Ch1 Flashcards
What are cells?
Cells are the smallest and basic units of life, whether it is a single cell that forms the entire organism or trillions of them in complex organisms like humans.
What are the universal features of cells?
- A plasma membrane
- Genetic information encoded in DNA
- Ability to replicate
- Ability to respond to the extracellular environment
- Ability to process energy
- Ability to regulate its own functions
What is the plasma membrane?
A bilayer of lipids that separates the cytoplasm from the outside environment.
What does DNA encode in a cell?
Genetic information.
What is homeostasis?
The process to maintain a constant internal environment despite external changes.
Fill in the blank: A living cell can _______.
replicate
What is thermoregulation?
A process that involves thermoreceptors, a change in temperature, and a response from skin and muscles.
How is cell size measured?
In micrometers.
What is the typical size range for eukaryotic cells?
10-100 μm.
Why do smaller cells have a higher surface area to volume ratio?
Changes in volume are not linear to changes in surface area.
What happens when a sphere increases in size?
Volume grows proportional to the cube of its radius while surface area grows proportional to the square of its radius.
What is a consequence of a surface-area to volume ratio that is too small?
Decreased rate of chemical exchange, leading to cell death.
What adaptations do prokaryotes have regarding size?
They are often small and divide before facing limitations due to cell size.
What is a key feature of eukaryotic cells compared to prokaryotic cells?
Eukaryotic cells have membrane-bound internal compartments called organelles.
What is the function of chloroplasts in plant cells?
Convert light energy to sugar.
What do lysosomes contain?
Enzymes to break up larger molecules.
What is the role of mitochondria?
Generate ATP from the oxidation of food molecules.
What is nucleoplasm?
A gel-like substance that fills the nucleus.
What controls the entry and exit of molecules in the nucleus?
Small pores in the nuclear envelope.
What do plasmids provide prokaryotes?
Survival advantages such as antibiotic resistance.
What is the function of the peptidoglycan cell wall in prokaryotes?
Physically protects the cell and helps maintain osmotic pressure.
What are thylakoids?
Membrane-bound compartments for photosynthesis in prokaryotes.
Fill in the blank: The layers surrounding a prokaryotic cell follow the order: _______.
Cytoplasm, plasma membrane, cell wall, capsule
