Topic L: Excretion in Plants & Animals Flashcards
The chemical equation for respiration?
Oxygen + sugar = Carbon dioxide + water + energy
When and how to sugar made in plants?
Sugar is made during the day via photosynthesis.
What process occurs with leaves at night?
Only respiration occurs as light is not available.
What processes occur with leaves during the day?
Both respiration and photosynthesis.
The chemical equation for Photosynthesis?
Carbon dioxide + water ==(Light&Chlorophyll)== sugar + oxygen.
During the night, what is the main waste gas produced in leaves, and why?
During the night, only respiration occurs as light is not available.
During the day, what is the main waste gases produced in leaves, and why?
During the day, both respiration and photosynthesis occur because both oxygen and light are present in good quantities.
How are waste gases removed from leaves?
They are removed via diffusion through the stomata.
Which three organs in humans remove excretory waste?
Kidney, Skin and lungs
Urine is the solution of waste products dissolved in water, One of these products is urea. What is urea, and where is it produced?
Produced from the breakdown of excess amino acids in the liver.
How many litres of blood are filtered through the kidneys per day?
1700 litres.
How many small “knots” of capillaries and their associated tubules are there in each kidney (Nephron)?
1,000,000 in each kidney.
Which substances can get through the capillary walls and hence be removed from the blood?
Urea, salt, glucose.
Which substances cannot get through? Why is this?
Red blood cells, proteins are to big.
What happens to some of the products that are filtered out of the blood early on?
Reabsorbed.
What percentage of the filtered fluid is returned to the blood?
99%
What is the process of artificially removing waste from the blood called?
Dialysis
Why does blood pressure increase between dialysis sessions?
Greater volume of blood.
What is the alternative to treatment on the kidney machine?
transplant
What are the problems associated with this alternative?
danger of surgery, rejection of donation.
Define Excretion?
The removal of the waste products of metabolism.
Define Ureter?
Transports urine from the kidney to the bladder.
Define Urea?
Produced from the breakdown of excess amino acids in the liver.
Define Urine?
A solution of urea + water + salts, stored in the bladder before being released from the body.
Define Nephron ?
Functional filtering unit of the kidney, also known as kidney tubules. Each kidney contains about a million nephrons.
Define Bowman’s Capsule?
A hollow cup of cells surrounding the glomerulus.
Define Glomerulus?
A dense network of capillaries where water, ions, glucose and urea are filtered from the blood into the tubules.
Define Glomerular filtrate?
The fluid forced out the glomerulus under high pressure. It contains water, glucose, urea, ions and other small molecules, but NOT blood cells and large molecules such as proteins.
Define Proximal convoluted tubule?
Site where the majority of the glomerular filtrate is reabsorbed. All of the glucose is reabsorbed back into the blood here by active transport.
Define Loop of Henle?
A U-shaped loop that runs down into the medulla of the kidney. It has a complicated role in concentrating the fluid in the tubule to allow more water to be reabsorbed into the blood.
Define collecting duct?
The tubule that receives urine from numerous nephrons. The permeability of its walls to water is controlled by ADH.
Define Ultrafiltration?
The process where fluid is forced out of the glomerulus under high pressure.
Define selective reabsorption?
The process where the substances we need, e.g. glucose, are reabsorbed from the tubules back into the blood stream.
Define active transport?
The transport of a substance across a biological membrane against a concentration gradient. Energy from respiration is required.
Define Osmoregulation?
The hormonal control of water levels in the blood.
Define ADH?
the hormone which increases the permeability of the collecting ducts, allowing more water to be reabsorbed back into the blood.
Define hypothalamus?
A region of the brain that contains special receptor cells which are sensitive to the solute concentration of the blood. it has several other roles e.g. it also contains the thermoregulatory centre which detects blood temperature.
Define Pituitary gland?
A small gland in the brain that releases several hormones, including ADH.
Define negative feedback?
Any mechanism which reverts a change in a system back to its normal value.
What is the purpose and excretion material of the kidneys?
Excretes: Urea, Purpose: Removes harmful urea and will keep the water content of the body stable.
What is the purpose and excretion material of the lungs?
Excretes: Carbon dioxide + Water Purpose: Removes the waste products produced by respiring cells.
What is the purpose and excretion material of the skin?
Excretes: Water and salts Purpose: Cools the body.
What are the three roles of the Nephron?
- Ultrafilteration
- Selective reabsorbtion
- Osmoregulation
What does the Renal Artery entering the kidney contain alot of?
-Lots of, oxygen, glucose, water, salt, urea.
What does the Renal Vein carry away from the kidney?
Less, oxygen, glucose, urea. The right amount of water and salt.
Where does Ultrafilteration take place?
In the Glomerlus, Bowman’s capsule.
Where does Selective reabsorbtion take place?
In the Proximal convoluted tubule.
Where does osmoregulation take place?
In the collecting duct.
Why do plants lose leaves in the cooler months?
reduce water loss;
less light;
less photosynthesis;
conserve energy / eq;
How does the body monitor Glucose levels?
- If glucose to high, message is sent to liver and tells to convert glucose to glycogen.
- Glucose levels go down
- Visa Versa.
