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TAKS review: DNA
TAKS Review
Obj. 2 TEK 6
(A) describe components of deoxyribonucleic acid
(DNA), and illustrate how information for specifying
the traits of an organism is carried in the DNA;
(B) explain replication, transcription, and translation
using models of DNA and ribonucleic acid (RNA);
(C) identify and illustrate how changes in DNA cause
mutations and evaluate the significance of these
changes;
(D) compare genetic variations observed in plants and
animals;
1. DNA is made up of
thousands of units called
nucleotides. What are the
three parts of the
nucleotide?
Sugar, phosphate group,
and nitrogen base
2. Which of these parts of
the DNA stores genetic
information?
The sequence (order) of
nitrogen bases.
TEK 6(A)
There are 4 kinds of
nitrogen bases in DNA:
A, G, C, & T
Adenine Guanine Cytosine Thymine
Phosphate
group
Deoxyribose
EXAMPLE
A G T T C G G A might give you blue eyes,
T G T C T A A G might give you brown eyes.
The order of the nitrogen bases dictates the
characteristics you have.
The order dictates which proteins are made in your cells,
and those proteins give you your traits.
TEK 6(B)
3. Nitrogen bases in DNA come in pairs.
T
C and A bonds to ______
G bonds to ______
4. If one side of the DNA is CAT TAC, then
what would the complementary side of the
DNA be?
CAT TAC
G TA A T G
An old TAKS question:
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Sickle-cell anemia is a disorder resulting from a
mutation that leads to the production of an abnormal
protein. Which component of the DNA molecule
provides instructions for the production of the protein?
A The phosphate groups
B The sugar molecules
C The sequence of nitrogen bases
D The bonds that hold the sugars to the bases
And another…
In all plant and animal cells, the nucleus contains long
molecules of DNA. Which of the following best
describes the function of DNA?
F DNA provides the shape and structure of the nucleus.
G DNA packages materials for transport through the
nucleus.
H DNA carries materials into and out of the nucleus.
J DNA contains the blueprint for producing the whole
organism.
And another…
If the template of a strand of DNA is 5'
AGATGCATC 3', the complementary strand
will be —
F 3' TCTACGTAG 5‘
G 5' CTACGTAGA 3‘
H 3' AGATGCATC 5‘
J 5' AGACGTCTA 3'
And even one more:
Erwin Chargaff studied the DNA of organisms within a
single species. Chargaff discovered that the amount of
adenine is about equal to the amount of thymine.
Which of these explains why the ratio of adenine to
thymine is nearly 1:1?
A Adenine and thymine pair with each other.
B Adenine binds with phosphates, while thymine binds
with nitrates.
C Adenine and thymine are identical in chemical
composition.
D Adenine bases contain a form of thymine.
One more…
The sequence of amino acids coded by a strand of
DNA directs the cell to make specific
A.
B.
C.
D.
Carbohydrates
Lipids
Proteins
Vitamins
DNA replication
TEK 6(B)
5. What happens just before a cell divides?
DNA replication occurs so that each new cell
can have an exact copy of DNA.
(Note: Body cells divide in mitosis to create
two identical cells that have identical DNA and
the same number of chromosomes.)
Think of the replicator on Star Trek:
replication means copying.
TAKS question…
If a cat has 38 chromosomes in each of its body
cells, how many chromosomes will be in each
daughter cell after mitosis?
F 11
G 19
H 38
J 76
Making Proteins
Review:
In what part of the cell are proteins made?
Where are the instructions for making those
proteins?
There are two steps in making proteins:
transcription and translation
DNA transcription
DNA transcription
DNA contains the instructions to make proteins.
Unfortunately, the instructions are in another
language, and the workers that will actually make
the proteins don’t understand it.
That’s where mRNA comes in – it will provide the
directions in a language the workers can
understand.
DNA transcription
In transcription, the DNA
is unzipped, and mRNA
is transcribed. The
instructions for making
proteins are written into
the mRNA.
Think of a prescription: the
doctor’s orders are
written down.
“script” means something
written down.
TEK 6(B)
6. Which nitrogen bases in found in RNA but not
in DNA?
Uracil –U
(A bonds to U in RNA)
7. What would the mRNA codon be that would be
created from the DNA sequence: CAT TAC?
DNA-
CAT TAC
mRNA- G UA A U G
TEK 6(B)
8. What is the process of copying the genetic
information in DNA to mRNA called?
Transcription
nucleus
Nucleus
What: Copies DNA to
make mRNA
Where: In the nucleus
Why: to carry
instructions out of
nucleus
mRNA
DNA
RNA
Polymerase
DNA translation
After the mRNA brings the instructions from the
nucleus to the site of protein production, the
protein is assembled during translation.
TEK 6(B)
9. mRNA contains information on what order to
put amino acids together to form a
Protein
______________
chain during the process of
translation.
10. The codon AUG codes for which amino acid?
AUG=
methionine
Let’s practice making a protein…
http://learn.genetics.utah.edu/content/begin/dna
/transcribe/
Practice question:
A cell with numerous ribosomes is probably
specialized for—
A.
B.
C.
D.
enzyme storage
energy production
protein synthesis
cell division
TEK 6(C)
11. What is a mutation?
is a change in genetic material (Change in
DNA leads to changes in protein chain.)
DNAMutation in one DNA base
mRNAAmino
Acid chain
(Protein)-
Causes changes in one mRNA base
New codon codes for a different amino acid
Sample TAKS question:
A mutation is defined as:
A.
B.
C.
D.
a change in an organism's DNA
the growth of an abnormal cell structure
the changing of a cell from one type to another
a way of changing mRNA to proteins
Question:
The molecule which acts as an intermediary
between the DNA and the ribosomes is
A.
B.
C.
D.
messenger RNA
transfer RNA
ribosomal RNA
intermediate RNA
TAKS question:
Mutations in DNA molecules can occur when —
F. replication of DNA is exact
G. a DNA enzyme attaches to an RNA codon
H. RNA codons are replaced by DNA
nucleotides
J. a change occurs in DNA nucleotide bases
Genetics Vocabulary Review
TEK 6(D)
Genotype: genetic make-up of an organism ex. Bb
Phenotype: expression of the genes of an organism
(ex. BLACK hair.)
Dominant: trait that is always expressed
Recessive: trait that can be hidden in the presence
of a dominant gene.
Gene: segment of DNA that codes for a protein that
controls a trait.
Trait: inheritable characteristic