Cell Organelles
Which organelle controls what enters and leaves the cell?
A. Nucleus
B. Chloroplast
C. Cell Membrane
D. Cytoplasm
C – Cell membrane
Explain why a whale is classified as a mammal even though it lives in the ocean. Provide two scientific reasons.
Breathes air, warm-blooded, feeds young milk.
Which is an acquired trait?
A. Freckles
B. A broken arm
C. Dimples
D. Hair color
B – Broken arm
T/F: Burning wood is a physical change because the wood just “looks different.”
False — new substances form (ash, smoke).
Which microorganisms can cause illness? (Select all that apply.)
A. Virus
B. Bacteria
C. Mold
D. Helpful gut bacteria
A. Virus
B. Bacteria
C. Mold
Which structures are found ONLY in plant cells? (Select all that apply.)
A. Cell wall
B. Chloroplast
C. Nucleus
D. Cytoplasm
A. Cell wall
B. Chloroplast
Which traits describe mammals? (Select all that apply.)
A. Warm-blooded
B. Lay eggs in water
C. Have fur or hair
D. Feed young milk
A. Warm-blooded
C. Have fur or hair
D. Feed young milk
Which of these are learned behaviors? (Select all that apply.)
A. A dog sitting on command
B. Birds migrating
C. A child riding a bike
D. Fish swimming at birth
A. A dog sitting on command
C. A child riding a bike
Which signs show a chemical change? (Select all that apply.)
A. Color change
B. Shape change
C. Gas production
D. Temperature change
A. Color change
C. Gas production
D. Temperature change
T/F: All microorganisms are harmful. Explain your answer.
False — some are helpful (digestive bacteria, yeast).
T/F: The nucleus is not important because the cell can survive without it.
False. The nucleus controls cell activities and holds DNA.
A plant is discovered that has needle-like leaves, produces seeds in cones, stays green all year, and does NOT make flowers.
How should this plant be classified?
A. Angiosperm, because it stays green all year and uses cones to attract pollinators.
B. Angiosperm, because the needle leaves show it can do photosynthesis like flowering plants.
C. Gymnosperm, because it produces seeds in cones and does not make flowers or fruits.
D. Gymnosperm, because all plants with green leaves and flowers are automatically gymnosperms.
C. Gymnosperm, because it produces seeds in cones and does not make flowers or fruits.
Explain the difference between an inherited trait and a learned behavior. Give one example of each.
Inherited = passed from parents (e.g., hair color). Learned = taught or practiced (e.g., playing piano).
A student mixes baking soda and vinegar and observes fizzing and bubbling. What type of change is this?
A) Physical change because the materials are only mixing, not forming a new substance
B) Chemical change because a new substance (carbon dioxide gas) is produced and the reaction cannot be reversed
C) Physical change because it can be poured back into separate containers
B) Chemical change because a new substance (carbon dioxide gas) is produced and the reaction cannot be reversed
Mold grows on strawberries left out overnight. Explain why the mold is harmful in this situation and how you know.
It spoils food and makes it unsafe to eat.
A scientist finds a cell with a cell wall, chloroplasts, and a nucleus. Identify the cell type and explain how each structure helped you make your decision.
Plant cell — cell wall and chloroplasts are only found in plants.
A student says, “All plants with cones are angiosperms.” Explain why this statement is incorrect using the correct plant classification words.
Cones = gymnosperms. Angiosperms produce flowers and fruits.
A student says, “A child’s accent is inherited.” Explain whether you agree or disagree and give evidence to support your reasoning.
Disagree — accents are learned from the environment.
A student mixes two powders. The mixture becomes warm and bubbly.
Explain why this is a chemical change using evidence from the observation.
Gas and temperature changes show new substances formed.
You find uncooked chicken in the refrigerator that has been left out for several hours.
Which statement correctly describes the microorganisms on uncooked chicken?
A) They are mostly helpful bacteria that help digest food when eaten raw.
B) They are harmful bacteria that can cause foodborne illness if the chicken is eaten.
C) They are neutral and will not affect humans in any way.
B) They are harmful bacteria that can cause foodborne illness if the chicken is eaten.
Compare the functions of the cytoplasm and the cell membrane. How do they work together to keep the cell alive? Explain using evidence.
Cytoplasm supports organelles; the membrane controls movement. Together they help the cell survive.
What is the main difference between an angiosperm and a gymnosperm?
A. Angiosperms keep their seeds inside a fruit or flower, while gymnosperms have seeds that are exposed in cones.
B. Angiosperms and gymnosperms both produce flowers, but angiosperms produce larger ones.
C. Gymnosperms make food through photosynthesis, while angiosperms do not.
A. Angiosperms keep their seeds inside a fruit or flower, while gymnosperms have seeds that are exposed in cones.
(Angiosperms = seeds in fruit/flowers; Gymnosperms = naked seeds in cones.)
A sunflower in a pot is leaning toward the window. Why is this happening?
A) It is an inherited trait that causes all flowers to grow at an angle
B) It is a learned behavior because the plant “knows” to move
C) It is a behavior called phototropism, where the plant grows toward light
C) It is a behavior called phototropism, where the plant grows toward light
A metal spoon left in a puddle of rain starts forming a reddish layer on the surface over several days. What type of change is this?
A) Physical change because the spoon is just getting wet and looks different
B) Chemical change because rust forms as iron reacts with oxygen and water, creating a new substance
C) Physical change because the spoon can still be used for stirring without affecting the rust
B) Chemical change because rust forms as iron reacts with oxygen and water, creating a new substance
A farmer adds nitrogen-fixing bacteria to soil. Explain how these microorganisms help plants grow and why they are considered helpful.
They convert nitrogen into a form plants can use.