regulate the cycle by
pausing cell division
if certain conditions
are not yet satisfied. checkpoint failures
lead to uncontrolled
division and cancer

Question 10

contractile ring

Answer 10

a cytoskeletal structure that forms in animal cells and many unicellular eukaryotes during cell division, contraction of which causes the plasma membrane to pinch inward and the cell to divide

Question 11

homologous chromosomes

Answer 11

the same size,
contain the same genes, and pair for meiosis
- one of each pair
is inherited from
the dad, and one
is from the mom
- Ychromosome is
not homologous

Question 12

allele

Answer 12

one of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome
- gene is a section of DNA that codes for one
or more related proteins or functional RNA. alleles are different forms of the same gene

Question 13

autosomes

Answer 13

any chromosome that is not a sex chromosome

Question 14

karyotype

Answer 14

the number and visual appearance of the chromosomes in the cell nuclei of an organism or species

Question 15

sex chromosomes

Answer 15

a chromosome involved with determining the sex of an organism, typically one of two kinds

Question 16

ploidy

Answer 16

refers to the number of chromosome
“sets” present in the nuclei of eukaryotic cells
- haploid: single chromosome set (n)
- diploid: two chromosome sets (2n)
- polyploid: greater than two sets of
chromosomes (3n, 4n, 5n, 6n, etc.)

Question 17

meiotic phase

Answer 17

meiosis (my-osis) is a special type of nuclear
division involved in sexual reproduction that
results in four different nuclei that are each
half of the original ploidy (example: 2n to n)
- cytokinesis is division of the cytoplasm that
results in two daughter cells (happens twice).
- as for mitosis, DNA replication occurs prior
to meiosis (during the S phase of interphase)

Question 18

meiosis 1

Answer 18

the number of chromosomes is reduced by one-half and for this reason, it is called reduction division

Question 19

meiosis 2

Answer 19

separation the sister chromatids and for this reason, it is known as equatorial division

Question 20

synapsis

Answer 20

the fusion of chromosome pairs at the start of meiosis

Question 21

recombination

Answer 21

the rearrangement of genetic material, especially by crossing over in chromosomes or by the artificial joining of segments of DNA from different organisms
- recombination during meiosis I produces
chromosomes with different combinations
of alleles than those found in the organism

Question 22

kinetochore

Answer 22

a complex of proteins associated with the centromere of a chromosome during cell division, to which the microtubules of the spindle attach. exist in eukaryotes

Question 23

homologous chromosomes

Answer 23

have the same genes in the same locations (loci)
but do not have the exact same DNA sequence

Question 23

homologous chromosomes

Answer 23

have the same genes in the same locations (loci)
but do not have the exact same DNA sequence

Question 24

meiosis

Answer 24

used to produce gametes that contain only half the number of chromosomes found in other cells in the organism

Question 25

differences between meiosis and mitosis

Answer 25

1. cells undergo two divisions in meiosis, while they only divide once in mitosis 2. homologous chromosomes separate into different cells during meiosis I, which produces daughter cells that are genetically different from the parent cel 3. at the beginning of meiosis I, homologous chromosomes can exchange corresponding regions (known as recombination or crossing over), which creates new versions of the chromosomes that were not present in either parent

Question 26

G1 phase

Answer 26

the period in the cell cycle from the end of cell division to the beginning of DNA replication - cell size - external signals - DNA damage

Question 27

synthesis (S) phase

Answer 27

phase of the cell cycle in which DNA is replicated, occurring between G 1 phase and G 2 phase

Question 28

G2 phase

Answer 28

the period in the cell cycle from the completion of DNA replication to the beginning of cell division - replication complete - DNA damage

Question 29

m phase

Answer 29

the period in the cell cycle during which cell division takes place - during metaphase - sees if spindle fibers are attached

Question 30

genetic variation

Answer 30

offspring from sexual reproduction, which requires meiosis during the life cycle, share traits with parents and siblings yet are also genetically distinct (except identical twins). - independent assortment - fertilization - recombination

Question 31

independent assortment

Answer 31

alignment of homologous chromosome pairs during meiosis I is independent and random

Question 32

sex paradox

Answer 32

asexual reproduction is far more efficient for producing offspring than sexual reproduction.

Question 33

nondisjunction

Answer 33

nondisjunction is an error that occurs during meiosis or mitosis in which chromosomes are incorrectly distributed to the daughter nuclei

Question 34

gametogenesis

Answer 34

the process in which cells undergo meiosis to form gametes

Question 35

oogenesis

Answer 35

the production or development of an ovum

Question 36

spermatogenesis

Answer 36

the production or development of mature spermatozoa