Unit 4: Chromosome Discovery and Chromosome Structure Flashcards
Carried traits from one generation to the next
Mendelian “factors”
Recognized and explored the fibrous network within the nucleus-termed as chromatin or “stainable material”
Walther Flemming
Observed cells in various stages of division and recognized that chromosomal movement during mitosis offered a mechanism for the precise distribution of nuclear material during cell division
Walther Flemming
Provided the first evidence that germ cell chromosomes imparted continuity between generations
Theodor Boveri
His work on Ascaris embryos provided one of the first descriptions of meiosis
Theodor Boveri
He is one of the pioneers of embryology
Theodor Boveri
Confirmed and expanded upon Boveri’s observation
Walter Sutton
Described the configurations of individual chromosomes stages of meiosis
Walter Sutton
Walter Sutton described the configurations of individual chromosomes stages of meiosis through ___
testes of Brachystola magna
Their experiments provided the physical basis of the Mendelian law of heredity - developed the “Chromosomal Theory of Inheritance”
Theodor Boveri
Walter Sutton
Experimentally demonstrated chromosomal theory of inheritance using Drosophilia melanogaster
Thomas Hunt Morgan, 1910
The experiment on Drosophilia melanogaster is also called ___
“Fly Room” experiments
Helped establish the chromosomal basis of heredity and sex
Calvin Bridges, 1916
Chromosomes are made of ___ and a single molecule of ___
Protein
DNA
Factors that distinguish one species from another
Chromosome
Enable transmission of genetic information from one generation to the next
Chromosome
Ensure daughter cell retains its own complete genetic complement
In mitosis
Enable each mature ovum and sperm to contain a unique single set of parental genes
In meiosis
Human chromosome has ___ autosomes and ___ sex chromosomes
44
2
Other DNA materials found in mitochondria
Extra-chromosomal DNA
Replicated condensed chromosome with sister chromatids
Metaphase chromosome
Two identical strands which are the result of DNA replication
Chromatids
Central region of chromosomes
Centromere
Primary constriction where sister chromatids are linked
Centromere
Consists of several hundred kilobases of repetitive DNA
Centromere
Responsible for chromosome movement at cell division
Centromere
Divides the chromosome into short arm and long arm
Centromere
Designated as p (petite)
Short arm
Designated as q (queues) or “g” = grande
Long arm
Chromosome type (no. of centromere):
Single centromere
Monocentric
Chromosome type (no. of centromere):
Reliably transmitted from parental to daughter cells
Monocentric
Chromosome type (no. of centromere):
Lacks centromere
Acentric
Chromosome type (no. of centromere):
Genetically unstable because they cannot be maneuvered properly during cell division and are usually lost
Acentric
Chromosome type (no. of centromere):
Two centromeres
Dicentric
Chromosome type (no. of centromere):
Also genetically unstable because it is not transmitted in a predictable fashion
Dicentric
Type of chromosome (centromere position)
Middle; yielding arms of roughly equal length
Metacentric
Type of chromosome (centromere position)
Centromere is centrally located
Metacentric
Type of chromosome (centromere position)
5 pairs in humans
Metacentric and Acrocentric
Type of chromosome (centromere position)
Off-center centromere; “q” and is longer
Submetacentric
Type of chromosome (centromere position)
Unequal length of chromosome arms
Submetacentric
Type of chromosome (centromere position)
13 pairs
Submetacentric
“___” means peak
Acro
Type of chromosome (centromere position)
Very close to one end; yielding a small short arm
Acrocentric
Type of chromosome (centromere position)
Often associated with small pieces of DNA called satellites, encoding rRNA
Acrocentric
DNA are called ___, encoding ___
satellites
rRNA
Type of chromosome (centromere position)
Centromere at the terminal end
Telocentric
Type of chromosome (centromere position)
Not found in humans
Telocentric
Discovered chromosomes type based on arms ratio
Levan et al., 1964
Determine the ratio of p and q arms of each chromosome type
Levan et al., 1964
Symbol for Metacentric
M/m
Symbol for Submetacentric
Sm
Symbol for Subtelocentric
St
Symbol for Acrocentric
T
Symbol for Telocentric
T
Arms length ratio of Metacentric
1.0-1.6/1.7
Arms length ratio of Submetacentric
3.0
Arms length ratio of Subtelocentric
3.1-6.9
Arms length ratio of Acrocentric
7.0
Arms length ratio of Telocentric
None
Father of genetics
Gregor Mendel
There is no separation of chromosome until ___
1882
Chromatin are ___ material
Stainable
T/F: meiosis is present in both nuclear and cellular level
T
Cornerstone of mitotic and meiotic analysis
Model animals
Brachystola magna is a ___
Grasshopper
“anchoring” proteins that become the base
Helper proteins
The only normal type of chromosome
Monocentric
Protein located at the centromere region
Kinetochore
Microtubule organizing center
Kinetochore
Facilitates spindle formation
Kinetochore
T/F: all types of chromosome for typing are monocentric
T
Type of chromosome (centromere position)
Found in plants
Telocentric
Tip of each chromosome
Telomere
Telomere repeats in hexameric sequence of ___
TTAGGG
Telomeres can be compared to the ___
Aglets of shoelace
Functions of telomere in preserving chromosome stability
Preventing abnormal end-to-end fusion of chromosome
Protecting the ends of chromosomes from degradation
Ensuring complete DNA replication
Having a role in chromosome pairing during meiosis
Elucidated factors explained by Mendelian Law
Walther Flemming
Part of the cell where the genetic material is found
Nucleus
Calvin Bridges contributed to the chromosomal basis of heredity and sex through ___
Nondisjunction
Nondisjunction happens during ___
Anaphase
Chromosome ___ looks like merged chromosome from chimpanzee and gorilla
Chromosome 2
Smallest chromosome
Y chromosome
Biggest chromosome
Chromosome 1
Chromosomes are arranged through ___
Size
Extra-chromosomal DNA are passed in a ___ manner
Matrilineal
Telomeres are a specific feature of ___
Eukaryotes
Important in the maintenance in information coded in the DNA at the end region
Telomeres
Histones are made up of ___ amino acids
Basic
Histones have ___ charge
(+)
“beads on a string”
Nucleosomes
Nucleosomes are made up of ___ subunits of ___ proteins
8
globular
Formation of a 3D zigzag structure is via ___ and other DNA-binding proteins
Histone 1
The linker DNA
Histone 1
Where microtubules attach
Kinetochore
“telo” means ___
end
a banding technique that cytogeneticists employ in order to produce a banding pattern in individual chromosome
Giemsa banding / G banding
determine the characteristic pattern of light and dark bands on a chromosome under a microscope
Banding techniques
a compound of methylene blue-eosin and methylene blue
Giemsa stain
Regions in the chromosome that stain rather lightly with G-banding tend to be ___ (less/more) transcriptionally active, euchromatic, and rich with ___ and ___
More
Guanine
Cytosine
the chromosomal regions that stain darkly tend to be ___ (more/less) transcriptionally active, heterochromatic, and rich with ___ and ___
Less
Adenine
Thymine
This technique produces a banding pattern in the heterochromatin of the centromeric regions.
C-banding
a family of tandemly repeated nontranscribed sequences
alphoid DNA
Centromeric regions of primate chromosomes are dominated by ___
Alphoid DNA
T/F: Satellite DNA belongs to the coding region of genome
F (noncoding)
Tandem repeats in satellite DNA occurs when a pattern of ___ or more nucleotides are repeated and repetitions are ___ to one another
2
Adjacent
Alpha Satellite
Repeating unit
171
Centromeric region
Beta satellite
Repeating unit
68
Pericentric region
Microsatellite
Repeating unit
2-10
Dispersed all over the chromosome
Minisatellite
Repeating unit
10-100
Telomere region
5 pairs metacentric chromosomes
1, 3, 16, 19, 20
Shape of spindle fibers:
Metacentric
V-shaped
Shape of spindle fibers:
Submetacentric
J-shaped
Shape of spindle fibers:
Acrocentric
I-shaped
Submetacentric chromosomes
2, 4-12, 17, 18, X
Acrocentric chromosomes
13-15, 21, 22, Y
T/F: Telomerase “replenishes” the telomere “cap” and requires ATP
F (no ATP required)
Telomerase can be reactivated and telomeres reset back to an embryonic state by ___.
somatic cell nuclear transfer
The phenomenon of limited cellular division was first observed by ___, and is now referred to as the ___
Leonard Hayflick
Hayflick limit