Cell Discovery & Theory
Who first named "cells" after observing cork bark under an early microscope?
Robert Hooke
Which structure acts as the "gatekeeper," controlling what enters and leaves the cell?
Cell membrane
Name two cell parts found in plant cells that are absent in animal cells.
Cell wall and chloroplasts
A cell has a rigid, rectangular wall, a nucleus, and green chloroplasts. What cell type is it?
Plant Cell
A chemical dissolves the cell membrane of an animal cell. What happens immediately?
Cell contents leak out, and the cell dies
Which Dutch scientist observed pond water and dental scrapings, calling the living microbes "animalcules"?
Anton van Leeuwenhoek
What is the primary job of ribosomes?
Making/assembling proteins
What is the primary function of chloroplasts?
Capture sunlight to make sugars/food (photosynthesis).
A cell has a flexible border, a distinct nucleus, and no cell wall. What cell type is it?
Animal cell
An antibiotic specifically targets and shuts down bacterial ribosomes. What vital substance can the bacteria no longer make?
Proteins
What scientific tool had to be invented and improved before scientists could observe cells and develop the Cell Theory?
Microscope
What is the jelly-like fluid that fills the cell and cushions internal parts?
Cytoplasm
Where do plant and animal cells keep their DNA (bacteria do not have this structure)?
The nucleus
A single-celled organism has a cell wall, ribosomes, and free-floating DNA, but no nucleus. What is it?
Bacteria cell
A mutation prevents a plant from forming cell walls. What will happen visually to the plant?
It loses structural support, cannot stand upright, and wilts/collapses.
What does the Cell Theory state about where all new cells come from?
Preexisting cells (living cells dividing)
What molecule carries the genetic instructions for building proteins in every cell?
DNA
Why do plant cells have a rigid, boxy shape while animal cells have flexible, irregular shapes?
Plant cells have a rigid cell wall; animal cells only have a flexible membrane.
A student identifies a cell under a microscope that has a cell wall and ribosomes. Can it be an animal cell? Why or why not?
No, animal cells never have a cell wall.
A plant is kept in total darkness for three weeks. Which specific organelle is rendered useless?
Chloroplasts
What are the three core principles of the Cell Theory?
1) All living things are made of cells.
2) Cells are the basic unit of life.
3) All cells come from preexisting cells.
Name all four structures found in every living cell on Earth.
Cell membrane, cytoplasm, ribosomes, DNA
True or False: Plant cells have a cell wall instead of a cell membrane. Explain why it's true or false.
False. Plants have both; the membrane sits just inside the wall.
An unknown single-celled organism lives in pond water and contains a nucleus and chloroplasts. Is it a bacterium? Why or why not?
No, bacteria never have a nucleus or chloroplasts.
"Bacteria aren't truly alive because they don't have a nucleus to protect their DNA."
This statement is scientifically incorrect.
Use Cell Theory to prove this is incorrect.
Cell Theory states that all cells are living units, with or without a nucleus.