Name: _Key______________________
Date: ________
Study Guide: DNA, Inheritance, Mutations, and Genetic Engineering
1. Relate DNA to chromosomes.
Chromosomes are what DNA is called when it’s ‘condensed’. That means is packaged up into little
Xs or chromosomes.
2. What are genes and where are genes located?
Genes are parts of chromosomes that hold information for particular traits. Since they are part
of a chromosome, that’s where they are located: on the chromosome.
3. Using any example, explain alleles in relation to genes.
We know we get 2 of each of our 23 chromosome pairs, one from the birth mother and one from
the birth father; these are a homologous pairs. Genes are located on the homologous pairs. Your
mom’s DNA might give one option or allele of a gene and your father’s another.
4. Describe 4 Gene mutations and the effects of them (notes: Point Mutations)
a. A silent mutation is when a nucleotide changes, but it doesn’t affect which amino acid is
made.
b. A non-sense mutation is when a nucleotide changes and makes the protein stop being made.
Those three nucleotides are called a STOP codon. An example of a this type of mutation is
cystic fibrosis.
c. A missense mutation is when a nucleotide changes and it does change the amino acid. An
example of this change is sickle cell anemia.
d. Frameshift mutations are caused by insertion or deletion of one nucleotide.
1. ALS is caused by insertion of one nucleotide!
2. Male color-blindness can be caused by the deletion of one nucleotide!
5. Describe 7 processes that can alter composition or number of chromosomes. (Chromosome Mutations)
a. Crossing over is really a mutation, though it’s totally normal! It occurs during Prophase I
of Meiosis I and it mixes DNA from our birth parents, so that the gametes (half cells) we
pass along have some of the DNA from both parents.
b. Nondisjunction is when a chromosome doesn’t separate in meiosis like it’s supposed to. It
makes a gamete (half cell) have double the amount of one chromosome than it should.
Nondisjunction is what causes a third chromosome in the 21st set of human chromosomes
(Down Syndrome). See the picture on the next page.
c. Duplication is when there are extra copies of a gene on the same chromosome.
d. Translocation is when two NON-homologous chromosomes trade pieces of DNA.
e. Deletion is when part of a chromosome is deleted.
f.
Insertion is when there is an extra piece of DNA on a chromosome that doesn’t belong.
g. Inversion is when a piece of a chromosome breaks off, flips upside down and is
reconnected.
6.
Describe 7 types of inheritance (We didn’t do this part yet!)
a. D
b. R
c. C
d. I
e. S
f.
P
g. M
7. What is genetic engineering? Period 2 did this part. Genetic engineering is when scientists alter the
DNA of an organism on purpose. Sometimes it’s just strange, like making glow in the dark pets.
Sometimes it’s for the benefit of people.
8. Using any example, explain how genetic engineering has both positive and negative effects on humans. (Please
answer using ACER or whichever essay format your English teacher suggests.)
Genetic engineering has positive and negative effects on humans. We read about apples that have
been altered so that they don’t turn brown. However, this could have a negative effect on a
farmer who is trying to grow apples that haven’t been engineered. Because pollen travels from
farm to farm, farmers can’t be sure which apple trees are fertilizing their apple trees. We’ve
learned about crossing over, so some of the DNA from the engineered apple could be inside
another farmer’s apples, just because a bee brought the pollen over. Some companies sue farmers
that have the engineered DNA in the apple even though the farmer can’t do anything to stop it!
So, genetic engineering can be both good and bad.
9. Using any example, explain how genetic engineering has had environmental consequences. (Please answer using
ACER or whichever essay format your English teacher suggests.)
We didn’t do this, yet.
10. Be sure you know how to use a Punnett square to predict inheritance. Not yet!