34 - Nucleic Acids: Structure and Function Flashcards
DNA synthesis
DNA replication
RNA synthesis
Transcription
Protein synthesis
Translation
DNA (full name)
Deoxyribonucleotide acid
4 monomeric deoxynucleotide units
1.) deoxyadenylate
2.) deoxyguanylate
3.) deoxycytidylate
4.) thymidylate
Phosphate terminal of DNA
5’ - hydroxy
Hydroxy terminal of DNA
3’ - phosphate
Discovered the double stranded helix
Watson and Crick
Non-coding strand that is the one being copies during RNA synthesis
Template strand
Matches the sequence of the RNA transcript that encodes the protein
Coding strand
Base bonding that contains 3 hydrogen bonds
Stronger bond allows it to be slightly resistant to melting at high temps and denaturation
Guanine and Cytosine bond
Number of hydrogen bond(s) between Adenine and Thymine
2 - hydrogen bonds
Occurs when there is a n increase in the optical absorbance of purine bases
Denaturation
Separated strands can reassociate at appropriate physiologic conditions by manipulating temperature and salt concentration
Renaturation
often referred to as the concept of hybridization
Reannealing process
Techniques that use the concept of hybridization
Southern and Northern Blot Techniques
DNA exists in what forms?
(1) Relaxed
(2) Supercoiled
(3) Negative supercoils
Enzyme that catalyze topological changes in the DNA by relaxing or inserting supercoils
used in cancer therapy
Topoisomerases
Replication process of the DNA where each strand of the parental DNA serves as the template and second strand of the daughter DNA
Semi-conservative process
Difference between DNA and RNA
- sugar moiety
- pyrimidine components
- structure
- base pairing
Can form many secondary structures by folding over, forming hairpin loops stabilized by intramolecular hydrogen bonds between complementary bases
Single stranded RNA
Classes of RNA
- Messenger RNA (mRNA)
- Transfer RNA (tRNA)
- Ribosomal RNA (rRNA)
- Small RNA
Most heterogenous RNA in abundance, size, and stability
messenger RNA
Is the addition of a guanine nucleotide with a methyl (CH3) group to the 5’ end;
Increases the stability of the mRNA and assists in the binding of the mRNA to the ribosome for translation
5’ cap
The addition of 50 to 250 adenine nucleotides to the 3’ end
Increases the stability of many mRNA molecules depending on the proteins that attach to it
poly(A) tail
(1) When DNA is copied as a whole
(2) when only a portion of the DNA is copied
(1) DNA replication
(2) DNA transcription to mRNA
base-pairs of 3 nucleotides on the mRNA
codon
In the triplet codon, the third AA is referred to as
wobble
enzymes that attach the correct amino acid to each tRNA
aminoacyl-tRNA synthetase
Complementary bases of the codon on the tRNA
anti-codon
Serve as molecular adaptors that bind to mRNA on one end and carry amino acids into position on the other
tRNA
rRNAs produced by cleavage and modification of initial transcripts
Mature rRNAs
Provides a mechanism for decoding mRNA into amino acids
rRNA
How does rRNA interact with tRNAs during translation
by providing peptidyl transferase activity
bring the necessary AA corresponding to the appropriate mRNA codon
tRNAs
- orange split - mRNA
- pink balls - tRNA (carries the amino acid)
- big violet ball - ribosome that contains the rRNA
Non-coding RNA gene
small RNA
Major types of small RNA molecules - their major function
1.) small nuclear RNA (snRNA) - involved in mRNA splicing
2.) small nucleolar RNA (snoRNA) -directs modification of rRNAs
3.) micro RNA (miRNA) and short interfeing RNA (siRNA) - regulate gene ecpression
Widely used in functional genomics
sRNAs
Holds a single strand of DNA together
phosphodiester bonds
Enzyme:
(1) specific for DNA
(2) specific for RNA
(1) Deoxyribonucleases
(2) Ribonucleases
Degrade both RNA and DNA; cleave internal phosphodiester bonds to produce either 3’-hydroxyl and 5-phosphoryl terminates or vice versa
Endonucleases
Recognize specific sequences in DNA
Restriction endonucleases
Pyrimidine components include adenine, guanine, cytosine, thymine.
DNA or RNA?
DNA
Double stranded – DNA or RNA?
DNA
Can be hydrolyzed by alkali – DNA or RNA?
RNA
What RNA molecules serve as molecular adaptors that bind to mRNA on one end and carry amino acids into position on the other?
tRNA
What type of RNA is the most heterogeneous in abundance, size and stability?
mRNA
The two strands of the double-helical molecule, each possess a polarity, are
A. Antiparallel
B. Constitutive
C. Denatured
D. Complementary
A. antiparallel
Information resides in the sequence of nucleotide on the
complementary strand
A. Coding strand
B. Template strand
C. promoter sequence
B. Template strand
Concomitant with the denaturation of the DNA molecule is an increase in the optical absorbance of the purine and pyrimidine bases, a phenomenon called
A. Complementarity
B. Hyperchromicity
C. Absorbance
D. Spectrophotometry
B. Hyperchromicity
During periods of active protein synthesis, many ribosomes can be associated with any mRNA molecule to for an assembly called
A. Ribozymes
B. Histones
C. Polysome
D. Nucleosome
C. Polysome
When the DNA molecule is twisted in the direction opposite from the clockwise turns of the right handed double helix found in B-DNA, you form supercoils
A. Triple helix
B. Double helix
C. Negative supercoils
C. Negative Supercoils
