Protein Synthesis

RNA Structure

& the Central Dogma

2 part process….

• RNA is made in process of transcription using a DNA

template

• The RNA molecules made in transcription are used to

make PROTEINS in the process of translation.

Multiple Choice

What is transcription?

• The process by which RNA is made using a DNA template

• The process by which proteins are made using the RNA

DNA

RNA

Protein

Transcription
Translation

Directions to
make proteins are
safely stored in
the nucleus

Carries the
directions to
the cytoplasm

Work to keep
the cell alive

Central Dogma of molecular biology

Reorder

Arrange the following into the correct order that shows the "Central Dogma" of Molecular Biology.

• RNA

• DNA

• Protein

1

2

3

• 1
• 2
• 3

What about RNA makes it so special?

• RNA = ribonucleic acid.

• RNA = intermediate molecule between DNA and the

proteins that are produced.

• RNA molecules are transcribed from a DNA template.

• The structure of RNA is very similar to the structure of

DNA, but there are structural differences between
DNA and RNA.

Structure of RNA

• RNA molecules are made of monomers of

nucleotides (this is similar to the structure of
DNA).

• A nitrogen base
• A 5-carbon sugar,

ribose

• A phosphate group

Structure of RNA continued

• RNA does not contain thymine (T), but contains the

base uracil (U) instead.

• RNA molecules are made from a DNA template.

• The base-pairing rules with RNA are that uracil (U)

pairs with adenine (A) and G pairs with C.

• RNA molecules are single stranded

• There are three forms of RNA: mRNA, tRNA, rRNA

DNA

RNA

How many
strands?

2

1

Nucleotide
subunit

Deoxyribose Sugar

Ribose Sugar

Bases

Thymine (T)
Adenine (A)
Guanine (G)
Cytosine (C)

Uracil (U)
Adenine (A)
Guanine (G)
Cytosine (C)

Phosphate

Group

Deoxyribose

Sugar

Nitro-

gen

Base

Phosphat

eGroup

Ribose
Sugar

Nitro-

gen

Base

T – A

G – C

U – A

G – C

Comparison of DNA & RNA

Types of RNA

• There are 3 types of RNA, including mRNA,

tRNA, and rRNA

Messenger RNA

• Messenger RNA, or mRNA, acts

as a template for assembling
amino acid sequences (make up
a protein).

• mRNA molecules have codons

which are read by anticodons
(on tRNA molecules) through
base-pairing rules.

Transfer RNA

• Transfer RNA, or tRNA, is folded

back on itself like a hair pin.

• tRNA contains an anticodon

that is complementary to a
specific codon on the mRNA.

• There are many forms of tRNA.

These correspond to each of the
20 amino acids that bind to
them.

Transfer RNA

• For tRNA molecules to

function properly, they
must
– become bound to the

appropriate amino acid

– recognize the

appropriate codon on
the mRNA sequence.

Ribosomal RNA

• Ribosomal RNA, or rRNA, is a

globular form that combines with
proteins to create the ribosome
subunits.

• There are two subunits, or parts, of

a ribosome.

• A complete ribosome is a binding

site for mRNA and tRNA molecules
to create a protein.

Ribosomal RNA

Why do we care about the structure & function

of RNA molecules?

• The three types of RNA molecules are involved in

making proteins.

• There is a two-part process that is the formation

of proteins.
– Transcription (use of information from DNA to create RNA)
– Translation (use of RNA to create proteins)

• DNA is the instruction manual
• RNA is a copy of the instructions, which is actually

used to make the proteins.

Transcription of RNA: Initiation

• DNA is used as a template to create RNA

molecules. Steps of transcription:

• (1) Initiation: RNA polymerase opens up the DNA.

12. Transcription of RNA: Elongation

• (2) Elongation: RNA polymerase attaches to free floating

RNA nucleotides in the nucleus to the unzipped DNA to
build a new RNA molecule. This occurs at a specific
“coding region.”

Transcription of RNA: Termination

• (3) Termination: RNA polymerase hits a termination

code, or stop code, is reached on the DNA molecule and
the RNA is released. The DNA zips back up.

Multiple RNA polymerases can transcribe the same gene at the
same time.

A cell can synthesize a large number of RNA transcription in a
short time.

Transcription of RNA

• All RNA molecules (mRNA, tRNA, and rRNA) are

made this manner.

• Newly created RNA leaves the nucleus through

the nuclear pores and enters the cytoplasm.

• Why make RNA?

– DNA is too big to leave the nucleus—DNA is two

strands & RNA is only one strand and made of
smaller pieces. RNA is template for making
proteins.

Transcription in Process

• http://vcell.ndsu.edu/animations/transcripti

on/movie-flash.htm

• http://www.youtube.com/watch?v=8kK2zwj

RV0M&list=PLixPK37fCIzGwmj2IVCLPlF
MaC60mdEpe

Translation of Proteins

Production of Proteins: Analogy

• DNA is the instruction manual, RNA is a copy of the

instructions, which is actually used to make the
proteins.

• Example of TOY Instructions

– Toy instructions start in another language (DNA)
– Toy instructions are transcribed into English (RNA)
– You can now use these instructions to build toy! (protein)

SPANISH
MANUAL

ENGLISH
MANUAL

ENGLISH
MANUAL

Basic Translation Definition

• Translation is the

creation of proteins
from the information
encoded in RNA.

• rRNA, tRNA, and mRNA

are all involved in the
process.

Codon Chart

• Each codon below from the codon chart is

from mRNA and codes for an amino acid.

Using the Codon Chart

• From the chart, tell me which proteins are

coded for by the following codons.
– UCG

– Serine

– AGA

– Arginine

– GGG

– Glycine

– UUG

– Leucine

– UAA

– Stop

drawings you need in your

notes

drawings you need in your

notes

In class notes:

Codon & Anticodon example

Translation Animation

•

Here is the whole process in animation form!

https://www.youtube.com/watch?v=gG7uCskUO

rA

Central Dogma