DAT Genetics Cheat Sheet Flashcards
Messenger RNA is the single-
stranded template for protein
synthesis
mRNA
clover-
shaped and transports amino acid to
its mRNA codon
tRNA
globular and forms part of the
ribosomes
rRNA
Copying of genetic information in cells
DNA replication
DNA replication starts at
specific nucleotide sequence
called the origin of replication
One new strand is made continuously, which one is it
leading strand
made in fragments, which strand
lagging strand
separates the DNA double helix into single
stranded DNA, forming a replication fork
helicase
Proteins that bind to
the single-stranded DNA near the replication fork to
keep the two strands of DNA apart
single stranded binding proteins
relieves the stress caused by unwinding
by breaking and rejoining strands
topoisomerase
is synthesized continuously as DNA unzips
leading strand
is synthesized discontinuously
lagging strand
what does the lagging strand produce
Okazaki frGMENTS
Short stretches of nucleotides
formed as the lagging strand is synthesized
Okazaki fragments
creates a small strip of RNA primer.
primase
DNA
polymerase needs this….
existing set of nucleotides from
the primer to begin synthesizing a new strand of DNA
synthesizes new DNA strand in 5’ →
3’ direction by adding nucleotides to an RNA primer
DNA polymerase iii
removes RNA primer and replaces it
with newly synthesized DNA
DNA polymerase i
seals the gaps in the phosphodiester backbone of
DNA between the Okazaki fragments
ligase
Segment of DNA that are added to the ends of
chromosomes to prevent loss of genomic info as
chromosome ends wear down
telomeres
Enzyme that creates telomeres
telomerase
For DNA to be replicated, it should first be
unwound by helicase
Process of synthesizing RNA from a
DNA template.
trasncription
In transcription, we bind and
transcribe a…
specific gene
gene. In DNA replication,…
the entire genome is replicated
Proteins that bind to the
promoter sequence and other regulatory sequences
to control transcription of a target gene
trasncription factors
Sequence RNA polymerase
attaches to; this is upstream of DNA that gets
transcribed
promotor region
The most effective way to prevent a gene from
being expressed is to…
delete the promotor region
Adding 5’ cap sequence to 5’ end and poly-A tail to
3’ end of mRNA for stability
post-transcriptional processing
3 steps of transcription
initiation, elongation, termination
RNA Polymerase attaches to promoter region on DNA and unzips DNA
into 2 strands
Initiation:
RNA Polymerase synthesizes RNA nucleotides using one DNA strand as
template
elongation
RNA Polymerase reaches a special sequence, detaches from the DNA,
and disassembles
termination
The process of
removing sections of pre-mRNA
transcript that are absent in the
mature mRNA and reconnecting the
remaining exons
RNA splicing
Protein-coding regions of
the genome
exons
Non-coding regions in
mRNA that do not encode
functional proteins
introns
Process
occurring during gene expression
that allows for production of
multiple protein types from a
single gene when different
combinations of exons are used
alternative splicing
The synthesis of proteins based on the sequence of mRNA
nucleotides
translation
Small ribosomal subunit binds to mRNA, and methionine-
tRNA binds to AUG start codon; large ribosomal subunit joins to form
a complete ribosome
initiation
tRNAs bring amino acids to a growing polypeptide chains)
enter at A site, then shift to P site, and finally to E site for removal
elongation
Translation terminates when the stop codons (UAG,
UAA, UGA) are encountered. These are recognized by release factors,
which cause the newly made polypeptide chain to be released
termination
what are the stop codons
UAG, UAA, UGA
A single nucleotide change causing substitution,
insertion, or deletion
point mutation
The codon is changed, but due to the
redundancies in codons, the same amino acid gets incorporated
as normal; protein function remains unchanged
silent mutation
results in a new codon that encodes a new
amino acid
missense mutation
converts an existing codon encoding an
amino acid into a stop codon, prematurely signaling the cell to
stop building a protein; it produces a truncated, usually non-
functioning protein
nonsense mutation
changes a wild type allele to a mutant allele
forward mutation
reverts a mutant allele to a wild type allele
backward mutation
results in a shifted reading frame of RNA
transcript, causing different amino acids to be translated and
resulting in impaired protein structure
frameshift mutation
mRNA sequence
without any mutation
wild type
Frameshift causing
extensive missense
base pair deletion
Frameshift causing
immediate nonsense
base pair insertion
(DNA is duplicated, cell
divides into two cells)
binary fission
replicates in both directions from a single point of
origin.
bacterial DNA
Small, circular double stranded DNA molecules that are
separate from the main prokaryotic DNA
plasmids
carry genes that are non-essential but may be beneficial
for survival
plasmids
Gene clusters that control
transcription and consist of promoter,
operator, structural genes
operons
DNA sequence where RNA
Polymerase attaches to
PROMOTOR
Region that can block the
action of RNA Polymerase if occupied
by a repressor
OPERATOR
Genes that code for
proteins that are to be produced (BACTERIA
STRUCTURAL GENES
Genes that
encode products that control the
expression of other genes (bacteria)
regulatory genes
Protein that binds to
the operator of prokaryotic genes
to decrease transcription
repressor
Protein
that binds to prokaryotic
operators to increase
transcription and assists the
attachment of RNA Polymerase
to promoter
Activator/enhancer
Operon in prokaryotic cell that encodes genes required for processing of lactose
lac operon
Presence of lactose induces the operon to produce…
lactose breakdown enzymes
A group of genes necessary to synthesize
tryptophan in prokaryotic cells
trp operon
DNA is transferred from a living
donor bacterium to a living recipient
bacterium by cell-to-cell contact
conjugation
a pilus
in conjugation, (bridge) to send
its DNA or plasmid to the recipient.
A competent
recipient bacterium
takes up free DNA
from the surrounding
trasnformation
DNA is
transferred from one
bacterium to another by
a bacteriophage
(virus that infects
bacteria)
transduction
Complete genetic information for an organism
genome
Majority of the human genome consists of
noncoding DNA
Set of all RNA molecules that can be
produced by a cell
trasncriptome
Complete set of proteins in an organism that
are expressed
proteome
do prokaryotes have larger genomes than euk
no
do prokaryotes have introns
noi
is there a correlation between genome size vs number of genes
no
Humans have less genes than
expected for their complexity
due to
alternative splicing
which has lower gene density, euk or prok
eukaryores
Stops gene expression by
tightening chromatin
organization of DNA and
without altering nucleotide
sequence
DNA methylation
Increases gene expression by
loosening chromatin
organization of DNA and
making it more accessible for
transcription
histone acetylation
decreases gene experession (epigenetic mechanism
DNA methylation
increases gene expression (epigenetic mechansims
histone acetylation
Temperature-Dependent Sex Determination is seen in
reptiles
Gender is determined by the environmental temperature
during a thermosensitive period of embryonic development
temperature dependent sex determination
Males develop in cold; females in
warm (ex. Turtles)
pattern I dev
Females develop in cold/hot; males in
medium (ex. Crocodiles)
pattern ii dev
Epigenetic mechanisms like DNA methylation, histone
acetylation, and non-coding RNAs are used to modify….
which hormones are expressed, which leads to certain sex hormone dev
Certain genes are expressed depending
on which parent they are inherited from
genomic imprinting
The body only expresses the genes
from one parent’s chromosome
rather than both while the….
the imprinted
genes on the other chromosome are
silenced via epigenetic mechanism
(not expressed!)
A set of genes are only expressed on the father’s Chromosome 15, while the mother’s
genes are imprinted
prader willi syndrome
in prader willi syndrome, When the genes on the father’s copy are mutated or deleted,
the child develops health
conditions
A (different) set of genes is only expressed on the mother’s Chromosome 15, while the
father’s genes are imprinted
angel mans syndrome
If the maternal copies of the gene are deleted or mutated, in angel mans syndrome…
health conditions result
