Download Cell Controls

http://i.livescience.com/images/080114-cell-control-02.jpg
Cell Controls
How does a cell
control its
processes?
DNA – deoxyribonucleic acid
• Unit of heredity
• Blueprint for proteins (instructions)
• Found in chromosomes in the nucleus of every
cell
http://imagecache2.allposters.com/images/pic/JAG/03-PS101-2~DNA-Posters.jpg
DNA
• Watson and Crick – proposed double helix
shape of molecule (twisted ladder)
DNA Structure
Monomer – nucleotide
1. Sugar (Deoxyribose)
2. Nitrogen Base
3. Phosphate
biology.clc.uc.edu/graphics/bio104/nucleotide.jpg
DNA Structure
Polymer – nucleic acid
Backbone made of sugar and
phosphate chain
Steps of ladder are nitrogen
bases
http://publications.nigms.nih.gov/thenewgenetics/i
mages/ch1_nucleotide.jpg
DNA Structure
Four possible nitrogen
bases in DNA
Adenine
Base pair rules
Thymine
Cytosine
Guanine
users.rcn.com/.../BiologyPages/B/BasePairing.gif
DNA Structure Video
• http://www.youtube.com/watch?v=qy8dk5iS1
f0&feature=player_embedded
DNA Model Lab
Purpose: create a model of a DNA molecule
1. Separate gumdrops into color groups.
2. Designate a color for each component of the
model, list in lab notebook.
3. Build a double helix model using toothpicks
for bonds.
4. Use p. 284 in the text for a guide.
DNA Model Activity Questions
Draw your model in your lab notebook. Answer:
1. In your model, are the sugar molecules directly across
from each other?
2. Are the phosphates molecules directly across from
each other?
3. What makes up the backbone?
4. How many adenine – thymine rungs did you make?
5. How many cytosine – guanine rungs did you make?
6. Is the arrangement of the bases of your ladder the
same as others in the class? Why or why not?
DNA Replication
• Makes an exact copy of
DNA molecule
• Occurs in nucleus before
cell division
• Each cell will have its
own set of instructions
http://www.topnews.in/health/files/Identical-Twins.jpg
DNA Replication Steps
1. Original DNA strand unzipped by enzymes,
base pairs separate
http://images.google.com/imgres?imgurl=http://upload.wikimedia.org/wikipedia/commons/thumb/7/70
/DNA_replication_split.svg/297pxDNA_replication_split.svg.png&imgrefurl=http://commons.wikimedia.org/wiki/Image:DNA_replication_s
plit.svg&usg=__8ipMfzUIe3bIB_V2tVy2tUoCmj0=&h=599&w=297&sz=74&hl=en&start=7&um=1&tbnid=g
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Den%26rls%3Dcom.microsoft:en-us%26sa%3DN
DNA Replication Steps
2. Free nucleotides base pair with open bases
DNA Replication Steps
3. Results in two identical copies of DNA
molecule
DNA Replication
Semi-conservative replication:
each new strand has one backbone of the
original strand
http://library.thinkquest.org/C0123260/basic%20knowledge/images/basic%20knowledge/DN
A/semiconservative%20replication.jpg
DNA Replication Practice
Original DNA
Strand
A
C
T
T
G
C
A
G
-
T
G
A
A
C
G
T
C
New DNA Strands
A
C
T
T
G
C
A
G
-
T
G
A
A
C
G
T
C
A
C
T
T
G
C
A
G
-
T
G
A
A
C
G
T
C
DNA Replication Video Clips
• http://www.youtube.com/watch?v=4jtmOZaIv
S0&feature=player_embedded
• http://www.youtube.com/watch?v=hfZ8o9D1
tus&feature=player_embedded
• http://www.youtube.com/watch?v=rpwjZX_z5
rg&feature=player_embedded
RNA – ribonucleic acid
•
•
•
•
Works to make proteins
Ribose sugar in backbone
Single stranded
Base pairs:
– Guanine, Cytosine
– Adenine, Uracil
– (No thymine in RNA)
http://images2.clinicaltools.com/images/gene/rna2.jpg
Three types of RNA
1. Messenger RNA (mRNA)
• Found in nucleus and at ribosomes
• Forms codons – 3 base sequence
• Does transcription – copies DNA code in
nucleus, moves to ribosome
Cell
Nucleus
www.ncbi.nlm.nih.gov/.../images/mrna.gif
mRNA video
Three types of RNA
2. Ribosomal RNA (rRNA)
• Makes up ribosomes
• Reads mRNA codons and helps assemble
amino acids in correct order
Three types of RNA
3. Transfer RNA (tRNA)
• Found in cytoplasm
• Transports amino acids to ribosomes and
assembles them into a protein (translation)
Three types of RNA
3. Transfer RNA (tRNA)
• Brings amino acid to
ribosome
• Anticodon pairs with
mRNA codon at the
ribosome
Amino
acid
Anti-codon
http://molbioandbiotech.files.wordpress.com/2007/09/trna1.gif
Types of RNA video
Compare DNA and RNA
Deoxyribonucleic acid
Ribonucleic Acid
Holds the code for making proteins
“The Boss”
Found in the nucleus of cells
Copies the codes and helps make
the proteins “The Workers”
Found in nucleus and cytoplasm
3 types
Messenger – mRNA
Ribosomal – rRNA
Transfer – tRNA
Double helix – 2 strands
Made of nucleotides
Backbone
Deoxyribose sugar
Phosphate
Single strand
Made of nucleotides
Backbone
Ribose sugar
Phosphate
Nitrogen Bases
Nitrogen Bases
Adenine
Thymine
Cytosine
Guanine
Adenine
Uracil
Cytosine
Guanine
DNA Rap
• http://www.youtube.com/watch?v=d1UPf7lXe
O8
Biology Central Dogma
DNA

RNA
Transcription

Protein
Translation
How are proteins made in a cell?
Transcription:
– Occurs in nucleus when a protein is needed
– DNA  mRNA
nucleus
http://www.scientificpsychic.com/fitness/transcription.gif
Steps of transcription
1. DNA unzips
2. Free mRNA nucleotides join the open DNA
bases
3. mRNA leaves DNA, DNA rezips
4. mRNA segment leaves nucleus, moves to
ribosome
Steps of transcription
Code is copied (transcribed) from DNA instructions
DNA =
T A C C G A T T G
mRNA =
A U G G C U A A C
mRNA codon = 3 bases, codes for 1 amino acid
RNA Transcription Practice
DNA strand: ATCCGGAATCCGTACGCTCTATAA
RNA strand: ____________________________
What is this process called?
Where does this process occur?
Where will mRNA go after being made?
What is the 3 base code on mRNA called?
What does it code for?
Biology Central Dogma
DNA

RNA
Transcription

Protein
Translation
Translation
• mRNA code is translated into a protein
• Occurs at ribosome
• mRNA codon = amino acid
• How do we know what codon codes for which
amino acid?
Amino Acid Chart
Steps of translation
1.
2.
3.
4.
5.
mRNA attaches to ribosome
rRNA reads codons
tRNA brings in amino acid
tRNA anticodon matches mRNA codon
amino acids joined by peptide bonds to form
a protein
www.dorlingkindersley-uk.co.uk/static/clipart...
Easter Eggs and Proteins
1.
2.
3.
4.
Find ONE egg
Copy the DNA code from your egg
Transcribe it into mRNA codons
Determine the anticodon sequence for each
message
5. Search out the correct anticodon card and
copy the word on back in lab notebook
6. Write the sentence from the revealed words
Protein Synthesis Practice
DNA: TACCGCTATCCCGAATAATAGAAT
Copy this table and complete. Answer questions.
DNA
TAC
Process

mRNA
Process

Amino
Acid
tRNA
Protein Synthesis Practice
• Where is DNA in the cell?
• Where are amino acids assembled?
• Where is the codon found? What is it used
for?
• Where is the anticodon found? What is it
used for?
• Did you build a protein? Why?