Biology STAAR Category Two

• F

• G

• H

• J

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NGSS.HS-LS1-1

NGSS.HS-LS3-1

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Which of these shows an example of an insertion mutation?

• A

• B

• C

• D

Answer explanation

An insertion mutation is a result of inserting new nitrogenous bases into DNA. In this model, new “K” and “L” genes have been inserted into the chromosome.

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NGSS.HS-LS3-2

A model of the genetic control of coat color in rabbits is shown.

Which Punnett square represents a cross that would produce albino offspring?

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Answer explanation

The albino allele (c) is recessive to all other alleles, so expression of the albino phenotype requires two copies of the allele. This option is the only option where two albino alleles would result.

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NGSS.HS-LS3-1

NGSS.HS-LS3-2

A model of transcription and a codon chart are shown.

Which amino acid would be coded first from the DNA strand being transcribed?

• Cys

• Phe

• Ile

• Met

Answer explanation

The first mRNA codon is AUG. AUG on the codon chart codes for the amino acid Met.

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NGSS.HS-LS1-1

NGSS.HS-LS1-6

A cellular process is shown.

Which of these is the most likely result of the process shown in the diagram?

• Chromosome replication will cease to avoid errors that result in mutations.

• Offspring will no longer express traits from previous generations.

• Gametes will contain new allele combinations.

• Chromatids will have less genetic variety.

Answer explanation

In meiosis, during the cellular process of crossing over, homologous chromosome pairs exchange parts with each other creating new allele combinations on each chromosome.

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NGSS.HS-LS3-1

NGSS.HS-LS3-2

What components make up the backbone of a DNA molecule?

• Purines and deoxyribose

• Pyrimidines and purines

• Deoxyribose and phosphate groups

• Phosphate groups and pyrimidines

Answer explanation

The backbone of a DNA molecule is made up of alternating deoxyribose sugars and phosphates.

A model of DNA is shown.

Which part of the DNA model is most directly associated with the coding of genetic information?

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Answer explanation

The variability in nitrogenous bases carries the genetic information that encodes for traits.

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NGSS.HS-LS1-1

NGSS.HS-LS3-1

E. coli has three genes that each code for different enzymes that break down lactose. Scientists conducted investigations about the production of these enzymes using samples of E. coli. Their results are shown in the table. Which conclusion about the production of the enzymes can be determined by analyzing the scientists’ results?

• Gene expression for the enzymes was controlled by the temperature of lactose.

• The genes for the enzymes were expressed in equal amounts during both experiments.

•  Gene expression for the enzymes was controlled by the presence of lactose.

• The genes for the enzymes were mutated before being expressed by the presence of lactose.

Answer explanation

The scientists’ results indicate that gene expression for the enzymes was controlled by the presence of lactose because enzyme concentration was high when lactose was present and low when lactose was not present.

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NGSS.HS-LS1-1

NGSS.HS-LS3-2

Which statement best describes a similarity among trees, cats, and amoebas?

• They are prokaryotic organisms.

• They are classified as members of the same kingdom.

• They have genomes that consist of the same number of genes.

• They contain DNA composed of the same four types of nucleotides.

Answer explanation

All organisms are composed of the same nucleotide bases.

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Which of the following best describes the role of ribosomes in a cell?

• A) They store genetic information.

• B) They synthesize proteins.

• C) They generate energy for the cell.

• D) They transport substances across the cell membrane.