Mixed Practice Questions Flashcards
Describe triglycerides
One glycerol molecule with three fatty acids
Joined together by ester bonds - esterification
Ventilation of the lungs involves muscles working together.
Describe expiration?
In expiration at rest, the external intercostal muscles and the diaphragm relax and the rib cage moves down and in.
Erythrocytes are formed from bone marrow stem cells. During this process they lose most of their organelles. What happens to erythrocytes in respiration.
They respire anaerobically because they do not have mitochondria
Explain, using examples, why multicellular plants need transport systems.
Plants have a small SA:V ratio, diffusion processes would be too slow to meet the metabolic demands hence need transports systems.
Plants need to transport water/ions from roots to other parts of the plant (xylem).
They need to transport sucrose from source to sink
What are the functions of the xylem
Transports water and mineral ions
Mechanical and structural support
What do bordered pits and lignin help do in vascular tissue
Bordered pits - allow lateral movement of water between xylem vessels.
Lignin - provides support and prevents it from collapsing
Water can act as a coolant and have thermal properties to ensure organs can live in an environment with relatively small changes in temperature.
Outline how other properties of water are essential for sustaining life on earth.
Water have cohesive and adhesive properties. Cohesive means water molecules are attracted to each other, so water can be drawn up the roots for plant survival. Adhesive between water molecules and surfaces, these both result in capillary action which is an efficient transport medium within living things.
when water turns into ice, it becomes less dense. Ice forms on the surface and hence forms an insulating layer below this maintains habitat for aquatic organisms.
Water is a polar molecule as the positive and negative regions of the molecule attract each other. It can act as a solvent in which many of the solutes in an organisms can be dissolved. Water can act as a medium for chemical reactions and help transport dissolved compounds into and out of cells.
Suggest one advantage of using a computer to collect data
Allows continual data collection and removal of human error
Describe what is meant by an endocrine gland
Works inside the body, group of cells that secrete hormones directly into the bloodstream.
The pancreas contains endocrine glands such as the Islets of Langerhans. It also contains cells that produce digestive enzymes. Suggest why the cells that produce digestive enzymes are described as exocrine.
They are not directly released into the blood but rather the ducts
Hormones can be steroid or non steroid. Steroids are lipid soluble.
Suggest the location of the receptors for steroid hormones and state a reason.
In the cytoplasm because steroid are lipid soluble so can pass through the phospholipid bilayer and enter another cells cytoplasm
Adrenal failure is caused by inability of the adrenal glands to produce sufficient amounts of cortisol and aldosterone.
Symptons are severe fatigue, weight loss, low blood pressure and salt craving
Cortisol regulate carbohydrate metabolism, if glucose levels are too low then not enough energy is supplied so severe fatigue.
Aldosterone regulates ion concentration and if this drops it causes low blood pressure and salt cravings
Explain why patients with pituitary tumour (adrenal cortex) have adrenal failure but still respond normally to situations of danger or excitement.
ACTH only affects the adrenal cortex.
Adrenaline is produced by the adrenal medulla and is responsible for flight or fight responses.
Explain what is meant by pluripotent.
Pluripotent can differentiate into all tissue type. They cannot form whole organisms such as placenta or umbilical cord.
Why is it necessary to maintain a constant flow of water in the respirometer for the fish
So enough oxygen can be supplied for aerobic respiration to occur so fish can survive
Suggest and explain precautions for fish to survive when being tested using respirometer for oxygen concentration
Maintain the correct pH so no damage to fish can occur
