Cells & Biochemistry
What organelle is known as the "powerhouse of the cell"?
Mitochondria
What is the basic unit of heredity?
Gene
Who proposed the theory of natural selection?
Charles Darwin
What system transports oxygen and nutrients throughout the body?
Circulatory system
What is the original source of energy for most ecosystems?
The Sun
What process do plants use to make glucose?
Photosynthesis
What is the genotype of a heterozygous individual?
One dominant and one recessive allele (Ex: Tt)
What is an adaptation?
A trait that helps an organism survive and reproduce.
What organ pumps blood throughout the body?
Heart
Organisms that make their own food are called what?
Producers (autotrophs)
Which molecule stores genetic information?
DNA
If two heterozygous parents (Tt × Tt) have offspring, what percentage will show the recessive trait?
25%
Individuals with favorable traits are more likely to survive and reproduce. This process is called what?
Natural selection
Which body system controls and coordinates body activities?
Nervous system
What is a food web?
Multiple interconnected food chains.
Enzymes speed up chemical reactions by lowering what?
Activation energy
What structure carries genes from parent to offspring?
Chromosomes
What evidence suggests different species share common ancestors?
Similar DNA, fossils, and anatomical structures.
What is the function of the alveoli in the lungs?
Gas exchange
Why are there fewer organisms at the top of an energy pyramid?
Energy is lost at each trophic level.
Explain why enzymes stop working properly at extremely high temperatures.
The enzyme becomes denatured and changes shape.
Why does meiosis increase genetic variation?
Crossing over and independent assortment create new gene combinations.
Why might a population become resistant to antibiotics?
Resistant individuals survive and reproduce, passing on the trait.
Explain how the digestive and circulatory systems work together.
The digestive system breaks down food and nutrients enter the bloodstream through the circulatory system.
Describe one effect of removing a top predator from an ecosystem.
Prey populations may increase, disrupting ecosystem balance.