chapter 8 (Microbial Genetics Diana's version) Flashcards
The science of heredity
genetics
the toal DNA contained within the cell is called the ___ , and what else does it consits
this is called the genome, it may also contain chromosomes and any plasmids present
Genes are contained on _____
are contained on chromosomes
what are the two fundamental similarity that sugar (deoxyribose) and nitrogenous have, other than nucleotides of DNA are composed of them?
they both contain carbon, although they differ
how can you tell the difference of carbon between nitrogenous base and deoxyribose
carbon in deoxyribose:
1’-5’ the “ ‘ “= indicate the prime, so typically we call it prime after
carbon in nitrogenous base
1 carbon
2 carbon
3 carbon
etc…
DNA forms a double helix : two strands of DNA are held together by hydrogen bonds in between bases
these hydrogen bonds always occur in between specific bases referred to as ______ ____
base pairing
by this time we know that adenine always pairs with thymine via how many hydrogen bonds?
via two hydrogen bonds
guanine always pairs with cytosine via how may hydrogen bonds?
via three hydrogen bonds
why does G:::C , the way it is and why is A::T the way it is?
why? because there are three opportunities in partial positive and partial negative charge, cytosine and guanine together
and it goes the same way for Adenine and Thymine, there are two opportunities for partial positive and negative charge
The Flow of Genetic Information:
1. Dna replicates before division so that each offspring received one complete copy of genome
what is this reffering to?
Photocopying, and in result you get two identical cell “daughter cell”
The strands of DNA are complementary to one another therefore what does that mean?
that means the sequence of one strand (parent strand) determines the sequence of the other
The adjacent nucleotides are linked together by ______
covalent phosphodiester bonds
draw the illustration of the dna replication (briefly) from linear-helical- and the seperation
synthesis of the first strand is continous and is known as
leading strand
synthesis of the second strand is discontinuous an is known as the
lagging strand
lagging strand synthesis is more slower or more faster than leading strand?
it is more slower and more labourioous than leading strand synthesis
The lagging strand must be made in 5’3 direction or 3’ to 5’ direction. Which one?
lagging strand must be made in the 3’-5’ direction.
what does antiparallel mean?
for any double stranded primer is for positioning the DNA
the term unihibited was used in class, what does it mean?
continously synthesized–> another term could be called as leading strand
another way of saying covalent bond? we know that peptide bond is one and polypeptide, what is another one?
phosdiester bond
RNA and protein synthesis:
name 2 characteristics , and fill in this blank:
The nucleotide sugar in RNA is ___ rather than __ sugar and ___ base is replaced with ____.
ribose, deoxyribose, thymine, uracil
- DNA directs the synthesis of proteins
-Genes are the sections of DNA that have instructions for a functional protein product
what kind of nucleotides do you need to make DNA?
RNA nucleotides and DNA nucleotides
___ serves as a short term copy of the gene that can be used to direct protein synthesis
mRNA
these are end cells - and will not be converted into proteins
rRNA and tRNA
rRNA and tRNA:….
assist with the process of protein synthesis, they are functional pieces of RNA
how do you elongate DNA?
DNA primase
how do you elongate RNA?
RNA primase
Transcription:
a strand of RNA is synthesized from a particular gene
- the mRNA synthesized is complementary to the gene
-Uracil is used in replacement of Thymine
transcription requires:
1.enzyme: RNA polymerase
2.a supply of RNA nucleotides
3.A DNA template
True or false. In transcription : RNA polymerase assembles nucleotides into new RNA chain , and uses RNA template as a guide
NO, false. Although RNA polymerase assembles nucleotides into new RNA chain, it uses a DNA template NOT A RNA TEMPLATE.
* to test your understanding name all the steps in transcription, from the best of your knowledge* write in a piece of paper (dont have to include iniation,elongation, and termination)
- whatever you pleased
steps of transcription:
- RNA polymerase bins to DNA at a specific site-promoter
-only one DNA strand serves as a template
-like DNA, RNA is made in a 5’-3’
2.RNA polymerase assembles nucleotides into a new RNA chain
-Uses the DNA template as a guide
3.RNA polymerase moves along template as teh new RNA chain grows
4.RNA polymerase reaches the end of the gene-terminator
5.RNA polymerase and newly formed single stranded RNA are released.
is it 3 prime or 5 prime , at the start of translation?
5 prime
the sequence of ___ in ___ determine sequence of amino acids in protein
codons, mRNA
(the genetic code)
The codons ___, ___, ____ are known as stop codons or nonsense codons, what does this indicate?
indicates the signal the end of translation
if you don’t need a lot of proteins , what can you do ? HOWEVER if you need more mRNA , what can you do??
if you don’t need a lot of proteins , you can cut them apart, however if you need more mRNA you can initiate it, they do not stay for long.
Name some characteristics of translation:
1-6 charcateristics
- mRNA attatches to the ribosome
2.tRNA carrying the correct amino acid enters the ribosome and binds to the mRNA
3.the next tRNA with the amino acid enters the ribosome and binds to the mRNA
4.Two aminoa cids are joined by a peptide bond - RIbosome moves down mRNA 5’-3’ direction and a steps 3-4 are repeated until a stop codon is reached
6.mRNA and protein are released from the ribosome
Is it true that all mutations are equal?
not true, not all mutations are equal
some changes are hard to detect-because they are so similar changes can be good or bad (disruptive)
point mutation (substitution)
Point mutation (substitution) as we know when dna is transcribed and translated an incorrect base result in an incorrect amino acid in the protein
they can also result in the same amino acid which is called what ?
redundant genetic code
stop codons may also be introduced prematurely ,what is this giving?
leads to shorter proteins referred to as truncated proteins
this is a dangerous mutation , and throws off the reading frame (very disruptive)
frameshift mutation
how do mutations occur, explain one of them(specifically mutations due to mutagens)
spontanenous mutation
mutations due to mutagens= occur because of agents which work to bring about mutations in DNA
example: UV light, radiation and some chemicals
regarless of the origion, mutations can result in these: in other words name what they mean:
- Means truncated (shorten) added a stop codon for example frameshift mutation
2.Same personality (same protein to the original)
3.calls for the same amino acid1
- non sense mutation
2.missense mutation
3.silent mutation
true or false :
plasmids could provide selective advantage
true
In invovled in bacterial mating which one would it be?
f plasmids
True or false: the F pilli also allows for the transfer of genetic material in between bacteria?
true
transfer of genetic information:
genetic material can be transferred in between bacterial cells in a number of ways
When DNA is transferred to other bacterial cells rather than to progeny it is referred to as
horizontal gene transfer
Conjugation describe it:
Bacterial mating
Male cell: has an F pilli referred to as F donor
Female cell: does not have an F pilli and is reffered to as F recipient
F pilus allows the attatchment of the F+ cell to the F- cell
A copy of the F plasmid can be passed through hollow tube to the F- cel
F- recipient cell now becomes an F+ cell
Describe if these events are true according to transduction:
the phage attaches to the bacterial cell wall and injects its DNA into the cell
the phage dna is replicated within the bacterial cell
THe phage DNA directs protein synthesis in order to make new phage
all are true
new phages are assembled and pieces of bacterial DNA are accidentally package into phage protein coats ,
the accident phage can infect another bacterial cell since the accident phage contains bacterial DNA the bacterial DNA is also injected into the next cell
DNA can now be incorporated into the bacterial chromsome
all are true as well
exchanging genetic information, providing information for other cell, to do something . In short (they can hand out genes)
conjugation
this is where a virus infect a bacteria (prokaryotic cells)
what is the term that we use when we say that they desire prokaryotic cell
this would be transduction
and the term would be known as phage
DNA replication:
The enzymes DNA ____ and ___ are responsible for unwinding and seperating the two DNA strands
DNA ___ is found only in bacteria and not in eukaryotic cells there it serves as an an antibiotic target.
gyrase, helical, gyrase
DNA replication:
DNA synthesis occurs by the enzyme DNA _______
Nucleotides are placed in the correct order based on the sequence of the parent strand
DNA ____ links the nucleotides together with phosdiester bonds
polymerase,polymerase
True or fase.
In DNA replication, hydrogen bonds form in between new strand and the parent strand linking them together.
True
how many codons are there? but realistically how many do they ask for amino acids because stop codons are included?
there are 64 codons, but only 61 qill ask for aminoa cids (the 3 are stop codons)
