12-1 DNA
_____________________ and _________________ discovered DNA in 1953.
Video:
Write down 3 things that you remember from the video: What is DNA and How does it Work?
1.____________________________________________________________________________
2. ____________________________________________________________________________
3. ____________________________________________________________________________
DNA stands for: ________________________________________________________________
Very large biomolecule made up of nucleotides
Called the “blueprints of life” because it contains ____________________________________
____________________________________________________. Proteins are essential for life.
DNA floats freely in the cytoplasm of _____________________________________________.
DNA is protected in the nucleus of _______________________________________________.
Chromosomes and DNA
A _______________________________________________________________________that is
passed down from parents to children and confers a
trait to the offspring. Genes are organized and
packaged in units called
“__________________________________.”
Each gene encodes for a certain
______________________________.
DNA is made of ___________________________________.
Nucleotide is a monomer of nucleic acids made up of 3 parts
-
________________________________________
-
________________________________________
-
________________________________________
There are four kinds of Nitrogenous bases in in DNA:
-
_______________________________________
-
_______________________________________
-
_______________________________________
-
_______________________________________
DNA Structure –
Made of 2 strands that wrap around each other to form a double helix (looks like a spiral
staircase)
The sides (a.k.a. the backbone) : Alternating Sugar, phosphate, sugar, phosphate
The middle: Nitrogen bases paired together.
Draw and image of DNA structure in the space below, include labels
Base Pair Rule (Chargaff’s Rule)
-
________________________pairs with____________________________________
-
________________________pairs with____________________________________
Q: DNA is a long molecule made of monomers called
a. nucleotides.
b. purines.
c. pyrimidines.
d. sugars
Q: In DNA, the following base pairs occur:
a. A with C, and G with T.
b. A with T, and C with G.
c. A with G, and C with T.
d. A with T, and C with T.
12–2 Chromosomes and DNA Replication
Replication of DNA
DNA molecules can_________________________________________. This is
called________________________. (ATP is the energy source)
Replication is important for reproduction and must occur every time a cell divides.
That way each cell has a complete set of instructions for making proteins.
Steps to DNA Replication
1. In the nucleus, ______________________________________between the nitrogen bases
of DNA (A, T, G, C).
2. This causes the DNA to unzip like a zipper.
3. Enzymes in the nucleus called ______________________________________directs free
floating nucleotides in the nucleus to attach to each strand following the rules of base
pairing.
4. Each strand serves as a template for the new strand.
5. This results in__________________________________________________________.
6. This is called ____________________________________________________,
producing two copies of DNA that each ______________________________________
_________________________.
Q: The first step in DNA replication is
a. producing two new strands.
b. separating the strands.
c. producing DNA polymerase.
d. correctly pairing bases.
Q: The first step in DNA replication is
a. producing two new strands.
b. separating the strands.
c. producing DNA polymerase.
d. correctly pairing bases.
Q: In addition to carrying out the replication of DNA, the enzyme DNA polymerase also
functions to
a.
b.
c.
d.
unzip the DNA molecule.
regulate the time copying occurs in the cell cycle.
“proofread” the new copies to minimize the number of mistakes.
wrap the new strands onto histone proteins.
12-3 RNA and Protein Synthesis
How does DNA give us our traits?
Genes are
____________________________________________,
and the proteins give us our traits
What are proteins?
A category of molecules, each with a unique shape, found EVERYWHERE in your body,
required for the structure and function of our body:
Examples of proteins include:
_____________________________________________________________________________
What monomer makes up proteins? ____________________________________________
Proteins (polymers) _____________________
______________________________________
(monomers) attached together.
There are __________ different kinds of amino acids found in living things.
There are thousands, maybe millions, of different kinds of proteins in living things.
Imagine that the twenty kinds of amino acids are like twenty different kinds of beads in a bead
kit……and we have an unlimited supply of them.
You could make an infinite number of different necklaces
from just those 20 different kinds of beads.
Different colors, sequences, shapes, and lengths
EACH NECKLACE HAS A DIFFERENT ___________________
Likewise, there are ___________________________________________________________
acids, and ______________________________________________________in living things!
What is the process to make a protein?
(Draw the diagram in the space below)
What is RNA? ______________________________________________________________
RNA is like DNA (it’s comprised of nucleotides), with a few differences:
Sugar is different (__________________instead of deoxyribose)
Nitrogen-containing bases include:
-
___________________________________________
-
___________________________________________
-
___________________________________________
-
___________________________________________
RNA is a _________________________________(not double ….the bases are unpaired)
3 Types of RNA
-
___________________________________
___________________________________
-
___________________________________
Messenger RNA
Messenger RNA (mRNA) – the “mirror image” of a DNA code (except Uracil replaces
Thymine); serves as the template from which proteins (specific amino acid sequences) are
built,________________________________________________________________________.
Ribosomal RNA
lRibosomal RNA (rRNA)–Ribosomes are made up of proteins and ribosomal RNA
(rRNA). “reads” the mRNA code during protein synthesis RNA
Transfer RNA
Transfer RNA (tRNA)– found in the cytoplasm,
______________________________________________________________________________
TRANSCRIPTION
The process ___________________________________________________________________
______________________________________________________________________________
1. With the help of enzymes (RNA polymerase), DNA and separates the DNA strands.
2. RNA polymerase then uses one strand of DNA as a template from which nucleotides are
assembled into a strand of RNA
3. The mRNA strand detaches from the DNA
4. The DNA “re-zips”
Let’s Practice
Given the DNA sequence below, what would be the mRNA code ?
ATTCGGGATAACCT
________________________________
The Genetic Code
A __________________ consists of _____________________________________________on
mRNA that specify a particular amino acid.
Each________________________________________________________________that is to be
placed on the polypeptide chain.
Some amino acids can be specified by more than
one codon.
TRANSLATION
Translation is the____________________________________________________________
_______________________________________________.
Translation __________________________________________________.
During translation, the cell uses information from messenger RNA to produce proteins.
Before translation begins…….Messenger RNA is transcribed in the nucleus, and then enters
the cytoplasm where it attaches to a ribosome.
Translation
-
Translation begins when an mRNA molecule attaches to a ribosome and the start
codon “AUG” is read, signifying the start of the amino acid chain.
-
As each codon of the mRNA molecule moves through the ribosome, the proper
amino acid is brought into the ribosome by tRNA.
-
In the ribosome, the amino acid is transferred to the growing amino acid chain
-
Each tRNA molecule carries only one kind of amino acid.
-
In addition to an amino acid, each tRNA molecule has three unpaired bases.
-
These bases, called the________________, are complementary to one mRNA codon.
The ribosome binds new tRNA molecules and amino acids as it moves along the mRNA.
The process continues until the ribosome reaches a stop codon, signifying the end of the
polypeptide
Q: A base that is present in RNA but NOT in DNA is
a. thymine.
b. uracil.
c. cytosine.
d. adenine.
Q: The nucleic acid responsible for bringing individual amino acids to the ribosome is
a. transfer RNA.
b. DNA.
c. messenger RNA.
d. ribosomal RNA.
Q: A codon typically carries sufficient information to specify a(an)
a. single base pair in RNA.
b. single amino acid.
c. entire protein.
d. single base pair in DNA.
12.4 Mutations
What are Mutations?
•
Changes in the _____________________________of DNA
(genetic material)
•
May occur in _________________________________ (aren’t passed to offspring)
•
May occur in __________________________________(eggs & sperm) and be
passed to offspring
Kinds of Mutations
Mutations that produce changes in___________________________________________
_________________________________________.
Mutations that produce changes in _______________________________are known as
___________________________________________________.
Gene Mutations
Gene mutations involving a change in one or a few nucleotides are known as
_____________________________because they occur at a single point in the DNA sequence.
Point mutations include_________________________________________________________.
Substitutions usually affect no more than a single amino
acid. _________________________________________
_____________________________________________.
An example of a disorder from substitution is:
The effects of insertions or deletions are more dramatic.
The addition or deletion of a nucleotide causes a shift in the grouping of codons,
therefore______________________________________________________________.
Changes like these are called_____________________________________.
In an insertion, an
_____________________________________________________.
In a__________________, the loss of a
___________________________________and the reading
frame is shifted. Amino Acid Sequence Changed.
Chromosomal Mutations
Chromosomal mutations involve__________________
______________________________________, break or are
lost during mitosis or meiosis.
Chromosomal mutations include deletions, duplications,
inversions, and translocations.
Deletions involve the loss of all or part of a chromosome.
Duplications produce extra copies of parts of a chromosome (sequence repeated).
Inversions reverse the direction of parts of chromosomes.
Translocations occurs when part of one chromosome breaks off and attaches to another.
Are Mutations Helpful or Harmful?
•
Mutations happen ____________________________
•
Almost all mutations are ____________________
•
Chemicals & UV radiation cause mutations
•
Many mutations are ______________________________________.
– Do you remember the name of that enzyme?
•
•
_____________________________________
Some type of ________________________________result from
___________(body cell) mutations
•
Some mutations may _____________________________________(beneficial)
Q: The type of point mutation that usually affects only a single amino acid is called
a. a deletion.
b. a frameshift mutation.
c. an insertion.
d. a substitution.
Q: A mutation that affects every amino acid following an insertion or deletion is called
a(an)
a. frameshift mutation.
b. point mutation.
c. chromosomal mutation.
d. inversion.
Q: A mutation that affects every amino acid following an insertion or deletion is called
a(an)
a. frameshift mutation.
b. point mutation.
c. chromosomal mutation.
d. inversion.