Download DNA Strand 2

Absentee SiLLwork_Central Dogma
Name & Period:
Directions: Use the notes from class and the attached reading to understand what these
problems are asking you to do. Complete each of the steps that are involved in the protein
synthesis below.
DNA  DNA code key:
C–G
G–C
A–T
T-A
Part one is to know the DNA code:
Use the DNA DNA code key to fill in the complimentary base pairs
on DNA strand 2.
DNA
1
2
3
4
5
6
7
8
9
10
ATG
TAT
ATC
GAA
AAC
TGC
CCC
TTG
GGG
TAA
1
2
3
4
5
6
7
8
9
10
Strand
1
DNA
Strand
2
Part two is to know the Central Dogma
First step in Central Dogma of Genetics is called Transcription - messenger RNA
pairs up bases off of DNA to form a code:
DNA  RNA code key:
C–G
G–C
A–U
T -A
Use DNA strand 2 along with the code Key for DNARNA to fill in the
blanks in the mRNA strand below.
3’
AUG
1
AAC
2
3
4
5’
GGG
5
6
7
8
9
10
Over 
Second step in Central Dogma of Genetics is called Translation - messenger RNA
delivers the DNA code to the ribosome and the ribosome translates the message
into a chain of amino acids that fold into proteins:
Use the RNA  Amino Acid code key (circular chart below) to find the amino acids that are
called by the codons in the strand of mRNA above.
Write the names of the amino acids in the box

List the Amino Acid Sequence based
on the RNA code above
1. ____Methionine_____
2. ___________________
3. ___________________
4. ___________________
5. ___________________
6. ___________________
7. ___________________
8. ___________________
9. ___________________
10. ___________________
Analysis of the Central Dogma of Genetics:
Explain protein synthesis from start (DNA) to finish (protein) and include terms
you learned form the class discussions and the presentations.
The Central Dogma Genetics: Gene (DNA) > mRNA >
Protein > Trait
DNA, Deoxyribonucleic Acid, the code for all life; all life is based on the same code in different orders. Strawberries
have a different order of code than a pine tree and a salamander has a different order of code than a giraffe. Yet, all
life is still based on the same four letters of the code, and those four letters are just symbols we use for the actual
molecules that make up DNA. DNA is a code of molecules called nucleotides, which are guanine(G), cytosine (C),
adenine(A), and thymine(T). Basically, the code is G,C,A,T in various orders for various organisms.
DNA is structured like a ladder. A ladder has two handles connected by rungs…well DNA has two strands
connected by the nucleotides. Each strand has nucleotides hanging off, and the nucleotides are chemically
attracted to each other to create the rungs of the ladder. C’s only bond with G’s, and A’s only bond with
T’s. The code lies within the nucleotides though, and the code is what makes the traits (fur color, eye color,
body type, etc) all organisms portray and express, including you and me.
DNA
These nucleotides –G,C,A,T- are code for the synthesis (putting together) of proteins and proteins make traits. The
long strands of DNA have special segments called genes and these genes hold the genetic code, or the blueprints for
life. DNA is used by the cell as the storehouse of information on how to build proteins. When the cell needs a
protein it uses the code stored in the genes of the DNA. It is the proteins that make the traits of all organisms.
mRNA
Messenger RNA (mRNA) is also a nucleic acid, but it is single stranded. All RNA is made up
of 4 nucleotides called guanine, URACIL, adenine, and cytosine. The code on mRNA is
different from DNA by one letter… the T is replaced by a U for Uracil. mRNA copies the
code of DNA onto a single strand of nucleotides, so the mRNA is the messenger of the code.
The mRNA delivers the code to a cell organelle called a Ribosome. The ribosome is like a
factory that synthesizes proteins out of amino acids. Once the Ribosome has the code it
knows what type of protein needs to be made for the organisms traits.
A type of protein
Transcription occurs between DNA and mRNA. Transcription is the process of making a mRNA copy of a
DNA gene sequence code. The nucleotides of the DNA and the mRNA molecules are arranged in a nucleotide code
called a codon. Each time a gene is copied onto mRNA it is codon after codon after codon until that segment of code
stops. Every time you see three nucleotides together it is called a codon and each codon calls for a specific Amino
Acid. There are only 20 amino acids in nature but there are 64 codons. T
Translation is the process that occurs between the mRNA and the Ribosome. Translation is the process of translating
the many codons of a messenger RNA (mRNA) into a chain of many amino acids during protein synthesis. Once again,
there are 20 amino acids and these amino acids float around in high concentration in the liquid cytoplasm of the cell
along with ribosomes. All proteins are made up of amino acids bonded together, and the amino acids are bonded
together by the ribosomes. Humans get amino acids from foods we eat.
So, the mRNA contains the codons from the DNA it copied. The codons on the mRNA are then read by a ribosome. The
ribosome will bind the codon and then signal to another type of RNA, called a transfer RNA (tRNA), to bring in a specific
amino acid. The amino acids are covalently bonded by the ribosome to form
a long chain of amino acids. When the codons of the mRNA end the chain
exits the ribosome and folds up into a protein. That is, a ribosome reads the
codons of the mRNA to arrange the amino acids into chain that forms
proteins which give us all traits.
DNA
mRNA
protein