UF MCB 2000 Exam 2 Questions &
Answers
State the difference between and give examples of vertical and horizontal gene
transfer? - ANSWERS-Vertical gene transfer: genes replicated and from parent to
daughter cells (1/2 of DNA comes from each parent cell)
-Horizontal gene transfer: One cell pairs up with other similar cell and DNA is
transferred from one cell to the other one, side by side,
-3 types: transduction: Viruses take gene from one bacteria when killing it and carry it to
another bacteria when attacking it (1. Generalized= carry random genes, 2. Specialized
= carry specific genes) (Disease causing genes transferred)
transformation: DNA is picked up from the environment (cells die around bacteria and it
engulfs the DNA around it), rare
conjugation: (MOST OFTEN) bacteria are side to side and one copies it's DNA and
gives it to the other, it involves PLASMID, and only example of direct contact with a
bridge forming with the help of pili. Donor makes copy of plasmid and puts gene in it
and gives it to other cell. (Can carry antibiotic resistant genes and disease causing
genes)
1.Name different RNA molecules. What is the role of each molecule? Which ones
contains Codon, anticodon - ANSWERS-mRNA role: be a template for making proteins
where ribosomes read it, contains Codons (every 3 base pairs representing an amino
acid), initation codon and 3 stop codons. (ribosome attaches to mRNA)
-tRNA role: fishes for amino acids and brings them to the ribosome and mRNA complex
where they fuse together to make proteins, contains Anti Codon 3 base pairs that is
complementary to mRNA's codon and attaches to mRNA codon
-rRNA role: helps form the ribosome as a part of it
Briefly describe replication, transcription, and translation. What is used as template for
each process? - ANSWERSReplication: DNA opens up, the 2 strands separate and 2
new strands are synthesized by DNA polymerase in one direction and fills the gap for
each strand, goes 5' 3' and complementary strand will be 3' 5'; one strand is always
synthesized straight (leading strand) while the other is made into pieces of multiple
primers (Okazaki fragments) and eventually is fused together to become one strand (the
lagging strand) makes 2 copies of double stranded DNA
-Replication: 1 DNA copied into 2 identical copies and after that can now divide into 2
new cells, cell division
-Transcription: makes RNA from DNA, (RNA needed as intermediate btwn proteins and
DNA, also as part of ribosomes, and for making proteins and helping synthesize
proteins), RNA polymerase reads DNA and makes a copy of RNA (polymerase knows
where genes start and end) gene expression controlled by transcription and if decide
not to make genes then bacteria doesn't make RNA
,-Translation: makes proteins, ribosome sits on mRNA and reads through mRNA and
tRNA takes the amino acids represented by Codons to ribosome and fuse amino acids
together to make proteins.
(Ribosomes are made of proteins and rRNAs)
-Template for replication: DNA
-Template for transcription: DNA
-Template for translation: RNA
What are the products of: Replication, Transcription, Translation and Reverse
Transcription? What are the differences between DNA polymerase an RNA
polymerase? What is the significance of reverse transcriptase? What is the source of
reverse transcriptase. What does it do? - ANSWERS-Products of Replication: 2
identical copies of DNA (semiconservative replication)
-Products of Transcription: 3 forms of RNA mRNA (template for protein), rRNA (part of
ribosome), tRNA (involved in protein synthesis)
-Products of Translation: Proteins
-Reverse Transcription: DNA
-Differences: DNA polymerase needs a primer made of RNA to start making DNA, RNA
polymerase makes RNA by sitting on DNA going in 5' 3' direction and reading genes
and then making RNA out of it. Reads a G so it puts a C and ....
-Significance of reverse transcriptase: can make DNA out of RNA and don't have to
have a gene just use enzyme Reverse Transcriptase
-Retroviruses: RNA viruses and they use it to turn RNA into DNA that can integrate as a
provirus (virus genes integrate into host cell DNA) and then use the DNA to replicate the
virus and then make RNA again.
Define/Explain/describe: Complementary strands, Anti-parallel, Semiconservative
replication, Double helix - ANSWERS- Anti-parallel: one strand has 5' and 3' and other
strand is antiparallel with this one across from it as 3' and 5'. (DNA)
- Complementary strands: The nitrogenous pairs must match up with G on one side and
C on the other or A on one side and T on the other. (DNA)
- Double helix: double stranded spiral (DNA)
- Semiconservative replication: daughter cell has HALF of DNA from parent DNA and
other half is new DNA.
List the enzymes and their functions involved in DNA replication - ANSWERSHelicase-
Unzipping DNA helix
Primase- Synthesizing RNA primer
DNA polymerase 3- adding bases to new DNA chain, proofreading chain
DNA polymerase 1- Removing primer, closing gaps, repairing mismatches
Ligase- Final binding of nicks during synthesis and repair
Topoisomerase's 1 and 3: supercoiling and untangling
What is the genetic material for viruses, DNA or RNA, single stranded or double
stranded? - ANSWERSit can be either or
, Where in eukaryotes and prokaryotes one can find DNA? - ANSWERS- Prokaryotes
DNA is found in: circular or linear chromosomes in supercoil in nucleode, plasmid
- Eukaryotes DNA is found in: linear chromosomes in nucleus, mitochondria and
chloroplast in plants
What are ribosomes made of? Prokaryotes and eukaryotes have different ribosomes?
What is the significance of this difference? - ANSWERSmade of: RNA and proteins
Prokaryotes have 70s; eukaryotes have 80s
Significance: the difference in size, antibiotics are designed to kill prokaryotic ribosomes
What is meant by recombinant DNA? - ANSWERSDNA molecules formed by laboratory
methods of genetic recombination (such as molecular cloning) to bring together genetic
material from multiple sources
1.What is the significance of RFLP? - ANSWERScan be used to trace inhertitance
patterns, identify specific mutations, and for other molecular genetic techniques.
DNA fingerprinting
Name several medical, Industrial, and agricultural applications of recombinant DNA. -
ANSWERSVacines, Genetic screening, protein synthesis, Genome mapping,
xenotransplant, DNA fingerprinting, Gene therapy, herbicide resistance, salt tolerance,
freeze/ pest resistance
Name the tools used to make a recombinant DNA. Example; how you cut DNA, how
you introduce the DNA to the host cell, how to track the DNA. What is meant by gene
library? Protoplast fusion? - ANSWERSPolymerase Chain Reactions: amplify DNA
Clone Selection: remove embryo contents and inject it
Separation of DNA molecules
Introduce DNA To host cell by introducing into a vector (usually plasmid) and inserting
DNA
Gene Libraries: collections of DNA clones that represent the entire genome of numbers
organisms
Protoplast fusion: enetic modification in plants by which two distinct species of plants
are fused together to form a new hybrid
Define spontaneous mutation. What causes spontaneous mutation? - ANSWERSA
random change in the DNA arising from error in replication occurring randomly
Define base analogs and explain how they may induce mutation - ANSWERSMolecule
that resembles bases; looks like a molecule and fits but doesn't function like it should
-Replaces the actual base; competitive inhibition
Define frame shift mutation, induced mutation - ANSWERSFrameshift mutation: when
one or more bases are inserted or removed from a newly synthesized DNA strand
