Exam 3 assignment questions
The most common microsatellite in humans is __________
(CA)n
Approximately how much DNA is wrapped around an octomer of histones?
146 base pairs
What length of DNA is associated with a nucleosome?
146 or 147 base pairs
In humans, what percentage of the genome encodes for proteins?
2%
If a piece of DNA is 50,000 base pairs long and the average linker is about 54 base pairs, how many nucleosomes would be present?
250
How many types of histone proteins are there?
5
What kind of cell would contain linear chromosomes found in sets and located in a nucleus?
A eukaryotic cell
STS
A marker that is found at only one site within the genome
STR
A microsatellite, contains repeat sequences that are typically between 50 and 200 base pairs in length
What is a nucleoid?
A region in a bacterial cell where the compacted chromosome is located
SNP (single nucleotide polymorphism)
A site where a single nucleotide is variable between individuals
In a FISH experiment, what molecule is incorporated into the single-stranded DNA probes that later allows for detection of the probes?
Biotin
How are the loop domains of bacterial chromosomes formed?
By nucleoid-associated proteins
What is the general function of the structural maintenance of chromosome (SMC) protein family?
Causing changes in chromosome structure
What is the name of the complex of DNA and protein found within eukaryotic chromosomes?
Chromatin
In positional cloning, which method is used to identify clones that are progressively closer to a gene of interest?
Chromosome walking
What are the key features of bacterial chromosome organization and structure? Multiple select question. Chromosomes have a single origin of replication Chromosomes generally have thousands of different genes Chromosomes have centromeres and telomeres Chromosomes are found in pairs Chromosomes are tens of millions of base pairs long Chromosomes are generally circular Chromosomes are linear Chromosomes are about a few million base pairs long
Chromosomes have a single origin of replication Chromosomes generally have thousands of different genes Chromosomes are generally circular Chromosomes are about a few million base pairs long
With a few exceptions, what is the general structure of bacterial chromosomes?
Circular
Which of the following is critical in the alignment of sister chromatids during metaphase?
Cohesin
Chromatin is the complex of __________ and _________ found within eukaryotic chromosomes.
DNA and Protein
Cytogenetic mapping
Determination of the locations of specific sequences relative to bands on chromosomes
Physical mapping
Determining the locations of genes and other DNA sequences using DNA cloning techniques
Linkage mapping
Determining the relative locations of genes on a chromosome based on their frequency of genetic recombination
Which of the following acronyms describes a technique used in chromosome painting?
FISH
What are the defining features of eukaryotic chromosomes?
Found in nucleus Linear Present in one or more sets
Which are examples of moderately repetitive sequences? Multiple select question. A gene encoding a transmembrane protein Genes encoding ribosomal RNA (rRNA) Sequences derived from transposable elements A gene encoding DNA polymerase Genes encoding enzymes
Genes encoding ribosomal RNA (rRNA) Sequences derived from transposable elements
Cytogenic mapping
Localization of genes using microscopy.
What is a mechanism of condensation shared by both prokaryotes and eukaryotes?
Loop domains
In terms of genome structure, what is a tandem array?
Many repeats of a short nucleotide sequence in a row
What kind of supercoils can form in B-DNA if the DNA is underwound by twisting the helix in a left-handed direction?
Negative supercoils
Where is the bacterial chromosome located?
Nucleoid
What does physical mapping provide that the other types of genetic mapping do not?
Number of nucleotide base-pairs between genes
In respect to eukaryotic genomes, what is sequence complexity?
Number of times a particular sequence appears in the genome
What kind of supercoils can form in B-DNA if the DNA is overwound by twisting the helix in a right-handed direction?
Positive supercoils
What types of amino acids are most responsible for the binding of histones to DNA?
Positively charged amino acids
Which enzyme is unique to the retro elements?
Reverse transcriptase
The group of proteins that hydrolyze ATP to catalyze changes in chromosome structure goes by the abbreviated name, the _________ family.
SMC
What is the name of the enzyme that degrades the cohesin molecules at anaphase?
Separase
How do sister chromatids separate during anaphase?
Separase degrades cohesin molecules at the centromere
What name is given to the entire complement of genetic material in an organism?
The genome
What are the main characteristics of the nucleoid? Each nucleoid is surrounded by a double-membrane. The nucleoid is in direct contact with the cytoplasm. Bacteria may have more than one chromosome, each within its own nucleoid region. Each nucleoid is diploid.
The nucleoid is in direct contact with the cytoplasm. Bacteria may have more than one chromosome, each within its own nucleoid region.
What is heterochromatin?
The tightly compacted regions of chromosomes
What is the goal of cytogenetic mapping?
To localize a gene to a site within a chromosomal banding pattern
What is the function of cohesin?
To promote the binding of sister chromatids
What is the composition of the octamer of core histone proteins in a nucleosome?
Two H2A, two H2B, two H3, two H4
Which of of these are found in the octamer of core histone proteins in a nucleosome? Multiple select question. One H1 Two H3 Two H2A Two H2C Two H2B Two H4 One H5 Two H2D
Two H3 Two H2A Two H2B Two H4
Physical mapping
Using DNA cloning to determine nucleotide sequence distance
Linkage mapping
Using genetic crosses to determine relative recombination distances
RFLP
Variations in the distance between restriction sites in individuals
A chromosome territory is defined as __________.
a region in the nucleus that is occupied by a single chromosome
A genetic distance of 1 mu corresponds to ______
a variable physical distance that depends on the recombination frequency.
If you were told that a chromosome was about a million base pairs long, had a single origin of replication, was circular, and contained about a thousand genes, then you would be confident that the chromosome was from a ________.
bacterium, bacteria, or prokaryote
If you were told that a chromosome was about a million base pairs long, had a single origin of replication, was circular, and contained about a thousand genes, then you would be confident that the chromosome was from a _____________.
bacterium, bacteria, or prokaryote
Cytogeneticists can distinguish one chromosome from another based on the ___________ patterns that are obtained when chromosomes are treated with certain dyes.
banding
The smallest number of contigs possible for an organism equals the number of ____________ in that organism.
chromosomes
With a few exceptions, bacterial chromosomes are __________ in shape.
circular, circles, or round
The function of condensin is to __________.
coat the chromosomes and condense them into heterochromatin through the compaction of radial loops
The SMC protein that promotes the binding of sister chromatids is called
cohesin
The number of times a particular base sequence appears in a genome is referred to as sequence _________.
complexity
A collection of clones, where each of the clones contains overlapping sequence is called a
contig
A series of clones that contain overlapping pieces of a chromosome are called a _______.
contig
A _______ is a combination of a plasmid vector and phage λ.
cosmid
The DNA from a ____________ vector can replicate in a cell like a plasmid or be packaged into a protein coat like a phage.
cosmid
The entire complement of genetic material in an organism is known as the ________.
genome
A region of a chromosome with highly compacted chromatin is called ______.
heterochromatin
When comparing bacterial and eukaryotic genomes, the bacterial genome is generally smaller and, therefore, contains ______ DNA and fewer ______.
less; genes
The experiment by Noll, 1974, supported the observation that histones were regularly spaced on chromosomes because __________.
limited digestion with DNase I resulted in DNA fragments that differed in size by approximately 200 bp
After the arrangement of nucleosomes into a 30-nm fiber, the next level of folding involves the formation of ______.
loop domains
To fit into a cell nucleus, the 30-nm fiber needs to be folded into___________ , which are called loop __________ .
loop, loop domains
The regions of bacterial chromosomes that contribute to chromosome compaction are called ______.
macrodomains microdomains
What units are used to measure the distance between loci in linkage mapping?
map units (mu)
The cells used in the FISH technique are first arrested during __________.
metaphase
Bacterial chromosomes are compacted by the formation _________________ of that form loops of 10,000 base pairs emanating from a core.
microdomains
Geneticists use several types of mapping strategies to identify the locations of genes. The approach that relies on DNA cloning techniques and allows computation of distances in base pairs is ________ mapping. The technique that is based on recombination frequencies between genes is ___________ mapping. The technique that locates genes relative to bands on chromosomes that are visible by microscopy is _________mapping.
physical , linkage , cytogenic
A site that has variation within the members of the population is said to be __________.
polymorphic
When DNA is turned in a right-handed direction __________.
positive supercoils are added
In some cases, moderately repetitive sequences are multiple copies of the same gene; for example, the genes which encode the ___________ required for ribosome function are moderately repetitive sequences.
rRNA
In many cases, variations in ___________ the of eukaryotic genomes are not related to the complexity of the species.
size, sizes, length, or lengths
When a large insert from one vector is digested by restriction enzymes and then smaller pieces are inserted into multiple vectors, this is called ____________ .
subcloning
t/f During the M phase, euchromatin of chromatids becomes heterochromatic.
true
t/f Histones possess positively charged amino acids
true
t/f Telomeres and centromeres are examples of constitutive heterochromatin
true
What units are used to measure the distance between loci in cytogenic mapping?`
distance between bands
Regions of chromosomes that have less condensed chromatin are called _________.
euchromatin
True or false: There is a close relationship between the complexity of a eukaryotic organism and genome size.
false
t/f Cohesin helps break the sister chromatids apart during anaphase
false
t/f Heterochromatin is transcriptionally active
false
If we compared the amount of DNA in the genome of a eukaryote to the amount of DNA in a bacterium would generally find that there is ______ DNA in the genome of a eukaryote than in the genome of a bacterium. This means there is likely a greater number of genes in the genome of the eukaryote.
more
DNA gyrase, or topoisomerase II, introduces ______ supercoils into DNA.
negative
Protein-encoding genes are typically ______ sequences.
nonrepetitive
Sequences found only once or a few times within a genome, including protein-encoding genes, are called ________ or __________ .
nonrepetitive, unique
The enzyme DNA gyrase introduces negative __________ into DNA.
supercoils or supercoiling
In a bacterium, the region of the cytoplasm where the compacted chromosome is located is called the __________.
nucleoid
The region of the bacterial cell where the chromosome(s) is/are located, and where the chromosomes are in direct contact with the cytoplasm is called the _______________.
nucleoid
To form loop domains in bacterial chromosomes, ______ protein either bend DNA or bridge regions of DNA.
nucleoid-associated
The DNA in a ____________ wraps around the core octamer of histone proteins and it takes 146 or 147 base pairs of DNA to form this structure.
nucleosome
Many different types of vectors are used in biotechnology. One of the major differences between vectors is the size of insert they can accept. Match the vector listed below with the size of insert it can accept. 1.)YAC 2.)BAC 3.) Cosmid 4.)Plasmid
YAC: 300,000 to 2 million BAC: 10,000 to 300,000 Cosmid: 5,000 to 50,000 Plasmid: 1,000 to 10,000
You are working in a lab and decide to repeat the Noll experiment that demonstrated the beads-on-a-string model for chromatin structure. However, you confuse the steps, and you isolate the DNA from the proteins prior to treating with DNase I. What results do you expect?
You will see nothing, or a small smear of DNA toward the very bottom of the gel.
What units are used to measure the distance between loci in physical mapping?
number of base pairs (bp)
Very short sequences of nucleotides that are repeated over and over is called a____________ __________ .
repetitive arrays
