Download DNA and Genes - Wayne County School District

DNA
Deoxyribonucleic acid (DNA) is made of
nucleotides
__________________.
 Remember that nucleotides are made of
three parts:
•a 5-carbon sugar,
_________________________________
•a phosphate group,
_________________________________
•and a nitrogen base
_________________________________

DNA

The nucleotides that make up DNA
deoxyribose and one
contain the sugar ___________
of four different nitrogen bases:
adenine (A), thymine (T),
_________________________________
guanine (G), or cytosine (C).
_________________________________
DNA


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:
A with T and C with G
________________________________
DNA

Write a complimentary strand of bases
for the following sequence:
ATTGCGTAGCTGATC
TAACGC ATCGACTAG
DNA

Watson and Crick
also discovered that
DNA is twisted in a
shape called a
______ _____.
double
helix
DNA looks like a
twisted ladder.
DNA

The ______________
make up the
base pairs
“rungs” of the ladder. And the sugar and
phosphate make up the “sides” of the
ladder. This is called the
sugar-phosphate backbone
____________________________.
DNA

DNA carries the code for proteins.
Proteins guide all cell and body chemistry.
DNA

Proteins are made from strands of
amino acids so DNA actually codes
____________,
for specific amino acids and the
ribosomes
_________________
assemble them to
make proteins.
In order for the proteins to be made
correctly, three processes must occur:
1. DNA replication
2. RNA transcription
3. and protein translation.
DNA Replication
DNA Replication

DNA replication is how DNA copies itself
S phase of _____________
interphase
during the ___
in order to pass traits on to new cells. The
new DNA is an exact copy of the existing
DNA.
DNA Replication

An enzyme called _____________
helicase
breaks the bonds between the nitrogen
bases and the two strands of DNA
unwind and separate.
DNA Replication



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
complimentary
base
______________ _____.
(A-T and C-G)
DNA Replication

The sugar and phosphate parts of the
free nucleotides bond together
forming a backbone for the
________________________________.
new strand of DNA
DNA Replication

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 semi-conservative
called ________________.
RNA
RNA

Ribonucleic acid (RNA) is also made of
different
nucleotides, but they are ___________
than the ones in DNA.
RNA

RNA has ___________
sugar instead of
ribose
deoxyribose and it contains a different
nitrogen base. Instead of thymine, RNA
uracil It still contains adenine,
has ______.
cytosine and guanine. RNA is also
__________________
whereas DNA is
single-stranded
double-stranded.
Transcription
Transcription

DNA stays in the _________of
cells. In
nucleus
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 called
transcription
____________________.
Transcription
a. DNA _____________
a small section
unwinds
like it does in replication.
b. Free RNA nucleotides pair with the
unwound section and their sugar and
phosphate parts bond to form the
backbone.
Transcription
c. Once the RNA copy is made it breaks
away from the DNA and the DNA
bonds back together
_______________________________.
d. The new strand of RNA leaves the
nucleus and takes its information into
cytoplasm and to the ribosome.
the _________
Transcription
Write a complimentary strand of RNA
for the following DNA base sequence:
ATTGCTGACGTGTCGATC
U AACGACUGCACAGCUAG

Transcription

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
Transcription
Ribosomal
 _________________
RNA (rRNA)makes up ribosomes; reads codons
Transcription

Transfer
_________________
RNA (tRNA)transfers amino acids to ribosomes
Transcription

Every sequence of three nitrogen bases
in mRNA is called acodon
___________. EX:
AUC, UUU, GCA These different codons
hold information to make specific amino
acids. Since there are four bases, ____
different
codon combinations are
64
possible.
Transcription

These 64 combinations make up the
twenty different amino
codes for the ________
acids. The mRNA genetic code is on
p.298 in your book. Learn how to read it.
Transcription

anticodon
An _____________
is a nitrogen base
sequence that is the opposite of the
original codon. It is found on tRNA and
has the corresponding
__________________
for the codon
amino acid
attached to it.
Transcription

Write the correct anticodon and amino
acid for the following codons:
 CUG AAG GCU UUC-
Translation
Translation

mRNA carries the codons to
_______________
so that proteins can be
ribosomes
assembled using the correct amino acid
sequence. This process is called
______________
translation and involves all three types
of RNA.
Translation
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.
Translation
b. As the mRNA is being read, it slides
through the ribosome. A new
tRNA
_________
attaches at every codon,
bonding its amino acid to the previous
and then it falls off.
Translation
c. The newly formed protein falls off
when the ribosome reads the
_____________.
stop codon
Mutations
Mutations
2. Sometimes there are mistakes in the DNA
sequence that may affect the genetic
information passed to offspring. This is
called a ____________.
mutation
Mutations
1. Some mutations are small and
undetected, but some may cause
problems.
Mutations
2. Things that cause mutations in DNA are
mutagens Some examples are
called __________.
X rays, UV light, and radioactive
substances.
Mutations
1.
There are two different types of mutations:
_________________________
and
gene
mutations
chromosomal
____________________________.
mutations.
Mutations
1.
Gene mutations (p.304 Figure 11.10):
Mutations
a. 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.
Mutations
a. _____________
mutation- a single base
Frameshift
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 it shifts the
reading of the codons by one base pair.
Mutations
7. Chromosomal mutations can happen
mitosis or meiosis
during ____________________.
Often,
parts of the chromosomes are broken off
and lost, or they break and rejoin
incorrectly, or join to the wrong
chromosome altogether.
Mutations
a. ____________part of a chromosome
Deletion
is left out.
Mutations
b. ____________Insertion part of a chromosome
breaks off and rejoins to the sister
chromatid, causing a duplication of a
gene on the same chromosome.
Mutations
c. Inversion- part of a chromosome
backwards
breaks off and is reinserted
__________.
Mutations
d. Translocation- part of a chromosome
breaks off and is added to another
chromosome.
Mutations
e. _________________Nondisjunction chromosomes
do not separate correctly and offspring
ends up with too many or too few
chromosomes. This causes birth
defects.