B4: Organisation in Plants & Animals Flashcards
What is the function of the right ventricle?
The right ventricle pumps blood to the lungs where gas exchange takes place.
What is the function of the left ventricle?
The left ventricle pumps blood around the rest of the body
What is blood?
A tissue
Why is coronary heart disease fatal?
The narrowing of the coronary arteries reduce the flow of blood resulting in a lack of oxygen for the heart muscles
How can faulty valves be replaced?
Using biological or mechanical valves
Where is the meristem found?
At the growing tips of roots and shoots of plants
What factors affect the rate of transpiration?
Temperature, humidity, air movement and light intensity
What 3 parts of a plant form a plant organ system for transport of substances around the plant?
Roots, stem and leaves
What is the role of stomata and guard cells?
Control gas exchange and water loss
What is the role of the circulatory system?
To transport oxygen and nutrients to the body
What 2 blood vessels does blood enter into the heart?
Vena cava and the pulmonary vein
What type of blood enters the heart via the pulmonary vein?
Oxygenated, as it has just come from the lungs
Which ventricle has thicker walls? Why?
The left ventricle because it pumps blood all the way around the body
Describe the movement of blood between the ventricles and the atria
Walls of the atria contract, pushing blood into the relaxed ventricles. Walls of the ventricles contract, pushing blood out of the heart. Simultaneously, more blood will enter the now relaxed atria. The cycle repeats
Where are pacemaker cells found?
In the right atrium
What is the function of the capillaries?
They exchange nutrients and oxygen with tissues
How are arteries adapted to their function?
Thick muscle walls to withstand high pressure and elastic fibres to stretch and recoil
How are capillaries adapted to their function?
1 cell thick and permeable, so that substances can easily diffuse through them
Which blood vessel has the largest lumen?
Veins
What nutrients are exchanged between the blood in the capillaries and the body tissues?
Glucose and amino acids
In which order does blood flow through the three types of blood vessels?
Artery, capillary, vein
How much of our blood are red blood cells?
45%
How are red blood cells adapted for their function?
They have a biconcave disk, to increase the surface area for absorbing oxygen. They also have no nucleus, which creates more space for haemoglobin and oxygen
What are 3 ways white blood cells defend against infection?
Phagocytosis, releasing antitoxins and producing antibodies
What are 2 functions of platelets?
Stop blood from leaving the blood vessel and prevents microorganisms from enter
What is the disadvantage of artificial blood?
It does not contain red blood cells
What are advantages of stents?
The surgery is quick and they are effective for a long time
What are disadvantages of stents?
Require surgery, meaning it can lead to risks. Blood clotting is also a high risk
What are advantages of statins?
Reduce levels of LDL
What are disadvantages of statins?
Have to be taken regularly and can cause side effects
What are disadvantages of biological and mechanical valves?
Requires surgery and ongoing risk of clotting
What are disadvantages of artificial/biological hearts?
Temporary fix, takes long to find a donor and could still be rejected
What are advantages of artificial hearts?
Immune system does not reject it
What are 2 problems that may be caused by faulty valves?
Not enough blood can pass through the valve and the backflow of blood
How is the alveolus adapted for its function?
1 thick layer of cells, creating a short diffusion path, increasing gas exchange. They have a large surface area and the alveoli walls are moist, so it allows the gases to dissolve
What is the name of the process by which oxygen moves through the wall of the alveoli into the blood?
Diffusion
How do you calculate breathing rate?
Number of breaths/time (mins)
Where is the stomata found?
The lower epidermis
Where in the leaf is where most of the photosynthesis happens? Why?
The palisade mesophyll. This is because it is packed full of chloroplasts
What is special about cells in the upper epidermis? Why?
They are transparent for sunlight to pass through
What reduces water loss in the leaf?
The waxy cuticle, which is a thin waterproof layer of lipids that the water can’t get through
Why are the stomata at the bottom of the leaf?
It is shadier, therefore cooler, so less water will evaporate
When are the stomata closed?
At night
What can the sugar from photosynthesis be used for?
Directly for energy or stored for later
How does increased light intensity affect the rate of transpiration?
This would mean brighter light, so more photosynthesis and also more evaporation of water as stomata will need to be open for carbon dioxide needed for it
How does increased temperature
Particles will have more energy, so more likely to evaporate
How does increased air flow affect the rate of transpiration?
Water will be blown off the leaf, leaving the concentration gradient high
How does increased humidity affect the rate of transpiration?
Decreases as water in the air is high, so less water will diffuse out of the leaf due to the decreased concentration gradient
