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RNA & Protein Synthesis. What makes you look like your parents?. Your parents passed down their DNA to you. What’s carried in your DNA that gives you your traits & characteristics? GENES! So, how does it work?. What is a gene?.
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What makes you look like your parents? Your parents passed down their DNA to you. What’s carried in your DNA that gives you your traits & characteristics? GENES! So, how does it work?
What is a gene? • A gene is a set of DNA instructions that control the production (synthesis) of proteins within the cell. For example, consider the gene for curly hair. How does your DNA have anything to do with your hair? How does it work? Is it magic? NO! ??
The gene doesn’t actually code for curly hair – it codes for a protein called keratin! • Your hair is made out of keratin! • Keratin coils up to form a helix. • If you have the curly hair gene, the keratin proteins in your hair form strong bonds between each other, which causes the hair to curl. • So, it’s the keratin that gives you curly hair!
So… • A gene is a set of DNA instructions that control the production (synthesis) of proteins within the cell. • This process, protein synthesis, involves 2 steps: transcription & translation.
How does a gene work? • DNA cannot leave the nucleus, so a copy is made in the form of a similar nucleic acid called RNA (ribonucleic acid) during transcription. • The RNA leaves the nucleus, attaches to a ribosome & then is used to make a protein during translation.
RNA Structure • RNA is similar to DNA: • RNA is a nucleic acid macromolecule. • RNA is made of nucleotides. • Do you remember the 3 parts of a nucleotide? • 1 5-carbon sugar • 1 phosphate group • 1 nitrogenous base
DNA vs. RNA • RNA contains the sugar ribose, while DNA contains the sugar deoxyribose. • RNA is single stranded, while DNA is double stranded.
DNA vs. RNA • RNA contains uracil instead of thymine. • Uracil, like thymine, is a pyrimidine! • Both DNA & RNA have adenine, cytosine, & guanine.
RNA – 3 Types • Messenger RNA (mRNA): acts as a messenger & carries a copy of the information in DNA to the ribosome where proteins are made
RNA – 3 Types • Ribosomal RNA (rRNA): found within ribosomes; ribosomes are made of both proteins & rRNA
RNA – 3 Types • Transfer RNA (tRNA): brings amino acids to the ribosome to be added to the protein chain that is being made • There is 1 tRNA for each of the 20 amino acids!
