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Brainteaser What's colorless and weightless, but if you put it into a barrel, the barrel would become lighter?

replication of organelles disappearance of the nucleolus Meiosis and mitosis are two different reproductive processes. What happens ONLY during meiosis? crossing over occurs replication of organelles disappearance of the nucleolus complete breakdown of the nuclear membrane

Review DNA can be found in the nucleus Ribosomes make proteins and are found in the cytoplasm How does DNA (which doesn’t leave the nucleus) get to the ribosomes in the cytoplasm? It becomes RNA and leaves through the nuclear pores.

DNARNA Proteins Traits Central Dogma DNARNA Proteins Traits This is the central theme of molecular genetics. This are the steps needed to get from a DNA double helix to your blue eyes.

Central Dogma How do you get from DNA to RNA to Proteins to Traits? Amino Acids DNA  RNA  PROTEINS  TRAITS TRANSCRIPTION TRANSLATION control

Transcription DNA to RNA

DNA vs. RNA DNA RNA Deoxyribonucleic Acid Deoxyribose sugar Double stranded N bases = A,T,C,G Found in the nucleus 1 type Contains a phosphate, sugar, N base. Ribonucleic Acid Ribose sugar Single stranded N bases = A,U,C,G Uracil replaces Thymine Found in the nucleus and cytoplams 3 types Contains a phosphate, sugar, N base.

DNA vs. RNA DNA RNA

Types of RNA Messenger RNA mRNA Carries info from DNA and delivers it to ribosome. Ribosomal RNA rRNA Structural component of ribosomes Transfer RNA tRNA Translates mRNA sequences into amino acid sequences

TRANSCRIPTION The process that makes RNA from DNA in the nucleus RNA Polymerase binds to a promoter region of DNA (sequence of DNA that signals the start of transcription) Enzyme unwinds DNA and separates 2 strands. One strand of DNA acts as a template for making RNA

3) Enzyme moves along bases of DNA in one direction 3) Enzyme moves along bases of DNA in one direction. It reads each nucleotide and pairs it with complementary RNA nucleotide. 4) Process continues until enzyme reaches a terminator (stop signal) 5) Enzyme detaches from DNA and releases RNA into nucleus

Transcription and Translation 12/25/2018 Transcription RNA polymerase acts here The enzyme RNA polymerase opens the DNA strands and synthesizes an RNA complementary to only one of the DNA strands. G. Podgorski, Biol 1010

Transcription and Translation 12/25/2018 Transcription is a Key Step in Trait Expression Transcription makes an RNA copy of DNA. G. Podgorski, Biol 1010

DNA - RNA What would the mRNA strand be if the DNA template is: (remember that A now pairs with U and C still pairs with G) ATC CAG TCA GAT CTA CCG TGA CTG

How does the DNA become RNA? Through a process called Transcription Steps: RNA Polymerase binds to a region of DNA that signals it to start making RNA. RNA Polymerase unwinds the DNA and separates into 2 strands. One strand of DNA acts as a template for making mRNA Enzyme moves along the DNA bases in one direction. It reads each nucleotide and pairs it with a complementary RNA nucleotide. Process continues until enzyme reaches a terminator (stop signal) Enzyme detaches from DNA and releases mRNA from the nucleus.

PROTEINS

2 Types: Structural = Build the body (skin, hair, muscle, blood) Enzymes = speed up, slow down, start, or stop cellular/chemical reactions (usually end in –ase)

DNA → Proteins → Traits Controls the Expression of Controls the Production of

TRAIT: HAIR COLOR VARIATION: THE DIFFERENT COLORS Traits vs. Variations Trait – a specific characteristic; eye color, or height that varies from one individual to another Variation – the differences that an organism can inherit for a trait TRAIT: HAIR COLOR VARIATION: THE DIFFERENT COLORS

Variations Of a Trait Differences Within a Protein → Results In

Examples: Trait = Eye color Variation 

Examples: Trait = Hair Color Variation 

Examples: Trait = Skin Color Variation 

Amino Acids Proteins are made up of repeating units called amino acids. All amino acids have a similar basic structure. There are about 20 different amino acids. A protein may contain anywhere from 50 to 5,000 amino acids. A different number and/or order of amino acids results in a different protein

DNA → Proteins → Traits Summary Makes up amino acids which make proteins DNA → Proteins → Traits Controls the Production of Controls the Expression of

Which function is characteristic of RNA, but NOT of DNA? transports proteins replicates itself transports amino acids carries genetic information