MIDTERM REVIEW
Honors Biology
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SB2: Students will analyze how biological traits are
passes on to successive generations.
– Distinguish between DNA and RNA.
– Explain the role of DNA in storing and transmitting cellular
information.
– Using Mendel’s Laws, explain the role of meiosis in
reproductive variability.
– Describe the relationships between changes in DNA and
potential appearance of new traits including – alterations
during replication, insertions, deletions, substitutions,
mutagenic factors, radiation, chemicals.
– Compare the advantages of sexual reproduction and
asexual reproduction in different situations.
– Examine the use of DNA technology in forensics, medicine
and agriculture.
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30. Complete a monohybrid cross. Long tails are
recessive to short tails in squirrels. Cross a long tail
squirrel with a heterozygote. Identify the
phenotypic and genotypic ratios.
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31. How are these patterns of inheritance different
from complete dominance?
a. incomplete dominance
b. codominant
c. sex-linked
d. multiple alleles
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MENDEL’S LAWS
• Law Of Dominance
• Law of Segregation
• Law of Independent Assortment
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• Mutation – DNA sequence is damaged or changed
which causes a mistake in the genetic message.
• CHROMOSOMAL MUTATIONS
• Deletion, Duplication, Inversion, Translocation,
Nondisjunction (Aneuploidy)
• Down’s (trisomy 21), Turner’s (XO), Klinefelter’s
(XXY)
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POINT MUTATIONS
– Substitution, Frameshift (deletion, insertion)
– Sickle Cell, Cystic Fibrosis
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• Why are frameshift mutations so bad?
• Factors that can cause mutations:
– Chemicals, radiation (X-rays, UV, gamma rays)
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17. A ________________ is a mistake or change in the DNA
sequence.
18. Identify some mutagenic factors.
19. Explain what occurs in the following types of chromosomal
mutations.
a. deletion –
b. duplication –
c. inversion –
d. translocation –
e. aneuploidy –
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20. List an example of an aneuploidy disorder.
21. What is nondisjunction?
22. A ________________ mutation is a change to a single
base pair that changes an amino acid in a protein.
23. What happens in a substitution mutation? How many
amino acids could be changed?
24. When a single nucleotide is added or deleted, it throws
the sequence of nucleotides and codons off resulting in a
______________.
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• GENETIC ENGINEERING: The process
of changing the genetic makeup of an
organism to introduce a desirable trait.
• Genes are transferred from one species
into another species resulting in a
transgenic organism that contains
recombinant DNA.
• Recombinant DNA contains DNA spliced
together from two different organisms.
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TRANSGENIC ORGANISMS
Transgenic plants
• help farmers grow crops more efficiently
and with less impact on the environment.
Transgenic animals
• widely used in medical research – as
sources of medically valued proteins or
pharmacologicals.
• food animals are being altered to be more
nutritious, disease resistant, or easier to
raise.
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• GENE THERAPY - The transfer of
normal or modified genes into a
person’s body cells to correct a
genetic defect or boost resistance to
disease - possibly cure genetic
disorders.
• It is a technique for correcting
defective genes that are responsible
for disease development.
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DNA FINGERPRINTING
• Restriction enzymes and gel
electrophoresis are used to splice and
separate DNA fragments.
• This process produces a gel containing a
banded pattern of DNA fragments that
are used to compare individuals.
• DNA can be replicated using Polymerase
Chain Reaction (PCR) to amplify the
DNA.
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25. What is genetic engineering? Give an example
of splicing genes to form a transgenic organism.
Define recombinant DNA.
26. How are transgenic organisms beneficial to the
medical field and agriculture? Provide examples!
27. What is Gene Therapy?
28. DNA ____________________ is the use of gel
electrophoresis and restriction enzymes to
separate DNA fragments resulting in banded
patterns.
29. How is PCR and gel electrophoresis used in
forensics?
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CENTRAL DOGMA
1. DNA replications with the help of DNA helicase (unwinds
and unzips), DNA polymerase (adds nucleotides) and DNA
ligase (binds Okazaki fragments). Replication.
2. DNA unzips with the help of DNA helicase.
3. RNA nucleotides bond the DNA template with the help of the
enzyme RNA polymerase. Transcription.
4. mRNA leaves the nucleus and travels to the ribosome.
5. tRNA bonds to mRNA with the help of rRNA, to place the
amino acids in proper order. Translation.
6. Amino acids form peptide bonds to create a protein, a
polypeptide, or a chain of amino acids.
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DNA
STRUCTURE
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How RNA differs from DNA:
– RNA is single strand of nucleotides.
– RNA is a copy of DNA used for protein synthesis.
– RNA nucleotides have a uracil base instead of
thymine.
– Otherwise, DNA and RNA are the same. Their
phosphates, sugars, and bases show the same
bonding patterns to form nucleotides and their
nucleotides bind to form nucleic acids in the same
way.
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1. What are the 2 types of nucleic acids?
2. A __________ is a sequence of nucleotides that codes
for a protein.
3. A __________________ is the monomer of DNA &
RNA.
4. What are the parts that make up a nucleotide of DNA?
a.
b.
c.
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5. What are the parts that make up a nucleotide
of RNA?
a.
b.
c.
6. What is the name of the bond formed
between the nitrogen bases called?
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• DNA REPLICATION
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TRANSCRIPTION
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• TRANSLATION
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CODON - ANTICODON
• mRNA = CODON
– Carrie protein codon sequence to the ribosome
• tRNA = ANTICODON
– carries amino acid to ribosome
• Amino acid = CODON
– Use codon NOT anticodon sequence to
determine amino acid
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8. Find the complimentary strand.
a. DNA strand A A T G C A
DNA strand
b. DNA strand A A T C G A
mRNA strand
c. mRNA strand G U U A A A
tRNA strand
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9. _________________ occurs when DNA makes a copy
of itself to form 2 strands of DNA.
10. ____ RNA carries genetic message of DNA into
cytoplasm.
11. ____ RNA brings amino acids to mRNA in ribosome
for protein synthesis.
12. ______________________ occurs when mRNA copies
a segment of DNA. Where does this occur in the cell?
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13. _____________________ occurs when mRNA is used
to make proteins. Where does this occur in the cell?
___________________
14. What is a codon?
15. What is an anticodon?
16. Transcribe and translate the segment of DNA.
DNA
CTT CGA ATA CGT
mRNA
amino acid
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CELL CYCLE
• A series of events of cell growth and division
• Steps of Cell Cycle: Interphase – G1, S, G2; M
phase – mitosis or meiosis; and Cytokinesis
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INTERPHASE
• G1 – longest phase, builds proteins,
carbohydrates, and lipids, and more
cytoplasm.
• S – DNA replication
• G2 – proteins synthesized, more organelles
made, cytoplasm expands
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Mitosis
• nucleus divides into 2 identical nuclei with
identical genetic information
• In Eukaryotes
– It is the main process of growth and repair. It is
the process by which unicellular and
multicellular organisms asexually reproduce.
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MEIOSIS
• Nucleus divides twice into 4 different nuclei with
different genetic information.
• In Eukaryotes, it is the formation of gametes for
sexual reproduction.
• Each gamete cell will contain one of the pairs of
homologous chromosomes
• As a result: 4 cells form from 1 parent cell and
they contain the haploid (N) number of
chromosomes
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1. What occurs in interphase?
2. What occurs in cytokinesis?
3. What causes the genetic variation in meiosis?