TOPIC 3 Flashcards
is the ordered sequence of events that occur in a cell in preparation for cell division
Cell Cycle
process in which the cell increases in size
gap 1, or G1, stage
stage that copies its DNA
synthesis, or S, stage
stage that copies its DNA
synthesis, or S, stage
process in which the cell prepares to divide
gap 2, or G2, stage
process in which the cell divides
mitosis, or M, stage
programmed cell death
apoptosis
the division of a cell into two separate and similar parts
binary fission
the body that contains the DNA and associated proteins
chromosome
type of asexual reproduction typically observed in prokaryotes and a few
single-celled eukaryotes. In this method of asexual reproduction, there is a separation of the parent cell into two new daughter cells. This process happens with the division and duplication of
the parent’s genetic matter into two parts. Here, each daughter cell receives one copy of its parent DNA.
Binary fission
Cells multiply chiefly by ______, a complex process that involves an equal division of the nuclear chromatin in kind and
amount.
mitosis
In the formation of body cells also called as _____the process of cell division is referred to as mitosis.
somatic cell
germ cells (egg
and sperm) undergo a special type of cell division known as _______
Meiosis
Before a dividing cell enters mitosis, it undergoes a period of growth called _______ which accounts for about 90 percent of a cell’s time in the normal cell cycle.
interphase
It is during ______ that the cell grows and copies its chromosomes in preparation for cell division.
interphase
Interphase consists of 3 periods of growth which are:
G1 phase
S phase
G2 phase
first gap of interphase
G1 phase
Phase where DNA synthesis
S phase
chromosomes are duplicated only during the _____.
S phase
The period prior to the synthesis of DNA. In this phase, the cell increases in mass in
preparation for cell division.
G1 phase
The period during which DNA is synthesized. In most cells, there is a narrow window of time during which DNA is synthesized.
S phase
The period after DNA synthesis has occurred but prior to the start of prophase. The
cell synthesizes proteins and continues to increase in size
G2 phase
In the latter part of _____, the cell still has nucleoli present
interphase
division of the nucleus, it has 4 stages.
Mitosis
4 stages of Mitosis
Prophase
Metaphase
Anaphase
Telophase
In ______, the chromatin condenses into discrete chromosomes.
Prophase
The nuclear envelope breaks down and spindles form at opposite poles of the cell.
Prophase
Chromatin fibers become coiled into chromosomes, with each chromosome having two chromatids joined at a centromere.
Prophase
The mitotic spindle, composed microtubules and proteins, forms in the
cytoplasm.
Prophase
The two pairs of centrioles (formed from the replication of one pair in Interphase) move away from one another toward opposite ends of the cell due to the lengthening of the microtubules that form between them.
Prophase
are microtubules that make up the spindle fibers
Polar fibers
which are specialized regions in the centromeres of chromosomes
Kinetochores
In ______, the spindle reaches maturity and the chromosomes align at the metaphase plate.
metaphase
a plane that is equally distant from the two spindle poles
metaphase plate
The nuclear membrane disappears completely
Metaphase
Polar fibers continue to extend from the poles to the center of the cell.
Metaphase
Chromosomes move randomly until they attach (at their kinetochores) to polar fibers from both sides of their centromeres.
Metaphase
In ______, the paired chromosomes (sister chromatids) separate and begin moving to opposite ends (poles) of the cell.
anaphase
At the end of ______, each pole contains a complete compilation of chromosomes.
Anaphase
The paired centromeres in each distinct chromosome begin to move apart.
Anaphase
Once the paired sister chromatids separate from one another, each is
considered a “full” chromosome. They are referred to as _________.
daughter chromosomes
In ______, the chromosomes are cordoned off into distinct new nuclei in the emerging daughter cells.
telophase
The polar fibers continue to lengthen. Nuclei begin to form at opposite poles.
Telophase
The nuclear envelopes of these nuclei form from remnant pieces of the parent
cell’s nuclear envelope and from pieces of the endomembrane system.
Telophase
Nucleoli also reappear.
Telophase
The genetic contents of one cell have been divided equally into two.
Telophase
the division of the cell’s cytoplasm
Cytokinesis
Cytokinesis begins prior to the end of mitosis in _____ and completes shortly after telophase/mitotic phase.
Anaphase
At the end of ______, two genetically
identical daughter cells are produced. These are diploid cells, with each cell containing a full complement of chromosomes
cytokinesis
In meiosis, four daughter cells are produced. These cells are ______ cells, containing one-half the number of chromosomes as the original cell.
Haploid
Sex cells undergo meiosis. When sex cells unite during fertilization, these haploid cells become a ______ cell.
Diploid
is a special type of eukaryotic cell division that produces haploid sex cells or gametes
from diploid cells
Meiosis
contain a single copy of each chromosomes
Haploid sex cells or gametes
contain two copies of each chromosome
diploid cells
the two halves of a duplicated chromosome
sister chromatids
Homologue pairs separate during a first round of cell division, called _______.
meiosis I
Sister chromatids separate during
a second round, called _____.
meiosis II
The starting cell is diploid, 2n = 4. Homologous chromosomes pair up and
exchange fragments in the process of crossing over.
Prophase I
Homologue pairs line up at the metaphase plate.
Metaphase I:
Homologues separate to opposite ends of the cell. Sister chromatids stay together.
Anaphase I
Newly forming cells are haploid, n = 2. Each chromosome still has two sister
chromatids, but the chromatids of each chromosome are no longer identical to each other.
Telophase I
a lattice of proteins between the homologous chromosomes, first forms at specific locations and then spreads to cover the entire length of the chromosomes
synaptonemal complex
The tight pairing of the homologous chromosomes is called ______.
synapsis
The synaptonemal complex supports the exchange of chromosomal segments
between non-sister homologous chromatids, a process called _______.
crossing over
cross-shaped structures where homologues are linked together
chiasmata
In ______, the homologous chromosomes are arranged in the center of the cell with the kinetochores facing opposite poles.
Metaphase I
The random or ________ of homologous chromosomes at the
metaphase plate is the second mechanism that introduces variation into the gametes or spores.
independent assortment
How many chromosomes pairs do human have?
23
In _____, the homologues are pulled apart and move apart to opposite ends of the cell. The sister chromatids of each chromosome, however, remain attached to one another and do not separate.
anaphase I
the chromosomes decondense and nuclear envelopes form around the chromatids in _______.
telophase I.
constriction of the actin ring that leads to cytoplasmic division
cleavage furrow
In plants, a ______ is formed during cell cytokinesis by Golgi vesicles fusing at the metaphase plate.
cell plate
In some species, cells enter a brief interphase, or _______, before entering meiosis II.
interkinesis
During ______, the sister chromatids
within the two daughter cells separate, forming four new haploid gametes.
meiosis II
During ______, chromosomes condense and the nuclear envelope breaks down, if needed. The centrosomes move apart, the spindle forms between them, and the spindle microtubules begin to capture chromosomes. The two sister chromatids of each chromosome are captured by
microtubules from opposite spindle poles.
prophase II
In ______, the chromosomes align on the metaphase plate in mitosis-like fashion, with the kinetochores of sister chromatids of each chromosome pointing toward opposite poles.
metaphase II
In _______, the centromeres of sister chromatids finally separate, and the sister chromatids of each pair, now individual chromosomes, move toward opposite poles of the cell.
anaphase II
the chromosomes arrive at opposite poles and begin to decondense. Nuclear
envelopes form around the chromosomes
telophase II
Importance of the process in the life cycle of a multicellular organism or cell;
Development of multicellular
adult from zygote.
Production of cells for growth, for repair & replacement of damaged/worn out cells.
Mitosis
Importance of the process in the life cycle of a multicellular organism or cell;
Produces haploid gametes for sexual reproduction.
Conserve chromosome number by half.
Introduces genetic variability
in the gametes.
Meiosis
Type of Reproduction: Asexual
Mitosis
Type of Reproduction: Sexual
Meiosis
Chromosome # in daughter cell: 2N
Mitosis
Chromosome # in daughter cell: N
Meiosis
Type of cells produced in the process: Diploid
Mitosis
Type of cells produced in the process: Haploid
Meiosis
Mother cell’s genetic make up compared to daughter cell’s genetic make up:
Identical to the mother cell
Mitosis
Mother cell’s genetic make up compared to daughter cell’s genetic make up: Genetically different to the mother cell and to each other
Meiosis
Number of nuclear divisions: One division sequence
Mitosis
Number of nuclear divisions:
Two division sequence
Meiosis
Number of times DNA is replicated
Both once in Mitosis and Meiosis
Does synapsis of homologous chromosomes occur? No
Does crossing over occur? No
Does independent assortment occur? No
Mitosis
Does synapsis of homologous chromosomes occur? Yes
Does crossing over occur? Yes
Does independent assortment occur? Yes
Meiosis
Type of cell that undergo the process (areas of the body) in Mitosis
Somatic/body cells
Type of cell that undergo the process (areas of the body) in Meiosis
Reproductive cells or gametes
When does cytokinesis occur? (1st or 2nd division) in Mitosis
1st division
When does cytokinesis occur? (1st or 2nd division) in Meiosis
2nd division
Number of daughter cells produced at the end of the process in Mitosis
Two
Number of daughter cells produced at the end of the process in Meiosis
Four
