DNA, RNA & Proteins Chapter 13

Transcription

1 DNA, RNA & Proteins Chapter 13 DNA stands for. What is DNA? - The genetic information that controls the activity of a cell. - Located in the of every one of your cells. What is the structure of DNA like? A DNA molecule looks like a twisted ladder called a. The sides of the ladder are made up of a chain of sugars and phosphoric acid. The sugar is. This is called the. The steps of the ladder are made up of nitrogen bases held together by. The DNA bases are: A- T- C- G- 1 sugar, 1 acid and 1 nitrogen base makes a. Nitrogen bases have base pairs. pairs with and pairs with Label the DNA diagrams below with the following terms: base pair, deoxyribose, hydrogen bond, nitrogen base, nucleotide, phosphoric acid If the sequence of nitrogen bases on one strand of DNA reads T A G G C C T A G C A T G A C What does the complementary strand of DNA read?. 1

2 are short pieces (groups of base pairs) of a DNA molecule. A gene consists of enough bases to code for many different proteins. Each gene controls something different, and it has a specific on a DNA molecule. When a DNA strand is tightly coiled, it makes a. Use the following terms to label the diagram: DNA, chromosome, nucleus, cell, chromosome, gene Proteins: Proteins are made up of long chains of. Some proteins are made of hundreds of amino acids. Proteins keep all of the parts of a cell and your body working properly. Proteins direct all of the in your body. If too many or not enough of certain proteins are made, then you can get sick. holds the codes for every protein your body needs to survive. Each of your cells is constantly making proteins to do all your body s necessary. To make a protein, the DNA molecule must be de-coded. To de-code the DNA information, we have to look at the order of nitrogen bases. DNA bases in a row are called a. Write the codons of this DNA sequence: G T A C C A T G C A T C G C T Every 3 DNA bases, or codon, codes for one amino acid. The order, or the, of the DNA nitrogen bases determines which protein will be made. It is very important the sequence is exact so the protein has the correct order of amino acids. WRONG OF AMINO ACIDS = WRONG Some codons even code for the cell to start or stop protein production. 2

3 This is a lot like our alphabet, read the following sentences: THE DOG BIT THE CAT. THE DOG BIT THE CAR. Only one letter is changed and the entire meaning of the sentence is different. Even if only ONE base is changed, then it could change which protein is made and what the cell will do. If there is a change in the DNA sequence, it is called a. How does the cell know what the DNA code is? DNA is located in the of the cell. The organelles that make proteins by putting together the long chain of amino acids are the. They are located in the of the cell. The ribosomes need the DNA code to make the proteins, but: 1.) They are in a different location than the DNA. 2.) They cannot understand DNA. SO: 1.) Something needs to get the information to them. 2.) Something needs to the code. What is RNA? RNA does both of those jobs. RNA is. 1 sugar, 1 phosphoric acid and 1 nitrogen base make a. RNA is a strand of nucleotides, unlike DNA which is a double strand of nucleotides. What are the parts of an RNA nucleotide? The sugar in an RNA molecule is. RNA also has a molecule, just like DNA. The RNA bases are: A- C- G- U- pairs with and pairs with 3

4 What are the different kinds of RNA? mrna- Messenger RNA Function: The single stranded RNA copy that carries the (DNA code) out to the cell. rrna- Ribosomal RNA Function: The RNA that makes. trna- Transfer RNA Function: The RNA that brings the to the ribosomes. How does the mrna get the DNA code it needs? Transcription: The process of making an molecule from a DNA strand. 1.) The DNA unzips. 2.) RNA nucleotides pair up with the complementary nitrogen base. If a strand of DNA reads G A T T G A C T A, what would the mrna strand read? What are the mrna codons? How do the ribosomes make proteins? trna has: 3 RNA nucleotides = an anti-codon and 1 amino acid (which amino acid is attached depends on which 3 RNA nucleotides and their order) What are the trna anti-codons for the mrna strand above? Translation: The process that uses the to make the correct sequence of amino acids. 1.) mrna brings the genetic code out of the nucleus into the cytoplasm of the cell and attaches to a ribosome. 2.) The ribosome helps the specific trna molecule to attach to the matching mrna codon. 3.) The amino acid that is attached to the trna molecule attaches to the amino acid on the one before it. 4.) The ribosome moves to the next codon to attach the next trna molecule to it until it is signaled to STOP by a stop codon. 4

5 Use the following terms to label the diagram: anti-codon, ribosome, mrna strand, amino acid, trna DNA to RNA to PROTEIN RECAP: 1. DNA separates 2. Free RNA pair with the DNA strand to make mrna. 3. mrna leaves the and attaches to a. 4. trna that is carrying a specific pairs with the appropriate mrna codon as the mrna slides across the ribosome. 5. When 2 amino acids are in place, they get bonded together. 6. The amino acids continue connecting until signaled by a. CAN YOU BREAK THE DNA CODE? Let s use your GENETIC CODE CHART to figure out what amino acids the codons code for. What amino acid does the codon AUU code for? What amino acid does the codon UGG code for? What codons code for the amino acid Glutamine? Try to master the code by following these steps: DNA Strand: G C A T T T A C C A T G A G C T G C Complimentary DNA : 5

6 mrna strand: trna anti-codons: Amino Acid Sequence:,,,,, 6

7 Check Your Understanding: (Use a separate sheet of paper if necessary) 1. Compare and contrast DNA and RNA. (What are they made of? Where are they found in the cell?) 2. What are the parts of a nucleotide? How are DNA nucleotides different from RNA nucleotides? (Create a chart that shows the location, function, shape and nucleotide structure of DNA, messenger RNA and transfer RNA.) 3. What are proteins made of? Why are proteins important? 4. What is the difference between transcription and translation? (Where does each occur? What is the end product of each process?) 5. Explain how proteins are made by reviewing the DNA to RNA to protein recap. Draw a series of 6 pictures that show what is happening in each step. 6. What amino acid sequence (protein) would be made from the following DNA strand: A T G G A T G G C T G A T A G 7. Give an example mutation that would not change the protein that is produced. Explain why. 7