LEVELS OF ORGANISATION
A colony of single-celled organisms living together but not fully dependent on each other.
Colonial organism
Animal tissue that connects, supports and binds, such as bone and blood.
Connective tissue
Organisms that must consume other organisms for nutrients.
Heterotrophs
The direction xylem moves water (up or down).
Up (roots to leaves)
Blood vessels that carry blood back to the heart.
Veins
Multicellular organisms are made of these cells, which cannot survive alone once separated.
Specialised cells
Unspecialised cells that can develop into any cell type.
Stem cells
The gas taken in by plants for photosynthesis.
Carbon dioxide
Name of vessel that transport sugars in plants, in which direction does it travel?
Phloem, Up/Down (throughout) to cells that need energy which is all
The smallest blood vessels, where exchange with tissues occurs.
Capillaries
[Image: Amoeba] This is an example of which type of organism (one cell)?
Unicellular
[Image: Red blood cells] Name one feature that helps this cell carry oxygen.
Biconcave shape (large surface area) / no nucleus / contains haemoglobin
[Image: Fish gills] Name this gas exchange structure.
Gills
[Image: Wilting plant] Water loss exceeding uptake causes this.
Wilting (excess transpiration)
[Image: Open circulatory system diagram (insect)] Name this type of circulatory system.
Open circulatory system
The level of organisation between "organ" and "organism."
Organ system
The waxy layer on the leaf epidermis that reduces water loss.
Cuticle
Two products of aerobic respiration.
Carbon dioxide and water
The substance in xylem walls that provides support and waterproofing.
Lignin
The liquid part of blood that carries dissolved substances.
Plasma
Why can't a single specialised cell, like a nerve cell, survive independently?
It relies on other specialised cells for functions it can't perform itself (division of labour)
[Image: Guard cells around a stoma] Name these cells and their job.
Guard cells — open and close the stoma
Explain why a large surface area improves gas exchange.
More area for gases to diffuse across at once, increasing exchange rate
How does high humidity affect transpiration rate, and why?
Decreases it — smaller concentration gradient between leaf and air
State one advantage of a closed circulatory system over an open one.
Faster transport / higher pressure / directs blood to specific organs efficiently