DNA: Replication Transcription Translation

Fill in the missing bases: T A C C T G A G C C T T C A A T G G A C T C G G AA G T

What do the letters of DNA stand for? Adenine A = ______________ Thymine T = ______________ Guanine G = ______________ Cytosine C = ______________

Structure of DNA: Who are the two scientists credited with discovering DNA: _________________ and ________________ James Watson Francis Crick

Structure of DNA: What is the DNA “backbone” made of? _________________ sugar and phosphate

Structure of DNA: What are the three parts of a nucleotide?

Structure of DNA: What does DNA stand for? ____________________ Sugar = Deoxyribose Macromolecule = Nucleic Acid Deoxyribonucleic Acid

DNA Replication What is DNA Replication? A process in your cell that makes a copy of your DNA before mitosis.

DNA Replication Why is DNA Replication important for cells and multicellular organisms? Every time a cell divides you need each new cell to have a complete set of DNA.

DNA Replication When does DNA Replication occur? During S phase of interphase, before mitosis.

DNA Replication What is a chromosome? Tightly wound DNA

DNA Replication What is DNA Polymerase? An enzyme that copies DNA by matching complimentary nucleotides to the original DNA strand.

DNA Replication STEP 1 DNA Polymerase breaks Hydrogen bonds of double helix apart. DNA

DNA Replication STEP 2 DNA Polymerase matches nucleotides to complementary bases. DNA T T A G

DNA Replication STEP 3 Two identical copies of DNA are formed.

DNA Replication DNA replication is considered ‘semi- conservative’. “Semi” means: “Conservative” means: Half Save

DNA Replication How is DNA replication semi-conservative? Explain in your own words!

DNA Replication Draw a picture of a chromosome without DNA replication, and one with DNA replication.

DNA and RNA Why do we need DNA in the first place? DNA has the instructions for every protein our body is made of

Chromosome before/after replication

DNA and RNA Picture of how DNA is used by our body:

DNA and RNA Picture of how DNA is used by our body:

DNA and RNA Picture of how DNA is used by our body:

Background: DNA  RNA Protein Where is DNA Stored?________________ What organelle makes proteins?__________ If this is so, where are proteins made? ____________ What problem does this pose? ___________ ________________________________ nucleus ribosomes cytoplasm DNA Cannot leave the nucleus to give directions to ribosomes.

Background: DNA  RNA Protein How does RNA solve this problem? RNA is a disposable copy of DNA that can leave the nucleus and travel to ribosomes.

RNA RNA’s structure is very similar to the structure of DNA except for 3 major differences.

DNA Sugar: Deoxyribose RNA Ribose ribose sugar

DNA Double Stranded RNA Single

DNA Bases: ATCG RNA AUCG Thymine Uracil ribose sugar

Full Name Messenger RNA Short Name mRNA Drawing

Full Name Transfer RNA Short Name tRNA Drawing

Full Name Ribosomal RNA Short Name rRNA Drawing RIBOSOME

Background: DNA  RNA Protein

Background: DNA  RNA Protein What is a protein? _______________________ Long chains of amino acids

What are some examples of proteins? Make up all your traits – hair type and color (keratin), what color your skin is (melanin), what enzymes you have to break down food (lactase, peroxidase, amylase), how strong you are (actin/myosin)

Background: DNA  RNA Protein DNA can not _______________________ DNA contains the directions to make ____________ Proteins can only be made in the ____________ by _______________ Leave the nucleus protein cytoplasm ribosomes

Background: DNA  RNA Protein What problem does this cause? DNA cannot leave the nucleus to give directions to ribosomes.

Background: DNA  RNA Protein How does RNA solve this problem? mRNA is a disposable copy of DNA that can leave the nucleus to go meet up with the ribosome!

Making a disposable copy (mRNA) from DNA. Transcription Transcription: Making a disposable copy (mRNA) from DNA.

RNA Polymerase opens the DNA strand of one gene (example: keratin) Transcription Description Step 1: RNA Polymerase opens the DNA strand of one gene (example: keratin)

Transcription Diagram Step 1:

RNA Polymerase matches complimentary bases to original DNA strand. Transcription Description Step 2: RNA Polymerase matches complimentary bases to original DNA strand.

Transcription Diagram Step 2:

Transcription Description Step 3: RNA Polymerase is finished, mRNA leaves the nucleus and goes to ribosome.

Transcription Diagram Step 3:

Transcription practice If this was the original DNA nucleotide strand, what would the mRNA copy look like? DNA: A T C C G A A G T G A T mRNA U A G G C U U C A C U A

Transcription Questions What does RNA polymerase do? Does RNA polymerase copy every gene in the nucleus? _______ Why? Make a copy of DNA called mRNA. No It only needs the piece of DNA (gene) that codes for the protein the cell needs.

Transcription Questions Just like we read several letters together to have meaning as words, a cell reads three bases together as a code for an amino acid (one part of a protein): Every three bases is called a: Examples: codon Proline, valine, isoleucine, tryptophan

Making protein from mRNA. Translation Translation: Making protein from mRNA.

mRNA leaves the nucleus to find a ribosome. Translation Description Step 1: mRNA leaves the nucleus to find a ribosome.

Translation Diagram Step 1:

A tRNA that matches the mRNA sequence clicks into place. Translation Description Step 2: A tRNA that matches the mRNA sequence clicks into place.

Translation Diagram Step 2:

The amino acids are linked together by a peptide bond. Translation Description Step 3: The amino acids are linked together by a peptide bond.

Translation Diagram Step 3: Peptide bond

Amino acid chain breaks off, folds up, and is ready to use. Translation Description Step 4: Amino acid chain breaks off, folds up, and is ready to use.

Translation Diagram Step 4:

Translation Questions How does the ribosome know where to start reading mRNA? There is a universal start codon AUG, which codes for Methionine

Translation Questions How does the ribosome know where to stop reading the mRNA? Stop codons

Translation Questions After tRNA has released its amino acid, where does it get another amino acid? When an organism eats food with protein, proteins are broken down into amino acids, which are then used to build more protein.

End IS

Structure of DNA: A T C G complimentary bases ____ always pairs with ____, and ____ always pairs with ____. The bases that pair with each other are called _____________________. C G complimentary bases

Structure of DNA: Categories Purines Pyrimidines Examples: Drawing: Nitrogen Bases can be separated into two different categories: Categories Purines Pyrimidines Examples: Drawing: Guanine Thymine Adenine Cytosine

Structure of DNA: thousands protein gene A single DNA molecule may contain ____________ of nucleotides (AKA: bases) The order of the nucleotides (bases) in a DNA is a code that provides instructions for making ____________. A segment of DNA that codes for a specific protein is called a ______. thousands protein gene

Structure of DNA: histones chromatin chromosomes In your cells, DNA wraps tightly around proteins called ___________ to produce a substance called ___________ which condenses during cell division (mitosis) to form structures called _______________. histones chromatin chromosomes

Structure of DNA: A segment of DNA that codes for a specific protein What is a gene: ______________________ _________________________. A segment of DNA that codes for a specific protein

What do proteins do? Make up all your traits – hair type and color (keratin), what color your skin is (melanin), what enzymes you have to break down food (lactase, peroxidase, amylase), how strong you are (actin/myosin)