NYSTCE NYSTCE Biology (006) 4

Question 1

Which process allows plants to convert light energy into chemical energy stored in glucose?

Accepted Answer

Photosynthesis

Answer

Photosynthesis uses light energy, water, and carbon dioxide to produce glucose and oxygen in chloroplasts.

Question 2

A mutation changes a codon from UAU (tyrosine) to UAA. What type of mutation is this?

Accepted Answer

Nonsense mutation

Answer

UAA is a stop codon, so this change prematurely terminates translation, classifying it as a nonsense mutation.

Question 3

Which organelle is primarily responsible for detoxifying harmful substances in liver cells?

Accepted Answer

Smooth endoplasmic reticulum

Answer

The smooth ER contains enzymes that detoxify drugs and other harmful compounds, and is especially abundant in liver cells.

Question 4

In a cross between two heterozygous individuals (Aa × Aa), what fraction of offspring are expected to be homozygous recessive?

Accepted Answer

1/4

Answer

A Punnett square for Aa × Aa yields AA : Aa : aa in a 1:2:1 ratio, so 1/4 of offspring are homozygous recessive (aa).

Question 5

Which of the following best describes the role of decomposers in an ecosystem?

Accepted Answer

They break down dead organic matter and recycle nutrients

Answer

Decomposers such as bacteria and fungi break down dead organisms and return nutrients like nitrogen and phosphorus to the soil.

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