Lesson 2: Cell Theory

Question 1

Who was the earliest recorded scholar to articulate the Spontaneous Generation Theory?

Answer 1

Aristotle (384 – 322 BC)

Question 1

What is the Spontaneous Generation Theory?

Answer 1

It is the theory that life spontaneously arose from inanimate matter.

Question 2

Who proposed that mice could arise from rags and wheat kernels left in an open container for 3 weeks?

Answer 2

Jan Baptista van Helmont (1600).

Question 3

Where does life come from?

Answer 3

Religion (God), Philosophy (self-worth), and Science (facts and evidence) have all wrestled with this question.

Question 4

What did Aristotle say about life and nonliving matter?

Answer 4

He said, “life can arise from nonliving matter.”

Question 5

What was Francesco Redi’s contribution to disproving spontaneous generation?

Answer 5

He performed an experiment in 1668 showing that maggots did not spontaneously generate on meat left out in the open air.

Question 5

What was John Needham’s argument regarding spontaneous generation?

Answer 5

He argued that microbes arose spontaneously after boiling broth infused with plant or animal matter.

Question 6

How did Lazzaro Spallanzani challenge Needham’s conclusions?

Answer 6

Spallanzani performed experiments showing that life was not introduced from the air but from microorganisms in the air.

Question 7

What was Louis Pasteur’s significant contribution to disproving spontaneous generation?

Answer 7

He filtered air through a gun-cotton filter and found microorganisms, suggesting that exposure to air introduced microorganisms rather than a “life force.”

Question 8

What is the phrase “Omne vivum ex vivo” and what does it mean?

Answer 8

It means “Life only comes from life.”

Question 9

Who discovered cells in a slice of cork and named them “cells”?

Answer 9

Robert Hooke (1665).

Question 10

What did Antoine van Leeuwenhoek discover with his microscope?

Answer 10

He observed red blood cells, sperm, and single-celled organisms, and discovered the nucleus.

Question 11

What did Robert Brown conclude about the nucleus in 1831?

Answer 11

He theorized that the nucleus is a fundamental and constant component of the cell.

Question 12

What did Matthias Schleiden state about plants?

Answer 12

He stated that all plants are composed of cells.

Question 13

What did Theodore Schwann conclude about animals?

Answer 13

He concluded that all animals are composed of cells.

Question 14

What is the Cell Theory as proposed by Schleiden and Schwann?

Answer 14

All living things are composed of cells.

Question 15

What did Rudolph Virchow theorize about cells in 1858?

Answer 15

He theorized that all living cells come from pre-existing living cells.

Question 16

What does “Omnis cellula e cellula” mean?

Answer 16

“All cells come from already existing cells.”

Question 17

What did Felix Dujardin discover about cells?

Answer 17

He concluded that cells are not hollow but filled with a jelly-like substance known as protoplasm.

Question 18

What did Ludolf Christian Treviranus say about cells?

Answer 18

He said that cells can be divided.

Question 19

What are the three main principles of Cell Theory?

Answer 19

1. All living things are composed of one or more cells. 2. All living cells come from other living cells by cell division. 3. Cells are the basic units of structure and function in organisms.

Question 20

What does it mean that cells are the “monomer” of any organism?

Answer 20

It means that cells are the fundamental building blocks of all living organisms.

Question 21

It is one of the explanations to the question “where does life come from”?

Answer 21

Spontaneous Generation Theory

Question 22

When did the Spontaneous Generation Theory persisted?

Answer 22

17th Century

Question 23

Who performed an experiment in 1668 showing that maggots did not spontaneously generate on meat left out in the open air?

Answer 23

Francesco Redi
(1626-1697)

Question 24

He predicted that preventing flies from having direct contact with the meat would
also prevent the appearance of maggots. He conducted an experiment to prove his claim.

Answer 24

Francesco Redi
(1626-1697)

Question 25

Who performed an experiment, he briefly boiled broth
infused with plant or animal matter, hoping to kill all preexisting microbes?

Answer 25

John Needham
(1713–1781)

Question 26

Who was the one who did not agree with Needham’s conclusions,
however, performed hundreds of carefully executed experiments using heated
broth? He believed that “life is in the air.”

Answer 26

Lazzaro Spallanzani (1729–1799)

Question 27

Who was the one discovered nucleus?

Answer 27

Antoine van Leeuwenhoek