Chapter 7 –3 Protein Synthesis



Packet 5: DNA & Protein Synthesis

Bio.3.1 Explain how traits are determined by the structure and function of DNA.

• Bio.3.1.1 Explain the double-stranded, complementary nature of DNA as related to its function in the cell.

• Bio.3.1.2 Explain how DNA and RNA code for proteins and determine traits.

• Bio.3.1.3 Explain how mutations in DNA that result from interactions with the environment (i.e. radiation and chemicals) or new combinations in existing genes lead to changes in function and phenotype.

Bio.4.1 Understand how biological molecules are essential to the survival of living organisms.

• Bio.4.1.2 Summarize the relationship among DNA, proteins and amino acids in carrying out the work of cells and how this is similar in all organisms.

Vocabulary

|DNA |Replication |Protein Synthesis |

|Double Helix |Template |Transcription |

|Nucleotide |Complementary bases |Translation |

|Deoxyribose |Base Pairing Rule |Amino Acid |

|Nitrogenous Bases |Helicase |Polypeptide |

|Guanine |Hydrogen bond |Peptide bond |

|Adenine |DNA Polymerase |Codon |

|Thymine | |Anticodon |

|Cytosine |RNA |Methionine / Start Codon |

|Phosphate Group |Ribose |Stop codon |

| |Uracil |Mutation |

| |Messenger RNA (mRNA) | |

| |Transfer RNA (tRNA) | |

| |Ribosomal RNA (rRNA) | |

| |RNA Polymerase | |

Assignments: Due Dates:

| | |

|DNA extraction lab |_______________ |

| | |

|DNA Structure Replication & RNA quiz |_______________ |

| | |

|Frimpanzee activity |_______________ |

| | |

|Packet 5 Test – DNA & Protein Synthesis |_______________ |

| | |

|Mutation worksheet |_______________ |

| | |

|Packet 5 Online Review | |

| | |

|Webquest | |

Notes: DNA Structure

Complete the notes using the puzzle pieces provided by your teacher and prior knowledge.

□ DNA stands for – __________________________________________________________________

□ What group of organic molecules does DNA belong to? ____________________________________

□ DNA is responsible for storing & transferring _____________________________________from one generation to the next. It also contains the codes for making all the ____________________ in your body.

□ The building blocks of DNA are _____________________________

□ Look at the 12 different nucleotides given to your group. What are the three parts of a nucleotide?

________________________, ________________________, ________________________

□ What two parts are identical between all the nucleotide pieces?

__________________________ AND ________________________

□ Notice one of the words ends in –ose. What type of molecule is this? ____________________. What group of organic compounds does this belong to? _________________________________.

□ What is the ONE part of a nucleotide that is different among the nucleotides pieces?

___________________________________

□ List the letters and names for the four nitrogen bases:

□ (_____) ______________________

□ (_____) ______________________

□ (_____) ______________________

□ (_____) ______________________

Arrange the pieces of nucleotides so you can fit them all together.

Your completed model should look like a ladder. Besides being shaped like a ladder, a DNA molecule is twisted. It looks like a spiral staircase. This shape is known as a ______________________ _________________________. However, your paper model cannot show this shape.

□ If DNA is “ladderlike,” which two molecules of a nucleotide form the sides or upright portion of the ladder?

____________________________ & ____________________________

□ Which molecules form the rungs (middle) of the ladder? _____________________________________

□ What is the pairing arrangement of the nitrogen bases? This kind of pairing is called complementary. The base pairing rule states that:

_______ pairs with________ _______ pairs with _______

□ If four guanine bases appear in a DNA model, how many cytosine bases should there be? ______________

□ Notice that the nitrogen bases are different sizes.

□ ___________________________ and __________________________ are larger and are made of 2 rings or units and are called purine bases.

□ __________________________ and ___________________________ are smaller and are made of only 1 ring or unit and are called pyrimdine bases.

□ A purine base always pairs with a _______________________________ base.

□ The bases pairs in the double helix are held together by weak hydrogen bonds.

□ A and T are held together by (#)_________ hydrogen bonds

□ C and G are held together by (#)_________ hydrogen bonds

□ The backbone of DNA is made up of alternating (D) __________________ and (P) ________________________ molecules which are held together by strong covalent bonds.

□ The two opposing strands are said to be __________________________, since by knowing one half you can figure out the other) Write in the correct letters on the right side of the DNA molecule in the picture to the right.

□ What is the same about DNA between all organisms? _________________

________________________________________________________________________________

□ What is different about DNA between all organisms? _____________________________________

________________________________________________________________________________

Notes: DNA Replication

Use the puzzle pieces to construct a strand of DNA 6 nucleotides long.

□ Write down the sequence of the strands here. You can just list the letters of the bases.

Original Strand 1 (Left Side): ___________________________________________________

Original Strand 2 (Right Side): __________________________________________________

□ Since the strands are complementary each strand can serve as a TEMPLATE for a new DNA molecule. Separate the two strands of DNA between the base pairs. It should now look like you have a broken ladder. The strands should be far enough apart that you can fit two new rows of nucleotides in between them. You will get 12 new nucleotides. These nucleotides are just floating around in the nucleus. Arrange these nucleotides to find the best fit with the 12 nucleotides in your original strands.

□ In the space below, write the sequence of your nucleotides in each strand.

Original strand #1: _____________________________________________________

New strand #1: _____________________________________________________

Original strand #2: ______________________________________________________

New strand #2: ______________________________________________________

□ Do the two new molecules contain the same number of rungs? ______________

□ Are the two DNA molecules exact copies of each other? ______________

□ This mode of replication is called ____________________________________ replication because each parental strand is used as a model (or template) for the generation of the new daughter (or complementary) strand. Color the backbone of original strand blue and the newly formed strand red. Identify the parts of the DNA molecule below as the Parent (original) strand or the Daughter (new) strand.

[pic]

Steps of DNA Replication:

1. An ____________________ (called __________________________) comes in and breaks the _______________________ bonds between the base pairs which causes the strand of DNA to split or “unzips” (what is left looks like a ladder cut in two).

2. The appropriate _____________________________________ are then matched up (by another enzyme called ________________________________________).

3. What you are left with is ____________________ identical strands of DNA

□ Why are the bonds between the nitrogen bases in DNA weak? _______________________________

□ Specifically when and why would DNA have to replicate? ____________________________________

____________________________________________________________________________________

DNA versus RNA & Protein Synthesis Notes

Notes: RNA

□ RNA also belongs to the ___________________________________________ group of organic molecules.

□ The building blocks of RNA are ________________________________________.

Differences between DNA and RNA

| |DNA |RNA |

|Stands for | | |

|Function | | |

|Structure (how many strands?) | | |

|Sugar in each | | |

|Nitrogen bases in each | | |

|Location | | |

|Picture of a nucleotide | | |

Three types of RNA:

1. _____________________________ RNA (mRNA)– carriers the code from the DNA in the

________________________ to the __________________________ in the cytoplasm.

Every three mRNA nucleotides is a ________________________________. How many are

in the mRNA pictured below? _______________

mRNA

2. __________________________________ RNA (rRNA) combines with proteins to make up the ___________________________________________, which is made up of two subunits that snap together around the mRNA.

3. _____________________________ RNA (tRNA) is the complement to the mRNA.

□ Its job is to bring ______________________ __________________________ to the ribosome to make the protein.

o The 3 letters on the tRNA is called an ________________________.

o How are codons related to anticodons? _______________________

_______________________________________________________

Notes: Protein Synthesis

• Protein Synthesis is the joining of _________________ _____________________in a specific sequence in order to form a protein or _______________________. There are only __________ different amino acids

What does an amino acid look like?

So why do we even need to make proteins???? Here are several important proteins.

• ______________________________ - help with the chemical reactions in your body (metabolism).

• ______________________________ - covers the red blood cells and helps carry oxygen to all the cells in your body. Remember your body needs oxygen to undergo ________________________ to produce 38 ____________ molecules giving your body energy.

• _____________________________ - helps maintain blood sugar homeostasis. Excess glucose is stored as glycogen in the muscles and liver.

• _____________________________ - Forms channels in the cell membrane to help transport substances in and out of the cell

• ____________________________ - These help with growth and development

• Makes up your muscles that help your body move.

Is every protein made at all times within an organism? _________________________________________

____________________________________________________________________________________

____________________________________________________________________________________

Flow chart of Protein Synthesis (Label the arrows with the 2 steps).

DNA mRNA protein

The DNA contains the code for making proteins. But DNA cannot leave the safety of the ___________________. Therefore, mRNA is formed from the DNA and leaves the nucleus taking the message out to the ______________________________ where proteins are made.

First Step = Transcription

▪ Occurs in the ________________________.

▪ ______________________ is used to form __________________________.

Second Step = Translation

▪ Occurs at the _______________________.

▪ The tRNA picks up a specific ______________ ______________ in the cytoplasm and ‘travels’ to

the mRNA (which is attached to the __________________________).

▪ The tRNA attaches to the mRNA. When 2 tRNA molecules are next to one another at the

ribosome a _________________________ bond forms between the 2 amino acids.

▪ Result – long chain of amino acids making the protein or ________________________. The protein is functional when it folds and changes shape. (See your teachers telephone cord demo).

[pic]

Diagram of Protein Synthesis (Transcription + Translation)

|Transcription |Translation |

|Label |Name |Label |Name |

|A | |C | |

|B | |D | |

| | |E | |

| | |F | |

| | |G | |

| | |H | |

[pic]

Notes: Mutations

Mutation – _____________________________________________________

Types of Mutations:

|Original Sequence |Specific Type of Mutation |Definition |Example |

|Point or Substitution| |change in DNA strand that does not change the amino acid |No disease |

|– one base is | | | |

|replaced with a | | | |

|different base | | | |

| | |causes one a.a. to change that is important to protein |Sickle cell anemia |

| | |function | |

| | |codon for an a.a. is changed into a stop codon so get a |Cystic fibrosis (protein produced has |

| | |protein that is short and nonfunctional |only the first 493 amino acids of the |

| | | |normal chain of 1480) |

|Frameshift – a base | |an entire base is inserted |Huntington’s Disease (degeneration of |

|is inserted or | | |brain cells) |

|deleted so the entire| | | |

|sequence is changed | | | |

|from that point on. | | | |

| | |An entire base is deleted. |some forms of muscular dystrophy |

Sentence Analogy:

Represents the Normal sequence: The red cat ate the fat rat.

____________________________ The red cat ate the fat rat.

____________________________ The red hat ate the fat rat.

____________________________ The red hat ate the

____________________________ The reb dca tat eth efa tra t

____________________________ The rec ata tet hef atr at

Causes of Mutations:

- Random errors in DNA replication

- mutagens – physical or chemical agents that cause mutations

o Ex: x-rays, UV rays

- Mutations are not always bad –they are a source of genetic diversity

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D

P

D

P

D

P

D

P

D

P

D

P

D

P

D

P

D

P

D

P

D

P

D

P

D

P

D

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D

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D

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D

P

D

P

rRNA

tRNA

There are 20 different R groups. This is what makes each amino acid different.

H

H

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