Size And Surface Area Flashcards
What do cells need to take in?
Oxygen
Nutrients
Why do cells need oxygen?
For aerobic respiration
What type of waste products do cells excrete?
Carbon dioxide
Urea
Why does heat need to be exchanged?
So organisms need to stay at the same temperature
What does an organisms surface area : volume ratio affect?
How quickly substances are exchanged
What type of surface are : volume ratio does smaller organisms have?
Higher surface area : volume ratio
What type of surface are : volume ratio does larger organisms have?
Smaller surface area : volume ratio
What substances do organisms need to supply all its cells with?
Glucose
Oxygen
Why do organisms need to remove waste products from every cell?
To avoid damaging itself
How do single-celled organisms transport substances?
Substances diffuse directly in and out of cells across the cell-surface membrane
What is the diffusion rate in single-celled organisms?
Quick because there is small distances the substances have to travel
Why, in multicellular organisms, is diffusion across the outer membrane too slow?
Some cells are deep within the body
Larger animals have a low surface area : volume ratio
What do multicellular organisms need to have to absorb and excrete substances?
Specialised exchange organs
What is mass transport?
Efficient system to carry substances to and from individual cells
What is mass transport in mammals?
The circulatory system
What is the circulatory system?
Blood carrying Glucose and Oxygen around the body
Also carries hormones, antibodies and waste CO2
What does mass transport involve in plants?
The transport of water and solutes in the xylem and phloem
What does the metabolic activity inside cells create?
Heat
What does the rate of heat loss from an organism depend on?
Surface area
If an organism has a large volume what is its surface area?
Relatively small
Making heat loss harder
Is an organism has a smaller volume what is its surface area?
Relatively large
Making heat loss easier
What type of metabolic rate does a smaller organism need?
High metabolic rate in order to generate enough heat to stay warm
What type of shape do animals with a small surface area : volume ratio?
Compact
What type of surface area : volume do animals with a less compact shape have?
Larger surface area : volume ratio increasing heat loss from their surface
What does animals with a high surface area : volume ratio tend to lose?
More water as it evaporates from their surface
What do small mammals living in cold regions need to do?
Eat large amounts of high energy foods such as seeds and nuts
What might small mammals have to kept warm when the weather is cold?
Thick layers of fur
Hibernate
What have larger organisms developed to help lose heat to keep cool?
Large ears to increase their surface area
