Download amino acids ribosomes

DNA and RNA
• Deoxyribonucleic acid
(DNA) is made of
nucleotides Remember
____________.
that nucleotides are made
of three parts:
Phosphate group, 5-carbon
__________________________
sugar and a nitrogen
__________________________
base.
______
• The nucleotides that make
up DNA contain the sugar
deoxyribose and one of
____________
four different nitrogen
bases:
adenine,thymine, guanine
__________________________
or cytosine
____________
• In 1953, scientists
____________________________________
James Watson and Francis Crick
discovered that DNA is made of two
chains of nucleotides joined
together. The nucleotides bond at
their nitrogen bases to hold the two
strands together. The bases pair
together:
Adenine with Thymine and
_________________________________
________________________________
Guanine with Cytosine
• Write a complimentary strand
of bases for the following
sequence:
A T T G C G T A G C T G A T C
• If you know the percentage of
one nitrogen base in a strand
of DNA then you can estimate
the amounts of the other three.
Chargaff’s Rule
This is ________________.
• Watson and Crick with the help
of Rosalind Franklin also
discovered that DNA is twisted
in a shape called a
double
helix DNA looks like a
____________.
twisted ladder.
base pairs make up the
• The ___________
“steps” of the ladder. And the
sugar and phosphate make up
the “sides” of the ladder.
This is called the
_________________________.
sugar-phosphate
backbone
• DNA carries the code for
proteins. Proteins guide all
cell and body chemistry.
• Proteins are made from strands
amino acids
of ____________,
so DNA
actually codes for specific
ribosomes
amino acids and the __________
assemble them to make
proteins.
• In order for the proteins to
be made correctly, three
processes must occur: DNA
replication, RNA
transcription, and protein
translation.
DNA Replication
• DNA replication is how DNA
S
copies itself during the ___
interphase in order
phase of ___________
to pass traits on to new cells.
The new DNA is an exact copy of
the existing DNA.
1. An enzyme called _________
helicase breaks
hydrogen bonds between the
the _________
nitrogen bases and the two strands
of DNA unwind and separate.
2. Free nucleotides that are floating
around in the cell attach and bond
to the unwound exposed bases to
form new pairs. They only bond
with the ____________________.
(Acomplimentary base
T and C-G)Enzymes called DNA
Polymerases help bond the
nucleotides.
3. The sugar and phosphate parts of
the free nucleotides bond together
forming a backbone for the
__________________.
new
strand of DNA
4. The result is two identical
strands of DNA consisting of one
side of the “new” DNA and one side
of the “old” DNA. This is called
__________________.
semi-conservative
•
•
•
The picture above
is a model of
DNA
____.
What does X
represent in the
picture above?
a nucleotide
_______________
What is the shape
of the picture
above?
double helix
______________
RNA
• Ribonucleic
acid (RNA) is
also made of
nucleotides,
but they are
__________
different than
the ones in
DNA.
• RNA has _______
ribose sugar instead
of deoxyribose and it contains
a different nitrogen base.
Instead of thymine, RNA has
uracil It still contains
______.
adenine, cytosine and guanine.
single-stranded
RNA is also ________________
whereas DNA is doublestranded.
Transcription
• DNA stays in the ________
nucleus of
cells. In order to get the
protein codes to the ribosome
for assembly, a copy must be
made and sent to them. This
copy is made of RNA. The
process that makes the copy is
RNA transcription
called __________________.
– DNA _______
unwinds a small
section like it does
in replication.
– Free RNA nucleotides
pair with the unwound
section and their
sugar and phosphate
parts bond to form the
backbone.
– Once the RNA copy is made it
breaks away from the DNA and
bonds back together
the DNA ____________________.
– The new strand of RNA leaves
the nucleus and takes its
information into the
cytoplasm and to the
__________
ribosome.
Adenine (DNA and RNA)
Cystosine (DNA and RNA)
Guanine(DNA and RNA)
Thymine (DNA only)
Uracil (RNA only)
RNA
polymerase
RNA
DNA
transcription animation
• Write a complimentary strand of
RNA for the following DNA base
sequence:
A T T G C T G A C G T G T C G A T C
• RNA has many responsibilities
in the cell. There are three
types of RNA
messenger RNA (mRNA)- made
– __________
during transcription; delivers
amino acid codes to the
ribosomes
– __________
ribosomal RNA (rRNA)- makes up
ribosomes; reads codons
– _________
transfer RNA (tRNA)- transfers
amino acids to ribosomes
• A isrRNA
_____, B is tRNA
_____ and C is
_____.
mRNA
•
•
Every sequence of three nitrogen
codon
bases in mRNA is called a ______.
EX: AUC, UUU, GCA These different
codons hold information to make
specific amino acids. Since there
are four bases, __
64 different codon
combinations are possible.
These 64 combinations make up the
codes for the ___
20 different amino
acids.
• An __________
anticodon is a nitrogen
base sequence that is the
opposite of the original
codon. It is found on tRNA and
has the corresponding
___________
amino acid for the codon
attached to it.
• Write the correct anticodon
for the following codons:
–
–
–
–
CUGAAGGCUUUC-
Translation
• mRNA carries the codons to
ribosomes so that proteins
__________
can be assembled using the
correct amino acid sequence.
This process is called
____________
translation and involves all
three types of RNA.
a. Once the mRNA has attached to
the ribosome, tRNA binds to the
start codon (always AUG) and
_____________
begins forming a chain of amino
acids.
b. As the mRNA code is being
“translated”, it slides through
the ribosome. A new tRNA
_____
attaches at every codon, bonding
its amino acid to the previous
and then it falls off.
c. The mRNA codon determines the
Amino acid that is joined to
___________
the growing protein.
d. The newly formed protein falls
off when the ribosome reads the
stop codon
___________.
translation animation
tRNA
mRNA
Ribosome
mRNA
anticodon
codon
• What process is shown above?
____________
translation
• Label structures A-G.
DNA
mRNA
tRNA
UAC
TAT
GCA
Amino acid
Mutations
• Sometimes there are mistakes
in the DNA sequence that may
affect the genetic information
passed to offspring. This is
mutation
called a _________.
• Some mutations are small and
undetected, but some may cause
problems.
• Things that cause mutations in
mutagens Some
DNA are called _________.
examples are X rays, UV light,
and radioactive substances.
• There are two different types
gene mutations
of mutations: _______________
chromosomal mutations
and ______________________.
• Gene mutations:
Point mutation- a change in a
– ______
single base pair in DNA. This
would result in a different
codon and a completely different
amino acid in the chain.
– ___________
Frameshift mutation- a single
base pair is added or deleted,
resulting in a shift in the
sequence. This results in amino
acid changes from the point of the
shift on, because if shifts the
reading of the codons by one base
pair.
• Chromosomal mutations can
division
happen during cell
_____________.
Often, parts of the
chromosomes are broken off and
lost, or they break and rejoin
incorrectly, or join to the
wrong chromosome altogether.
Deletion
– _________part of a chromosome
is left out.
– Insertion
__________- part of a chromosome
breaks off and rejoins to the
sister chromatid, causing a
duplication of a gene on the
same chromosome.
– Inversion- part of a chromosome
breaks off and is reinserted
backwards
__________.
– Translocation- part of a
chromosome breaks off and is
added to another chromosome.
Chromosomal Mutations
Nondisjunction
• _______________chromosomes do
not separate correctly and
offspring end up with too many
or too few chromosomes. This
causes birth defects.