Chapter 8: From DNA to Proteins (DAY ONE)
What is DNA?
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Your “genetic” information (___________________________)
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___________________________________________________________________
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DNA is an example of a nucleic acid which is an organic compound/major macromolecule
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The monomer (basic building block) of DNA is a ___________________________________ many
nucleotides join to form a long chain of DNA.
Nucleic Acids
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NUCLEIC ACIDS are built from subunits called ____________________
Overview: Structure of DNA
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DNA is a long macromolecule made up of units called nucleotides. Each
_______________________________________ is made up of 3 basic parts:
▪
a _____________________________________ (DEOXYRIBOSE is the sugar in DNA)
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a _____________________________________
▪
a _____________________________________
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The function of DNA is to _________________________________________ genetic information!
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SUGAR in DNA is_______________________________
Deoxyribonucleic Acid
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_____________________________ STRANDED
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Backbone (sides of ladder) made of _______________________and _______________________
DNA Structure: What does DNA look like?
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Classic Shape: “____________________________________________”
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The ___________________________________ of the “ladder” are made up of alternating
________________________________________________________.
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The “steps” or ___________________________________ of the “ladder” are made of 4 major
________________________________________:
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▪
Adenine
3. Cytosine
▪
Thymine
4. Guanine
When looking at the Nitrogen Bases….
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__________ always pairs with __________
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__________ always pairs with __________
Structure of DNA: Closer Look
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There are 4 kinds of nitrogenous bases in DNA
o
The __________________________ (larger, double rings)
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A = ___________________
▪
o
G = __________________
The ________________________________ (smaller, single rings)
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C = __________________________
▪
T = __________________________
Nitrogenous Bases – Steps of a Ladder
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___________________________________ (2 rings)
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___________________________________ (1 ring)
Double Helix
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A double helix looks like a twisted ladder or _____________________________________
o
The 2 strands of the double helix are held together by ________________________________
between adenine and thymine and between guanine and cytosine
▪
__________________________ always pair
▪
__________________________ always pair – this is known as the principle of
__________________________________ base-pairing rules
▪
These are known as _____________________________ rules
Rosalind Franklin
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At the same time of Watson and Crick, Franklin and her aide Maurice Wilkins were studying DNA.
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They used ____________________________ crystallography
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When DNA is bombarded with x-rays, atoms in DNA diffract on the x-rays in a pattern than can be
captured on film.
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Her x-rays showed an ______________________ surrounded by a circle
James Watson and Francis Crick Double Helix
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Developed an accurate model of DNA’s three-dimensional model called a
____________________________
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Published their findings in ______________________, to show their double helix model
o
Two strands of DNA wind around each other like a ______________________________
o
Strands are _____________________________________
Chromosome Structure in Eukaryotes
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DNA is:___________________________________________________________; Found in
______________________
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Eukaryotic chromosomes are made of ________________ & ___________________called
______________________
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Together the DNA & histone proteins forms a bead-like structure called a
_____________________________________
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Nucleosomes pack together to form thick coiled fibers. When cell is NOT dividing, these fibers are
spread out in nucleus as __________________________________. (Allows reading of code)
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When cell gets ready to divide, the fibers pack even more tightly to form
_____________________________.(Makes it easier to move DNA during mitosis)
DNA Replication: Why Replicate?
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In preparation for cell division (________________________________ the
____________________________________ of Interphase), a cell must duplicate its genetic info (DNA)
to pass on to the new daughter cells.
Overview: DNA Replication
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Replication __________________________ the genetic information.
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________________________________________ model suggested a way that DNA could be copied.
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Single DNA strand can serve as a ___________________________, or pattern, for a new strand.
o
Process by which DNA is copied during the cell cycle is called
____________________________________.
o
Replication assures that every cell has a _____________________________ set of
_________________________________ genetic information.
o
Remember, DNA is divided into ________________ chromosomes that are replicated during
the cell cycle.
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Each strand of the DNA double helix has all the information needed to
_________________________________ the other half by the mechanism of base pairing
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Because each strand can be ______________________________________________ the other
strand, the strands are said to be complementary.
Duplicating DNA
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Before a cell divides, it duplicates its DNA in a copying process called
___________________________________
o
During DNA replication, the DNA molecule:
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Separates into ___________ strands
▪
Produces __________________________ complementary strands following the rules of
base pairing
o
Each strand of the double helix of DNA serves as a _________________________, or model,
for the new strand
How is DNA copied?
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The structure of DNA explains how it can be copied. Each strand has all the info needed to construct
the _________________________________other half. If strands are separated,
_________________________ rules allow you to fill in the complementary bases.
Complementary Base Pairing
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____________________________________________
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____________________________________________
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So a complementary strand would look like this
o
Therefore, the strand ______________________________________ will replicate as:
_______________________________________
DNA Replication
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Sites where strand separation and replication occur are called ________________________________
Replication Steps
1. Enzymes “unzip” molecule by breaking__________________________________ that hold the strands
together and unwind it.
2. _________________________________________ joins nucleotides using original strand as template
and ___________________________________________for errors.
3. Copying happens in ____________________________ directions along the two strands & in
__________________________ places at once.
How Replication Occurs:
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DNA replication is carried out by a series of ___________________________________:
o
These enzymes _____________________________________________________________
other functions
o
Each strand then serves as a template for the attachment of
________________________________________________________
1. This is known as a ______________________________________________ process
because old strands are used to make new strands
2. The result is ___________________________________________ that are identical,
each one having one original strand and one new strand
Chapter 8: From DNA to Proteins (DAY TWO)
RNA
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_______________________________________________________
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Chain of nucleotides, each made of
_________________________________________________________________________________
containing base
•
•
Differs from DNA by:
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Sugar is _________________________________
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Has ___________________________________ instead of thymine
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Is a _____________________________ stranded structure
RNA IS USED TO ____________________________ PROTEINS
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Remember: proteins are built from _______________________________________
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Protein synthesis occurs on _____________________________________________
Base Pairs in RNA
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__________________________________________
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__________________________________________
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THERE IS NO __________________ IN RNA!
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The 3 types of RNA
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______________________________ = (messenger) codes for polypeptides
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______________________________ = (ribosomal) makes up ribosomes.
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RIBOSOMES are the protein builders!!!
______________________________ = (transfer) brings the amino acids to the ribosome during protein
synthesis
2 Stages in Making Proteins
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______________________________________________ – using DNA template to make
mRNA strand
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–
Writing the code
______________________________________________ – using mRNA strand to create
polypeptides
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Reading the code
TRANSCRIPTION: _______________________________________________________
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DNA is in the nucleus
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Proteins are made in the cytoplasm
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Where? _________________________________________________
Transcription: DNA ______________________________________
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This is the process by which mRNA is produced/written (transcribed) from DNA. This process occurs in
the nucleus, because DNA is TOO LARGE to leave the
_______________________________________.
The Major Steps of Transcription
1. ___________________________ gets unzipped
by____________________________________________.
2. The __________________________________ reads along one DNA strand and uses it as a template,
reading one ______________________ at a time.
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_________________________________ are groups of 3 nucleotides that code for a specific
amino acid.
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You can think of _________________________ as “__________________________” in a
sentence. Each __________________________________________________________; each
_____________________ (which are made of nitrogen bases) = a
_____________________________; each codon (or word) means something in the mRNA
sentence…the ________________________________________ code for an
_______________________________________________!!!!
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“___________________________” codon = _________________________
(Methionine)
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“___________________________” codons =
_________________________________________
3. __________________________________is produced/ __________________________________ with
the complimentary nucleotides.
4. The polymerase keeps making the _______________________ until a
“______________________________” codon is reached.
5. When the “stop” is reached, the new strand of ____________________________________ breaks
away, leaves the nucleus through the nuclear pore, and _______________________________ to the
________________________________. This is where protein synthesis begins.
6. The next major process of translation will occur at the ribosome, in the cytoplasm of the cell.
Transcription: You be the RNA polymerase!
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DNA Strand = _____________________________________________
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What is the complementary mRNA?
o
_________________________________________________
Translation: (cell’s way of ________________________________________ the mRNA message)
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Happens on _______________________________________
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Transfer RNA (tRNA) __________________________________ and brings in the correct amino acid
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Process that ______________________________________________, or translates, an mRNA
message into a polypeptide.
o
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One or more polypeptides make up a protein.
Remember, the “language” of nucleic acids uses four nucleotides:
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DNA: ___________________________________________
o
RNA: __________________________________________
“Language” of proteins, on the other hand, uses ______________ amino acids.
o
Amino acids are coded by mRNA bases sequences.
Translation: ____________________________________________________________________________
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The synthesis of polypeptides (PROTEINS) by the ribosome using the message carried by the mRNA.
Steps of Translation
1. The _____________________________________________________ to the first codon of
__________________________.
2. A _______________________________________________________ matches up to the first codon
on the ________________ – this is always __________________________________________”
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An anticodon is the complimentary base pair that matches the codon. For example, if the codon
is ___________________, the anticodon is _________________________________.
3. The ________________________________ is carrying an
____________________________________.
4. The ribosome (________________________________) _____________________________ the
_______________________ through and ______________________________ the next codon and
_____________________________ up the correct _________________________________; bringing
the next _______________________________________into line.
5. The ribosome binds the first and second amino acids together.
6. The _____________________________________________ after they “drop off” the amino acids.
7. This process occurs over and over until a ________________________________________ is met.
8. The result is a chain of polypeptides __________________________________________.
The Genetic Code
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The dictionary of the genetic code =
______________________________________ mRNA codon chart
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64 Codons – only _______________ amino acids
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______________________________
Last letter can change without mutation…
Ex: UUA & UUG both leucine
Practice
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What amino acid does the codon UUU code for?
________________
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What amino acid does the codon GAC code for?
________________
Start and Stop Codons – What’s a gene?
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A _______________________________ amino
acid is found at the beginning of most proteins –
_______________________________________. The codon for this is
____________________________.
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A ___________________________________ codon DOES _____________________ CODE FOR
ANY AMINO ACID – it is the signal that the protein is complete and can be released…
Translation: the basic concept
1) ______________________________ (ribosomal RNA) attaches to
__________________________and starts reading the
_________________________________
2) ______________________________ (transfer RNA) – carries amino acids and attaches them
to the growing protein chain
3) When protein production is complete, the ribosome releases the
___________________________
Translation: the basic concept continued….
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mRNA feeds into the ribosome
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________________________________________
tRNA decodes the mRNA
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How? ________________________________________________________________
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aa’s coded for by ____________________________ are attached to ______________________;
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aa’s brought by tRNA link up to form a protein _________________________________________
_____________________________ carries DNA’s instructions
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Central dogma of molecular biology:
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___________________________________ copies DNA
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Transcription converts ________________________________ into an intermediate molecule,
RNA
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Translation interprets an RNA message into a string of amino acids, called a
_____________________________.
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Single or multiple polypeptides working together to form a
_____________________________________.
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______________________________________________________
Chapter 8: From DNA to Proteins (DAY THREE)
Mutations
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Mutations are _______________________________________ in DNA that may or may not affect
phenotype.
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Mutations are any changes that take place in DNA:
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Can be spontaneous or caused by _______________________________________________
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Chemicals, high temperatures, UV light,
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Radiation
Can ___________________________________________ the genetic code, and be replicated
when forming new body cells.
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In sex cells, can be ___________________________________________ to offspring.
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Mutations can be neutral, beneficial, or harmful
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ex: Blue eyes – a mutation that occurred 6-10,000 years ago, can be traced back to
one ancestor
Point mutations
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_________________________________________: change in single base pair of DNA
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if does not affect the length of the code, will just change the amino acid in that position –
_________________________________________
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if does change the length of the code, is called a frameshift mutation, and are two types:
________________________________ AND
_______________________________
Some mutations affect a single gene, while others affect an entire chromosome.
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A mutation is a change in an organism’s DNA.
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Many kinds of mutations can occur, especially during _______________________________________.
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A point mutation substitutes ___________________________________ for another;
____________________________
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Change in _____________________________ base pair of DNA
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Many kinds of mutations can occur, especially during replication.
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A frameshift mutation __________________________________________ a nucleotide in the DNA
sequence.
Chromosomal Mutations
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Chromosomal mutations affect many genes.
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Chromosomal mutations may occur during _____________________________________
o
Gene duplication results from unequal _________________________________.
Effects Chromosome Numbers and Chromosome Shapes
1. Mistakes in numbers of chromosomes:
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_________________________________ -- members of a pair of homologous chromosome do not
move apart properly
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result in offspring that have
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________________________________ – abnormal chromosome number
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Trisomy or Monosomy or Polyploidy
2. Mistakes in shape of chromosomes:
a. _________________________________ – part of chromosome is broken off and lost
completely
b. _________________________________ – broken fragment of chromosome attaches to
sister chromatid so
section is repeated on that chromatid
c. _________________________________ – when fragment reattaches to original
chromosome but in reverse order
d. _________________________________ – broken fragment attaches to a nonhomologous
chromosome
Mutations may or may not affect phenotype.
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Chromosomal mutations tend to have a big effect.
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Some gene mutations change phenotype.
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A mutation may cause a ____________________________ stop codon.
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A mutation may change protein _______________________ or the active site.
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A mutation may change gene _________________________.