The Chromosomal Basis of Heredity Flashcards
It is the series of events that take place in a cell leading to its replication.
Cell Cycle
Type of Cells
Prokaryotic
Eukaryotic
It is multicellular and have a defined nucleus.
Eukaryotic
Unicellular and lacks a defined nucleus.
Prokaryotic
The method by which prokaryotes produce
new individuals that are genetically identical to the parent organism.
Binary fission
A less complicated and much more rapid process than cell division in eukaryotes.
Binary fission
Eukaryotic cells have a cell
cycle of _________ , which is divided into phases.
16 to 24 hours
A molecule that carries genetic information in living organisms. It looks like a twisted ladder (double helix) and is found inside the nucleus of our cells.
DNA
The basic physical unit of heredity and it is
passed on from generation to generation in cells.
Gene
It determines the characteristics of the individuals produced.
Gene
The entirety of genes or genetic material that
is present in a cell or organism.
Genome
It contains all of the information needed to build and make an organism function.
Genome
A thread-like structures present in the nucleus, which carries genetic information from one generation to another.
Chromosome
chroma – ______; some - ____
colour, body
refers to its staining ability by certain dyes
chroma – colour; some - body
In 1842, he first observed the rod-like
structure present in the nucleus of the plant cell.
Karl Nageli
In 1888, he coined the term ‘chromosome’.
W. Waldeyer
In 1902, they suggested that chromosomes are the physical carrier of genes in the eukaryotic cells.
Walter Sutton and Theodor Boveri
It is clearly visible only when the cell is undergoing division.
Chromosome
In this phase, chromosomes are visible as
thin chromatin fibres present in the
nucleoplasm.
Interphase
During ___ _____, the chromatin fibres condense and chromosomes are visible with distinct features.
cell division
One of the longitudinal subunits of a replicated chromosome joined to its sister chromatid at the centromere.
Chromatids
A region of repetitive DNA at the end of chromosomes, which protects the end of the
chromosome from destruction
Telomere
The point at which two parts chromatids of a chromosome join and at which the spindle
fibers are attached during cell division
Centromere
The centromere is in the middle forming two equal arms.
Metacentric
The centromere is placed near to one end resulting in one shorter and one long arm.
Acrocentric
The centromere is placed terminally.
Telocentric
It is the growth cycle of an individual cell consisting of the following phases:
Interphase & Mitotic Phase.
Cell Division
The period between mitotic divisions - that is, G1, S and G2.
Interphase
In this phase, metabolic changes prepare the cell for division.
G1 Phase
In this phase, the cell increases in volume (nucleus & cytoplasm are enlarging toward mature size) by imbibing water & nutrients & building new protoplasm.
G1 phase
In this phase, each of the 46 chromosomes is duplicated by the cell.
S under Interphase.
In this phase, the cell “double checks” the duplicated chromosomes for error, making any needed repairs.
G2 phase
In this phase, DNA synthesis replicates the
genetic material. Each chromosome now consists of two sister chromatids.
S phase
In this phase, there is active synthesis of RNA and proteins necessary for chromosome synthesis. The mitotic spindles are also starting to be formed.
G2 Phase
The process by which a cell divides to form two new cells, either to produce identical cells (mitosis) or to produce cells with half the number of chromosomes (meiosis)
Cell division
2 types of cell division
Mitosis
Meiosis
A process of cell division by which one cell results in two daughter cells, each with a set of chromosomes identical to that of the parental cell.
MITOSIS
It is important for:
* replacement of worn out or damaged tissues
* repair of injuries,
* multicellular growth and development by
increasing the number of cells
Mitosis
Mitotic division occurs in two parts:
Karyokinesis (nuclear division)
Cytokinesis (cytoplasmic division)
A phase having the prophase, metaphase, anaphase, and telophase
Karyokinesis
A phase wherein the nuclear membrane begins to break and spindle fibers appear.
Early Prophase
A phase wherein the centromere joins each pair of sister chromatids to the spindle fiber. The nucleoli and nuclear membrane completely disappears.
Late Prophase
A phase wherein the chromosomes line up along the middle of the cell (equatorial plate).
Metaphase
A phase wherein spindle fibers shorten due to depolymerization, pulling the sister chromatids apart and drawing them to the opposite poles of the cell.
Anaphase
A phase wherein the chromosomes regroup into two nuclear structures.
Telophase
This begins during telophase wherein the cytoplasm is divided between the two cells forming two daughter cells.
Cytokinesis
In plant tissues, the cytoplasm is divided via ___ ____ _____ where separation starts from the inside of the cell towards the periphery
cell plate formation
Somatic cells
All other cells (Blood, Skeletal, Stem, Fat, Neuron…)
Germ line cells
Sperm, Egg
The sequence of two cell division, each cell divides twice while the chromosomes are duplicated only once, resulting gametes have only half the chromosome number of the original cell
Meiosis
One of a pair of chromosomes with the same gene sequence, loci, chromosomal length, and centromere location
Homologous chromosome
A portion of a chromosome that serves as the basic unit of heredity.
Gene
A pair of two homologous chromosomes formed by synapsis during the early stages of meiosis.
Bivalent
The group of four sister chromatids inside the homologous chromosome pair.
Tetrad
I. A bivalent means 4 chromatids and 2 centromeres
II. One bivalent consists of 2 homologous chromosomes
Both statements are correct
A bivalent consists of ______ pair/pairs sister chromatid/chromatids and ______ pair/pairs of
homologous chromosomes.
two, 1
the pairing of two chromosomes that
occurs during meiosis
Synapsis
The exchange of corresponding parts
between non-sister chromatids of
homologous chromosomes producing a
new combinations is called
Crossing over
The exchange of corresponding parts between non-sister chromatids of homologous chromosomes producing a
new combinations is called
Chiasma
Synapsis is ______ in mitosis and _____in meiosis.
absent, present
The # of cells formed in mitosis is __ ____ cells while in meiosis is __ ______ cells.
2 diploid, 4 haploid
