Genes and Heredity Lesson 1 and 2 Rreview

What did Gregor Mendel discover about the principles of heredity?

• The structure of DNA is a double helix.

• Genetic material is genes on DNA.

• A dominant factor can hide the expression of a recessive factor when both are present.

• Mothers contribute factors for some traits while fathers contribute factors for others.

An organism that is considered a hybrid has

• two dominant alleles

• one dominant and one recessive allele

• two recessive alleles

• a mutation

Which of the following represents a homozygous recessive genotype?

• BB

• Bb

• bb

• More than one answer is correct.

The ________ of an organism is the physical characteristics we see, while the __________ describes the combination of alleles that are inherited.

• genotype, phenotype

• alleles,

  traits

• traits,

  alleles

• phenotype, genotype

An allele whose trait always shows up in the organism when present is called ______________.

• dominant

• recessive

• genotype

• phenotype

How does the probability of inheriting certain traits change every time two parents produce offspring?

• It doubles.

• It does not change.

• It is half of the previous probability.

• It depends on the trait.

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NGSS.HS-LS3-3

NGSS.HS-LS4-3

Genes are carried from parents to offspring on structures called

• alleles

• chromosomes

• chromatids

• genotypes

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NGSS.HS-LS3-1

My cat, Raj, has 38 chromosomes in his body cells. How many chromosomes does he have in his sex cells?

• 38

• 19

• 76

• 22

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Which of the following examples of cell division describes meiosis?

• A bacterium divides to make two identical daughter cells.

• A skin cell divides rapidly to replace tissue damaged by a scrape.

• A cell separates its genetic material and forms 2 daughter cells.

• A plant produces pollen with half the number of chromosomes of the parent cells.

Prior to the separation of chromosomes, what process occurs to allow for minor variations in traits to form?

• crossing over

• mitosis

• meiosis

• replication

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NGSS.HS-LS3-2