Kidneys And Food Flashcards
What are proteins made of? What are they for?
- elements C, H, O, N and sometimes S
- made up of amino acids
- needed to maintain cell function and repair cells and tissues
How do you test for protein? Where do you find it?
- biuret reagent. Light blue to purple
* seafood, meat, eggs
What is fibre made of? why do we need it? Where is it found?
- elements C, H, and O
- 1000s of glucose molecules
- needed to help keep dig system healthy and prevent constipation. Can’t digest
- found in cereals, rice, beans, nuts
What are minerals? Why do we need them? Where are they found?
- salts needed by body in small amounts, e.g. Calcium to keep bones healthy, iron for haemoglobin
- in milk and meat
What are vitamins? Why do we need them? Where do we find them?
• organic substances needed in small amounts
A: good vision, maintenance and formation of skin, immune system(anti-oxidants). Dairy, eggs, fatty fish, mango, spinach
C: aids absorption of iron and copper, helps fight infection. Citrus fruit, blackcurrants
D: aids absorption of calcium. Found in sunlight on skin
Why do we need water?
• carry substances around body and replaced lost water
What are carbohydrates made of? Why do we need them?
- C, H, and O
* short term energy storage. Mono- use in resp, quick energy. Poly- broken down into glucose for resp
How do you test for carbohydrates? Where do you find them?
• mono- benedict’s reagent. Blue ➯ brick red when heated
Sugar, cakes, etc.
• poly- iodine. Brown ➯ blue/black
Bananas , brown rice, potatoes
What are lipids made of? Why do we need them? Where are they found?
- made of C, H, and O
- glycerol and 3 fatty acids
- long-term energy storage
- eggs, fish, milk
How do you find out the energy in a sample of food?
• fill boiling tube w water
• weigh water
• measure temp at start
• wound food on needle and burn under water
• measure temp at end
Energy (cal) = (mass of water x temp rise) / mass of food
What is peristalsis?
Series of wave like contractions to move food along to the digestive system. Mechanical action is needed
How is absorption made efficient?
- large SA w many villi and microvilli
- short diffusion distance, villus wall thin and close to blood vessels
- high conc gradient. Rich blood supply has low conc of food molecules ∴ food diffuses quickly
What are the types of digestion?
- mechanical, e.g. Teeth
* chemical, e.g. Enzymes
What are enzymes?
Biological catalysts in metabolic reactions. Work by lower activation energy. Different enzymes catalyse only their particular reaction, as each amino acids folds a different way to form the active site where the substrate binds. The substrate shape is complementary to the active site.
What are anabolic and catabolic reactions?
Catabolic- breaking down
Anabolic- building up
How does temperature affect enzymes?
• below optimum temp:
Lower RoR. KE increases as temp increases ∴ more collisions and substrate base-combos ∴ RoR increases
• optimum temp: (roughly 37 °C) highest RoR
• above optimum temp:
Enzymes denature, active site changes shoe, RoR decreases rapidly
How does pH affect enzymes?
• below/above optimum pH ➯ enzymes denature ➯ active site changes chape ➯ fewer substrate-base combos ∴ RoR decreases rapidly • optimum pH ➯ highest rate of reaction
What happens in the mouth?
Starch turns into maltose, ∵ of amylase from salivary gland
What happens in the stomach?
- proteins digest in to amino acids by pepsin made in stomach lining
- stomach v acidic ∵ pepsin work best at low pHs
What happens in the duodenum?
- starch breaks down into maltose via amylase made in salivary gland, and then into glucose via Maltase made in pancreas
- proteins digested into amino acids by trypsin, from pancreas
- lipids are digested into glycerol and fatty acids by lipase form pancreas, and helped by bile
What does bile do?
- produced in liver and stored in gall bladder
- neutralises pH as food leaves stomach
- emulsifies lipids into droplets ∴ larger SA for lipase action
What is an experiment to study the effect of temperature on enzymes?
- cut potatoes into small cubes
- get 5 test tubes and pt 3cm of hydrogen peroxide in each
- add 10 cubes to each test tube
- incube for 10 mins at different temps (e.g. 35, 30, 35, 40, 45)
- record height of oxygen bubble produced
What is digestion?
Large insoluble food molecules broken down into smaller ones
What is absorption?
Soluble molecules produced by digestion are taken from gut (mostly small intestine) and transported around body via circulatory system
What is assimilation?
Cells of tissues absorbing the molecules for use
What is egestion?
Removal of indigested waste products as faeces
What is excretion?
Removal of things used in cells processes, via urine and sweat
What are the medulla, pelvis, cortex, and nephron?
Medulla- lighter middle layer of kidney
Pelvis- central cavity which collects urine
Cortex- darker outer layer
Nephron- filtration unit where urine is prduced
How do we remove waste from the body?
Skin- urea, water, salt, via sweat
Mouth- CO2, water, via exhalation
Kidneys- urea, water, salt, via urine
What are the purposes of the kidneys?
Excretion- getting rid of urea and excess alt from blood
Osmoregulation- reabsorbing moe/less water into blood to maintain correct conc
Why do we need to remove waste?
- urea toxic and produces ammonia
- excess water has osmotic effect and can burst cells
- excess salt is bad for osmotic effect and can effect metabolic processes
What is in urine vs clean blood?
Urine: urea, some salts, some water
Clean blood: amino acids, cells, glucose, proteins, some water, some salts
What happens in the nephron?
Ultrafiltration:
➯ blood arrives at glomerulus at high pressure, and small molecules squeeze through pores in wall into the bowman’ capsule
➯ blood cells/large molecules stay in blood ∵ too big to fit through
Selective reabsorption:
➯ useful molecules, e.g. Glucose, amino acids move back into blood via active transport
➯ some water moves into blood via osmosis
➯ urea stays in filtrate
➯ cells lining PCT have many mitochondria for resp for active trans
➯ have a folded membrane ∴ large SA
3. Water reabsorbed into blood via collecting duct. Urea + excess water becomes urine
What happens when you are thirsty?
• lower water conc in blood
• hypothalamus stimulates pituitary gland to release ADH
• ADH makes collecting duct more permeable
∴ more water reabsorbed into blood and less urine produced
Negative feedback:
• thirst centre in hypothalamus stimulated
• ∴ you drink
• water conc in blood rises
What happens when you are not thirsty?
- high water content in blood
- hypothalamus does not stimulate pituitary gland to release ADH
- makes collecting duct less permeable to water
- less water reabsorbed into blood, more urine produced
What happened in dialysis?
- blood enters machine and flows between dialysis membranes
- dialysis fluid has salt, amino acids, glucose and water in normal quantities, but no water ∴ urea and excess salt/water are removed via diffusion/osmosis into the fluid
- fluid w urea discarded whilst cleaned blood goes back to body
