BioBioChem 5 Molecular Genetics Flashcards
defn DNA Genome
all of the DNA in the organism
Nuclear Genome has ___ chr
23
Mitochondrial genome has ____ _____ chromosome
1 circular chromosome
Mitochondrial genome is inherited by the ____
mom
Zygote (___loid, __n_
diploid, 2n
Cell cycle is G1 to ___ to G2 to ___
G1,S,G2,M
What part of the cell phase are most cells hanging out?
G1 (growth phase)
What is the S phase?
DNA rep
G2
Growth
-get big to divide
M phase
mitosis, meiosis
Defn DNA methylation
add CH3 to cytosine (C)
DNA methylation triggers gene ____ which means there is __ gene expression and causes heterochromatin formation and prevents transcription proteins from binding
silencing, no
histones proteins are ____charged and are a ___ concentration of amino acids (___ and ____)
positively, high, Arg (R), Lys (K)
DNA has a ___ charge because it has a ___ group
negative, phosphate
Heterochromatin is when we have ______ wound DNA around histones. (called _____)
tighlty, nucleosome
Defn Nuclesome
DNA around histone
Heterchromatin means there is no gene expression b/c…
DNA is inaccessible
We can add acetly groups to the histones which ____ off DNA from histones because they are ___ the charge
loosen, neutral
Histone acetylation forms ____
euchromatin
How do we get the DNA to loosen off the histones (euchromatin)
Histone acetylation
Euchromatin can have gene expression T/F
T
DNA methylation forms ___
heterochromatin
Histone acetylation forms ___
euchromatin
I can alsoform heterchromatin by ____ of histones
DEacetyaltion
I can also form euchromatin by ___ of DNA
DEmethylation
You can also methylate and phosphoylate the histone but must test for whether is forms heterchromatin or euchromatin
Between primary mRNA and mature mRNA there is ___ ______
RNA processing
RNA processing only occurs in ___ cells
Euk
Noncoding RNA exs (5)
tRNA
rRNA
SiRNA and MiRNA
SnRNA
promoter
where RNA polymerase binds
the coding strand is the ___ sequence as the RNA made except T is __
exact, U
A binds to __ in RNA
U (instead of T)
parts of the coding mRNA
- 5’ UTR (untranslated region)
- exons (codons)
- introns (optional in a gene, removed before translation)
- 3’ UTR
Introns are optional in a gene and are removed before ____
translation
How many bonds are there between A and U
2
How many bonds are there between C and G
3
RNA processing can also be called
post-transcriptome control
RNA processing is only in __ cells and is only for __ mRNA
euk, coding
What is the first step in RNA processing?
adding a 5’ cap (7-methylguanosine cap)
What does adding a 5’ cap do?
stability. (decreases mRNA breakdown)
40s ribosome (small unit) bind to start translation
What is the 2nd step of RNA processing?
add 3’ poly A tail (~300 A’s)
What is the purpose of adding a 3’ poly A tail
stability, role in translation
Splicing is when I remove RNA ____
introns
splicing (remove RNA introns) changes the seq to create the final mRNA to create ___ coding
protein
Alternative splicing is when we remove __ and some specific ____
introns, exons
Alternative splicing allows us to use the same DNA the same primary mRNA and results in a different ___
protein
mRNA is exported from the ___ to the ___
nucleus, cytosol
mRNA in the cytosol make ___
protein/peptide
exons/codons/coding region/open reading frame
Start Codon
AUG
AUG is for ___
Met (M)
What is the first amino acid in every protein?
Met
What are the three stop codons?
UAA, UGA, UAG
At the stop codon the __ ___ binds, and the __ leaves
release factor, ribosome
The ___s ribosome binds at the ___ cap and looks for ___
40s, 5’ cap, AUG
5’ cap is the backwards __
G
the ___s ribosome binds the AUG
60s
Downstream always means toward the __’ end
3’
Create peptide bonds as _____/____ with anticodon binds mRNA codons
tRNA/aa
Protein modification is called a post-______ mod
translational
DNA polymers are constructed from 4 ______, each consisting of a ____ group, _________ sugar and a ______ base
nucleotides, phosphate, nitrogenous
Purines
PURE AG
G has an ____ on a ring
oxygen (G looks like an O)
Pyramide
cut py once (C,T,U). One ring
Mutation for DNA where c-> is because of
deamination (loss of NH2)
How can we distinguish DNA and RNA? which carbon
the 2nd carbon
If it is an H it is a deoxyribose
if it is a OH ribose (RNA)
Nuceloside
Nitrogenous base attached to a ribose sugar
Nucleotide
Nuceloside + phsophate group
Does G and C have a higher melting point or A and T
G and C because they have 3 hydrogen bonds
what enzymes unwinds DNA?
topoisomerase
Prokaryotes have ____ origin of replication in a ____ chromosome
1, circular
Lagging strands are also called _____ and are ________ replication
okazaki fragments, discontinuous
_ sites for leading strands and __ sites for lagging strands
2, 2 (bidirectional)
Helicase unwinds DNA strands (break __-bonds)
H-bonds
Single stran binding proteins (SSC) keep ____
2 strands apart
Leadings strands are made going ____ the fork
towards
DNA pol III
new synthesis
DNA pol I
has 3-5’ exonuclease for proofreading. It also has a 5-3’ exonuclease to remove RNA primers and replace with DNA
What enzyme remoes RNA primers
DNA pol I
DNA ligase
seals the gap
creates phosphodiester bond b/w 2 DNA fragments
Fidelity also means
accuracy
The ends of euk chromosomes are called ___
telomeres
Telomerase (which lengthens telomeres) is active in (4)
fetus, stem cells, germ line cells, cancer
A gene codes for the production of an ____ prodict
RNA
rRNA
(ribosomal) RNA component of a ribsosome
-bind mRNA and hold in place in ribosome
tRNA
transfer RNA
-bring an aa into the ribosome, tRNA anticodon binds the mRNA codon
what two RNA are involved in translation
rRNA and tRNA
siRNA and miRNA decide if ____ is translated
mRNA
RNA can exit the nucleus, DNA —
cannot, remains in the nucleus
TATA box is an AT rich area beacuse it makes it easier because it has __ bonds
2
What types of compounds have RNA and protein?
Ribosome and splicesome
snRNPs + snRNA is the ___
spliceosome
Lariat
the removed sequence (most times made of introns)
Splicing. What are the two rxns?
1st attack is the 5’ splice side (upstream)
2nd attack: attack of 3’ splice site (downstream)
Unambiguous
a codon codes for an amino acid (very specific)
Degenerative
one amino acid may have more than one 3 nucelotide (Proline) (CCC,CCG,CCA,CCU)
What is the third position in the amino acid called?
wobble
Wobble
the third nucleotide can loosely bind wrong base (this is okay for degenerative)
Universal
nearly every living organism uses the same genetic code
What are the 3 stop codons?
UAA - u are annoying
UGA - u go away
UAG - u are gone
prok have a sedimentation co-efficient of ___ and ___ with a total of
30s and 50s (70s)
Euk has a sedimentation co eff of __ and __ with a total of ___
40s 60s 80s
shine Dalgarno sequence
SD boc at the 5’ UTR in prokaryptes
The A site is where new ____ with amino acid enters
tRNA
40s binds 5’ cap, scan to AUG. @AUG, initiator tRNA bind, large subunit binds, new tRNA in A site
Secretory pathway is from the ___ to the _____ to the plasma membrane via _______
RER, Golgi, plasma membrane
DNA mutations are ___stranded DNA changes
double
Silent point mutation
single nucleotide is changed but has no effect because it is the same aa
Missesne point mutation
a change in one nucleotide and causes a diff aa
Nonsense point mutation
one nucletode change causes the codon to be a stop codon
Frameshift mutations result from ___ or ___ of nucelotides in multiples other than 3
deletion, insertion
Forward mutation will change the gene even ___ from its original change
more
most mutations are ___
neutral
Translocation is moving )))) to another chromosome
dsDNA
Proto-oncogenes are ____ oncogenes are not
normal
Oncogenes only need one copy to be gas pedal are are called a ____ function gene
gain of function gene
A tumor suppressor gene is a gene whose product normally ____ the cell from unrestricted growth
protects
Both copies must be nonfunctional to get cancer for which gene?
tumour suppressor gene
How many chromosomes do humans have and what is their shape?
23 per genome x 2 = 46 and they are linear
How are autosomal chromosomes organized?
largest to smallest
XX is ___ XY is ___
female, male
Tuner’s syndrome is ___
XO
Kleinfelters is _ _ _
XXY
a karyotpe is taken at which phase in mitosis?
metaphase
2 chromosomes is 4 ____
chromatids
what are common epigenetic changes? 2
DNA methylation
Histone modification: acetylation, methylation, phosphorylation
what happens at each stage?G1, S, G2, mitosis
Growth, DNA rep, get bigger to divide, divide DNA
Cytokinesis is when the cell ____
pinches into 2 different cells
Prophase: DNA ____
condenses
