Nutrition and Gas Exchange in Plants
Give the blanced formula equation for photosynthesis.
6CO2 + 6H2O → C6H12O6 + 6O2
What is the function of Lipase, Amylase, Maltase, Trypsin.
Lipase - Lipids to fatty acids
Amylase - Starch to maltose
Maltase - Maltose to glucose
Trypsin - One of the proteases to turn protein
What are the main excretory organs and their products.
Skin - Ions
Lungs - CO2
Kidneys - Urine (water, salts, ions, urea).
What a 3 types of blood cells and their function
Red - Transport oxygen
White (Lymphocytes) fight infection
Platelets - Clot the blood.
What is a tropism - give the 4 main tropisms.
Directional response by plants to a stimuli.
Hydro - to/ away from water
Photo - Light
Thigmo - Touch
Geo/ Gravi - Gravity
What is a limiting factor, give 2 examples and explain how they affect rate of photosynthesis
Reactants: CO2, Glucose, Water - Will run out
Chloroplast availability - Can have enough reactants, but chloroplasts can only carry out one process at a time.
What is the function of accessory organs in the ailamentary canal - gall bladder, liver, pancreas.
Liver produces bil. Gall bladder stores and release bile, pancrease produces digestive enzymes (and glucagon to help with homeostasis).
Describe how water is reabsorbed into the blood in the collecting duct.
Water moved via osmosis in the nephron. ADH increases permeability of the walls of the collecting duct, when high water ADH is produced.
Name the four chambers of the heart in the correct order of blood flow starting from the body.
Right atrium → Right ventricle → Left atrium → Left ventricle.
In roots - inhibits elongation. Diffuses to the bottom cells, so top cells elongate causing roots to curve downwards.
In shoots - promotes elongation. Diffuses to the shaded side, so shaded cells elongate causing roots to curve towards sunny side.
How are leaves adapted for efficient gas exchange?
3 adaptations
Large surface area for diffusion
Thin for a short diffusion path
Stomata to allow gases in and out
Air spaces in the spongy mesophyll to increase gas movement
Palisade at the top with lots of chloroplasts
Any other reasonable adaptation
Describe the lock and key model and induced fit of enzymes.
Every enzyme has a specific active site that binds to a specific substrate (like a lock and key). When the sunstrate-enzyme complex forms, then the enzyme with adjust its shape slightly to fit the substrate perfectly.
What substances in the blood would you not expect to see in the urine and why?
Glucose and proteins. Proteins are too big, glucose is reabsorbed quickly to use for respiration.
Give 2 structural differences between veins nad arteries and explain their function.
Valves in veins prevent back flow
Thick, muscular wall to allow high pressure blood to pass through.
Using the reflect arc 'sr - StoRM - e' describe the response to touching a cactus.
stimulus (spine) is detected by receptor (skin). Sensory neuron sends electrical impulse by the relay nuron to the motor neuron, which causes the effector (muscle) to move hand.
Explain how the gas exchange in a leaf changes between day and night.
In the day, photosynthesis occurs, so carbon dioxide is taken in and oxygen is released.
At night, photosynthesis stops, but respiration continues, so the plant takes in oxygen and releases carbon dioxide.
Explain how bile helps with the digestion of fats, even though it is not an enzyme.
Bile emulsifies fats by breaking large fat droplets into smaller ones, increasing the surface area for lipase enzymes to act on. This speeds up fat digestion.
Explain how ADH is produced in response to high or low blood water - and its affect on urine.
High blood water, less ADH, less reabsorbed, less concentrated urine.
Low blood water, more ADH, more water reabsorbed, more concentrated urine.
Explain the role of lymphocytes and memory cells in the immune response, and how this leads to immunity after infection or vaccination.
When a pathogen enters the body, lymphocytes recognize its antigens and produce antibodies to neutralize it. Some of these lymphocytes become memory cells, which remain in the blood.
If the same pathogen enters the body again, memory cells quickly recognize it and produce antibodies faster and in larger quantities.
Describe a homeostatic loop for thermoregulation
Body gets too cold so hypothalamus signals the response causing vasocontriction, shivering, hairs rising. If we get too hot, hypothalamus responds by signalling the skin to produce sweat and blood vessel to vasodilate.
Describe an experiment you could use to show that light is needed for photosynthesis.
Take a plant that has been kept in the dark for 48 hours to destarch it.
Cover part of one leaf with black paper (no light) and leave the plant in sunlight for a few hours.
Boil the leaf, then place it in ethanol to remove chlorophyll.
Rinse and test with iodine solution
The area that received light turns blue-black (starch present), the covered part stays brown (no starch), showing light is needed for photosynthesis.
Describe what would happen to protein digestion if the pH in the stomach was raised significantly, and explain why.
Protein digestion would slow down or stop because pepsin, the protease in the stomach, works best in acidic conditions (low pH). A higher pH would denature pepsin, changing its active site so it can no longer break down proteins.
Describe the movement of a water molecule through a nephron in a person with high blood water concentration.
Bowmans capsule, PCT, Loop of Henle, DCT, Collecting duct, Bladder
Describe how the circulatory system is a double circulatory system, and explain the advantage of this in humans.
The circulatory system is double because blood passes through the heart twice in one complete circuit: once through the pulmonary circuit (heart → lungs → heart) and once through the systemic circuit (heart → body → heart).
Advantage: This allows for higher pressure and faster delivery of oxygenated blood to the body tissues, which is essential for high metabolic rates in humans.
Describe how glasses can increase eyesight for someone with hypertopia or myotopia.
Myotopia - shortsightedness, rays of light converge in front of the retina, glasses cause convergence later. Person can see close things clearly.
Hypertopia - longsightedness, rays of light converge in 'behind' the retina, glasses cause convergence sooner. Person can see far away things clearly.