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DNA, RNA, & Proteins.

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Presentation on theme: "DNA, RNA, & Proteins."— Presentation transcript:

1 DNA, RNA, & Proteins

2 Proteins Proteins are large biomolecules made up of amino acids

3 Perform many functions in cells such as:
Structural (ex: keratin, collagen) Storage (ex: albumin in eggs) Transport (ex: hemoglobin) Hormonal (ex: insulin) Receptor on cells’ surfaces Defensive (ex: antibodies) Contractile (ex: actin & myosin in muscles) Enzymes which speed up chem. reactions (ex: lactase)

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6 1° structure: Amino acids form a chain
2° structure: chain becomes pleated or twisted 3° structure: folds into 3D shape 4° structure: more than one amino acid chain

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8 How to Make Proteins (a.k.a.: Protein Synthesis)
Assembled at ribosome Remains in the nucleus Nucleus  ribosome

9 DNA vs. RNA RNA: Thymine (T) switched to Uracil (U) Single stranded
Sugar is a ribose

10 Three Kinds of RNA… mRNA (messenger RNA) – carries code for protein synthesis to ribosome rRNA (ribosomal RNA) – combines with protein to form ribosome tRNA (transfer RNA) – carries amino acid to ribosome

11 Two Steps of Protein Synthesis:
1) Transcription (DNA -> mRNA) 2) Translation (mRNA -> protein)

12 Part 1: Transcription DNA is copied into a small strand of mRNA that CAN leave the nucleus

13 Part 2: Translation mRNA brings code to ribosome Ribosome reads three mRNA bases at a time, and puts the appropriate amino acid in place These three base “sets” are called codons

14 As the ribosome reads the mRNA codons, tRNA (transfer RNA) brings the amino acids.
Each tRNA has an anticodon that base pairs with the codons on one end and a corresponding amino acid on the other end. The amino acids are held together by peptide bonds forming a polypeptide (protein). tRNA continues to bring amino acids until a STOP codon is read. When translation stops, the polypeptide is released.

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16 20 possible amino acids used to make proteins
Can you determine the corresponding amino acids to the RNA codon? CAC:_________________ GUA:_________________ GCU:_________________ AGG:_________________ 20 possible amino acids used to make proteins 64 possible combinations of codons This leads to duplicates So, mistakes can made without preventing the protein from working!

17 Let’s practice building a small protein!
DNA Triplet TAC AGA TGT GAA GTG CGG CCT ATT mRNA Codon Amino acid

18 Whoops! A random mutation occurred!
DNA Triplet TAC AGA GT GAA GTG CGG CCT ATT mRNA Codon Amino acid


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