DNA:ReplicationTranscriptionTranslation

Fill in the missing bases:

A T G G A C T C G G AA G T

T A C C T G A G C C T T C A

What do the letters of DNA stand for?

•A = ______________Adenine

•T = ______________Thymine

•G = ______________Guanine

•C = ______________Cytosine

Structure of DNA:

•Who are the two scientists credited with discovering DNA: _________________ and ________________

James WatsonFrancis 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

TAGT

DNA Replication STEP 3

•Two identical copies of DNA are formed.

DNA Replication

•DNA replication is considered ‘semi-conservative’.

•“Semi” means: •“Conservative” means:

HalfSave

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? ___________ ________________________________ ________________________________

nucleusribosomes

cytoplasmDNA

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.

DNASugar: Deoxyribose

RNA Sugar: Ribose

ribose sugar

DNADouble Stranded

RNA Single Stranded

DNABases:ATCG

RNA Bases: AUCG

ribose sugar

Thymine

Uracil

Full Name Messenger RNA

Short Name mRNA

Drawing

Full Name Transfer RNA

Short Name tRNA

Drawing

Full Name Ribosomal RNA

Short Name rRNA

DrawingRIBOSOME

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!

Transcription

•Transcription:

Making a disposable copy (mRNA) from DNA.

Transcription

•Description Step 1:

RNA Polymerase opens the DNA strand of one gene (example: keratin)

Transcription

•Diagram Step 1:

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.

NoIt 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

Translation

•Translation:

Making protein from mRNA.

Translation

•Description Step 1:

mRNA leaves the nucleus to find a ribosome.

Translation

•Diagram Step 1:

Translation

•Description Step 2:

A tRNA that matches the mRNA sequence clicks into place.

Translation

•Diagram Step 2:

Translation

•Description Step 3:

The amino acids are linked together by a peptide bond.

Translation

•Diagram Step 3:Peptide bond

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:

•____ always pairs with ____, and •____ always pairs with ____.•The bases that pair with each other are

called _____________________.

A TC G

complimentary bases

Structure of DNA:

•Nitrogen Bases can be separated into two different categories:

Categories Purines Pyrimidines

Examples:

Drawing:

GuanineAdenine

Thymine

Cytosine

Structure of DNA:

•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

proteingene

Structure of DNA:

•In your cells, DNA wraps tightly around proteins called ___________ to produce a substance called ___________ which condenses during cell division (mitosis) to form structures called _______________.

histoneschromatin

chromosomes

Structure of DNA:

•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)