RNA và cấu trúc phân tử, đặc tính sinh học

RNA
RNA
Ribonucleic Acid
Ribonucleic Acid
Structure of RNA
Structure of RNA

Single stranded
Single stranded

Ribose Sugar
Ribose Sugar

5 carbon sugar
5 carbon sugar

Phosphate group
Phosphate group

Adenine, Uracil, Cytosine, Guanine
Adenine, Uracil, Cytosine, Guanine
Types of RNA
Types of RNA

Three main types
Three main types

Messenger RNA
Messenger RNA
(mRNA) – transfers
(mRNA) – transfers

DNA code to ribosomes for translation.
DNA code to ribosomes for translation.

Transfer RNA
Transfer RNA
(tRNA) – brings amino
(tRNA) – brings amino
acids to ribosomes for protein synthesis.
acids to ribosomes for protein synthesis.

Ribosomal RNA
Ribosomal RNA
(rRNA) – Ribosomes are
(rRNA) – Ribosomes are
made of rRNA and protein.
made of rRNA and protein.
Transcription
Transcription

RNA molecules are produced by copying part
RNA molecules are produced by copying part
of the nucleotide sequence of DNA into
of the nucleotide sequence of DNA into
complementary sequence in RNA, a process
complementary sequence in RNA, a process
called
called
transcription
transcription
.

.

During transcription, RNA polymerase binds to
During transcription, RNA polymerase binds to
DNA and separates the DNA strands. RNA
DNA and separates the DNA strands. RNA
polymerase then uses one strand of DNA as a
polymerase then uses one strand of DNA as a
template from which nucleotides are
template from which nucleotides are
assembled into a strand of mRNA.
assembled into a strand of mRNA.
mRNA
mRNA
How Does it Work?
How Does it Work?

RNA Polymerase looks for a region on
RNA Polymerase looks for a region on
the DNA known as a promoter, where it
the DNA known as a promoter, where it
binds and begins transcription.
binds and begins transcription.

RNA strands are then edited. Some
RNA strands are then edited. Some
parts are removed (
parts are removed (
introns
introns

) - which are
) - which are
not expressed – and other that are left
not expressed – and other that are left
are called exons or expressed genes.
are called exons or expressed genes.
The Genetic Code
The Genetic Code

This is the language of mRNA.
This is the language of mRNA.

Based on the 4 bases of mRNA.
Based on the 4 bases of mRNA.

“
“
Words” are 3 RNA sequences called
Words” are 3 RNA sequences called
codons
codons
.
.

The strand aaacguucgccc would be
The strand aaacguucgccc would be
separated as aaa-cgu-ucg-ccc the amino
separated as aaa-cgu-ucg-ccc the amino
acids would then be Lysine – Arginine –
acids would then be Lysine – Arginine –

Serine - Proline
Serine - Proline
Genetic Codes
Genetic Codes
Translation
Translation

During translation, the cell uses information
During translation, the cell uses information
from messenger RNA to produce proteins.
from messenger RNA to produce proteins.

A – Transcription occurs in nucleus.
A – Transcription occurs in nucleus.

B – mRNA moves to the cytoplasm then to the
B – mRNA moves to the cytoplasm then to the
ribosomes. tRNA “read” the mRNA and obtain
ribosomes. tRNA “read” the mRNA and obtain
the amino acid coded for.
the amino acid coded for.

C – Ribosomes attach amino acids together
C – Ribosomes attach amino acids together
forming a polypeptide chain.
forming a polypeptide chain.

D – Polypeptide chain keeps growing until a
D – Polypeptide chain keeps growing until a
stop codon is reached.

stop codon is reached.
Translation to Protein
Translation to Protein
Translation
Translation
Mutations
Mutations

Gene mutations result from changes in a
Gene mutations result from changes in a
single gene. Chromosomal mutations
single gene. Chromosomal mutations
involve changes whole chromosomes.
involve changes whole chromosomes.
Gene Mutation
Gene Mutation

Point Mutation
Point Mutation
– Affect one nucleotide
– Affect one nucleotide
thus occurring at a single point on the
thus occurring at a single point on the
gene. Usually one nucleotide is
gene. Usually one nucleotide is
substituted
substituted
for another nucleotide.
for another nucleotide.


Frameshift Mutation
Frameshift Mutation
–
–
Inserting
Inserting
an extra
an extra
nucleotide or
nucleotide or
deleting
deleting
a nucleotide
a nucleotide
causes the entire code to “shift”.
causes the entire code to “shift”.
Gene Mutation
Gene Mutation
Chromosomal
Chromosomal
Mutations
Mutations

Deletion
Deletion
– Part of a chromosome is deleted
– Part of a chromosome is deleted

Duplication
Duplication

– part of a chromosome is
– part of a chromosome is
duplicated
duplicated

Inversion
Inversion
– chromosome twists and inverts the
– chromosome twists and inverts the
code.
code.

Translocation
Translocation
– Genetic information is traded
– Genetic information is traded
between nonhomologous chromosomes.
between nonhomologous chromosomes.
Chromosomal
Chromosomal
Mutations
Mutations
Mutations
Mutations
More Mutations
More Mutations
Gene Regulation
Gene Regulation

In simple cells (prokaryotic) lac genes

In simple cells (prokaryotic) lac genes
which are controlled by stimuli, turn
which are controlled by stimuli, turn
genes on and off.
genes on and off.

In complex cells (eukaryotic) this process
In complex cells (eukaryotic) this process
is not as simple. Promoter sequences
is not as simple. Promoter sequences
regulate gene operation.
regulate gene operation.
Review
Review