B4(4.1-4.9) Organising Animals and Plants Flashcards
Name the four main components of blood.
-Red blood cells
-White blood cells
-Platelets
-Plasma
What is the function of platelets?
-To form blood clots - prevents the loss of blood and stops wounds from becoming infected
Why is the human circulatory system a double circulatory system?
-blood passes through the heart twice for every circuit
around the body
How does the structure of an artery relate to its
function?
–has a small lumen and thick, elasticated walls that can
stretch (carries blood away from the heart under high pressure)
How does the structure of a vein relate to its function?
-Doesn’t need thick, elasticated walls, but has valves to prevent blood flowing the wrong way(carries blood back to the heart at low pressure)
How does the structure of a capillary relate to its function?
-Has a one-cell-thick wall to provide a short diffusion distance (carries blood to cells and tissues)
List the structures air passes through when breathing in.
-Mouth/nose ➞ trachea ➞ bronchi ➞ bronchioles ➞ alveoli
What is the function of the red blood cells?
-Bind to oxygen and transport it around the body
What is the function of the white blood cells?
-Defend the body against pathogens
What is the function of the plasma?
-Transports blood cells and substances around the body
Why is a leaf an organ?
-There are many tissues inside the leaf that work together to perform photosynthesis
How is the upper epidermis adapted for its function?
-Single layer of transparent cells allow light to pass
through
-Cells secrete a waxy substance that makes leaves
waterproof
How is the palisade mesophyll adapted for its function?
-Tightly packed cells with lots of chloroplasts to absorb as much light as possible for photosynthesis
How is the spongy mesophyll adapted for its function?
-air spaces increase the surface area and allow gases to
diffuse quickly
What is the function of the guard cells?
-control the opening and closing of the stomata
What is the function of the xylem?
-Transport water and mineral ions from the roots to the
rest of the plant
Give three adaptations of the xylem.
-made of dead cells
-no end wall between cells
-walls strengthened by a chemical called lignin to
withstand the pressure of the water
What is the function of the phloem?
-transport dissolved sugars from the leaves to the rest of the plant
What is the purpose of translocation?
-transport dissolved sugars from the leaves to other parts of the plant for respiration, growth, and storage
Define the term transpiration.
-movement of water from the roots to the leaves through the xylem
What is the purpose of transpiration?
-provide water to keep cells turgid
-provide water to cells for photosynthesis
-transport mineral ions to leaves
Name four factors that affect the rate of transpiration.
-temperature,
-light intensity,
-humidity,
-wind speed
What effect does temperature have on the rate of
transpiration?
-higher temperatures increase the rate of transpiration
What effect does humidity have on the rate of
transpiration?
-higher levels of humidity decrease the rate of
transpiration
