Nucleic Acids (Lec) Flashcards
T/F - Cells in an organism are exact replicas
T
T/F - Cells have information on how to make new cells
T
polymers in which repeating unit is nucleotide
Nucleic Acids
two biological molecules that possess heterocyclic nitrogenous bases as principal components of their structure.
Nucleotides and nucleic acids
IMPORTANCE OF BOTH:
*Elements of heredity and transfer of characteristics from parents to offspring
*Energy metabolism such as Adenosine triphosphate (ATP), CTP and GTP
Two Types of Nucleic Acids
DNA
* Deoxyribonucleic Acid
RNA
* Ribonucleic Acid:
Found within cell nucleus; is the storage and transfer of genetic information that is passed from one cell to other during cell division
DNA
Occurs in all parts of cell with a primary function to synthesize proteins
RNA
three components of Nucleotides:
◦ Pentose Sugar: Monosaccharide
◦ Phosphate Group (PO43-)
◦ Heterocyclic Base
difference of nucleoside and nucleotide
Nucleosides contain only sugar and a base whereas Nucleotides contain sugar, base and a phosphate group
Pentose Sugar
what sugar is present in RNA
Ribose
Pentose Sugar
what sugar is present in DNA
2-deoxyribose
Structural difference of the two:
◦ a —OH group present on carbon 2’ in ribose
◦ a —H atom in 2-deoxyribose
RNA and DNA differ in the __ in their nucleotides
identity of the sugar unit
Nitrogen-Containing Heterocyclic Bases (5)
PYRIMIDINE DERIVATIVES:
thymine (T)
cytosine (C)
uracil (U)
PURINE DERIVATIVES
adenine (A)
guanine (G)
found in both DNA and RNA
Adenine (A), guanine (G), and cytosine (C)
found only in RNA
Uracil (U)
found only in DNA
Thymine (T)
difference of pyrimidine and purine
- Purines are larger because they have a two-ring structure while pyrimidines have only one
third component of a nucleotide that is derived from phosphoric acid (H3PO4)
Phosphate
Under cellular pH conditions, the phosphoric acid is ___ to give a hydrogen phosphate ion (HPO42-)
fully dissociated
DNA Nucleotides (4) with deoxyribose sugar and their abbreviations
adenine = dAMP (deoxyadenosine 5’ -monophosphate)
guanine = dGMP (deoxyguanosine 5’ -monophosphate)
cytosine = dCMP (deoxycytidine 5’ -monophosphate)
thymine = dTMP (deoxythymidine 5’ -monophosphate)
RNA Nucleotides (4) with ribose sugar and their abbreviations
adenine = AMP (adenosine 5’ -monophosphate)
guanine = GMP (guanosine 5’ -monophosphate)
cytosine = CMP (cytidine 5’ -monophosphate)
uracil = UMP (uridine 5’ -monophosphate)
nucleic acid backbone found in all nucleic acids
Sugar-phosphate groups
a nucleotide polymer in
which each of the monomers contains ribose, a
phosphate group, and one of the heterocyclic
bases adenine, cytosine, guanine, or uracil
ribonucleic acid (RNA)
a nucleotide
polymer in which each of the monomers contains
deoxyribose, a phosphate group, and one of the
heterocyclic bases adenine, cytosine, guanine,
or thymine.
deoxyribonucleic acid (DNA)
Sequence of nucleotides in
DNA or RNA
Primary Structure
Features of the Primary Structure:
- Phosphodiester bond at 3’ and
5’ position - 5’ end has free phosphate and
3’ end has a free OH group - Sequence of bases read from 5’
to 3’
The secondary structure of nucleic acids involves what
two polynucleotide chains coiled
around each other in a helical fashion
T/F - The polynucleotides run anti-parallel (opposite directions) to each other, i.e., 5’ - 3’ and 3’ - 5’
T
T/F - The bases are located at the center and hydrogen bonded (A=T and GΞC)
T
Base composition of DNA:
: %A = %T and %C = %G
T/F - the sequence of bases
on one polynucleotide is complementary
to the other polynucleotide
T
pairs of bases in a nucleic acid structure that can
hydrogen-bond to each other.
Complementary bases
strands of DNA in a double helix with
base pairing such that each base is
located opposite its complementary base
Complementary DNA
Shows hydrogen bonding
between bases in linear fashion
DNA
Nucleotides are linked together covalently by?
phosphodiester bonds (linkage between the 3’ carbon atom of one sugar molecule and the 5’ carbon atom of another, deoxyribose in DNA and ribose in RNA.)
Base Pairing
T/F - One small and one large base can fit inside the DNA strands:
T
Base Pairing
Hydrogen bonding is stronger with?
A-T and G-C
Base Pairing
A-T and G-C are called?
complementary bases
T/F - Purine always pairs with Pyrimidine
T
complementary strand of 5’ A–A–T–G–C–A–G–C–T 3’
3’ T–T–A–C–G–T–C–G–A 5’
determined that in DNA, the amount of one base, a purine, always approximately equals the amount of a particular second base
Erwin Chargaff
obtained high-resolution X-ray images of DNA fibers that suggested a helical, corkscrew-like shape.
Maurice Wilkins and Rosalind Franklin (1952)
in 1953, took advantage of Chargaff’s results and the data obtained by Rosalind
Franklin and Maurice Wilkins in X-ray diffraction studies on the structure of DNA to conclude
that DNA was a complementary double helix.
James Watson and Francis Crick
nucleic acid base that has good stability
DNA
nucleic acid base that has weak stability
RNA
nucleic acid base that is double stranded
DNA
nucleic acid base that is usually single stranded
RNA
Types of RNA Molecules (3)
Transfer RNA (tRNA)
mRNA
rRNA
Delivers amino acids to the sites for protein synthesis and are the smallest (75–90 nucleotide units)
Transfer RNA (tRNA)
carries informationfrom DNA inside the nucleus
and takes it to ribosomes for
protein synthesis.
mRNA
