DNA, RNA and Genes Science 10 – 2017/18 Mrs. Day

DNA - Review What is DNA made of? How is DNA put together? Just remember – SPBHSL S = sugar (deoxyribose) P = phosphate group B = base (nitrogenous base) H = helix (spiral staircase) S = strands (2) L = location (nucleus)

DNA - Review What is DNA’s function? DNA:

DNA and Genes How are DNA and genes related? Chromosomes is tightly wound up strands of DNA.

DNA and Genes How are DNA and genes related? Genes are a section of DNA. The sequence of DNA that codes for a protein = a gene. Proteins have many functions, one is to determine the traits of an organism.

How does DNA make proteins? DNA, a double stranded molecule is TOO BIG to leave the nucleus. Ribosomes make proteins - in the cytoplasm of the cell. So … how does DNA and genes make proteins? The protein message must be carried from the nucleus -> cytoplasm -> ribosomes

Transcription: In the nucleus RNA makes a copy of the gene information on the DNA RNA is like DNA except: RNA is single stranded RNA is linear, not helical RNA contains Ribose, not deoxyribose sugar RNA bases are A, C, G, U (Uracil replaces thymine RNA is like a disposable copy of a segment of DNA. A copy of a single gene.

Translation – in the cytoplasm: As the RNA molecule is a single strand, it is smaller than DNA – so it can leave the nucleus and go into the cytoplasm Once in the cytoplasm, the RNA and ribosomes bind together. The ribosome reads the RNA code. The RNA code tells the cell what amino acids to bring to the ribosome. Amino acids are the building blocks to make proteins. Remember – the RNA code has all the information to make a single gene. And, a gene is the code for a specific protein. This process is complicated. You will learn it in more detail biology 12.

In Summary – turning DNA information into proteins is a 2 step process: Step 1 – Transcription Step 2 - Translation:

In Summary Genes are a section of DNA. The sequence of DNA that codes for a protein = a gene. Transcription: RNA makes a copy of the gene in the nucleus RNA takes the information to the cytoplasm Translation: In the cytoplasm, RNA binds to a ribosome. The ribosome reads the RNA code and the cell brings the required amino acids to build the specific protein (or gene). Proteins and genes determine the traits of an organism.