Chapter 7 –3 Protein Synthesis



Notes: DNA (Deoxyribonucleic Acid)

• DNA is a very _______________ nucleic acid found in __________ cells.

o In eukaryotic cells, DNA is stored in the _________________ of the cell.

o The DNA in a single cell contains all of the _____________ _______________ needed to create an organism.

▪ These instructions can be passed on from one generation to the next.

The building blocks of DNA:

Every DNA molecule is made by joining many ____________________ (monomer) together

o There are ____ different DNA nucleotides.

o Each nucleotide is made up of 3 parts:

o The is a ____________________ GROUP

o is ______________________ (a sugar in DNA)

o A ___________________ BASE (such as G, C, A or T)

A Large Molecule:

o For DNA to form, MANY ____________________ bond together. DNA’s shape is called a _____________ ________________, which means it looks like a twisted ladder.

o DNA’s shape was discovered by: __________________ & _________________

The BASE PAIRING RULES states that in a DNA molecule:

❖ G always pairs with ____

❖ A always pairs with ____

The opposite strands in DNA are _________________________ (which means that they fit together like puzzle pieces… they are NOT identical)

Question: If there are 1000 Guanine in a molecule of DNA, what must also be true?_______________________

If you know the DNA molecule is made up of 5000 nucleotides, what else can you determine?

Before a cell can divide, it must make a copy of all its instructions (the DNA).

___________________ - the name of the process in which the cell makes an identical copy of all of its DNA.

□ When cells reproduce asexually, they split in half. That means ½ of everything goes to each new cell. Each cell must get an identical copy of the DNA.

The steps of replication are shown below:

Replication of DNA is a _____________________________________ process. This means that every molecule of DNA is made up of one original strands and one newly created strand.

• The picture on the left shows a strand of DNA that is going through replication.

• The middle picture shows the newly formed DNA molecules. Each one contains 1 of the strands from the original molecule.

Structure of DNA

Fill in all the answers that best completes each statement

1. The shape of DNA is called a ___________________ _____________________.

2. Which scientists discovered the true shape of DNA? _________________ & _________________

3. DNA is made up of many individual ________________________________ joined together

4. Each nucleotide is made up of three parts (shown in the picture to the right), they are:

Part 1 = _____________________________

Part 2 = _____________________________

Part 3 = _____________________________

5. Two nitrogen bases are held together by weak __________________ bonds.

6. Which nitrogenous bases in DNA are complementary to one another?

A. _______________________ pairs with _______________________

B. _______________________ pairs with _______________________

7. The sides (or backbone) of the DNA ladder is made up of two parts that alternate:

_____________________ and _____________________

8. A strong _______________________________ bond holds the sides of the DNA ladder together. (The bond between the two compounds in question number 8)

9. Two __________________ _____________ join together to make up the “rungs” of the DNA ladder.

10. DNA is unzipped & two identical copies of DNA are made by a process called __________________.

11. A cell must make a copy of all of its DNA before the cell is able to ___________________________

12. A piece of a molecule of DNA is made up of 1000 nucleotides. If you know that 20% (or 200) of the nucleotides contain Thymine, then how many nucleotides must contain Guanine?

You must show your work and explain how you came to your answer in order to receive credit!!

Across

4. The name of the enzyme that unzips the two

strands of DNA.

5. The type of strong bond that holds that backbone

of a DNA molecule together.

6. Cytosine is complementary to __.

7. The genetic code of all cells is written it the __.

10. The type of weak bond that holds two bases together

12. The enzyme that builds the new strands of DNA during replication

13. The process in which DNA makes an exact copy of itself.

14. The other scientists that discovered the shape of DNA.

16. A is the symbol for which base?

17. G, C, A and T are the 4 different ___ found in a DNA molecule.

Down

1. What do the initials DNA stand for?

2. The sugar in a DNA nucleotide

3. The rule that tells you that G always pairs with C and A pairs with T.

5. When you know one half of a DNA molecule, you know the other since it is ___ .

8. The backbone of DNA is made up of a sugar and a ___ group.

9. One of the men that discovered the shape of DNA?

11. The shape of DNA

15. The monomers or building blocks of DNA.

Notes: RNA (Ribonucleic Acid)

RNA is a ___________________ Nucleic Acid than DNA.

The building blocks of RNA:

□ RNA is made up many _____________________________ (just like DNA).

□ Each RNA nucleotide is made up of 3 parts

1. _______________________________ – a sugar

2. A _____________________________ group

3. A _____________________________ base (G, C, A & ___)

|Characteristics: |RNA |DNA |

|Sugar used in a nucleotide | | |

|# strands in a molecule | | |

|nitrogen bases used | | |

There are three main types of RNA (each with a different shape & a different job):

|Type of RNA |What it does |Other info |What it looks like |

| |Carries a recipe from the DNA |It is complementary to a single | |

| |(in the nucleus) to a ribosome |strand of DNA. | |

| |(in the cytoplasm) | | |

| | |3 mRNA letters are called a | |

| | |____________ (ex: AUG) |A long straight chain (has Us – no Ts) |

| |Combines with proteins to form |Made up of two parts (subunits) that|Protein wrapped around RNA |

| |the ribosome. |snap together around the mRNA. | |

| | | | |

| | | | |

| |Delivers the correct amino |Transfer = move | |

| |acids to the ribosome |It also translates the recipe that | |

| | |the ribosome is reading | |

| | | | |

| | | | |

| | | | |

| | | | |

| | | |You see a ‘t shape’ in the middle of it |

How is RNA made?

□ A small piece of DNA is used to create a strand of RNA… this is called _______________________.

➢ Each molecule of mRNA contains a single ________________________ for making one protein.

▪ DNA is the entire cookbook of all the recipes your cells will ever need to survive.

Study Guide: Comparing DNA & RNA

Directions: Read each statement and place a check mark under DNA, RNA or both.

| |DNA |RNA |

|Ex: Nucleic Acid |( |( |

|Deoxyribonucleic Acid | | |

|Ribonucleic Acid | | |

|Ribose | | |

|Deoxyribose | | |

|Phosphate group | | |

|Adenine | | |

|Thymine | | |

|Uracil | | |

|Made out of nucleotides | | |

|Single stranded | | |

|Can be found inside the nucleus or in the cytoplasm | | |

|Stays inside the nucleus | | |

|Contains a single recipe for making a protein | | |

|Double helix | | |

|Picks up and delivers amino acids | | |

|Involved in Replication | | |

|Involved in Transcription | | |

|Part of the ribosome | | |

A strand of DNA is being used to make a strand of RNA. Use the words from the word bank to label the parts of the molecules (some terms may be used MORE than once).

[pic]

1. When DNA unzips to make more DNA, the process it is going through is called ____________________.

2. When DNA unzips and to be copied into a strand of RNA, the process occurring is called _________________.

3. DNA and RNA are both made of ____________________; ___________ is very large and contains 25,000+ recipes or instructions; __________ is much smaller and is only a copy of 1 of the recipes or instructions.

4. This type of RNA carries amino acids to the ribosome - ________________________.

5. This RNA is found as part of a ribosome - _________________________.

6. This RNA contains a recipe for making a protein. It travels from the DNA to a ribosome _________________.

Notes: Protein Synthesis

Protein Synthesis = making a protein by joining together many _________ __________ in a specific order.

▪ There are only __________ different amino acids normally found in most humans.

o __________________________ amino acids must be eaten because the body can’t make them.

o __________________________ amino acids can be made by the body from other amino acids.

▪ The _________ & _________of the amino acids affect which protein is made.

• Each protein can be ______________ to ________________ of amino acids long.

▪ The original recipe for making the protein is stored in the ___________________.

▪ A copy of the instructions has to be sent to the __________________ so that it can make the protein.

[pic]

1st Step = Transcription (a.k.a. making a copy of the recipe)

▪ A complementary strand of ______________ is formed from a strand of DNA.

o This occurs in the _____________________.

2nd Step = Translation (a.k.a. building the protein)

▪ The ____________________ builds the protein.

Specifics about Translation… the second part of protein synthesis

After transcription, the mRNA carries a ______________________ for making a protein to the ribosome. The recipe is written using the letters G, C, A & U.

|Step1 |Step 2 |Step 3 |Step 4 |Step 5 |

|A ribosome attaches to the mRNA |The ribosome reads the |A tRNA enters the ribosome carrying an |The ribosome moves down the |The ribosome is |

|at the letters _________ (this is|mRNA letters in sets of |__________ ________________. |mRNA to read the next codon… |finished making the |

|the ________ _________). |3. | | |protein when it reads |

| | |It can only drop off an amino acid if the tRNA |Steps 2 and 3 are repeated |a _______ codon on the|

|These three letters are special |Every 3 mRNA letters are|is complementary to the mRNA. |hundreds of times until a long |mRNA. |

|because they show the ribosome |called a ___________. | |chain of amino acids is joined | |

|where the recipe starts. | |Three tRNA letters that match up with mRNA are |together. | |

| | |called an _____________________. | | |

The amino acids are held together by _______________ bonds.

• A chain of amino acids is called a ___________________ or protein.

Some examples of important proteins in our body:

• _________________________ - speed up the chemical reactions in your body (metabolism).

• _________________________ - covers the red blood cells & helps carry oxygen to the cells in your body.

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

Diagram of Protein Synthesis (Transcription + Translation)

|Transcription |Translation |

|Label |Name |Label |Name |

|A |Nucleus |C | |

|B | |D | |

| | |E | |

| | |F | |

| | |G | |

| | | | |

What are methionine and phenylalanine?

_______________________________________

Practice with Transcription & Translation

Use the chart on the right to complete the questions & the table.

1. Find the amino acid Methionine on the chart below. What are the 3 letters in its codon (start in the middle)? ____________

2. Which two mRNA codons both code for the amino acid histidine? _____________________ & ______________________

3. What are the six different mRNA codons code for Arginine? List them __________________________________________

4. Which codons code for a STOP instead of an amino acid? ____________________________________________________

|DNA (triplet) |mRNA (codon) |Amino Acid |

|T | | |

|T | | |

|T | | |

|C | | |

|G | | |

|C | | |

|C | | |

|T | | |

|A | | |

|A | | |

|C | | |

|T | | |

Below is another amino acid table that can be used to look up mRNA codons. Use this chart to complete the following table & questions (the one below is the one that you can expect to see on your exam and the EOC).

|DNA (triplet) |mRNA (codon) |Amino Acid |

|A | | |

|A | | |

|A | | |

|G | | |

|T | | |

|C | | |

| |G | |

| |G | |

| |A | |

| | |Tryptophan |

| | | |

| | | |

| |G | |

| |U | |

| |G | |

|Firs|A |Lysine |Arginine |Isoleucine |Threonine |A |Thir|

|t | |Lysine |Arginine |Methionine |Threonine |G |d |

|Lett| |Asparagine |Serine |Isoleucine |Threonine |U |lett|

|er | |Asparagine |Serine |Isoleucine |Threonine |C |er |

|in | | | | | | |in |

|the | | | | | | |the |

|codo| | | | | | |codo|

|n | | | | | | |n |

| |G |Glutamic acid |Glycine |Valine |Alanine |A | |

| | |Glutamic acid |Glycine |Valine |Alanine |G | |

| | |Aspartic acid |Glycine |Valine |Alanine |U | |

| | |Aspartic acid |Glycine |Valine |Alanine |C | |

| |U |Stop codon |Stop codon |Leucine |Serine |A | |

| | |Stop codon |Tryptophan |Leucine |Serine |G | |

| | |Tyrosine |Cysteine |Phenylalanine |Serine |U | |

| | |Tyrosine |Cysteine |Phenylalanine |Serine |C | |

| |C |Glutamine |Arginine |Leucine |Proline |A | |

| | |Glutamine |Arginine |Leucine |Proline |G | |

| | |Histidine |Arginine |Leucine |Proline |U | |

| | |Histidine |Arginine |Leucine |Proline |C | |

| | |A |G |U |C | | |

| | |Second Letter in the Codon |

1. What process uses DNA to make mRNA? _______________________________________________________________

2. What process occurs at the ribosome (reading the mRNA & building the chain of amino acids)? ____________________

3. What could happen if you make a mistake making the mRNA from the DNA? ___________________________________ __________________________________________________________________________________________________

4. When the cell makes these mistakes we call them __________________________________________________________.

Notes: Changes in the Genetic Code

__________________________ = A change (mistake) in the DNA sequence

• Can be _________________________ and even reduce ones chance of survival.

o Necessary _________________________ may be changed or not made at all.

o Can ____________________ the cell from functioning correctly. Some forms of ______________ are the result of a mutation in a gene that tells the cells to stop dividing.

• Mutations can actually be ____________________ to a species since they help provide genetic diversity.

o Changes in our appearance are due to mutations in human DNA.

• What causes mutations:

o Exposure to __________________________ and/or certain _______________________

o Some mutations are simply random mistakes or changes.

|DNA Mutations |

| Original DNA: TAC - TCG - CTA - ACT |

|RNA: AUG - AGC - GAU - UGA |

|Original Amino Acids: Methionine - Serine – Aspartic Acid - STOP |

|________________ mutations: A replacement of a nucleotide(s) in the DNA sequence. |

|Original DNA: TAC CCG CTA ACT | |

|Mutated DNA: TAC CCG CTA ACT | |

|RNA: AUG GGC GAU UGA |Usually only ___ amino acid is changed with this mutation. |

|Mutated Amino Acids: Methionine-___________–Aspartic Acid - STOP | |

|__________________ mutations: nucleotide(s) is/are added or taken out. A shift will occur in how the strand is read. |

| |Changes to the protein can happen anywhere… |

|Deletion: |The number of amino acids that change will depend upon the |

|Original DNA: TAC TCG CTA ACT C |___________________ of the mutation in the DNA. |

| |Changes to amino acids in a protein will mostly likely change the |

|Mutated DNA: TAC CGC TA A CTC |_____________ of a protein. This may: |

|RNA: AUG GCG AUU GAG |_________ the protein from being able to do its job. |

|Mutated Amino Acids: Methionine --___________–-___________–-___________– |Make the protein __________________________ (can be good or bad). |

| | |

|Insertion: | |

|Original DNA: TAC TCG CTA ACT C | |

|Mutated DNA: TAC TCG CTA AAC T | |

|Mutated RNA: AUG AGC GAU UUG A | |

|Mutated Amino Acids: Methionine - Serine – Aspartic Acid – -___________ | |

Hemoglobin is a protein in red blood cells; it is made out of 146 amino acids… its recipe is over 440 nucleotides long.

Sickle Cell Anemia is caused by a DNA mutation in which ___ letter (nucleotide) in the instructions for making hemoglobin is wrong.

The end result causes defective red blood cells to form in the body (shown on the right)

Protein Synthesis Overview

Protein Synthesis (Transcription and Translation):

1. Transcription is making a strand of ______________ using ______________ as a template.

2. Where does transcription occur in the cell? _________________________________________

3. Use the DNA sequence below to complete the transcription of DNA into mRNA. You have already been given the first codon (AUG).

(DNA) TAC-AGG-GTA-TAA-CCA-CGA-TCT-GGG-ATT

(mRNA) A U G - _______ - _______ - ______ - _______ - ______ - ______ - ______ - _______

4. Use an amino acid chart to look up each mRNA codon above. Write down the amino acid coded for by each codon. Be sure to put them in the correct order (the first one has been done for you).

Methionine - _______________________________________________________________

______________________________________________________________________________

5. After the mRNA was made in the nucleus, where does it go to finish protein synthesis? __________

6. Translation is using the instructions written in mRNA to create a ______________________ made out of many _________________ _________________ joined together.

7. What is the amino acid for the DNA* code CTT? ______________________________________

What is the amino acid for the DNA* code GTT? ______________________________________

Does the amino acid change if the DNA code mutates from the code CTT to GTT? ___________

8. If an amino acid only appears on the chart once, what will happen if there is a mutation in the code for that amino acid? ______________________________________________________________

9. Look at the chart. Which amino acids have only one codon (in other words, their name is only on the chart one time)? ______________________________________________________________

10. What is the amino acid for the DNA code CCA? _______________________________________

What is the amino acid for the DNA code CCG? _______________________________________

Does the amino acid change if the DNA code mutates from the code CCA to CCG? ___________

11. For the amino acids that are on the chart more than once, is it possible that a mutation may not change the amino acid that is being coded for? _________________________________________

12. Which 3 amino acids are LEAST likely to change if there is a mutation (hint: it has to do with how many different codons there are for the amino acids on the chart)? _______________________________________________________________________________

13. Which amino acids on the table below are MOST likely to change if there is a mutation? Explain. _______________________________________________________________________________

Test Review: DNA, RNA & Protein Synthesis

1. What do the initials DNA stand for? ______________________________ ____________________

2. What do the initials RNA stand for? _____________________________ ____________________

3. DNA is responsible for storing and transferring all of the ________________ information from one generation to the next.

4. DNA and RNA are made from many __________________________ joined together (what are their monomers?) .

5. The shape of each DNA molecule is called a ____________________ _____________ (2 words).

6. The shape of DNA was discovered by _________________________________ & ____________________________

7. Name the 3 parts that make up all nucleotides:

1. __________________________

2. __________________________

3. __________________________

8. In DNA, each nucleotide is paired with a specific nucleotide:

2 Adenine will always pair up with ______________________.

3 ______________________ will always pair up with Guanine.

9. The above statement is called the ______________________ ______________________ Rule.

10. Two opposing strands of DNA are held together by a weak ________________________________ bonds.

11. The two strands are said to be ___________________________ (Since by knowing one half you can figure out the other).

12. The process in which DNA makes an exact copy of itself is called ____________________________________.

13. Why is it necessary for a cell to make an exact copy of its DNA. What is it getting ready to do?_____________________

__________________________________________________________________________________________________

14. A / An enzyme called ________________________ causes the double stranded DNA to split or “unzip” by breaking the bonds between the base pairs which.

15. A second enzyme called ____________________________________ is responsible for building the new strand of DNA (and also checking it for mistakes).

16. Changes or mistakes in DNA are called _____________________________.

17. List three basic differences between DNA and RNA:

4 DNA__________________________________________RNA_______________________________________

5 DNA__________________________________________RNA_______________________________________

6 DNA__________________________________________RNA_______________________________________

18. Identify the RNA that would form from the following strand of DNA: G C A T T C A T G

________________________________

19. If the above strand of DNA was changed to: GCA GTC ATG Circle the mutation.

What type of mutation caused this change? ________________________________________

20. Where are the following types of RNA found in a cell.

7 mRNA - _________________________________________________________________________

8 tRNA - _________________________________________________________________________

9 rRNA - _________________________________________________________________________

21. Label boxes B & C with the name of the process (replication, translation or transcription) and A, D & E with the name of the structure (rRNA, amino acid, DNA, codon or mRNA)

[pic]

22. Transcription and translation are the two steps involved in ___________________ ____________________ (2 words).

23. Three nucleotides of mRNA are called a/an __________________________________________________.

24. Three nucleotides of tRNA are called a/an ___________________________________________________.

25. Where are the proteins made in a cell (which organelle)? ____________________________________________________

26. Proteins (or polypeptides) are made out of many ________________________ that are bonded together.

27. When using the amino acid table, the codons that do not code for an amino acid are called ____________ ____________.

28. What is the purpose of the above codon? _________________________________________________________________

29. How many mRNA nucleotides would be used to produce a protein that is 1000 amino acids long? To get credit you must show your work (calculations) below.

30. What type of mutation is most likely to cause the biggest change in a protein? ___________________________________ Explain why. _______________________________________________________________________________________ __________________________________________________________________________________________________

Complete the following information.

DNA mRNA Amino Acid

1. How many AMINO ACIDS make up the above portion of this protein? ________________________

2. What TYPE OF BOND is holding the amino acids together? _________________________________

3. How many CODONS are shown above? _________________________________________________

4. How many mRNA NUCLEOTIDES are needed to make up the above section of protein? _________

-----------------------

DNA

CROSSWORD PUZZLE

H

Word Bank

• Covalent Bond

• Deoxyribose

• Hydrogen Bond

• Nitrogen base

• Nucleotide

• Phosphate group

• Ribose

A

U

G

CG

A

UA

A

A

T

A

C

G

A

TRYPTOPHAN

D

E

____________________ ___

Protein Synthesis has 2 steps = _____________________ + ______________________

DNA mRNA Protein

G

F

B

C

E

A

____ = Cytosine ____ = Guanine

____ = Adenine ____ = Thymine

□ The backbones (sides) are made up of alternating ___________ & _______________ molecules which are held together by _______________ covalent bonds.

□ The steps or rungs are made up of pairs of nitrogenous bases held together by WEAK ____________ bonds.

C

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