Science Life Science Flashcards

Which organelle is responsible for producing ATP through cellular respiration in eukaryotic cells?

Answer: Mitochondria

Mitochondria are the site of cellular respiration, where glucose and oxygen are converted into ATP energy.

A scientist observes that a population of moths shifts from mostly light-colored to mostly dark-colored after industrial pollution darkens tree bark. This is an example of:

Answer: Natural selection

Natural selection favored dark moths because they were better camouflaged on soot-darkened trees and survived to reproduce more.

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

Answer: They break down dead organisms and recycle nutrients

Decomposers like fungi and bacteria break down dead organic matter, returning essential nutrients to the soil.

In a DNA double helix, adenine always pairs with:

Answer: Thymine

Adenine pairs with thymine via two hydrogen bonds in DNA, following Chargaff's base-pairing rules.

A plant is moved from a sunny window to a dark closet for two weeks. Which change would most likely occur first?

Answer: Leaves turn yellow due to chlorophyll breakdown

Without light, the plant cannot produce chlorophyll or use existing chlorophyll, causing leaves to yellow (chlorosis).

Which process allows water to move from an area of low solute concentration to high solute concentration across a cell membrane?

Answer: Osmosis

Osmosis is the passive movement of water across a semipermeable membrane from a region of lower solute concentration to higher solute concentration.

Which level of biological organization is MOST inclusive?

Answer: Ecosystem

An ecosystem includes all living organisms (populations, communities) plus their abiotic environment, making it the most inclusive level listed.