Genetics Ch. 11 Achieve

The inactive form of chromatin

heterochromatin

The more darkly-staining form of chromatin is

heterochromatin

a core composed of _____ proteins interacts with DNA through hydrogen bonding and ionic bonds

histone proteins

If DNA is twisted in the ___ direction, it becomes underwound.

left handed

Which statement about cellular DNA in incorrect? -DNA exists in the cell as very long, tightly packed molecules. -Supercoiling allows cellular DNA to be packed into a small space. -Most cellular DNA is positively supercoiled. -Supercoiling of cellular DNA is controlled by topoisomerases. -Supercoiling makes the separation of the two strands of DNA easier for replication and transcription.

-Most cellular DNA is positively supercoiled.

Which of the statements are true of endosymbiotic theory? -states that an ancestral eukaryotic cell engulfed an aerobic protobacteria -explains the origin of all organelles found within a eukaryotic cell -explains the origin of some eukaryotic organelles, such as chloroplasts -provides insight about why mitochondria can survive outside of a eukaryotic cell -explains why mitochondria contain their own genetic information

-States that an ancestral eukaryotic cell engulfed an aerobic protobacteria -explains the origin of some eukaryotic organelles, such as mitochondria . -explains why chloroplasts contain circular DNA similar to bacteria .

Which statements about euchromatin and heterochromatin are correct? -The majority of transcription takes place on euchromatin. -Most genes are present in heterochromatin. -Heterochromatin is less condensed than euchromatin. -Euchromatin largely consists of repeated sequences. -Euchromatin undergoes condensation and decondensation throughout the cell cycle.

-The majority of transcription takes place on euchromatin. -Euchromatin undergoes condensation and decondensation throughout the cell cycle.

Eukaryotic DNA consists of -unique sequences of DNA. -moderately repetitive DNA sequences. -highly repetitive DNA sequences. -all of these.

-all of these.

Histone proteins -enable mitochondrial DNA to replicate with nuclear DNA before mitosis. -organize DNA into separate chromosomes at the beginning of mitosis. -release bound DNA to enable nuclear division during mitosis. -attach to DNA and form compacted DNA-protein associations.

-attach to DNA and form compacted DNA-protein associations.

Which organelle or organelles contain DNA of their own? -endoplasmic reticulum -chloroplasts -Golgi apparatus -mitochondria

-chloroplasts and mitochondria

When a solution containing double‑stranded DNA is heated, the hydrogen bonds that hold the two strands can be weakened and eventually broken, separating the strands completely. This process is called -hybridization. -denaturation. -renaturation. -double‑strand break.

-denaturation.

Most of the centromere and telomere structures consist of -G-C repeats -heterochromatin -kinetochore -euchromatin

-heterochromatin

When a circular DNA gets underrotated by the action of cellular enzymes, the DNA is said to exhibit -negative supercoiling. -positive supercoiling. -relaxed state. -bubbling.

-negative supercoiling.

Which term describes the tertiary structural organization of chromosomal DNA that allows the long strand to be packed and fit into the cytoplasm of the cell? -centromere -base pairing -supercoiling -telomere -double helix

-supercoiling

How does chromosome compaction differ during metaphase and interphase in eukaryotes? -Maximum chromosome compaction occurs during interphase. -There is no chromosome compaction in interphase. -Chromosomes are more compacted in interphase than in metaphase. -Chromosomes are more compacted in metaphase than in interphase.

Chromosomes are more compacted in metaphase than in interphase.

DNA is wrapped around histone proteins and coiled to form a dense fiber called chromatin. Which statement describes the function of the chromatin conformation of DNA? -The condensed DNA in chromatin is transported out of the nucleus. -Single‑stranded DNA can be stored in the nucleus as chromatin. -DNA is wrapped around histone proteins to regulate gene expression. -Chromatin allows DNA to be degraded by histone proteins.

DNA is wrapped around histone proteins to regulate gene expression.

If DNA structure is described as "beads-on-a-string," a "string" is the

DNA molecule

Which histone protein is not included in the histone "core" that is often described as the "beads"? -H3 -H4 -H2B -H2A -H1

H1

How do interspersed repeated DNA sequences differ from tandemly repeated DNA sequences? -The repeats in tandemly repeated DNA are present in only several thousand copies in a genome, but the repeats in interspersed repeated DNA are present in hundreds of thousands to millions of copies in a genome. -Open reading frames are usually found in interspersed repeated DNA, but not in tandemly repeated DNA. -Tandemly repeated DNA has been shown to disrupt genes and cause disease in humans, but interspersed repeated DNA is never associated with human disease. -Interspersed repeated DNA is derived from transposable elements, but tandemly repeated DNA is not.

Interspersed repeated DNA is derived from transposable elements, but tandemly repeated DNA is not.

___ is a DNA-protein complex

chromatin

The less condensed form of chromatin

euchromatin

True or false: The C value, which indicates the amount of DNA in a haploid genome, always correlates to the complexity of the organism. true false

false

One effect of _____ supercoiling in bacterial chromosomes is to promote separation of the two strands of DNA in the double helix.

negative

Underwinding results in ______________ supercoiling

negative

A distinct clump of prokaryotic DNA observed via electron microscopy is referred to as a -nucleolus. -nucleosome. -nucleus. -plasmid. -nucleoid.

nucleoid

If DNA structure is described as "beads in a string", a "bead" is a

nucleosome

Overwinding results in _____ supercoiling

positive

If DNA is twisted in the ___ direction, it becomes overwound.

right handed

In a circular bacterial chromosome, the structure of DNA is a _____ double helix.

right handed

Select the function of the centromere in the transmission of genetic information. -the formation of the mitotic spindle -the duplication of DNA -the assembly of 50S and 30S ribosomal subunits -the production of energy to drive cell division -the attachment point for sister chromatids

the attachment point for sister chromatids

mtDNA and cpDNA contain rRNA and tRNA genes of their own for their organelle‑specific functions. true false

true