DNA

• Biologie / Verzorging
• Middelbare school
• havo, vwo
• Leerjaar 3,4

Welcome!

Today:

Explanation about DNA (TB p. 194)

Working on exercises 

How are interviews doing?

What are we going to learn today:

We are going to learn:

What DNA is, where you can find it, and what it does. 

What DNA consists of. 

How DNA is read, and how proteins are being made out of it. 

The differences between DNA and RNA.

DNA in the human

As we have discussed during the previous chapter, all characteristics are stored in the DNA. Your DNA is determined on the moment the sperm cell of your father fertilizes the egg cell of your mother. All the cells in your body are a copy of that cell.  

Where is DNA?

You have 46 chromosomes, which you can find in the nucleus. You get 23 of your mother, and 23 of your father. Chromosomes consists of histones and DNA. All of your DNA is called the genome. 

Building the genome

DNA

DNA consists of 2 strands, built up with phosphorus and sugar. However, between these strand you will find nucleotides. You have 4 variants of those : A, T, C and G. Every connection between strands consists of 2 nucleotides: A is always attached to a T, a C is always attached to a G. 

DNA --> Recipe for proteins

Proteins

Every human is mostly built up from water and proteins. Proteins are being made by connecting amino acids in a certain sequence; much like a pearl necklace. This is called a polypeptide chain. 

DNA and ribosomes

DNA is the recipe for proteins. First however, you need to find the correct recipe, make a copy of that, and bring that copy to the place where the protein is produced. When the correct piece of DNA is found, your body will make a copy of that in the form of mRNA, and will bring it to the ribosomes. Here the protein will be produced. 

DNA and RNA

RNA is different than DNA. RNA only consists of one strand, whereas DNA consists of two. 

RNA also doesn't have a T, but has a U. This means that A is not connected to a T, but to a U. 

In the ribosomes, 3 letter in the DNA code for one amino acid (codon). 

Translation codon to amino acid

Homework for next week

The homework for next week are the exercises of paragraph 2.2 on page 32, and the corresponding exercises of the textbook. You don't need to make exercise 6. 

How are you doing with the interviews?

The interviews need to be finished in 2 weeks (audio recording only). How many have you done so far? Talk with your group and make agreements with each other.