Chapter 1 Cell Theory

five big ieas in bio

1. evolution

2. structure and function

3. information flow and storage

4. transformation of energy and matter

5. systems

define cell

a highly organized unit of life (smallest) bound by a plasma membrane with chemical reactions inside.

minimal requirements to call something a cell

1. reproduces

2. genetic info

3. ability to evolve

4. requires energy

5. made of cells

two main cell types

prokaryote and eukaryote

prokaryote

pro=before, karyo=nucleus

• no membrane bound organelles, no nucleus, single-celled, small and simple

eukaryote

eu=true, karyo=nucleus

• have nucleus, have MBO, single or multi cellular, large and complex

similarities and differences in prokaryote and eukaryote

small, no nucleus, no mbo VS large, complex, mbo

examples of single celled eukaryotes

diatoms (algae)

amoeba (protist)

examples of single celled prokaryotes

bacteria

examples of multi-celled eukaryotes

molds(fungi), elodea (aquatic plant), heart cells

true or false: cells are general

NOOOOO, when it says “basic” prokaryote or eukaryote that is not accurate bc all cells differ…there is NO standard cell

full cell theory

cells are the basic unit of life, all living things are made of cells, and all cells come from pre-existing cells

who started cell theory and what did they do

Rober Hooke (1665), made a microscope and examined corks, termed small pores as “cells” after cells inhabited by monks. ALL ORGANISMS ARE MADE OF CELLS

who came next in cell theory

Anthony van Leeuwenhoek, he developed a much more powerful microscope and looked at all types of things and drew what he saw.

who came third in cell theory and what did he add

Rudolph Virchow (1858), “all cells come from preexisting cells”

the 2 competing hypotheses

1. spontaneous generation (cells just generate)

2. all cells come from preexisting cells

Pasteur’s experiment to decide between the two hypotheses

a) nutrient broth in straight neck flask, boil it to kill living cells, pre-existing cells enter flask from air (can support both hypotheses)

b) nutrient broth in swan-necked flask, boil to sterilize, pre-existing cells from air enter but are trapped in the neck (SUPPORTS 2ND HYPOTHESIS)

how did pateurs exp support cells from cells

cells went into the neck of the flask but not in the main part, proving that the cells are from the pre-existing cells in the air not just spontaneous generating in any broth. (only appear where they have contact to the air)

Pasteur’s exp hypo, variables, control

• Control: Normal/open flask

• Independent variable: Ability of airborne microorganisms to reach the broth

• Dependent variable: Microbial growth in the broth

• Hypothesis: Microorganisms come from existing microorganisms rather than spontaneous generation.

Redi’s experiment (1668)

meat, fly, and maggots:

one open jar —>got maggots (from flies)

corked jar—> no maggots (no spont gen)

cloth over jar—>no maggots (no spont gen)

what makes up cells

molecules/compounds

what makes up molecules

atoms