Chromosomes

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__________ is where different chromosomes are painted different colours by hybridisation with different fluorescent dyes
Chromosome painting/FISH
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Chromosomes are stained with giemsa, and show _____________ G bands that are specific to each chromosome homologue pair
Transverse
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_______________ replicate mid to late S phase and are relitively gene poor
G bands
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___________ replicate early in S phase and are relatively gene rich
R bands
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Chromosomes can be sorted by size and centromere position, there are __________ sets sorted from group A to G
7
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The X chromosome is in the conventional group _________
C
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The Y chromosomes is in the conventional group ____________
G
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The estimated gene number is _____ in humans
32000
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A ____________ chromosome is where the centromere is near the middle of the chromosome
Metacentric
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A _________ chromosome is where the centromere is between the center and the tip
Submetacentric
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A ___________ chromosome is where the centromere is closer to one end than the center
Acrocentric
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A _________ chromosome is where the centromere is at the tip of the chromosome and there is no p arm
Telocentric
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Chromosome condensation __________ from one part of a chromosome to another
Varies
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Actively expressed regions of chromosomes are _______________ and called euchromatin
Less condensed during interphase
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Regions that have fewer levels of expressed genes ___________ and are called heterochromatin
Remain condensed during interphase
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This type of chromatin shows variable levels of condensation
Facultative heterochromatin
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This type of chromatin is permanently condensed, it's found mostly in centromeres and telomeres and contains repetative sequences
Costitutive heterochromatin
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G1, S and G2 are phases of _________
Interphase
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Gametic nuclei are ________
Haploid
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DNA in the chromosomes is replicated during __________
S interphase
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Mitosis itself is usually the _________ period of the cell cycle
Shortest
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Prophase 1 is divided into 5 substages, leptotene, zygotene, pachytene, diplotene and diakineses - these terms describle the
Appearance of chromosomes at each stage
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In ____________, the chromosomes first become visible, beadlike chromomeres are visible along the length of the chromosome
Leptotene
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In __________, pairing of homologous chromosomes occurs
Zygotene
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In ____________, synapsis is completed and crossing over between homologous chromosomes occurs, the chromosomes continue to shorten and thicken
Pachytene
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In __________, the chromosomes are held together by chiasmata which become prominent, and the synapsed chromosomes begin to start to repel
Diplotene
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In __________, the chromosomes repel
Diakinesis
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Homologous chromosomes _____ undergo extensive crossing over
Can
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The model currently favoured for the homologous recombination is the _______________
Double strand break and repair
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Duplex DNA molecules with double stranded breaks arre ___________
Very efficient at initiating recombination with a homologous unbroken duplex
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A DNA loop with double stranded breaks invade unbroken homologues forming ____________
D loops
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The amount of DNA in picograms contained within the haploid nucleus of a eukaryotic organism
C value
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__________ are those higher order twists and turns that form on a helical molecule under torsinal stress
Supercoils
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Helicase unwinding causes this
Supercoiling
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A ____________ is a section of DNA that is wrapped around a core of proteins.
Nucleosome
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Each chromosome of the homologous pair occupies ______________ in the interphase nucleus
Its own territory
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C value paradox shows the ____________ between multicellular eukaryotes and genome size
Lack of correlation
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The C value paradox does not mean there are different numbers of genes it means that in higher organisms, much of the DNA has
Functions other than coding for proteins, such as transposable elements and repetitive sequences
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Why must the DNA molecule be compacted
To fit inside the cell
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If no twisting is present except the double helix, then the DNA is
Relaxed
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A circular DNA molecule would respond to _______ by a) forming bubbles of unpaired bases, and/or b) twisting to in the opposite way of underwinding to form right handed negative supercoiling
Underwinding
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If twists in DNA are left handed, then the supercoiling is
Positively supercoiled
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If the twists of the DNA helix are right handed then the DNA is
Negatively supercoiled
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____________ enzymes are responsible for increasing or decreasing the amount of supercoiling by cutting a single strand
Topoisomerase i
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___________ enzymes are responsible for increasing or decreasing the amount of supercoiling by cutting a double strand
Topoiomerase ii
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Independance of loops in bacterial nucleoids 'chromosomes' is thought to be linked to
Proteins that bind to DNA
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The DNA of all eukaryotic chromosomes is associated with numerous protein molecules, in a stable ordered aggregate called
Chromatin
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5 major types of _________ proteins, that forms aggregates with DNA are, H1, H2A, H2B, H3 and H4
Histone
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The positive charge that histones have, due to large amounts of lysine and arginine, enables them to __________
Bind with DNA
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Histones will dissociate from DNA if put in ____________ salt concentrations
High
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Histone proteins from different organisms are largely _________ with the exception of H1
Similar
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The bead like units in chromatin are called __________
Nucleosomes
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Nucleosome fibers fold into a left handed helix, with __________ nucleosomes per turn forming the 30nm chromatin fiber
6
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Chromosome territories __________ from cell types
Remain the same
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Chromatin domains with few genes tend to be near the ______
Pheriphery of the nucleus
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Chromatin domains with lots of genes tend to be near the
Interior of the nucleus
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Spaces between chromatin domains are called ________
Interchromatin compartment
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The kinetochore is a complex of DNA and proteins, the __________ is the central component
Centromere
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The _______ is the site at which the spindle fibers shorten, allowing chromosomes to move toward the poles in mitosis and meiosis
Kinetochore
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Centromeres show structural _________ among species
Variation
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____________ appear to have centromeric sequences spread throughout their length
Holocentric chromosomes
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The conentional type of centromere is the __________
Localized centromere
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In __________ the microtubules attach to a single region (the kinetochore)
Localized centromeres
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The ______________ DNA is contained in a structure designated the centromeric core particle
Centrome
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The end of a linear chromosome is composed of a special DNA protein structure called a ___________
Telomere
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The mechanism for end restoration of DNA relies of _______ enzyme
Telomerase
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________ works by adding tandem repeats of a simple sequence to the ' end of a DNA strand
Telomerase
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________ undergoes base pairing with the telomere repeat an serves as a template for telomere elongation by the addititon repeating unit
Guide RNA
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Telomeric regions are also associated with proteins that inhibit gene expression in the region, this is known as ________
Telomeric silencing
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Mutations in the RAP1 gene that produce a Rap1 protein that can't bind to telomere sequences, _____________ is observed
Massive telomere elengation
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Within telomeres, telomeric DNA is ocganized in 3D conformations that include _________
G quartets
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Guanine bases can hydrogen bond with one another to form ___________
G quartets
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Other cards in this set

Card 2

Front

Chromosomes are stained with giemsa, and show _____________ G bands that are specific to each chromosome homologue pair

Back

Transverse

Card 3

Front

_______________ replicate mid to late S phase and are relitively gene poor

Back

Preview of the front of card 3

Card 4

Front

___________ replicate early in S phase and are relatively gene rich

Back

Preview of the front of card 4

Card 5

Front

Chromosomes can be sorted by size and centromere position, there are __________ sets sorted from group A to G

Back

Preview of the front of card 5
View more cards

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