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Genetics Review Guide
Name_______________________
Activity 55
1) What are the inherited bits of information that are passed directly from the
parents’ cells to the offspring’s cells? Genes.
2) Why do scientist that study genetics, study organisms such as yeast, plants, and
fruit flies? These organisms reproduce quickly and easily show inherited traits.
3) Can anything affect an inherited trait or do genes determine everything about
you?
Environmental factors can determine if genes are expressed and to what extent they
show themselves.
Activity 57
1) Do the offspring of two parents ever look exactly like either parent? Why not? No,
because they are a combination of the genes from both parents and not from only
one parent.
2) What type of organisms only reproduce asexually? Single-celled organisms.
3a) How similar are the offspring to the parent in asexual reproduction? They are
exact copies of the parents.
3b) What is the exception to the answer above and why? When a mutation occurs
when the DNA is being copied and before the cell divides into two. This would result
in at least one of the two cells being different than the original cell.
4) What kind of organisms can reproduce both asexually and sexually? Multicellular
organisms
5) The union of the sperm cell and the egg cell is called what? Fertilization
6) The part of the cell that contains the genes is called what? Nucleus
Activity 59
1) How can tossing a coin help you understand how organisms inherit genes from
their parents? A coin has two sides and a coin toss has a 50/50 chance of either a
head or tails. Each parent has two copies of each gene and the child has a 50/50
chance of inheriting either copy of that gene from that parent.
Activity 60
1) What did Mendel study patterns of inheritance with? Why was it a good choice?
Peas plants. They reproduce quickly and have many observable dominant and
recessive traits.
2) Based on his observations, what were Mendel’s three major conclusions?
a. Genes can be dominant or recessive and recessive genes can be “hidden” because
their traits do not show themselves in each generation.
b. Every plant has two copies of each gene for each characteristic.
c. Each plant receives only one copy of each gene from each parent.
Activity 61
1) What is the relationship between genotype and phenotype? Genotype is which
type of genes you have for each trait. Genotype therefore determines what your
observable traits are, and that is your phenotype.
2) What is a Punnett square? A table to determine the probabilities of traits in
offspring as determined by the genotypes of their parents.
3) Review page D-37 on how to read and create Punnett square.
Activity 63
1) Place in order from smallest to largest item the following three words;
chromosome, cell, gene.
Smallest-gene-chromosome-cell-Largest
2) Why do multicellular creatures need to make more cells?
To replace damaged cells, worn out cells, and growth larger.
3) How many chromosomes does a human have in most of their cells? How many
pairs of chromosomes? 46 chromosomes, 23 pairs of chromosomes
4) Some people have two copies each for all 23 of their chromosomes and some only
have two copies for 22 pairs of their chromosomes, why is that? Males only have one
copy of an X chromosome and one copy of a Y chromosome and two copies each for
the remaining 22 pairs of chromosomes.
5) Are complex traits and diseases the result of a single gene? Explain. No, complex
traits and diseases are usually a result of multiple genes and environmental factors.
Activity 66
1) In a pedigree, females are represented by what symbol? And males by what
symbol? Females are represented by circles and males by squares.
2) How can you tell if a trait might be recessive? The trait may skip a generation
before reappearing in later generations.
3) What is a carrier? A carrier is a heterozygous individual who carries a recessive
gene for a disease but does not suffer from the condition caused by the disease.
Activity 68
1) Explain how blood type was used to determine whether children and adults may
be related and if blood types demonstrate dominant and recessive patterns of
inheritance? Genes inherited from parents determine the type of blood one has. If a
child has a blood type that is not present in either of the possible parental adults,
then the child must be someone else’s child. Blood types do show some dominant
and recessive tendencies, with A and B type blood being dominate to type O blood.
Activity 69
DNA fingerprinting can be used to diagnose people for genetic diseases such as
Marfan Syndrome but it can also do what else? Identify people compared to
previous samples of their own genetic material, and the genetic material of their
parents and close relatives.