MA 2: How Genetic Information is Organized
Which of the following are examples of heterochromatin. a. telomeric DNA b. repetitive DNA c. centrometeric DNA
ALL a. telomeric DNA b. repetitive DNA c. centrometeric DNA Repetitive DNA is often associated with heterochromatin. -At the centromere, these heterochromatic repetitive sequences facilitate binding of spindle fibers during segregation of homologous chrmosomes and sister chromatids -Telomeric repetitive sequences are involved in teh maintenance of the chromosome's structural integrity.
Which of these statements about heterochromatin are TRUE? a. Heterochromatin is found in the telomeres and centromere b. Heterochromatin has relatively few genes c. Heterochromatin remains relatively condenses (tightly coiled) during the cell cycle.
ALL are true. a. Heterochromatin is found in the telomeres and centromere b. Heterochromatin has relatively few genes c. Heterochromatin remains relatively condenses (tightly coiled) during the cell cycle.
In humans, it appears that the 20,000 functional genes occupy less than ________ of the human genome.
a. 10% b. 2% c. 35% d. 90% e. 5%
LINES and SINES are repetitive sequences that make up about _________ percent of the human genome. a. About 35% b. About 10% c. less than 2% d. About 5% e. About 90%
a. About 35%
What is the first order of chromatin packing? a. Coiling around nucleosomes b. Formation of a solenoid c. Formation of a 300-nm fiber d. Looping of 300-nm fibers
a. Coiling around nucleosomes The first order of chromatin packing occurs when DNA coils around nucleosomes, whereby DNA is reduced to about one-third its original length
Viral chromosomes exist in a variety of conformations and can be made up of... a. DNA or RNA b. DNA, RNA or protein c. RNA only d. protein or lipid-coding sequences d. DNA only
a. DNA or RNA
______a________ -less chromatin condensation -many expressed genes _______b_______ -condensed chromatin -few expressed genes
a. Euchromatin b. Heterochromatin Chromatin exists in different states of compaction and relaxtion that regulate access to DNA by regulatory proteins. -Heterochromatin regions of chromosomes are relatively inaccessible to transcriptional proteins either transiently (in the case of facultative heterochromatin) or nearly always (in the case of constitutive heterochromatin) -In contrast, in euchromatic chromosome regions, transcriptional proteins and enzymes are more easily able to gain access to DNA.
TATAGCGTAGCTACGT repeated in tandem over and over is a gene sequence that codes for a protein. a. False b. True
a. False The majority of repetitive DNA serves no known fuction.
A sequence of about 300 base pairs is found at different locations on many different chromosomes in the genome. The sequence shows up about 550,000 times in the genome. This illustrates a: a. SINE b. STR c. LINE d. VNTR
a. SINE Sequence is not a tandem because it is not next to each other over and over, instead it is found in many places in the genome. Thus ut us either a SINE or LINE. Sequences less than 500 base pairs are considered SINES.
The E coli chromosome is circular and double-stranded DNA. a. True b. False
a. True
Unique DNA (nonrepetitive DNA) codes for a protein product, such as an enzyme. a. True b. False
a. True
Which of the following have circular chromosomes made of double-stranded DNA? a. chloroplasts b. eukaryotic nuclear chromosomes c. prokaryotes d. mitochondria
a. chloroplasts b. eukaryotic nuclear chromosomes c. prokaryotes d. mitochondria
Each human contains an identical set of VNTRs a. True b. False
b. False
Viral genomes are always linear, double-stranded DNA. a. True b. False
b. False
The second order of chromatin packing occurs when nucleosomes coil together to form a fiber that is 300 nm in diameter. a. True b. False
b. False The second order of chromatin packing occurs when nucleosomes coil together to form a solenoid fiber that is 30 nm in diameter.
CGCGCGCGCGCGCGCGCGCGCGCGCGCGCGCGCG represents a sequence we would categorize as a: a. Short interspered element (SINE) b. Short tandem repeat (STR) c. Variable number tandem repeat (VNTR) d. Long interspersed element (LINE)
b. Short tandem repeat (STR) (CG) repeated over and over is a short sequence repeated in tandem (next to each other)
All EXCEPT which of the following are examples of repettitive DNA? a. telomere DNA b. telomerase gene DNA c. variable number tandem repeat (VNTR) DNA d. SINE DNA
b. telomerase gene DNA The DNA sequence constituting the gene for telomerase is euchromatin and is relatively unique.
Chromatin is made of a. DNA b. proteins c. DNA and proteins
c. DNA and proteins
What makes up the protein component of a nucleosome? a. eight different types of histone proteins b. one tetramer of histone proteins c. two tetramers of histone proteins d. histone H1 protein
c. two tetramers of histone proteins The proteins component of a nucleosome is compsoed of two tetramers of histone proteins. One tetramer is composed of two units each of histones H2A and H2B, and the other is composed of two units each of histones H3 and H4.
What makes up the protein component of a nucleosome? a. Eight different histone proteins b. Histone H1 protein c. One tetramer of histone proteins d. two tetramers of histone proteins
d. two tetramers of histone proteins The protein component of a nucleosome is composed of two tetramers of histone proteins. One tetramer is composed of two units each of histones H2A and H2Bm and the other is composed of two units each of histones H3 and H4.
In E. coli, the genetic material is composed of a. RNA and protein b. linear, double-stranded DNA c. circular, double-stranded RNA d. polypeptide chains e. circular, double-stranded DNA
e. circular, double-stranded DNA
Living organisms are categorized into two major groups based on the presence or absence of a nucleus. What group is defined by the presence of a nucleus? a. mitochondrial organism b. bacterium c. prokaryotic organism d. virus e. eukaryotic organism
e. eukaryotic organism
