BIO 2 GO! NUCLEIC ACIDS

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1 BIO 2 GO! NUCLEIC ACIDS 3115 Nucleic Acids are organic molecules that carry the genetic information for every living organism. All living things contain nucleic acids. The DNA and RNA are responsible for providing a plan for the construction of new cells and organisms. Failures in this system lead to mutation and sometimes death. At the end of this unit of study, you should be able to do the following: 1. Describe and explain the basic structure of DNA and RNA 2. Describe and explain the function of DNA and RNA 4. Describe and explain the process of DNA replication 6. Describe and explain the basic structure of a nucleotide 7. Describe and explain the function(s) of a nucleotide 8. Be able to use the following terms correctly: DNA RNA nucleotide double helix single strand DNA replication genetic information sugar, phosphate, nitrogen bases

DNA tells the cell how to build whatever it needs. DNA also makes up the genes for all living organisms, including humans.

2 Nucleic Acids 3115 Let s keep this simple. When we talk about nucleic acids we are talking about either DNA or RNA. DNA is the most important. DNA is an organic molecule that stores the genetic information, or building plan, for all living things. DNA tells the cell how to build whatever it needs. DNA also makes up the genes for all living organisms, including humans. Genes and protein are what make up the chromosomes for all living things. The chromosomes carry all of the genes. They are located in the nucleus of every living cell.

3 REMEMBER THIS!!! DNA and RNA are examples of the nucleic acids. Interesting Scientific Fact: A human being has about 100,000 genes. Function of DNA, RNA DNA has 1 important function. Its job is to store and semd the correct genetic information from 1 generation to the next - from parent to child. RNA has several functions: To copy the DNA of a cell and transfer the DNA s information to the ribosomes so they can make new protein for use by the cell. Question 1. What are the two types of nucleic acids? Question 2. What is the function of DNA? Question 3. What are the 2 functions of RNA? DNA Explained DNA stores the genetic information for all living things - including you. In other words, DNA determines what all living things will look like. That is called the genetic information for an organism. Genetic information is the plan that determines what all living things will look like and what they can do. DNA stores the genetic information and is responsible for correctly transferring the plan from one generation to the next. In your case, for instance, your DNA determines your height, hair color and eye color. DNA also determines whether a living organism will grow into a tree, a turtle, or you. Living things receive their DNA from their parents. You inherited your DNA from your mother and father. One half came from your mother and one half came from your father. That is why children often look like their parents. That is why all oak trees look alike. That is why all rockfish look alike.

Interesting Scientific Fact: Sometimes the genetic information is not transferred correctly. As a result, the offspring may inherit something different from that of the parents.

4 Interesting Scientific Fact: Sometimes the genetic information is not transferred correctly. As a result, the offspring may inherit something different from that of the parents. This process is called a mutation. Whenever the offspring do not correctly inherit the DNA plan from a parent, a mutation has occurred. Sometimes they produce abnormalities in the offspring. In humans such abnormalities include sickle cell anemia. Sometimes the mutations are even fatal. Example of a mutation Line 1 is a normal strand of DNA. Line 2 has a piece of DNA being cut out of it. Line 3 is the new piece of DNA that is now different from the original (Line 1) so it is called a mutation. Interesting Scientific Fact: A number of things in the environment seem to cause mutations in humans. Some of the better known are: ultraviolet light, certain toxins (drugs), and radiation. REMEMBER THIS!!! Genetic information is the plan that determines what a living thing will look like. DNA is the genetic information. DNA is found in the nucleus of all living cells in every living organism. Interesting Scientific Fact: Werewolves do not exist. However, there is a gene in humans that if inherited from both parents, causes a lot of hair to grow on the upper body and even cover the face, ears, nose, cheeks, forehead, even eyelids-much like a picture of a werewolf. This gene does not affect personality. In fact, there are pictures of a family in Europe that passed this gene on from generation to generation. They were regarded with great admiration by the rulers at that time.

5 Question 4. Describe and explain how genetic information and DNA are related. Question 5. Explain how genetic information is transferred from parent to offspring in all living things. Question 6. What determines whether a living organism will grow into a human or a flower? RNA Explained One of the things that RNA does is to make a copy of the DNA and take the DNA s information to a place in the cell (the ribosome) where it can be read to make protein for use by the cell. As you have already learned, protein is widely used to make all living things. For instance, proteins make up muscles, tissues and organs. The RNA is responsible for copying the DNA correctly and having another part of the cell create the new protein. It is important to know that both DNA and RNA look similar because they are made from nucleotides. We will discuss nucleotides in the next section. REMEMBER THIS!!! One function of RNA is to copy DNA and then transfer its information to another part of the cell use the copy to make protein.

Nucleotides Explained Nucleotides are the building blocks that make up both DNA and RNA. Nucleotides contain 3 parts: sugar, phosphate, and a nitrogen base.

6 Nucleotides Explained Nucleotides are the building blocks that make up both DNA and RNA. Nucleotides contain 3 parts: sugar, phosphate, and a nitrogen base. Although the sugar and phosphate is the same in all nucleotides, the nitrogen bases may vary. That is why there is more than 1 type of nucleotide. Nucleotides have a phosphate group, a sugar (deoxyribose sugar) and a nitrogen base (the Adenine). Interesting Scientific Fact: bases in every adult human. There are about 3,000,000,000 nitrogen REMEMBER THIS!!! All nucleotides are made from 3 things: a sugar, a phosphate, and a nitrogen base. REMEMBER THIS!!! Both DNA and RNA are composed on nucleotides. Question 7. How would you describe and explain the function of RNA?

Question 8. What is the importance of nucleotides? Question 9. What are the three parts of a nucleotide? Question 10. If you were going to build a single strand of RNA, what would you need to use?

7 Question 8. What is the importance of nucleotides? Question 9. What are the three parts of a nucleotide? Question 10. If you were going to build a single strand of RNA, what would you need to use? DNA Replication putting it all together The way DNA is made is an interesting process. First it is important to know a little about the structure of a DNA molecule. You already know that DNA is made from nucleotides. You probably do not know this next part. In every molecule of DNA there are two strands of DNA, much like a ladder. Now imagine twisting the ladder so that it looks more like a circular staircase. This is called a double helix. DNA is a double helix. It would look like a twisted ladder. This is important to remember. In the first step of DNA replication the double helix is divided so that DNA is separated into 2 separate strands. Imagine cutting the steps of a ladder top to bottom so that the ladder splits into two identical pieces. That is what happens to the DNA. When the DNA strands are separated, new nucleotides come in to replace the DNA strand that has been separated. Because of this, each

8 DNA strand gets what it needs to become a double helix again. As a result, there are now 2 double helix (helices) instead of just 1. The DNA has replicated itself! REMEMBER THIS!!! DNA divides, separates, and attracts new nucleotides to replace the strand that split away. Interesting Scientific Fact: DNA and RNA work together to make protein. Protein, as you recall, is the type of molecule of which most living things are made. Here is how it works. The first part of the process is similar to DNA replication the DNA double helix splits and separates. After the DNA has separated into 2 strands, the RNA comes in and makes a copy of the DNA. However, RNA is a single strand. Therefore it can only copy one side of the DNA at a time. In other words, it copies only one side of the ladder. The RNA then takes copies of the DNA to a particular place in the cell, called ribosomes, where the RNA tells the ribosomes how to arrange the amino acids in order to make the correct protein for the construction or repair of the living thing. That is how protein is made. You will need to know this process in a later chapter. REMEMBER THIS!!! DNA is a double helix, RNA is a single strand. Question 11. How would you describe and explain a double helix to someone? Question 12. Explain the process where RNA helps to make proteins.

9 Similarities and Differences in DNA, RNA Similarities 1. Both DNA and RNA are made from nucleotides 2. Both are found in every living cell Differences 1. DNA is a double helix, RNA is a single strand 2. DNA stores the genetic information; RNA makes copies of the DNA code and transfers that information to the ribosomes to make protein.

10 Summary Nucleic acids are molecules in a cell that store a code, also called the genetic information, for that cell. This code helps the cell arrange its amino acids together in the correct order to make its proteins. The two types of nucleic acids are DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). DNA and RNA molecules are made of nucleotides. Nucleotides are linked together to make DNA and RNA like amino acids are linked together to make proteins. A nucleotide is made of three parts, a sugar, a phosphate group, and a nitrogen base. In DNA, there are four different types of nitrogen bases. DNA is two strands of nucleotides, hooked together and twisted into a ladder shape called a double helix. RNA is a nucleic acid that is a single strand of nucleotides. Its job is to copy the code in the DNA and to use the copy to make a cell s proteins. DNA s role is to store genetic information, or code, in the nucleus of a cell. It also allows parents to pass on their genetic information to their offspring. James Watson and Frances Crick (at left) discovered the structure of DNA in 1953, building of the work of other scientists Chargraff, Franklin, and Wilkins.

11 Nucleic Acids Self Test Matching 1. single strand a. molecules that store a code 2. amino acids b. RNA ( ribonucleic acid ) DNA ( deoxyribonucleic acid ) 3. nucleic acids 4. DNA 5. RNA 6. nucleotides 7. double helix c. copies the DNA code d. building blocks of DNA and RNA e. shape of an RNA molecule f. building blocks of a protein g. shape of a DNA molecule True or False 1. The code in DNA helps the cell arrange its amino acids together in the correct order to make its proteins. 2. The two types of nucleic acids are DNA and RNA. 3. Amino acids are the building blocks of nucleic acids. 4. Nucleotides are the building blocks of nucleic acids. 5. A nucleotide is made of a sugar, a phosphate, and a nitrogen base. 6. There are several different nitrogen bases. 7. Carbohydrates are a major component of nucleic acids 8. RNA is made of two strands of nucleotides. 9. A double helix is like a twisted ladder. 10. The shape of DNA is a double helix. 11. The job of RNA is to store genetic information in the nucleus of a cell. 12. A function of DNA is to allow parents to pass on their genetic information to their offspring.

12 13. The function of RNA is to help the cells use the code in the DNA to make new proteins for the cell. Completing Sentences nucleic acids DNA RNA nucleotides sugar phosphate nitrogen base double helix single strand 1. The two types of nucleic acids are and. 2. are the building blocks of nucleic acids. 3. Each nucleotide is made of a, a and a. 4. A double helix is used to describe the shape of. 5. A single strand is used to describe the shape of. 6. The shape of a DNA molecule is called a. 7. are molecules that help the cell make its proteins correctly. 8. RNA and DNA are classified as. 9. The shape of an RNA molecule is described as.

13 Answer the following. 1. What are the two types of nucleic acids? 2. What are the building blocks of nucleic acids? 3. What are the three parts of a nucleotide? 4. What is the shape of a DNA molecule? 5. How are RNA and DNA different?

14 Nucleic Acids Answer Sheet Question 1. What are the two types of nucleic acids? Question 2. What is the function of DNA? Question 3. What are the 2 functions of RNA? Question 4. Describe and explain how genetic information and DNA are related. Question 5. Explain how genetic information is transferred from parent to offspring in all living things. Question 6. What determines whether a living organism will grow into a human or a flower? Question 7. How would you describe and explain the function of RNA?

15 Question 8. What is the importance of nucleotides? Question 9. What are the three parts of a nucleotide? Question 10. If you were going to build a single strand of RNA, what would you need to use? Question 11. How would you describe and explain a double helix to someone? Question 12. Explain the process where RNA helps to make proteins.

Chapter 6. Genes and DNA. Table of Contents. Section 1 What Does DNA Look Like? Section 2 How DNA Works

Chapter 6. Genes and DNA. Table of Contents. Section 1 What Does DNA Look Like? Section 2 How DNA Works Genes and DNA Table of Contents Section 1 What Does DNA Look Like? Section 1 What Does DNA Look Like? Objectives List three important events that led to understanding the structure of DNA. Describe the