7 - Unit 5, Section 1

DNA and RNA

Unit 5, Section 1

Multiple Choice

Review time! A __________ is a type of biological molecule that provides structure to an organism: they're made of aminos acids chemically bonded together.

• Protein

• Nucleic Acid

• Carbohydrate

• Lipid

Multiple Choice

Review time! This is the organelle responsible for making proteins.

• Ribosome

• Mitochondria

• Vacuole

• Endoplasmic Reticulum

• DNA - deoxyribonucleic acid

• So, we need to know about:

  • Deoxyribose

  • Nucleic Acids

• What are those?

• How do they fit together?

• How do they carry information?

What Is DNA?

Review - What Is DNA?

• DNA is made of a sugar-phosphate "backbone" that holds it all together

• There are four nucleotides:

  • Adenine (A)

  • Thymine (T)

  • Guanine (G)

  • Cytosine (C)

• A and T form "base pairs," as do G and C

• Since nucleotides bond to each other, two backbones line up to form a long molecule

• The molecule curls around itself like a spiral staircase

• This shape is called a "double helix"

The Double Helix

• The information in DNA is organized into genes

• Gene - a fragment, or part of DNA that is responsible for making a protein

How Does DNA Carry Information?

• Protein - a biological molecule made of amino acids

• The amino acids are bonded together like beads on a necklace

• Each protein is made of a specific sequence (order) of amino acids

Proteins

Genes and Proteins: A Pattern

• A gene is part of DNA that's responsible for making proteins

  • Each gene is made of nucleotides in a specific order

• A protein is a molecule that provides structure to organisms

  • Each protein is made of amino acids in a specific order

• Can we find a pattern here?

• DNA cannot leave the nucleus

• Proteins are made by ribosomes, which exist outside the nucleus

• How is this possible?

• RNA!

RNA

• RNA - ribonucleic acid

• RNA is made of:

  • Ribose (a sugar)

  • Nucleic Acids

• There are four nucleotides:

  • Adenine (A)

  • Uracil (U)

  • Guanine (G)

  • Cytosine (C)

RNA

• Messenger RNA (mRNA) - carries information from the DNA to the ribosomes

• Ribosomal RNA (rRNA) - part of the ribosomes and helps make proteins

• Transfer RNA (tRNA) - brings specific amino acids to the ribosomes

The Three Types of RNA

• Codon - a set of three nucleotides

• Each codon is a code for one amino acid

• So, a series of codons can be used to make a series of amino acids

• Each gene is read, the amino acids are put together in the correct order, and a protein is made!

Proteins and Genes

Activity - Decoding Codons