Embed Size (px)
DESCRIPTION
DNA Structure. DNA Replication. Biotech. Transcription. Translation. 100. 100. 100. 100. 100. 200. 200. 200. 200. 200. 300. 300. 300. 300. 300. 400. 400. 400. 400. 400. 500. 500. 500. 500. 500. What are the three components of a nucleotide?. Answer. Sugar - PowerPoint PPT Presentation
Citation preview
200
300
400
500
100
200
300
400
500
100
200
300
400
500
100
200
300
400
500
100
200
300
400
500
100
DNA Structure
DNAReplication Biotech TranscriptionTranslation
What are the three components of a nucleotide?
Answer
•Sugar•Phosphate
•Nitrogen base
Name the nitrogen bases in DNA
Answer
•Thymine•Adenine•Guanine•Cytosine
Indicate the type and number of bonds that hold the DNA strands
together
Answer
•Hydrogen bonds•2 between adenine and thymine•3 between guanine and cytosine
If the percentage composition of adenine in a DNA molecule is 10%
then what are the percent compositions of the other 3 bases.
Answer
•Thymine = 10%•Guanine = 40 %•Cytosine = 40%
What specific types of bond attaches the nitrogen base to the sugar?The phosphate to the sugar?
Answer
Nitrogen base + sugar = glycosylPhosphate + sugar = phosphodiester
Note: Both are covalent bonds!
What enzyme unwinds DNA at the fork by breaking hydrogen bonds
between nitrogen bases?
Answer
helicase
What enzyme relieves stress further up the fork?
Answer
DNA gyrase
What enzyme binds complimentary bases and what direction does it
move? What has to be in place first before this enzyme can bind to the
template?
Answer
DNA polymerase III which moves in a 5′ to 3′ direction. An RNA primer laid down by
RNA primase must be in place first.
What are the names of the fragments of the sections on the lagging strand
and what enzyme joins these sections?
Answer
Okazaki fragments are joined by DNA ligase.
How does the fact that DNA replicates semi-conservatively
decrease the possibility of errors made during DNA replication?
You must first explain the term semi-conservatively.
Answer
Semi-conservative replication means that each parent strand serves as a template from which a copy can be made. This template serves as the
checkpoint when DNA polymerase I and III proofread the newly synthesized strand.
What molecular biology technique would be the most appropriate for
analyzing the size of DNA fragments?
Answer
Gel electrophoresis
What are three circumstances where one might want to amplify the
amount of DNA by PCR?
Answer
Studying fossil remainsDNA found at scene of crime
Early diagnosis of disease (HIV)
Observe the following DNA fingerprint and determine who
should remain a suspect.
Answer
JOHN
What does a restriction endonuclease do?
Answer
Recognizes and cuts DNA at a specific sequence.
How are recombinant bacteria differentiated from the original
bacteria?
Answer
Recombinant bacteria also received a marker gene (eg. Antibiotic
resistance) that allows them to be easily distinguished when culturing.
Does transcription require a primer?
Answer
No
What must be recognized to initiate transcription?
Answer
Promoter
What enzyme creates the mRNA strand and what direction does it
move?
Answer
RNA polymerase synthesizes mRNA in a 5′ to 3′ direction.
What is an intron?An exon?
Which is removed by what enzyme?
Answer
Introns = non-coding regions of mRNAExons = coding regions of mRNA
Spliceosomes remove introns
What modifications must be made to the ends of the mRNA transcript
before it can leave the nucleus and why must these occur?
Answer
Cap – methyl guanineTail – Poly A tail by poly A polymerase
To prevent degradation by enzymes in the cytoplasm
Where in the cell does translation occur?
Answer
Cytoplasm at the ribosomes
What is necessary to initiate translation? Indicate the specific
sequence of this initiator.
Answer
Start codon (AUG) on mRNA is recognized by the ribosome.
Differentiate between a codon and an anticodon.
Answer
Codon = 3 nucleotide bases on mRNA that code for one amino acid
Anticodon = 3 nitrogen bases on tRNA that are complimentary to the codon on mRNA.
What are the three types of RNA and what are their functions in
translation
Answer
Messenger RNA – brings copy of gene to be readRibosomal RNA – reads or translates mRNA copy
by exposing 3 bases at a timeTransfer RNA – brings in amino acids to form
polypeptide
Which is more harmful; a substitution or a deletion?
