Rev 1 Flashcards
What is the smallest unit of life?
Cell
Approximately how many cells make up the human body?
About 37 trillion
List two specific types of cells in the human body and explain what they are specialized to do.
- Neurons: specialized for transmitting nerve impulses
- Red blood cells: specialized for carrying oxygen
List several key things that all cells have in common.
- Plasma membrane
- Cytoplasm
- Genetic material (DNA)
- Ribosomes
List three examples of early-untested hypotheses that became widely accepted.
- Spontaneous generation
- Miasma theory
- The four humors
Describe the Theory of Abiogenesis (AKA ‘Spontaneous Generation’)
The belief that living organisms can arise from non-living matter
Summarize Redi’s experimentation and what he concluded.
Redi demonstrated that maggots do not arise from decaying meat, concluding that life does not spontaneously generate.
Describe the changes that Redi made during his second experiment.
He used sealed jars and jars covered with gauze to prevent flies from accessing the meat.
List the characteristics common to all organisms according to R. H. CAGER.
- Cellular organization
- Homeostasis
- Adaptation
- Growth and development
- Energy use
- Reproduction
What invention revolutionized the study of biology?
The microscope
What did Needham observe under the scope after boiling meat broth and sealing it?
Murky broth with microorganisms
What did Needham conclude?
That microorganisms could spontaneously generate from the broth.
List two possible reasons why the broth could have become murky with microorganisms.
- Contamination during the experiment
- Incomplete sterilization of the broth
What changes did Spallanzani make when repeating Needham’s experiment?
He sealed the flasks before boiling them to eliminate contamination.
How did Pasteur allow for fresh air without allowing microbes into the broth?
He used swan-neck flasks that allowed air in but trapped microorganisms.
Describe the process of ‘Pasteurization’.
Heating liquids to a specific temperature to kill harmful microorganisms.
List the contributions of Van Leeuwenhoek.
First to observe and describe single-celled organisms using a microscope.
List the contributions of Hooke.
Coined the term ‘cell’ after observing cork under a microscope.
List the contributions of Brown.
Discovered the nucleus in plant cells.
List the contributions of Schwann and Schleiden.
Schwann proposed that all animals are made of cells; Schleiden proposed that all plants are made of cells.
List the three main principles of the Cell Theory.
- All living organisms are composed of cells
- The cell is the basic unit of life
- All cells arise from pre-existing cells
