10/16/24, 11:16 Cell Bio Lecture 8-13 - professor
AM O'Halloran
Reading the Genome
● DNA is moving from
heterochromatic to euchromatic
structures so we can read it
● First we must convert the DNA to
intermediate RNA which is turned into
protein
○ DNA is just a stable template for all
the proteins we will ever need. We
can replicate the DNA and it is
found in all the cells. We can also
pass this down to progeny.
From DNA to RNA
● Gene Expression- the process by which
cells read out the instructions in their
genes
● Nucleotides in RNA get polymerized
similar to how DNA is polymerized.
Protein is sometimes
the goal, but not always. tRNA, rRNA, and snRNA are all untranslated. Micro rna
stops expression.
● In Eukaryotes, Protein-Coding Genes Are
Interrupted by Noncoding Sequences
Called Introns
○ Parts of the DNA that is
transcribed but not translated
● Introns Are Removed from Pre-mRNAs
by RNA Splicing
● Mature Eukaryotic mRNAs Are Exported
from the Nucleus
○ Spliced RNA are translocated to
the ribosomes on the ER which
translate the mRNA to protein
● mRNA Molecules Are Eventually
Degraded in the Cytosol
● There are different regulatory proteins that determine how many RNA
transcripts should be made from each gene. Sometimes the genes can be
coregulated. Each gene has a promoter region that controls the expression of
the gene. It will recruit transcription factors that will determine how
transcripts are put out. Not all genes are expressed at the same level. This
isn’t a stable organization and changes over time.
● Certain cells will make a lot of a type of transcript while other cells won’t make
as much
of that transcript. This is called spatial control.
about:blan 1/
k 8
, 10/16/24, 11:16 Cell Bio Lecture 8-13 - professor
AM O'Halloran
● At a certain time point or in response to a certain event, a gene could be
expressed but later expressed at a lower level. This is temporal control.
● RNA, unlike DNA, doesn't have
a clear structure. mRNA is
single stranded and can form
complicated structures. They
can loop on each other if there
is self-complementarity and
form hydrogen bonds.
● Where this occurs, the mRNA
will form helices. But because
we don’t have complete
complementarity, we will just
have stretches of helices.
● We can get non-conventional base
pairs via other interactions such as
electrostatic.
● Transcription Produces RNA That
Is Complementary to One Strand
of DNA
○ The coding strand of the DNA is
going to have the same
sequence as the RNA with the
exception of uracils.
○ RNAP will use the template
strand and add
complementary base pairs to
get a copy of the coding
strand. We can use primers to
amplify sequences in
experiments.
about:blan 2/
k 8
AM O'Halloran
Reading the Genome
● DNA is moving from
heterochromatic to euchromatic
structures so we can read it
● First we must convert the DNA to
intermediate RNA which is turned into
protein
○ DNA is just a stable template for all
the proteins we will ever need. We
can replicate the DNA and it is
found in all the cells. We can also
pass this down to progeny.
From DNA to RNA
● Gene Expression- the process by which
cells read out the instructions in their
genes
● Nucleotides in RNA get polymerized
similar to how DNA is polymerized.
Protein is sometimes
the goal, but not always. tRNA, rRNA, and snRNA are all untranslated. Micro rna
stops expression.
● In Eukaryotes, Protein-Coding Genes Are
Interrupted by Noncoding Sequences
Called Introns
○ Parts of the DNA that is
transcribed but not translated
● Introns Are Removed from Pre-mRNAs
by RNA Splicing
● Mature Eukaryotic mRNAs Are Exported
from the Nucleus
○ Spliced RNA are translocated to
the ribosomes on the ER which
translate the mRNA to protein
● mRNA Molecules Are Eventually
Degraded in the Cytosol
● There are different regulatory proteins that determine how many RNA
transcripts should be made from each gene. Sometimes the genes can be
coregulated. Each gene has a promoter region that controls the expression of
the gene. It will recruit transcription factors that will determine how
transcripts are put out. Not all genes are expressed at the same level. This
isn’t a stable organization and changes over time.
● Certain cells will make a lot of a type of transcript while other cells won’t make
as much
of that transcript. This is called spatial control.
about:blan 1/
k 8
, 10/16/24, 11:16 Cell Bio Lecture 8-13 - professor
AM O'Halloran
● At a certain time point or in response to a certain event, a gene could be
expressed but later expressed at a lower level. This is temporal control.
● RNA, unlike DNA, doesn't have
a clear structure. mRNA is
single stranded and can form
complicated structures. They
can loop on each other if there
is self-complementarity and
form hydrogen bonds.
● Where this occurs, the mRNA
will form helices. But because
we don’t have complete
complementarity, we will just
have stretches of helices.
● We can get non-conventional base
pairs via other interactions such as
electrostatic.
● Transcription Produces RNA That
Is Complementary to One Strand
of DNA
○ The coding strand of the DNA is
going to have the same
sequence as the RNA with the
exception of uracils.
○ RNAP will use the template
strand and add
complementary base pairs to
get a copy of the coding
strand. We can use primers to
amplify sequences in
experiments.
about:blan 2/
k 8
