Cat Biology

Different types of mutations can occur in DNA. The diagram represents a type of mutation.

• A silent mutation results in the insertion of a different amino acid.

• A substitution occurs with the adenine base.

• A deletion of a cytosine base occurs.

• A base is inserted into one strand of the DNA.

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NGSS.HS-LS3-2

The grasslands of the Tibetan plateau are home to plateau pika, which are prey for many predators of the grasslands. The grasslands are a watershed for much of the area and drains large quantities of groundwater during the rainy season. Pikas' extensive burrows help drain groundwater rapidly and are used as nesting sites by many bird species. Many people want to eradicate pikas because they compete with livestock for grass. What will most likely happen if the plateau pikas are completely removed from the grasslands?

• The ecosystem will become unstable because predators will have fewer prey, the birds will have fewer nesting sites, and the area downriver will become vulnerable to flooding without the burrows to aerate the soil and provide drainage for monsoon rains.

• The ecosystem will become more stable because the pika will be replaced by other species of small mammals that can fill the niche, bird species will adapt to nesting aboveground, and the soils will become compacted without the burrows.

• The ecosystem will become unstable because the predators will migrate to nearby ecosystems, the birds will nest in nearby trees, and the soils will be aerated by other small mammals.

• The ecosystem will become more stable because the pika will no longer be there to eat the grasses, the birds will migrate to other ecosystems during nesting season, and the soils will be able to absorb more of the monsoon rains without the pika burrows.

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NGSS.HS-LS2-6

NGSS.HS-LS4-5

Albinism is an autosomal recessive condition. Which circle graph shows the genotype probability when an albino female mates with a male that is heterozygous for the albinism trait?

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NGSS.HS-LS3-1

NGSS.HS-LS3-2

Differences in traits such as hair texture are determined by differences in —

• the location of sugar groups in DNA

• the sequence of nucleotides in DNA

• the number of nitrogenous bases in DNA

• the molecules attached to the phosphate in DNA

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NGSS.HS-LS1-1

NGSS.HS-LS3-1

Researchers combined sequences of fruit-fly DNA from a gene for a particular trait with frog DNA. The mixture was heated to separate the DNA strands. Cooling allowed the single strands to form pairs. The researchers observed that some of the fruit-fly DNA paired with frog DNA. The results provide evidence that —

• similar nucleotides are present in both fruit-fly and frog DNA

• fruit flies and frogs can be made to develop some of the same physical traits

• heat can cause mutations in the DNA sequences of organisms

• the replication of genetic material can occur at any temperature

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NGSS.HS-LS3-1

In gel electrophoresis a DNA sample from an unknown donor is placed in a small well at one end of a special gel-coated plate. Samples from known donors are placed in other wells on the plate. An electric current is passed through the plate, causing the DNA fragments to separate. The size and location of the separated fragments can be compared for similarities. The more similar the locations and sizes of the fragments, the more closely the donors of the samples are related. The diagram shows four samples being compared with an unknown sample. The donor of which sample is most closely related to the donor of the unknown sample?

• Sample 1

• Sample 2

• Sample 3

• Sample 4

A student researching bacteria concluded a report with the claim in the box. Which statement correctly addresses the validity of the claim?

• The claim is valid because many studies and experiments have shown that bacteria disrupt homeostasis.

• The claim is invalid because there are many types of bacteria that help organisms maintain homeostasis.

• The claim is invalid because only microorganisms such as viruses disrupt the health of organisms.

• The claim is valid because bacteria cause disease.

In Holstein cattle the allele for black hair color (B) is dominant over the allele for red hair color (b), and the allele for polled (P), or lacking horns, is dominant over the allele for having horns (p). What is the expected phenotypic ratio of the offspring of a BbPp × BbPp cross if these alleles sort independently?

• 16 black/polled : 0 black/horned : 0 red/polled : 0 red/horned

• 12 black/polled : 0 black/horned : 0 red/polled : 4 red/horned

• 4 black/polled : 4 black/horned : 4 red/polled : 4 red/horned

• 9 black/polled : 3 black/horned : 3 red/polled : 1 red/horned

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NGSS.HS-LS3-2

Which of these is the direct result of an error in the transcription of a DNA nucleotide?

• The nuclear membrane is ruptured.

• Amino acids do not bond to tRNA.

• A codon sequence is incorrect.

• Transportation of mRNA does not occur.

Which diagram demonstrates how crossing-over contributes to genetic variety during meiosis?

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NGSS.HS-LS3-2