5.1 DNA Structure and Organization in the Cell Flashcards
Frederick Griffith
was the One of the first key investigations that would help to establish DNA as the genetic material. (the mouse experiment)
nucleotide
the
repeating unit
of nucleic acids;
composed of a sugar
group, a phosphate
group, and a
nitrogenous base
each nucleotide in DNA is composed of
a five-carbon deoxyribose
sugar, a phosphate group, and a nitrogen-containing base, Also, there are four different nitrogenous bases in DNA that can be categorized into two different forms: purines and pyrimidines. the purine bases are adenine (A) and guanine (G). pyrimidine bases are cytosine (C) and thymine (T).
each nucleotide in RNA is composed of
In
RNA, all but one of the bases are the same as those of DNA. RNA has
uracil (U) in place of thymine.
Chargaff’s rule
in
DNA, the percent
composition of
adenine is the same
as thymine, and the
percent composition of
cytosine is the same as
guanine
from Hershey and Chase discovered
that DNA is the hereditary material
from Levene discovered
that DNA is a polymer of nucleotides, and that each of the four types of nucleotides contain a phosphate group, a deoxyribose sugar, and one of four possible nitrogen-containing bases (adenine, guanine, cytosine, or thymine)
from Chargaff discovered
that DNA is composed of repeating units of nucleotides in !xed
proportions that vary with di#erent species
complementary base
pairing
in DNA,
the interaction of
bases of nucleotides
on opposite strands
through the formation
of hydrogen bonds
antiparallel
the
directionality of the
two strands in a DNA
molecule; the strands
run in opposite
directions, with each
end of a DNA molecule
containing the 3! end
of one strand and the
5! end of the other
strand
genome
the complete
genetic makeup
of an organism; an
organism’s total DNA
sequence
gene
the basic
unit of heredity that
determines, in whole
or part, a genetic trait;
a specific sequence
of DNA that encodes
for proteins and RNA
molecules, and can
contain sequences that
influence production of
these molecules
DNA supercoiling
the
formation of additional
coils in the structure of
DNA due to twisting
forces on the molecule
nucleoid
a structure in
bacteria that contains
the chromosomal DNA
regulatory sequence
a sequence of DNA that
regulates the activity of
a gene
histone
a member of a
family of proteins that
associate with DNA in
eukaryotic cells, which
acts to help compact
the DNA
nucleosome
the
condensed structure
formed when double-
stranded DNA wraps
around an octamer of
histone proteins
is there a correlation between an organisms complexity and genome size
no
chromatin
the
non-condensed form
of genetic material
that predominates for
most of the eukaryotic
cell cycle; consists of a
complex of DNA and
proteins
