Central Dogmalab Activity

Name:______Date:______Period:_____

Central DogmaLab Activity

Introduction:

Every cell in your body has the same "blueprint" or the same DNA. Like the blueprints of a house tell the builders how to construct a house, the DNA "blueprint" tells the cell how to build the organism. Yet, how can a heart be so different from a brain if all the cells contain the same instructions? A cell has the ability to turn off most genes and only work with the genes necessary to do a job. Remember, a gene is section of DNA that codes for a specific trait.

Pre-Lab Questions:

What is a gene? ______
Where are chromosomes/chromatin located in a eukaryotic cell? ______
What nitrogen bases are found in DNA? ____, ____, ____, ____ In RNA? ____, ____, ____, ____
How many strands does DNA have? ______RNA? ______

Circle the underlined words below that correctly completes the sentence.

mRNA is synthesized in transcription / translation.
mRNA has codons / anti-codons.
tRNA brings amino acids to the nucleus / ribosomes.
tRNA has codons / anti-codons.
tRNA transfers amino acids during transcription / translation.
Ribosomes are the site of where transcription / translation takes place.

Objective:

In this lab activity, you will explore the flow of information from DNA to Gene Expression and practice transcription and translation.

Procedure:

Place the cards in the appropriate boxes on the CENTRAL DOGMA mat on the lab table.
Record you answers below. You only need to write the letters of the cards in the boxes below.

In the simulation below, you will examine the DNA sequence of a fictitious organism: the Snork. Snorks were discovered on the planet Dee Enae. Snorks only have one chromosome with 3 genes. Your job is to analyze the genes of its DNA and determine the traits.

Snork DNA and Traits

Codon / Amino Acid Number / Amino Acid Sequence / Trait
AUG / 20 / 20-11-13 / Hairless
UCG / 16 / 20-12-13 / Hairy
AAC / 2 / 16-2-5 / 4-legged
UUG / 4 / 16-4-5 / 2-legged
GGG / 11 / 9-8-8 / Round Body
CCC / 5 / 9-4-8 / Square Body
UUU / 8
AAA / 9
CCA / 12
AUA / 13

Below you will find the chromosome from a Snork. Each gene has only 3 amino acids that code for it. Your job is to determine the sequence of amino acids for your specimen. In the chart below, write down the complimentary mRNA, the amino acid sequence mRNA codes for, and the related trait.

*Be sure to use the mRNA on the codon chart above.*

DNA / TACGGTTAT / - / AGCAACGGG / - / TTTAACAAA
mRNA / - / -
Amino Acids / - / -
Trait / - / -

STAAR Practice Questions:

_____ 1 Which of the following describes the function of DNA?

A encoding genetic information

B storing energy in chemical bonds

C speeding up biochemical reactions

D destroying substances that enter the cell

_____ 2 Which of these best describes the correct sequence in the expression of a trait?

A trait  gene enzyme B gene  protein  trait

C protein  gene  trait D gene  trait  DNA

_____ 3 Transfer RNA molecules pick up amino acids which are free in the cytoplasm and carry them to? [NY EOC]

A lysosomes B chromosomes

C nuclei D ribosomes

_____ 4 Which factor most affects the order of amino acids in a protein?

A the DNA located in the nucleus of the cell

B the cell in which the protein is located

C the amount of ATP available for the cell’s use

D the area in a cell where proteins are produced

_____ 5 Looking at the diagram above, whichlabel represents the coding part of DNA?

A 1

B 2

C 3

D all of the above

_____ 6 Which molecule is paired with its correct role in protein synthesis? [TN09 EOC]

A nucleus – forms peptide bonds

B ribosome – carries DNA instructions

C mRNA – joins amino acids

D tRNA – transfers amino acids

E DNA – leaves the nucleus

_____ 7 How do the functions of DNA and RNA differ? [AR08 EOC]

A DNA directs protein transport, while RNA aids in energy production.

B DNA aids in energy production, while RNA directs protein transport.

C DNA stores genetic information, while RNA relays genetic information for protein synthesis.

D DNA relays genetic information for protein synthesis, while RNA stores genetic information.

_____ 8 Which relationship is most similar to the relationship below? [NC08 EOC]

tRNA : ribosome

A book : publisher

B truck : factory

C key : lock

D baker : pie

E boss : workers

_____ 9 Carol and her mom have similar noses, eyes, and hands. Which of the following explains why

Carol and her mom have similar traits?

A Carol inherited DNA from her mom only

B Carol inherited chromosomes from her mom only

C Carol inherited the genes that code for these traits from her mom

D Carol inherited the proteins that code for these traits from her mom

Transcription – Translation Practice

Directions:This is a gene, a section of DNA. Fill in the missing DNA & RNA nitrogen bases using the base pairing rules. When filling in mRNA, use the coding strand of DNA. Translate the mRNA codons and find the amino acids using the Genetic Code chart.

The Genetic Code

Fill in the sequence of the Central Dogma below:

______→ ______→ amino acids → ______→ ______