2.1 Cell Intro - AI Flashcards
What is the smallest unit that can carry out life processes?
A cell
A cell is the basic unit of all living things.
What are the roles of cells? List them.
- Transport materials
- Obtain and use energy
- Dispose of waste products
- Replicate
- Respond to the environment
What type of cells are specialised to transport oxygen?
Red blood cells
Red blood cells do not replicate themselves.
Who first observed cells directly and in what year?
Robert Hooke in 1665
What did Robert Hooke discover when observing cork?
Empty spaces contained by walls, which he named cells.
Before the discovery of cells, what did the Greeks believe we were made up of?
- Earth/black bile/melancholy
- Water/phlegm
- Fire/yellow bile/choleric
- Air/blood/sanguine
What was the belief regarding spontaneous generation?
Life could spontaneously generate from nothing.
What discipline studies cells?
Cell biology
What are the basic principles of Cell Theory? List them.
- All living things are made up of cells
- Unicellular organisms are single cells
- Multicellular organisms are two or more cells
- A cell is the basic unit of life
- Cells can arise from pre-existing cells
What additional points have modern science added to Cell Theory?
- Energy flow occurs through cells
- Genetic information is passed on from cell to cell
- All cells have the same basic chemical composition
What is the definition of life according to NASA?
Life is a self-sustaining chemical system that is capable of Darwinian evolution.
What is a more recent working definition of life?
Living organisms use energy to build molecular structures and to reproduce or replicate, following specific instructions embedded within the organism.
What is the longest cell in the human body?
A motor neuron cell, approximately 1.3m long.
What is the largest human cell and what is the smallest?
Largest: ovum; Smallest: sperm.
How many cells are estimated to be in the average human body?
Between 75 and 100 trillion cells.
How many neurons are estimated to be in the human brain?
Approximately 86 billion neurons.
