Warm Up

In your journal write a short paragraph on

discussing your feelings about cloning? Think about such things as…

Is it okay to clone endangered species?

How about humans?

If someone in your family died, would you want them cloned?

YOU HAVE 10 QUIET MINUTES!!!!!!!!!!!!!!!!!!

DNA, RNA and Protein SynthesisChapter 12

PROTEIN REVIEWProteins are large molecules formed by

smaller molecules (monomers) called amino acids.

Amino acids are known as the building blocks of proteins.

In your body, proteins aid in muscle contractions, give structure to cells and act as enzymes.

Nucleic Acids Review

Both DNA and RNA are known as nucleic acids.

Just like the building block for proteins are amino acids, the building blocks for nucleic acids are NUCLEOTIDES.

DNA

Deoxyribonucleic acidFundamental building block of all

living things.Passes on information from

generation to generation by duplicating itself.

The Components and Structure of DNA

Long molecule made up of subunits called NUCLEOTIDES

Phosphate group

Nitrogenous base

5 Carbon Sugar: DEOXYRIBOSE

NUCLEOTIDE

The only part that changes in a DNA molecule is the nitrogenous base!

Phosphate group

Nitrogenous base

5 Carbon Sugar: DEOXYRIBOSE

1. ADENINE2. THYMINE3. GUANINE4. CYTOSINE

NITROGENOUS BASES

Four different nitrogen bases in DNA:

1. Adenine Purines

2. Guanine 2 rings

3. Thymine Pyrimidines

4. Cytosine 1 ring

The Components and Structure of DNA

DNA is shaped like a double helix.Backbone of DNA is formed by sugar and

phosphate groups from each nucleotide.Bases stick out sideways from the chain.Nucleotides can be joined together in any

order.

Who discovered DNA?

In 1953, Watson and Crick were the first to identify the structure of DNA.

Won a noble prize in 1962.

Complementary Base Pairing

ONLY CERTAIN BASES CAN LINK TOGETHER. THESE BASES ARE CALLED “COMPLEMENTARY”.

A always pairs with T

C always pairs with G

* Bases are held together by hydrogen bonds. Reason for Chargaff’s rules.

Chromosomes and DNA Replication

DNA is located in the nucleus only – never found in the cytoplasm – think of it as being on house arrest.

Long molecules, in E.coli ( a very very small bacterium) there are 4,639,221 base pairs

Chromosome Structure

Every nucleus of a human cell contains more than 1 meter of DNA

Chromatin- DNA that is tightly wound around proteins called histones

Histones group together to make NUCLEOSOMES which fold DNA into tiny spaces in the cells nucleus.

Duplicating DNA – aka REPLICATION

Before a cell divides through mitosis, it must replicate (copy) it’s DNA.

Process of replication ensures that each new daughter cell will have a complete set of the DNA molecules.

DNA Replication

One DNA strand serves as a template to

build the other.

1st the DNA strand “unzips” or splits down the middle.

2nd Complementary nucleotides attach to the single strands

Details of REPLICATION

Carried out by a series of enzymes (speed up the reaction)1. The enzyme Helicase “unzips” the DNA by breaking

the hydrogen bonds between the base pairs, causing the strand to “unwind”

2. DNA polymerase (another enzyme) joins individual nucleotides to their “partner”, after it is done it proofreads to make sure there are no mistakes.

The chance in a mistake is reduced to 1 error per every billion nucleotides!

replication animation

Complementary Strands

Fill in the blanks:

One side of DNA: ACTGGCTATGC

Other side : TGACCGATACG

GENESCoded DNA instructions that control

the production of proteins within the cell.

THE BIG PICTURE

Three Important Points to Remember

1.Chromosomes are made of DNA

2.Segments of DNA code for a protein

3. Protein in turn, relates to a trait (eye color, enzymes, hormones..)

FROM GENES TO PROTEINS: Decoding the information in DNA

Traits such as eye color as encoded in DNA.

How are these traits passed on from generation to generation?

This job takes both DNA and something

called RNA.

FROM GENES TO PROTEINS: RNA

Like DNA, RNA is a nucleic acid, ribonucleic acid. RNA differs from DNA in 3 ways. Allows for the ability to copy a single DNA sequence

DNA RNA

Double stranded

Single stranded

Sugar is deoxyribose

Sugar is ribose

Nucleotides ACTG

Nucleotides ACUG

RNA

Most RNA molecules are involved in protein synthesis (the making of proteins)

Three different types of RNA

1. mRNA - messenger

2. tRNA - transfer

3. rRNA - ribosomal

Messenger RNA

Carry copies of instructionsServe as messengers from DNA to the

rest of the cell (because DNA cannot leave the nucleus)

Ribosomal RNA

Proteins are assembled on ribosomesRibosomes are made up of proteins and

RNA.

Transfer RNA

Transfers each amino acid to the ribosome as it is coded by messages in mRNA.

Needed for the last step of synthesis production

FROM GENES TO PROTEINS: Uracil instead of Thymine

No thymine bases are found in RNA, instead uracil pairs with adenine.

DNA RNA

A-T A-U

C-G C-G

From DNA to RNA

Original DNA strand

ATTACGAAGGCTA

UAAUGCUUCCGAU

New RNA strand

FROM GENES TO PROTEINS: The Big Picture

2 STEP PROCESS:

1st. TRANSCRIPTION- from DNA to RNA

2nd. TRANSLATION - from RNA to proteins.

FROM GENES TO PROTEINS: Transfer of Information, From DNA to RNA

TRANSCRIPTION 1. Enzyme RNA polymerase unzips the

DNA strand located in the nucleus.2. Uses one strand of the DNA as a

template to assemble a single strand of RNARESULT OF TRANSCRIPTION – ONE SINGLESTRAND OF RNA

****THIS IS NOT THE SAME AS DNA REPLICATION****

Promoters

How does RNA polymerase know where to start unzipping the DNA strand?

Enzyme binds to DNA in specific regions known as promoters.

Act as a signal telling RNA polymerase where to start and stop.

Transcription vs. Replication

RNA Editing – Introns vs. Exons

INTRONS – part of the DNA molecule NOT involved in protein synthesis

EXONS – part of DNA that is involved or “expressed” in protein synthesis

After RNA transcribes the DNA strand it must cut out the introns while it is still in the nucleus. The remaining exons are then spliced back together to form the final mRNA.

Why do we need mRNA?

Remember, DNA is only found in the nucleus of the cell.

mRNA is needed to carry information out of the nucleus to other parts of the cell.

For example,

Imagine that your name is DNA and you are

on house arrest. If you need McDonalds you must

send someone else with your message (order) to

McDonalds.

translation

The Genetic Code

Language of mRNA is called the genetic code.

Code is written using the four letters AUCG

FROM GENES TO PROTEINS: The Genetic Code, Codons

The mRNA instructions are written as three nucleotide sequences called CODONS.

Each nucleotide triplet in mRNA specifies for a particular amino acid.

Each codon along the mRNA strand corresponds with a specific amino acid.AUC GGA UUA CCC CODON CODON CODON CODON

mRNA codes for Specific Amino Acids

mRNA

AUC GGA UUA CCC

CODON CODON CODON CODON

Isoleucine Glycine LeucineProline

Now you try……………

UAAStopUGUCysteineGAUAspartic acid

FROM GENES TO PROTEINS: RNA’s Roles in

TranslationTakes place in the cytoplasm at the ribosomes. In order for translation to occur, mRNA must migrate to the ribosomes.

tRNA and ribosomes help in the synthesis of proteins. Proteins are made from mRNA.

The mRNA moves out of the nucleus to the ribosomes. There tRNA carries the amino acid to it’s correct codon. The sequence is then converted into an amino acid sequence.

FROM GENES TO PROTEINS: Translation

tRNA consists of a single strand of RNA with an amino acid linked to the end.

Each tRNA contains an

anticodon – three nucleotide

sequence that is complementary

to an mRNA codon.

From DNA mRNA tRNA Proteins

DNA Strand ATCGATCCG

mRNA Strand UAGCUAGGC codons

tRNA Strand AUCGAUCCG anti-codons

Proteins Isoleucine, etc

Break it down...

What happens when there is a mistake?

Normally process is very accurate, but occassionaly they make a mistake known as a mutation.

ex. THE DOG BIT THE CAT

THE DOG BIT THE CAR

**One change can make a huge difference!

3 Types of Mutations

1. Point mutation – only a single nucleotide changes. (Only changes one protein)

ATCGAA Serine, ArginineATGGAA Stop, Arginine

2. Deletion mutation – base is removed or entire segments.

THE CAT ATE THE ATA TE

3. Frameshift mutation – base is added or deleted, causes a change in all of the amino acids after the mutation. Causes the gene to be read wrong. Ex. Include deletion and addition mutations.

DID YOU KNOW?????????????

IF YOU HAVE HAD YOUR PILLOW

FOR OVER 5 YEARS, ONE TENTH OF IT’S TOTAL WEIGHT IS DUST MITES AND

THEIR POOP!

DID YOU KNOW????????????

The average human produces a quart of saliva a day!! That’s about 10,000 gallons in a lifetime!

Warm UP #1 Something to ponder… Warm UP’s on page 62

It is the year 2020. Cloning techniques have been perfected. Dr. Rice, M.D. C.C. (medical doctor, certified clonologist) has a sample of Abraham Lincoln’s DNA in her laboratory. Dr. Rice has always admired honest Abe and thinks the world could use more people like him. She has the technology, but wonders if she should go through with the cloning of Abe.

1. Give three pros and three cons concerning the possible consequences of this experiment.

Did you know?

A goldfish has a memory span of 3 seconds.

Things to ponder part 2 A woman in her 40’s, and her husband, age 43,

have tried for years to have children. She has had three miscarriages, and her doctors warned her that due to her age any baby born now may suffer from birth defects.

Nonetheless, the recently delivered a boy 3 early. He died soon after birth and she was

devestated. Dr. Rice saved some of his skin cells to be used for cloning.

The couple desperately wants a child of their own and fear cloning may be their only chance. Should they be allowed to clone the infant? List three arguments supporting and three arguments opposing the cloning of the infant.

Did you know?

A snail's reproductive organs are in its head.

Did you know?

Cows can have regional accents

Did you know?

There are more insects in ten square feet of a rain forest than there are people in Manhattan.

Did you know?

Mosquitoes have 47 teeth.

Did you know?

The only continent without reptiles or snakes is

Antarctica.

Did you know?

A frightened dog puts it's tail between it's legs because it covers the scent glands in the anal area. Since the anal glands carry personal scents that identify individual dogs, the tail-between the-legs behavior is the canine equivalent of insecure humans hiding their faces.

Did you know?

The biggest ant colony was found on the Ishikari Coast of Hokkaido: 306 million worker ants and 1 million queens lived in 45,000 interconnected nests over an area of 2.7 square kilometres (1,7 square miles). A worker ant will live for up to 5 years; while a Queen will live up to 25 years.