Lesson 1: Origin and Importance of Cytogenetics Flashcards
it occurs among somatic cells or body cells
mitosis
it is the study of normal and abnormal chromosomes based on their morphology, structure, arrangement, and numerical status?
Cytogenetics
chromosomes each still composed of two chromatids move toward the opposite plate
Meiosis II Prophase II
nucleosomes that are linked together by the DNA
Chromatin
The sister chromatids of each chromosome now move as two individual chromosomes toward opposite poles.
Meiosis II Anaphase II
Result of Meiosis
Four haploid cells
process of linking of the replicated homologous chromosomes. The resulting chromosome is termed as tetrad
synapsis
Main Components of Chromosomes
- DNA
- Histone Proteins (and non-histone proteins)
- RNA
(and polysaccharides)
Mutations in the HBB gene can cause
Sickle Cell Anemia
Tetrads line up along the equator of the spindle
Meiosis I Metaphase I
“Packages” that contain the DNA
chromosomes
The cell “doublechecks” the duplicated chromosomes for error, making any needed repairs
G2
Its goal is to reduce chromosome number by half
Meiosis
Similar to telophase of mitosis, except only one set of (replicated) chromosomes in each cell.
Meiosis I telophase I
It is where a sex cells undergo a special type of cell division
meiosis
basic repeating subunit of chromatin packaged inside the cell’s nucleus
nucleosomes
four types of chromosome based on the location of the centromere
- Metacentric
- Sub-metacentric
- Acrocentric
- Telocentric
composed of two chromatids from each chromosome
tetrad
The kinetochores of sister chromatids are attached to microtubules extending from opposite poles
Meiosis II Metaphase II
Packaged DNA is referred to as
Chromatin
The centromeres of each chromosome finally separate, and the sister chromatids come apart
Meiosis II Anaphase II
Each of the 46 chromosomes is duplicated by the cell
S - Synthesis phase
Parent cell becomes 2 daughter cells with identical genetic information
cytokinesis
short arm and long arm are separated by a primary constriction called
centromere
Refers to the regular and repetitive physical and chemical process taking place within the
cell.
cell cycle
repeating unit of chromosomes
nucleosome
Main protein of nucleosomes
Histone
Purpose of cytokinesis in cell cycle
Cytoplasmic Division
Histone proteins that are wrapped by the DNA helix
nucleosomes
Resting phase in cell cycle
G0
Chromosomes are located in
cell nucleus
Common technique for chromosome staining
Giemsa (or Leishman) stain
Sex cells are what kind of cells?
haploid cells
Pairing of homologous chromosomes happens in
Meiosis I Prophase I
Why does the chromosome needs to be visualized?
to count the number and determine the structure
Centromeres remain intact
Meiosis I Anaphase I
Cell cycle is simply ______
cell reproduction
What are the Biogenetic Levels?
Level 1: Cell (nucleus)
Level 2: Chromosome
Level 3: Nucleic Acid (DNA)
Level 4: Gene (DNA Segment)
Cell -> Chromosome -> DNA
chromatin fiber that are linked together
chromosome
how many chromosome does a human has?
23 pairs or 46 chromosomes
Cytoplasm divides
through the action of ______, a fiber ring composed of protein
actin
spool-like proteins where DNA is tightly wrapped/coiled around
Histones
chromatids break and may be reattached to a different homologous chromosomes, producing chromosomes with new associations of genes
crossing-over
Chromosome “arms”
“p” - short arm
“q” - long arm
Tetrads separate and are drawn to opposite poles by the spindle fibers
Meiosis I Anaphase I
Mitosis divided into 5 substages:
- Prophase
- Prometaphase
- Metaphase
- Anaphase
- Telophase
Spindle fibers attach to the centromere region of each homologous chromosome pair
Meiosis I metaphase I
Cellular contents, excluding the chromosomes, are duplicated
G1
a technique used to produce thin, alternating bands along the length of the entire chromosome that create unique patterns on each homologous set and allows for their identification
G-banding
Under the microscope, chromosomes appear as:
thin, thread-like structures
A spindle apparatus forms
Meiosis II Prophase II
Cell Cycle
- G0 – Cell cycle arrest
- G1 – Gap 1 Phase
- S – Synthesis Phase
- G2 – Gap 2 Phase
The physical location of a specific gene on a chromosome
Locus or loci
Chromatids separate
Anaphase II
Cell cycle arrest
G0
Because of crossing over in meiosis I, the two sister chromatids of each chromosomes are ‘not’ identical
Meiosis II Metaphase II
The chromosomes are positioned in the metaphase plate as in mitosis
Meiosis II Metaphase II
Cytokinesis usually occurs simultaneously forming two haploid daughter cells
Meiosis I Telophase I
