The Central Dogma- Week 7/8 Flashcards
Define molecular biology as a subject
the study of the formation, Structure and function of MACROMOLECULES essential for life (e.g. amino acids) & their role in STORAGE & TRANSMISSION of genetic information.
Define the “central dogma” of molecular biology
The sequences of DNA,RNA & proteins contain the information required for translation & transcription and protein function
Describe the building blocks of DNA
-Nucleic acids (linear polymers made up of nucleotides)
-Pentose Sugars (ribose & deoxyribose)
-Organic bases (purine-2 rings & pyrimidine-1 ring)
-Phosphate group-linked by phosphodiester bonds
what does DNA and RNA stand for
DNA; Deoxyribonucleic acid
RNA; Ribonucleic acid
what way are phosphodiester bonds formed in DNA
from 5’-3’
Describe the mechanism of DNA replication
BOTH strands serve as templates for replication of a complementary strand
Define the molecular machinery involved in DNA replication & describe how it works
DNA polymerase- catalyses DNA synthesis
- begins at ‘replication origin’
- requires RNA primer
- adds dNTPs to 3’ -OH group (as it goes in 5’–3’ direction)
what direction does DNA polymerase ONLY synthesises at
5’ to 3’
how does the strand of DNA which is anti-parallel to the 5’—3’ strand get synthesised
-Lagging strand copied as short fragments: 1000 bases long in the 5’ to 3; direction
what are the lagging short fragments called
Okazaki fragments
what are the enzymes & primers called and what is their role that aid the synthesis of lagging strand
- Fragments started on by RNA primer made by DNA primase
- Fragments joined by DNA ligase enzyme
what are the enzymes & proteins required for DNA replication
-Helicase: Unwinds strands of DNA
-Topoisomerase: Relieves twists in DNA ahead
-Single Strand Binding Proteins(SSBP): prevent rewinding of DNA
-DNA Primase: Synthesis of RNA primer
-DNA Polymerase: Synthesis of new DNA
-Clamp Proteins: Hold polymerase in place
-DNA Ligase: joins Okazaki fragments
what are the purines nitrogenous bases
adenine and guanine
what are the pyrimidines nitrogenous bases
uracil
thymine
cytosine
Cellular DNA replication requires:
a. Transfer RNA
b. Primase
c. Ribosomes
d. Nucleosomes
e. Reverse transcriptase
b. Primase
The principle difference between a nucleoside and nucleotide is:
a. Phosphate group
b. Phosphoester bond
c. 5-carbon sugar
d. Organic base
e. Methyl residue
a. Phosphate group
What does the abbreviation dATP stand for?
a. 5’-deoxyadenosine-3′-triphosphate
b. 3’-deoxyadenosine-2′-triphosphate
c. 2’-deoxyadenosine-4′-triphosphate
d. 2’-deoxyadenosine-5′-triphosphate
e. 3’-deoxyadenosine-1′-triphosphate
d. 2’-deoxyadenosine-5’-triphosphate
- How many copies of the rRNA genes are there in the human genome?
a. 2
b. 20
c. 200
d. 2000
e. 20000
c. 200
The combined error rate for DNA replication is roughly:
a. 1 in 10
b. 1 in 100
c. 1 in 10^2
d. 1 in 10^4
e. 1 in 10^9
e. 1 in 10^9
Which of the following is not part of mRNAs processing?
a. Exon excision repair
b. Intron removal
c. RNA cap structure
d. Poly(A) tail
e. UTRs
a. exon excision repair
- Cellular RNA synthesis:
a. Requires primers
b. Employs helicase and gyrase
c. Is also known as transcription
d. Is also known as translation
e. Takes place in a 3´ to 5´ direction
c. is also known as transcription
Mature eukaryotic mRNA:
a. Contains only exons
b. Is polycistronic
c. Is found only in the cytoplasm
d. Has a poly(A) tail
e. Is usually short-lived
d. Has a poly(A) tail
Which of the following reactions are known to be carried out by a ribozyme?
a. DNA synthesis
b. Transcription
c. RNA splicing
d. Protein hydrolysis
e. Polysaccharide hydrolysis
c. RNA splicing
