Name __________________________________________________ Date ________________ Period ________
Chapter 3 and 4 Study Points
Discuss the following study points on a separate sheet of paper. You will receive 10
classwork points for this completed study guide. Use examples or drawings as
appropriate.

What do you know about Mendel, his observations, and his research?
Mendel was a monk who studied pea plants. He crossed plants with specific
characteristics, and his results formed the foundation of modern genetics. He
found that when he crossed two purebred plants (tall x short) the dominant
characteristic appeared in all offspring. He then crossed the F1 generation
(children) and found that the lost trait reappeared ¼ of the time.

Know the difference between hybrid/purebred and
homozygous/heterozygous. How are offspring different based on the
different types of parents?
Hybrid and heterozygous are synonyms. These organisms have one
dominant allele and one recessive allele (Bb)
Purebred and homozygous are synonyms. These organisms have two
dominant or two recessive alleles (BB or bb).
Offspring can be different if their parents are heterozygous and they get the
recessive from each parent (Bb and Bb parents and child is bb)

What are traits and how are they determined?
Traits are specific characteristics, like hair color or seed shape. Traits are
determined by the genes we have. We get these genes from our parents.

Describe and be able to give an example of genotypes and phenotypes.
Genotype is the allele combination. An example is Bb
Phenotype is the physical description of the alleles. An example would be
brown hair or blue eyes.

Complete a Punnett square and determine the genotypes of the parents
based on a description (dominant, recessive, heterozygous, etc.). You choose
the trait and the parents. Be able to explain the possible offspring with
evidence from your Punnett square.
Parents are both heterozygous. Offspring are homozygous dominant,
heterozygous and homozygous recessive. 1 out of 4 will show the recessive
trait

Describe the complex patterns of inheritance.
Incomplete dominance is when one allele is only partially dominant. An
example is when red and white flowers produce pink flowers.
Codominance is when both alleles are expressed equally. An example is when
red and white flowers produced checkered flowers with each color
represented.
Multiple alleles are when there are many allele choices but we still only get
two from each parent. One example is fur color in rabbits or cats.
Polygenic inheritance is when many genes control one trait. Human height is
an example.

Describe how sex cells are different from body cells; including what happens
during meiosis.
Sex cells have half the chromosomes of body cells. In humans, sex cells (egg
and sperm) have 23 chromosomes and body cells have 46 chromosomes.

Explain the structure and function of DNA including how DNA is replicated.
DNA is composed of sugars, phosphates, and nitrogen bases. The nitrogen
bases pair up (A with T and T with A) (C with G and G with C). In DNA
replication, an enzyme unzips the DNA, free nitrogen bases with sugars and
phosphates attached find their match, and an enzyme zips them back up. The
result is two identical strands of DNA

Explain how mutations occur and if they can be inherited.
Mutations are changes in DNA. They can only be inherited if they are on the
DNA of a sex cell. Mutations on body cells cannot be passed down to
offspring.

Describe how cancer is formed and any treatments that can occur.
Cancer is formed when mutated cells divide and reproduce in the body. The
cells can group together to form tumors. Cells entering the bloodstream can
spread throughout the body.
Treatments include chemotherapy, surgery, radiation, and natural
treatments.

Be able to answer the Big Question with evidence from classwork, labs,
readings, and discussion:
o Why don’t offspring always look like their parents?
Use page 90-91 to help answer this questions. Answers can include
dominant/recessive traits, mutations, patterns of inheritance, environmental
factors, acquired traits, and other factors. Be sure to include evidence and
explanations when answering this question.