e Flashcards
Why do arteries have a narrow lumen?
Maintain blood at high pressure
Why do arteries have a thick layer of muscle?
To direct the flow of blood to the parts of the body that need it
Why do veins pump blood at low pressure?
Because blood has travelled around the body causing it to lose pressure
Why is cell differentiation important
Cells can be specialised to carry out functions more efficiently so they can then perform various vital functions in the body
What would happen if a plant was placed in pure water
The plant would gain water and become turgid
What would happen to red blood cells if they were placed in pure water?
They would gain water and swell, eventually burst
Why do root hair cells have a large projection?
increase surface area for absorption of minerals
What is anaerobic respiration?
An exothermic reaction of which glucose is broken down to release energy without oxygen
Equations for aerobic respiration (word and symbol)
Glucose + oxygen → Carbon dioxide + water
C6 H12 06 602 6C02 6H20
Why do multicellular organisms need a specialised surface for gas exchange
Large animals have a small surface area to volume ratio
The rate of diffusion is too slow to supply the core cells with sufficient oxygen
How do multicellular organisms differ from single celled organisms
multicellular organisms have a circulatory system/ specialised organisms for exchanging substances
Single celled rely on diffusion for exchanging substances
When animal cells are placed in pure water they swell then burst, whereas plants become turgid. Why is this?
Plant cells have a strong cell wall made of cellulose which prevents them bursting
Which molecules are able to diffuse into and out of cells?
Only small molecules such as water, glucose, and amino acids, can diffuse into/out of cells. Large molecules like proteins and starch are too big.
What is aerobic respiration?
An exothermic reaction in which glucose reacts with oxygen to release energy which can be used by cells in the form of ATP
How do cells use energy from respiration
muscle contraction
Maintaining body temperature
Moving substances around the cell
