Week 4a: Movement of Substances Flashcards
Substances that can be moved into cells: (8)
- Oxygen
- Water
- Glucose
- Protein
- Carbon Dioxide (in plant cells)
- Amino acids
- Hormones
- Salt (ions)
Substances that can be moved out of cells: (2)
- Carbon dioxide (particularly in animals)
- Waste (urea)
Inorganic nutrients required by plants (3)
Nitrogen, phosphorus, magnesium
Heterotrophic cells cannot photosynthesise. Therefore:
They must be supplied with a source of energy through their food.
Most metabolic activity in cells produces ______ which can be ____ if they accumulate.
WASTE PRODUCTS which can be TOXIC
As soon as CO2 is produced, it is transported:
Out of cells and into the blood stream of animals to be removed via the lungs/
In plants, excess carbon dioxide is produced if rate of aerobic respiration is greater than the rate of photosynthesis. How is it removed?
It is excreted from the leaves/
What is UREA?
A metabolic waste produced in animals, created by a biochemical process in the liver.
How is UREA excreted?
Urea moves out of the liver into the bloodstream, where it is removed by the kidneys to be excreted in urine.
Why do waste products need to be removed?
In order to maintain a stable intracellular environment.
Removal of waste enables ___
Metabolic processes to occur efficiently without disruption
For products to enter or leave cells, they must:
Cross the cell membrane via membrane transport processes.
The rate of movement is determined by: (3)
- Surface area to volume ratio of the cell
- Concentration gradients
- Physical + chemical nature of the substance
What is meant by surface area to volume?
As the size of the cell increases, the surface area to volume ratio decreases. This results in decreased efficiency in exchange of materials.
Why are most cells very small?
This allows them to get their requirements and excrete waste more easily via diffusion.
