STAAR Reporting Category 2

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.

Tags

NGSS.HS-LS1-1

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.

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

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.

Tags

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?

• 
• 
• 
• 

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.

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

A model of DNA is shown.

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

• 
• 
• 
• 

Answer explanation

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

Tags

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.

• A

• B

• C

• D

• F

• G

• H

• J

Tags

NGSS.HS-LS1-1

NGSS.HS-LS3-1

• A

• B

• C

• D

Tags

NGSS.HS-LS1-1

• F

• G

• H

• J