Unit 6 - Cellular Reproduction

Why is cell division important?

1. growth and development

2. tissue repair and maintenance

3. reproduction in unicellular organisms

The two types of cell division

mitosis and meiosis

Who was known as the “Father of Biology”?

Aristotle

True or False: Aristotle believed in spontaneous generation

True

spontaneous generation

mistaken belief that organisms can be produced from non-living sources (abiogenesis)

Who challenged Aristotle’s theory and tried to disprove spontaneous generation?

Francesco Redi

Describe Redi’s experiment

Jar 1: open with flies and maggots

Jar 2: sealed with no flies

Jar 3: mesh cloth with maggots

Conclusions of Redi’s experiment

1. Proved maggots came from flies

2. First experiment to test hypothesis concerning spontaneous generation

Why didn’t Redi’s experiment completely disprove spontaneous generation?

1. People still did not believe life came from life

2. Instead they believed something “in the air” created life.

Who invented the simple microscope?

Leeuwenhoek

What was Leeuwenhoek’s impact after inventing the microscope?

He discovered microorganisms, renewing the long debate over spontaneous generation

What did Louis Pasteur believe in?

microorganisms came from cells called spores

True or False: Louis Pasteur advocated for spontaneous generation

False

Describe Pasteur’s experiment and its results

S-Flask: no growth 

Normal Flask: growth

Outcome of Pasteur’s experiment

1. Disproved spontaneous generation

2. led to the theory of biogenesis

biogenesis

life comes from life

What was Virchow’s claim in 1858?

all cells come from other cells

What was the conjoined outcome of Virchow and Pasteur’s works?

1. Cells are the basic unit of life

2. All cells are reproduced from other cells

3. All life must come from life

cell cycle

1. ordered series of events involving cell growth and cell division that produces two new daughter cells

What phase of the cell cycle do cells spend most of their life in?

interphase

interphase

cell undergoes normal growth processes while also preparing for cell division

3 stages of Interphase

1. G1 phase: cell growth

2. S phase: DNA replication

3. G2 phase: preparation for division

What happens at the G1 checkpoint?

see if DNA is damaged

synthesis phase

1. cell growth

2. DNA synthesis/replication

3. chromatin

what happens at the G2 checkpoint?

check to see if the DNA was replicated correctly