Terms in this set (43)
Which base pairs are found in DNA?
A-T and C-G
What type of bond connects base pairs?
Which structure is on the 3' end of a DNA strand?
A hydroxyl group
What does the term "genetic code" refer to?
The correspondence between the 4-letter nucleotide alphabet of DNA and the 20-letter amino acid alphabet of proteins
Which structure is normally on the 5' end of a DNA strand?
A phosphate group
The two strands of DNA in a double helix are:
antiparallel in orientation.
I'm a bulky base that clings extra tightly to my more petite partner on the opposite side of the double helix. Who am I?
Although my nucleotide partner is nearly twice my size, we are remarkably well matched. Of course, when the heat is on, we tend to go our separate ways. Who am I?
I'm a nitrogen-containing base, just like those other guys. So I'm not sure why they don't let me into their exclusive "DNA tie club." Who am I?
Individual DNA strands are considered polar because:
one end terminates in a hydroxyl group, the other in a phosphate.
In their 1953 paper on the double-helical structure of DNA, Watson and Crick famously wrote: "It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material." What did they mean?
Each strand in a DNA double helix contains all the information needed to produce a complementary partner strand.
In the early part of the twentieth century, scientists thought that proteins were the most likely carriers of genetic information because proteins:
are so chemically diverse
Each chromosome contains:
one long, double-stranded DNA molecule.
Which of the following is true for most genes?
A) A gene is a segment of DNA that contains the instructions for making a particular protein.
(B) A gene is a segment of DNA that contains the instructions for making a particular RNA.
(C) A gene is a unit of heredity that contains instructions that dictate the characteristics of an organism.
The human genome contains approximately how many genes?
What evidence suggests that the large amount of excess "junk" DNA in a genome may serve an important function?
A portion of "junk" DNA is highly conserved in its DNA sequence among many different eukaryotic species.
Eukaryotic chromosomes contain a single DNA replication origin
The specialized DNA sequences that cap the ends of eukaryotic chromosomes are called:
The specialized DNA sequence that allows duplicated eukaryotic chromosomes to be separated during M phase is a:
C) cap the ends of linear chromosomes and prevent them from being recognized by the cell as broken DNA in need of repair.
(D) contain repeated nucleotide sequences that are required to replicate the ends of linear chromosomes.
What structure in an interphase eukaryotic cell contains ribosomal RNA and proteins for the formation of ribosomes?
The DNA in eukaryotic chromosomes is folded into a compact form by interactions with:
The complex of DNA and proteins that makes up a eukaryotic chromosome is:
Histone proteins pack DNA into a repeating array of DNA-protein particles called:
What statement about nucleosomes is false?
Nucleosomes are found only in mitotic chromosomes.
Which statement is true about the association of histone proteins and DNA?
Histone proteins have a high proportion of positively charged amino acids, which bind tightly to the negatively charged DNA backbone.
What histone protein is thought to act as a linker that pulls nucleosomes together into a regular repeating array, resulting in a 30-nm fiber?
In the light microscope, DNA molecules are MOST visible:
in a cell that's dividing
Histones are an example of a sequence-specific DNA-binding protein.
The majority of human DNA is not known to be useful to our cells.
Human females have 23 different chromosomes, whereas human males have 24.
Prokaryotes have chromosomes that are circular in structure. Which of the following would such chromosomes lack?
Because nucleosomes play a key role in packaging DNA into chromosomes, they bind to the DNA molecule very tightly and, once they are assembled, they cannot be moved.
How do chromatin-remodeling complexes work?
They use the energy from ATP hydrolysis to alter the arrangement of nucleosomes, rendering certain regions of the DNA more accessible to other proteins.
The tails of the core histone proteins can be chemically modified by the covalent addition of what type of chemical group?
In the chromatin of interphase chromosomes, regions of the chromosome that contain genes being expressed are generally more compact, while those that contain quiescent genes are more generally more extended.
What is the general name given to the most highly condensed form of chromatin?
Histone tail modifications establish and maintain the different chromatin structures found in heterochromatin and euchromatin
All are true...
A cell can permanently condense and silence an entire chromosome during development.
A cell will temporarily decondense its chromatin to allow access to specific DNA sequences for replication, repair, or gene expression.
A cell will temporarily decondense its chromatin to give proteins rapid, localized access to specific DNA sequences.
When a cell divides, its chromatin structures will typically be inherited by its daughter cells.
You would expect to see all of these in heterochromatin
Gene-poor region of chromosome
Silenced X chromosome
NOT: Chromosomal regions carrying genes that encode ribosomal proteins
are the form in which DNA is replicated.
Once heterochromatin has been established, it will often spread until it encounters:
a barrier DNA sequence
When a cell divides, its chromatin structure is completely reset.