What structure controls what enters and leaves the cell?
Cell membrane
What is the process of breathing in called?
Inhalation
What organ pumps blood throughout the body?
The heart
When you turn on a light bulb, what energy transformation occurs?
Electrical energy → Light and heat energy.
What does the cell wall do?
Provides structure and support for the cell.
Name the jelly-like substance that fills the cell.
Cytoplasm
What is the main function of the respiratory system?
To take in oxygen and remove carbon dioxide
What is the main function of the circulatory system?
To transport oxygen, nutrients, and waste around the body.
What type of energy is stored in food?
Chemical energy.
What organelle in plant cells carries out photosynthesis?
Chloroplast
What is the function of the nucleus?
It controls the cell’s activities and contains DNA
What system works closely with the respiratory system to transport oxygen?
The Circulatory System
Name the three main types of blood vessels.
Arteries, veins, and capillaries.
In a toaster, what form of energy is transferred to the bread?
Heat energy
List three structures found in plant cells but not in animal cells.
Cell wall, chloroplasts, large central vacuole
Name the three principles of the cell theory
1. cells are the basic units of life
2. all cells are made of pre existing cells
3. all living things are made up of cells
Why do alveoli have thin walls?
To allow gases to easily diffuse between air and blood.
What is the difference between oxygenated and deoxygenated blood?
Oxygenated blood carries oxygen from the lungs to the body; deoxygenated blood carries carbon dioxide back to the lungs.
Explain the difference between energy transfer and energy transformation.
energy moves from one object to another; Transformation = energy changes from one form to another.
What green pigment do plant cells contain?
Chlorophyll
What organelle is responsible for making proteins?
Ribosomes
Name the pathway air takes to reach the lungs.
Nose → trachea → bronchi → bronchioles → alveoli.
Describe the complete pathway of blood starting and ending at the heart.
Heart → arteries → capillaries → veins → back to the heart.
A machine outputs 80 J of useful energy for every 200 J it takes in. Calculate its energy efficiency.
80 ÷ 200 × 100 = 40% efficient.
Why don’t animal cells need chloroplasts?
Because animals don’t make their own food — they eat other organisms.