Genetics Test Study Guide

Genetics Test Study Guide

*** KNOW YOUR VOCAB!!! It is a BIG part of this test

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Remember ** = state standards that will be on the test, exam and possibly the MME

Part 1: Heredity

**B4.1A Draw and label a homologous chromosome pair with heterozygous alleles highlighting a particular gene location.

**B4.1B Explain that the information passed from parents to offspring is transmitted by means of genes that are coded in DNA molecules. These genes contain the information for the production of proteins

**B4.1d Explain the genetic basis for Mendel’s laws of segregation and independent assortment.

**B4.3d Explain that the sorting and recombination of genes in sexual reproduction result in a great variety of possible gene combinations from the offspring of two parents.

Define the following key terms:

- Gene =

- Dominant =

- Recessive =

- Genotype =

- Phenotype =

- Allele =

- Trait =

- Homozygous/Pure =

- Heterozygous/Hybrid =

 How do traits of parents get passed on to offspring? How many alleles for a

one trait do you get from each parent?

 Who is known as the "Father of Genetics"? Why / what did he do?

 Explain the Law of Segregation =

 Explain the Law of Independent Assortment =

 How many alleles for each gene does a gamete have? Genetically speaking,

 Draw and label a homologous chromosome pair with heterozygous alleles highlighting a particular gene location (check out your notes to help!)

Part 2: Inheritance of Traits

**B4.1c Differentiate between dominant, recessive, codominant, polygenic, and sex-linked traits.

 Dominant alleles are represented by what kinds of letters?

 Recessive alleles are represented by what kinds of letters?

 What has to happen for an individual to inherit a recessive trait?

 Explain what happens in incomplete dominance. Give an example:

 Explain what happens in codominance. Give an example:

 What is a polygenic trait? Give an example

 What is a Sex-linked gene? Which chromosome is a sex-linked gene most

likely to

 be found on?

 What is a “carrier”? Who can be a carrier – guys or girls?

 Why is a disorder like color-blindness (which is X-linked and recessive) more

 What is probability? How is it used in genetics?

Part 3: Punnett Squares

**B4.1e Determine the genotype and phenotype of monohybrid crosses using a Punnett Square.

Check out the internet for many practice quizzes/tutorials on Punnett squares, or the “Gene Screen” APP.

 What is a punnett square and how is it used?

 What are “offspring” and where are they shown on a punnett square?

 Be able to create them and analyze them for outcomes: Use punnett squares to

determine the possible offspring of the following crosses. What is the genotypic ratio and what it the phenotypic ratio for each?

1. Complete dominance: Rr x rr (R = round seeds, r = wrinkled seeds)

2. Codominance: GG x gg (G = Green pods, g = yellow pods)

Part 4: Dihybrid Squares

Assume that all examples in our dihybrid crosses represent complete dominance. Be able to create them and analyze them for outcomes:

1. Given a TtRr x TtRr (T=Tall, t=short, R=round, r=wrinkled)

Q. What is the probability of producing a short offspring with round peas?

2. In summer squash, white fruit color (W) is dominant over yellow fruit color (w) and disk-shaped fruit (D) is

dominant over sphere-shaped fruit (d).. If a squash plant homozygous for white, disk-shaped fruit is crossed with a plant homozygous for yellow, sphere-shaped fruit, What is the probability of the offspring having the same phenotype of the White squash parent plant?

3. In cats. A straight tail (S) is dominant to a bent tail (s). Brown fur color (B) is also dominant to white fur (b).

Part 5: Environmental Influences

**B4.2E Propose possible effects (on the genes) of exposing an organism to radiation and toxic chemicals.

**B4.3e Recognize that genetic variation can occur from such processes as crossing over, jumping genes, and deletion and duplication of genes.

**B4.3f Predict how mutations may be transferred to progeny.

**B4.3g Explain that cellular differentiation results from gene expression and/or environmental influence (e.g., metamorphosis, nutrition).

**B4.4a Describe how inserting, deleting, or substituting DNA segments can alter a gene. Recognize that an altered gene may be passed on to every cell that develops from it and that the resulting features may help, harm, or have little or no effect on the offspring’s success in its environment.

**B4.4c Explain how mutations in the DNA sequence of a gene may be silent or result in phenotypic change in an organism and in its offspring.

**B4.2A Show that when mutations occur in sex cells, they can be passed on to offspring (inherited mutations), but if they occur in other cells, they can be passed on to descendant cells only (non-inherited mutations).

**B4.2B Recognize that every species has its own characteristic DNA sequence

**B4.2D Predict the consequences that changes in the DNA composition of particular genes may have on an organism (e.g., sickle cell anemia, other).

**B4.4b Explain that gene mutation in a cell can result in uncontrolled cell division called cancer. Also know that exposure of cells to certain chemicals and radiation increases mutations and thus increases the chance of cancer.

 Name some examples of things that can influence whether or how a gene will

be expressed:

 Define mutation =

 What are some examples of mutations?

 What types of mutations can be passed on to the offspring?

 What types stay inside the individual?

 How is every species different?

 What can happen if there is a change in the DNA sequence?

 What are frameshift mutations? What would be an example?

 What can crossing over and jumping genes cause?

 Are all mutations harmful? Do all mutations show up in a phenotypic change?

 What is cancer?

 What are some possible causes for cancer?

 How can genetic disorders like sickle cell anemia occur?

Part 6: Applied Genetics

**B4.2h Recognize that genetic engineering techniques provide great potential and responsibilities. (Benefits, drawbacks, specific tools and techniques)

 What does “selective breeding” produce? (think about horses, dogs, cats,

crops, etc…)

 Explain the phrase "genetic engineering provides great potential and

responsibilities."

 What is genetic engineering?

 (What are the 3 steps to make a transgenic organism?

 Give some examples of how genetic engineering can help in the fields of

industry, agriculture and medicine: