2018 EOC Review for Grade 7

A DNA molecule is shaped like a

• long thin rod
• straight ladder
• double helix
• triple helix

During DNA replication, adenine always pairs with

• guanine (G)
• cytosine ©
• thymine (T)
• adenine (A)

What did Gregor Mendel do to study different characteristics in his genetics experiments?

• He studied only asexual plants.
• He studied on tall and short pea plants
• He cross-pollinated plants
• He cross-pollinated both plants and animals

What does the notation TT mean to geneticists?

• two dominant alleles
• heterozygous alleles
• at one dominant allele
• one dominant and one recessive allele

What does a Punnett square show?

• all the possible outcomes of a genetic cross
• only the dominant alleles in a genetic cross
• only the recessive alleles in a genetic cross
• all of Mendels discoveries about genetic crosses

What happens during meiosis?

• Two sex cells combine.
• Chromosome pairs separate and are distributed into new sex cells.
• Each sex cell copies itself to form four new chromosomes.
• Chromosome pairs remain together when new sex cells are formed.

A heterozygous organism has

• three different alleles for a trait
• two identical alleles for a trait
• only one allele for a trait
• two different alleles for a trait

An organism"s genotype is its

• genetioc makeup
• feather color
• physical appearance
• stem height

The gradual change in species over time into a new species is called

• adaptation
• natural selection
• evolution
• variation

How does Natural Selection lead to evolution?

• Stronger offspring kill weaker members of the species
• Helpful variations accumulate among surviving members of the species
• `Overproduction provides food for surviving members of the species
• Environmental changes favor weaker members of the species