Chapter 3 Part 1 Flashcards
(22 cards)
What does the theory of spontaneous generation state?
Life arose from nonliving matter
This belief dates back to Aristotle and the ancient Greeks.
Who conducted the first significant experiment against spontaneous generation?
Francesco Redi
His experiment showed that flies must have access to meat for maggots to develop.
Which scientist is credited with conclusively disproving spontaneous generation?
Louis Pasteur
His swan-neck flask experiment demonstrated that life only comes from life.
What was the contribution of Robert Hooke in the study of cells?
First observed cells in the 1660s
However, cell theory was not widely accepted until much later.
What does the endosymbiotic theory suggest?
Mitochondria and chloroplasts originated from bacteria
This theory is supported by significant structural and genetic evidence.
What theory of disease was replaced by germ theory in the 19th century?
Miasma theory
Key figures in this transition included Semmelweis, Snow, Pasteur, Lister, and Koch.
How do prokaryotic cells differ from eukaryotic cells in terms of genetic material?
Prokaryotic cells have genetic material in a nucleoid
Eukaryotic cells have a membrane-bound nucleus.
What is a common feature of prokaryotic cells regarding cell morphology?
They typically share a similar cell morphology and cellular arrangement
This is characteristic of prokaryotic cells of the same species.
What do most prokaryotic cells have that helps maintain cellular morphology?
A cell wall
It also protects against changes in osmotic pressure.
What is extrachromosomal DNA found in prokaryotic cells?
Plasmids
These are separate from the nucleoid.
What is the size of prokaryotic ribosomes found in the cytoplasm?
70S
This distinguishes them from eukaryotic ribosomes.
What is the purpose of inclusions in some prokaryotic cells?
To store nutrients or chemicals
They can be used for various functions.
What process allows some prokaryotic cells to survive in a dormant state?
Sporulation
Endospores can germinate when conditions improve.
What does the cell envelope in prokaryotic cells consist of?
A plasma membrane and usually a cell wall
This structure is essential for prokaryotic cell integrity.
What are bacterial membranes primarily composed of?
Phospholipids with integral or peripheral proteins
The fatty acid components are ester-linked.
How do some molecules cross the bacterial membrane?
By simple diffusion
Most large membrane structures require cellular energy.
What are the two types of cell wall compositions in prokaryotic cells?
Peptidoglycan (bacteria) or pseudopeptidoglycan (archaea)
This distinction is important for classification.
What characterizes gram-positive bacterial cells?
A thick peptidoglycan layer
Gram-negative cells have a thin layer surrounded by an outer membrane.
What are glycocalyx coatings produced by some prokaryotic cells for?
Aiding attachment to surfaces and evasion of the host immune system
Examples include capsules and slime layers.
What are fimbriae and pili used for in prokaryotic cells?
Attachment to surfaces and transfer of genetic material
Pili are specifically involved in genetic material exchange.
How do some prokaryotic cells move through water?
Using flagella
Peritrichous bacteria use runs and tumbles for movement.
What defines eukaryotic cells?
The presence of a nucleus containing the DNA genome
This is a fundamental distinction from prokaryotic cells.
