This week, we talked about DNA…

• T goes with…?• G goes with…?

• What does DNAlook like?

• Ok, so now we’ll talk about RNA…

What’s RNA?

• RNA is short for Ribose Nucleic Acid. It helps our body decode DNA and it helps assemble proteins.

What’s the difference between DNA and RNA?

• RNA single-stranded while DNA has two strands.

• RNA contains Ribose sugar instead of Deoxyribose sugar.

• RNA uses uracil(U) instead of thymine (T).

Three Types of RNA

• There are three types of RNA.

• Most RNA molecules have only one job – protein synthesis.

Three Types of RNA

• Messenger (mRNA): a messenger between DNA in the nucleus and ribosomes in the cytoplasm

Three Types of RNA

• Transfer (tRNA): transfers amino acids to the ribosomes to build proteins

Three Types of RNA

• Ribosomal (rRNA): makes up part of the ribosome; clamps/hold onto mRNA and hold it in place

Three Types of RNA

• Label the three types of RNA…

Ribosomal RNA (rRNA)

Messenger RNA (mRNA) Transfer RNA (tRNA)

PROTEIN SYNTHESIS

Essential Idea:DNA RNA Proteins

(This is important. That’s why it’s so BIG! Circle it, put a big star by it. I wouldn’t be telling you

do this if it wasn’t an IMPORTANT IDEA. )

PROTEIN SYNTHESIS

• What? Using info from DNA to make proteins– The sequence of DNA bases is a code for how to

make proteins. • Where? Takes place in the nucleus and

cytoplasm of a cell• Why? So our cells can make the proteins need

for important processes all over our bodies– Ex. in humans, how we make hair, fingernails,

hemoglobin, insulin, enzymes, etc…

PROTEIN SYNTHESIS

DNA RNA Proteins• How?–DNA RNA by transcription–RNA proteins by translation

Transcriptalatiowhat?

• Don’t worry, by the end of this you will be EXPERTS! (Pros, masters, geniuses, magicians, super synthesizers --- trust me, you got this).

• First, we’ll talk about transcription.

TRANSCRIPTION

• What? Making mRNA molecules by using the DNA sequence as a template

• Where? Takes place in the nucleus• Why? So that a disposable copy of the

“protein instruction manual” stored in DNA can be transferred to the ribosome and used to make a protein

• How?

Steps in Transcription

Transcription is just like DNA replication (almost) except that we are making messenger RNA instead and U is put in place of T

Steps in Transcription: Separation of Strands1. The enzyme RNA polymerase uses one DNA

strand as a template

Steps in Transcription: Separation of Strands1. Only one gene is copied at a time; mRNA is

made at the start of a gene sequence

Steps in Transcription: Base Pairing

2. Free RNA nucleotides are matched to exposed DNA nucleotides (A=U, C=G)

Steps in Transcription: Bonding of Bases

3. Sugars and phosphates bond to form a new backbone

Steps in Transcription: Termination/Stop Codon

4. Transcription stops when a terminator/ stop codon (end of the sequence) is reached

Steps in Transcription: Results of Transcription

5. The mRNA molecule is acomplementary (opposite)copy of the DNA sequence

Steps in Transcription

5. Each three-nucleotide set on the mRNA is called a codon, which represents a different amino acid

Let’s practice transcription:

DNA: ATC CGT AAG CTC GTC

mRNA: UAG GCA UUC GAG CAG

Let’s practice transcription:

DNA: GGC TAA TCG ACT GCA

mRNA: CCG AUU AGC UGA CGU

Let’s practice transcription:

DNA: ATC GAC GCT CAT CGA

mRNA: UAG CUG CGA GUA GCU