This document provides instructions for a genetics assignment with three parts. Part I involves transcribing and translating DNA sequences, including an original sequence and two mutations, and answering questions about transcription, translation, and how mutations may affect proteins. Part II involves completing a Punnett square for cystic fibrosis inheritance and calculating offspring probabilities. Part III asks how meiosis and sexual reproduction produce genetically different offspring through steps in meiosis and the fertilization process. The student is to complete a graphic organizer with responses.
Complete all three parts and answer all questions.Download Graph.docx
1. Complete all three parts and answer all questions.
Download
Graphic Organizer
for answering all questions
and genetics exercises in this assignment.
Part I: Genetics – From Genes to Proteins, Mutations
Background:
DNA represents the architectural blueprint for all living
systems, encoding specific instructions in the sequence of its
four nitrogen-containing base pairs that are necessary for
building the organism.
During the process of transcription, the information in the DNA
codons of a gene is transcribed into RNA.
A change in the DNA sequence, for example as a result of a
"mistake" during DNA replication, is defined as a mutation.
Mutations may result in a change in the "blueprint," which may
then change the resulting protein product.
Assignment details for part one:
Transcribe and translate EACH of the
three
following DNA gene sequences.
Turn these in using the graphic organizer. The letters represent
the DNA N-base sequences of the genes.
The first is the original gene. The next two are mutations of the
original. Note that the changes (mutations) are shown in red.
Original Gene sequence 3'-T A C C C T T T A G T A G C C A
C T-5
Mutated gene sequence 1 3’-T A C
G
C T T T A G T A G C C A
T
T-5'
Mutated gene sequence 2 3’-T A
A
C C T T T A
2. C
T A G
G
C A C T-5’
Also, answer the following questions:
What is the significance of the first and last codons of an
mRNA transcript?
What meaning do these mRNA codons have for protein
synthesis?
Did the mutations result in a change in the final proteins? If so,
describe the change.
In general, why might a change in amino acid sequence affect
protein function?
Part II: Inheritance of Traits or Genetic Disorders
Background
: Cystic fibrosis is an inherited disease that affects the
respiratory, digestive, or reproductive systems of the body, with
symptoms ranging from mild to severe. Bob and Sally are
recently married. Upon deciding to plan a family, both Sally
and Bob find out that they are both
heterozygous
for
cystic fibrosis
, but neither of them has symptoms of the disorder.
Assignment details:
Complete a
Punnett Square for cystic fibrosis
for this couple using the following alleles:
C = normal allele
; and
c = allele for cystic fibrosis
.
Complete the Punnett Square in the graphic organizer.
Also answer the following questions:
Based on the Punnett square, calculate chances (percentages)
for the following:
3. for having a healthy child (not a carrier)
a child that is a carrier for the cystic fibrosis trait
a child with cystic fibrosis
Be sure to submit these percentages as part of your assignment
in the Graphic Organizer.
Part III: Cell division, sexual reproduction and genetic
variability
Background
: Eukaryotic cells can divide by mitosis or meiosis. In humans,
mitosis produces new cells for growth and repair; meiosis
produces sex cells (gametes) called
sperm
and
eggs.
Although mutations are the ultimate source of genetic
variability, both meiosis and sexual reproduction also can
contribute to new genetic combinations in offspring.
Assignment Essay Question:
How do both meiosis and sexual reproduction (fertilization)
produce offspring that differ genetically from the parents? Be
sure to talk about the
two
specific steps in meiosis that increase variability as well as the
process of fertilization.
You will submit your Graphic Organizer with all answers in
your Submit Assignment area.
Provide references in APA format. This includes a reference list
and in-text citations for references used throughout the
assignment. Note that there is a Reference page for listing
sources included on the Graphic Organizer.
You will submit your Graphic Organizer with all answers.
Please submit your assignment.
Student Name
4. Date
Questions
Student Response
Part I
Original DNA Strand:
3’-T A C C C T T T A G T A G C C A C T-5’
Transcription (base sequence of RNA):
Translation (amino acid sequence):
Mutated gene sequence o
ne:
3’-T A C
G
C T T T A G T A G C C A
T
5. T-5'
Transcription (base sequence of RNA):
Translation (amino acid sequence):
Mutated gene sequence two:
3’-T A
A
C C T T T A
C
T A G
G
C A C T-5’
Transcription (base sequence of RNA):
Translation (amino acid sequence):
What is the significance of the first and last codons of an
mRNA transcript?
Explanation:
What meaning do these mRNA codons have for protein
synthesis?
6. Explanation:
Did the two mutations result in a change in the final proteins? If
so, describe the change.
Response/ explanation:
In general, why might a change in amino acid sequence affect
protein function?
Explanation:
Part II
Punnett Square
a.
Chances (%) for healthy child, not a carrier
b.
Chances (%) for child that is carrier for cystic fibrosis trait
c.
Chances (%) for child with cystic fibrosis
Fill out/adapt Punnett Square:
______
7. _____
______
______
a.
Chances (%) for healthy child, not a carrier:
b.
% for child that is carrier for cystic fibrosis trait:
c.
% for child with cystic fibrosis:
Part III: Essay
How do both meiosis and sexual reproduction (fertilization)
produce offspring that differ genetically from the parents?
·
Include steps in meiosis that increase variability
