Transcript
BACK TO THE PROPERTIES OF LIFE
CELLS REPRODUCTIONMETABOLISM-
USE OF ENERGY
HEREDITY RESPONSIVENESSGROWTH AND DEVELOPMENT
INTERNAL BALANCE
THIS TIME WE ARE TALKING ABOUT
GROWTH AND DEVELOPMENT
Which begins in our cells
Since we just finished learning about chloroplasts (photosynthesis) and mitochondria (respiration), we are
now moving on to another cell organelle: the nucleus.
Some questions to start us off…take a moment to try to answer #1-4 with your
table partner
How High?! JUMP!
It’s the Control Center of the Cell- directs all cells activity
Think back to the cell/the city What is the job of the Nucleus?
What’s in the nucleus?
THE NUCLEOLUS
So then we can say that the Nucleus makes proteins
Let’s take a deeper look
And what is the job of the nucleolus?
To make ribosomes
And what do ribosomes do for the cell?
They make protein!
Break it Down!The nucleus houses the cells information in the form of
What is the purpose of DNA?It stores
for the cell
What does DNA form?
DNA
hereditary info and makes proteins
Chromosomes
DNA has 3 Main Jobs…
• It stores hereditary information (Genes)
• It begins the process to make proteins for the organism- aka “Protein Synthesis”
• Controls the growth and development
of new organisms.
But what do we even need
protein for?
Good Question!
Organisms are constantly making protein. From what you know about protein, why do you think we need to make it all the time?
Talk the matter over with your table partner.
We need protein for…Our body tissues- as they get replaced and
repaired. Proteins are the stuff we/life is made of.
To make the enzymes our bodies need for chemical reactions
Growth and repair.
DNA- What is it?
• Deoxyribonucleic Acid
• Double Stranded and helical (twists around like a spiral staircase)
• Consists of: Carbon, Hydrogen, Oxygen, Nitrogen and Phosphorus-
“PONCH”(remember that from Big 4 unit?)
DNA’s Structure• DNA is made up of NUCLEOTIDES• Nucleotides are made up of three
components:
1.A nitrogenous base
2. A sugar (called deoxyribose)
3. A phosphate group
The structure looks like a ladder. Twisted.
The backbone is made up the sugar and phosphate and the rungs are the nitrogen bases.
DNA StructureThe pair of nucleotides is held together
by a Hydrogen bond (1 pair is like 1 step on a twisted ladder).
The “backbone” of DNA, or the sides of a ladder are the sugar and phosphate
Sugar Sugar
PhosphateGroup
PhosphateGroup
NitrogenousBase
NitrogenousBase
Held together by a Hydrogen Bond
The 4 Nitrogenous Bases
Although all nucleotides in DNA have IDENTICAL Phosphate and Sugar groups, there are 4 different Nitrogenous Base options
Adenine- A
Guanine- G
Cytosine- C
Thymine- T
Called PURINES
Called PYRIMIDINES4
These 4 Bases are Very Picky!
Adenine (A) only pairs with Thymine (T), and Cytosine (C) only pairs with Guanine (G)
In other words,
A----T
G----C
Now for a FUN way to remember this…
Ants on Toast (A----T)
And…
Green Cheese (G----C)
The importance of the nucleotide sequence
• The sequencing of the nucleotide bases determines the information that is needed to make proteins.
• The combinations of nucleotides is an actual code (message) for different amino acids.
• Do you remember? What are amino acids?
Now that you know all about DNA…you need to figure out how it does its job!
ALL CELLS CONTINUALLY DIVIDE
WHEN THEY DO, THE DNA REPLICATES (COPIES ITSELF) SO THAT EACH NEW
CELL HAS A SET OF INSTRUCTIONS ON HOW TO RUN THE CELLS ACTIVITIES
Without the DNA, the cell would not be able to function!
Library Analogy
• Cedar Rapids, My home town• One library in a city of 100,000• Town needed a new library.• Town was divided by the Cedar River (rivers bio)• How to go about making two equal library’s?• Copy all of the materials and separate them into
the two new libraries.• How does each library compare in relationship to
the other one?
Cedar Rapids
Cedar Rapids Iowa 2008
So, How does DNA Replicate?YOU TELL ME!
JOURNAL TITLE “DNA REPLICATION”
(after a bit of cutting and learning on your own please write out the answers to the
questions on page 3 of your packet. Then write a journal entry describing the
detailed process of DNA replication )
DNA SNIPPING ACTIVITY
EnzymesBecause enzymes are used in the next activity,
you should know what they are-
• Most enzymes end with the letters “ase”.
An enzyme is a protein that speeds up a chemical
reaction!
Open your journal and write a description of DNA replication when you have completed the DNA replication assignment.
•
Detailed Steps in DNA Replication
• Begin with one copy of double stranded DNA (this is your template or parent strand)
• DNA Helicase (an enzyme) breaks the hydrogen bonds between the bases (A---T, or C---G). DNA Helicase is the “Unzipper”.
Replication Steps
DNA Polymerase, the matchmaker, brings the appropriate DNA nucleotides or bases to the parent strand. It brings the single bases “hanging out” in the nucleus to their mate!
DNA Ligase, the connector, attaches the sugar of one nucleotide to the phosphate of the next nucleotide. Sugar and phosphate alternate on the backbone.
We owe it to DNA
Polymerase!
MINI REVIEW Which enzyme breaks the hydrogen bonds between the
nucleotide bases in DNA, so it can separate and replicate?DNA Helicase
Which enzyme is the matchmaker? It helps the extra, unmatched nucleotides in the nucleus find a mate.
DNA Polymerase (Think Polly the matchmaker)
Which enzyme connects the nucleotides together as the strand grows?
DNA Ligase(think ligament- it links)
RANDOM JOKE BREAKHa Ha Ha…
The Wonderful Thing About
Tiggers
Why doesn't Tigger have any friends?
He plays with Pooh
What do you think would happen if a mistake occurred during DNA
replication? Let’s think!
WE WILL GET A MUTATION!
Mutations that occur during DNA replication are called…
POINT MUTATIONS
POINT MUTATIONS EXAMPLES ARE
Base Pair AdditionBase Pair Addition
Base Pair DeletionBase Pair Deletion
Base Pair SubstitutionBase Pair Substitution
•Knowing what you do about DNA structure what do you think causes each of the above mutations.
What causes mutations?
MUTATION CAUSES: Mutagens
1.1. Natural Causes- mistakes in the DNANatural Causes- mistakes in the DNA
•IN THE IN THE CLEANING SUPPLIESCLEANING SUPPLIES YOU USE YOU USE
•IN THE IN THE TOBACCOTOBACCO THAT PEOPLE USE THAT PEOPLE USE
2. Environmental Factors…Mutagens2. Environmental Factors…Mutagens
•IN THE IN THE FOOD FOOD YOU YOU EATEAT
3. UV-Rays & X-Rays3. UV-Rays & X-Rays
How many people do you know who smoke?
1 out of every 3 tobacco users will die from a tobacco
related illness.
Think for a second and count them.
TobaccoTobaccoStinksSucksSmellsAnd KILLS
In the dentist’s office, why do they place a lead apron over a person’s lap?
They want to protect the reproductive organs. If a mutation occurs in the reproductive organs, it may end up disfiguring a future child, or worse.
4. Heavy Metals
• Lead • Mercury• Cadmium• (Not heavy
metal like Metallica)
MUTATION CAUSES CONT…
5. UV Raysa. Holes in the ozone
layerb. Tanning beds
6. Nuclear radiation
Things that cause mutations are called
Mutagens
Exposure to mutagens can cause mutations in 2
general areas.1. Mutations in the sex cells, eggs and sperm.What do you think these mutations might lead to?
2. Mutations in the other cells of the body. What do you think these might lead to?
BIRTH DEFECTS OR DEATHBIRTH DEFECTS OR DEATH
CANCERCANCER
If you do not mind…
•Please stand up if you or someone in your Please stand up if you or someone in your immediate family has had cancer.immediate family has had cancer.
•Please stand up if someone you are related Please stand up if someone you are related to has had cancer.to has had cancer.
•Please stand up if you know someone Please stand up if you know someone personally who has had cancer.personally who has had cancer.
•Please stand up if you have a friend who is Please stand up if you have a friend who is related to someone who has had cancer.related to someone who has had cancer.
So what exactly is this disease?
Cancer is a disease where cellsCancer is a disease where cellsbegin to divide by mitosis begin to divide by mitosis
uncontrollably.uncontrollably.
A mutation(s) can occur in one single cell, and by the process of mitosis it can grow into tens of thousands or more cells in a relatively short period of time.
What forms when a cell has What forms when a cell has undergone mitosis uncontrollably undergone mitosis uncontrollably
for a while in one central spot?for a while in one central spot?
A Tumor
Cancer Treatments
1. Surgerical removal of cancer1. Surgerical removal of cancer
2. Chemotherapy- Treatment with 2. Chemotherapy- Treatment with drugs that kill cancer cells or make drugs that kill cancer cells or make
them less active.them less active.
3. Radiation- 3. Radiation- uses high-energy uses high-energy waves, such as X-rays (invisible waves, such as X-rays (invisible
waves that can pass through most waves that can pass through most parts of the body), to damage and parts of the body), to damage and
destroy cancer cells.destroy cancer cells.
4. Another option is a STEM CELL 4. Another option is a STEM CELL TRANPLANTTRANPLANT
Radiation and anti-cancer drugs are very good at destroying
cancer cells, but unfortunately they also destroy healthy cells.
http://www.leapingmedia.com/Media/TransplantAnimation.movhttp://www.leapingmedia.com/Media/TransplantAnimation.mov
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Protein Synthesis
What happens after we have made our DNA? What does it do from here?
RNA copies the gene information from the DNA and brings it to the ribosomes to make proteins.
So… What is this RNA that we are talking about?
RNA- What is it?
Ribonucleic Acid
Single stranded
Made of nucleotides (which contain a nitrogen base, a sugar, and a phosphate group)
RNA Structure
Contains the sugar Ribose (hints the R in RNA), instead of Deoxyribose that is found in DNA
As with DNA, there are 4 bases- Adenine, Guanine, Cytosine, and … URACIL (which one is different?)
The Uracil takes the place of Thymine, so it pairs with Adenine
WHAT ARE SOME DIFFERENCES BETWEEN
DNA AND RNA?DNADNA
Has thymine
Deoxyribonucleic acid
Double Helix
RNARNA
Has Uracil
Ribonucleic acid
Single stranded
A-----U in RNA
Ants on Utters (instead of Ants on Toast)!
This is utterly ridiculous!
Guanine still pairs with Cytosine (Green Cheese)
So this is CRYSTAL CLEAR…
DNA Replication and Protein Synthesis are 2 SEPARATE Steps!
Although Protein Synthesis uses DNA to make protein, the DNA Replication process is completely DIFFERENT. The only similarity is that they both make more of “something”.
How to get to a Protein
STEP 1: Transcription
RNA copies DNA
Step 2: Translation
RNA makes proteins
Of course, there are some steps that help this process along.
These processes taken together…
Are called protein synthesis, or gene expression.
DNA Transcription RNA Translation Protein
So, How does Protein Synthesis work?
YOU TELL ME!
(after a bit of cutting and learning on your own please write out a step by step
process for how this occurs)
MORE SNIPPING ACTIVITY
YES AGAIN!
ANIMATIONS
http://www.ncc.gmu.edu/dna/ANIMPROT.htm
•http://www.execulink.com/~ekimmel/translate.htm
•http://207.207.4.198/pub/flash/26/transmenu_s.swf
•VERY GOOD ONE BELOW
PROTEIN SYNTHESIS SUMMARY
STEP 1: Transcription
WHERE: In the nucleus
WHAT: RNA polymerase does its jobs: Splits DNA strand. RNA copies recipe from DNA strand. DNA strand zips up again. mRNA now newly formed prepares to leave the nucleus.
STEP 2: Translation
WHERE: On the ribosome
WHAT: mRNA sits on ribosome with its codons exposed. tRNA anticodons match with the codons bringing with them amino acids. Amino acids link. tRNA go away. Amino acid chain (aka polypeptides) forms protein.
Codon to Protein
A codon sequence “stands for” a certain amino acid (the building block
of proteins!)
For example, ACG stands for Threonine (an amino acid)
When a string of mRNA’s codons are “read” by tRNA’s anticodon, amino acids are put together in the specified order to make a protein!
Chonps Activity
Make a funky
creature!!!
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