Download Genetics Intro/DNA Replication/Protein Synthesis Review Answer Key

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Biology 135: Genetics Intro, Protein Synthesis, & Replication Review
GENETICS INTRODUCTION
1) Define genetics.
The scientific study of heredity and inherited characteristics
2) Who is considered the “father of genetics?” What type of plants did he use to perform
the first genetic experiments?
Gregor Mendel; Pea Plants
3) Using the letter B, list what the genotype would be for the following:
a. Homozygous Recessive: bb
b. Homozygous Dominant: BB
c. Heterozygous Dominant: Bb
4) Brown eyes are dominant to blue eyes. A mother is heterozygous for brown eyes and a
father is homozygous for brown eyes. Create a Punnett square in the space below and
record the percent probability of both the phenotypes and the genotypes.
GENOTYPES:
PHENOTYPES
BB - 50%
Brown Eyes: 100%
Bb - 50%
5) Attached earlobes are dominant over unattached earlobes. Mom is homozygous for
attached earlobes and dad has unattached earlobes. Create a Punnett Square in the space
below and record the percent probability of both the phenotypes and genotypes.
GENOTYPES:
PHENOTYPES:
Ee: 100%
Attached Earlobes: 100%
6) In the chart below, give a brief description of each pattern of inheritance that is “beyond
basic dominant and recessive” in the left column and give an example of that type of
inheritance in the right column.
Inheritance Type
Description
Example
Codominance
Both alleles contribute to
the phenotype
A black feather chicken is
crossed with a white
feather chicken; the
resulting offspring is a
black and white speckled
chicken
Incomplete Dominance
-a case where one allele is A white flower is crossed
not completely dominant
with a red flower and the
over the other; the
offspring are pink flowers
heterozygote is somewhere
in between the two
homozygous phenotypes
Polygenic Trait
Traits produced by the
Human skin color
interaction of several genes
Multiple Alleles
Genes have more than two
alleles
Rabbit’s fur color could be
full color, albino,
Himalayan, or Chinchilla
DNA STRUCTURE
1) Complete Chargaff’s Rule for base pairing in a DNA molecule. A=T and G = C
2) What are the three parts that make up a DNA nucleotide?
Deoxyribose Sugar, Phosphate, Nitrogen Base
3) What scientist used X-Ray diffraction to find that the strand of DNA are twisted around
each other like coils of a spring?
Rosalind Franklin
4) What team of scientists built the first model of the DNA “double helix?”
James Watson & Francis Crick
RNA & PROTEIN SYNTHESIS
1) Explain three of the main differences between DNA & RNA.
-DNA has Deoxyribose Sugar, RNA has Ribose Sugar
-DNA is double stranded, RNA is single stranded
-DNA has Thymine as a Nitrogen Base, RNA has Uracil as a Nitrogen base
2) Fill in the blanks below to complete the “central dogma” of Biology.
DNA -> RNA -> Protein
3) What enzyme is responsible for constructing a complementary mRNA strand for a
template DNA strand in the process of protein synthesis?
RNA Polymerase
4) The construction of a mRNA molecule from a template DNA strand is known as the
process of Transcription. This process occurs in the Nucleus of the cell.
5) The construction of an amino acid chain from a template mRNA strand is known as the
process of Translation. This process occurs at the Ribosome of the cell.
6) What molecule is responsible for carrying the proper amino acids to the mRNA chain at
the ribosome? (What does it stand for?)
tRNA (Transfer RNA)
7) What holds together the amino acid chain in order to create a protein?
Peptide Bond
8) Transcribe the following DNA strand into a complementary mRNA strand:
AT G G C G TAAT C C G AT C G AATA C G G AT T
U A C- C G C -A U U- A G G- C U A -G C U -U A U -G C C -U A A
Translate the above mRNA strand into the proper amino acids in the space below. (Hint: Use
your amino acid codon circle chart.)
Tyr- Arg - Iso - Arg - Leu - Ala - Tyr - Ala - Stop
9) What is considered the “start codon?”
AUG
10) Define mutation.
DO NOT DO THIS QUESTION
11) Choose two of the types of mutations that we have learned about in class. Define each
type of mutation and provide an example of each type of mutation in the space below.
DO NOT DO THIS QUESTION
DNA REPLICATION
1) During what phase of the cell cycle does DNA replication occur?
Interphase
2) What enzyme unzips and unwinds the DNA double helix to begin the process of DNA
replication?
DNA Helicase
3) What enzyme in DNA Replication is responsible for adding nucleotides to the new strand
of DNA that is being created?
DNA Polymerase
4) What is the result of DNA replication?
Two identical DNA molecules
5) Why is DNA replication important and necessary?
So every newly created cell has a complete set of DNA