Studied by 0 people
Looks like no one added any tags here yet for you.
Define a balanced diet
food intake in appropriate proportions to sufficiently provide the body with energy for growth and other factors like repair and fighting diseases
importance of carbs?
provide energy/glucose
importance of protein?
repair of muscles
importance of lipids?
stores energy/glucose
Importance of vitamins, minerals and water?
vits and mins: required in small quantities to support health. Water needed to conduct chemical reactions in cells.
Define an enzyme
Enzymes are proteins which break down macro nutrients so they they can be absorbed into the body. They can break break down larger molecules into smaller molecules or smaller molecules into larger molecules. Also, they are biological catalysts; speed up digestion.
Example of vitamin A and function
eggs, liver, to fight infections, for better vision and healthy skin
Example of vitamin C and function
citric fruits, for skin and blood vessel health, balances pH levels
Example of vitamin D and function
red meat, helps calcium absorption
Example of calcium and function
milk, leafy greens, healthy and strong bones, muscles, helps blood clotting
Example of iron and function
beans, nuts, make red blood cells
Example of fibre and function
whole grains, greens, help digestion(break down food)
Investigation link
reagent and positive results for following food samples: starch, reducing sugar/glucose, protein, fat &oil
starch- iodine: from dark yellow to dark blue
glucose/reducing sugar- Benedict’s solution: from blue to a red-ish precipitate
protein- Biuret’s solution: from blue to lilac
fat & oil/lipids- Ethanol: from colorless to a white precipitate
Define digestion
break down of food from large, insoluble molecules into small, soluble ones for absorption of nutrients
Define an enzyme and describe its structure
a protein made up of amino acids and biological catalyst(speeds up reaction without being used up itself) to help digestion
made of chains of amino acids that are joined into a long chain and folded into a unique 3D structure
role of amalyse
to break down starch into sugar(MALTOSE)
role of protease
to break down proteins into amino acids
role of lipase
to break down fats into glycerin/glycerole/fatty acids
Explain why enzymes are so specific about which reaction they catalyze
Each enzyme has an active site that is uniquely shaped/complementary to a specific substrate. Their shapes are determined by the sequence of amino acids in their structure.
Factors that affect enzyme activity
Temperature(if it’s too hot, exceeding an enzyme’s optimum, it will denature/active site isn’t functional)
pH(if the pH is too low or high, beyond an enzyme’s optimum, the enzyme’s shape irreversibly alters)
Enzyme concentration(the denser the enzyme concentration, the quicker enzymes will break it down)
Substrate concentration(the more substrates there are to break down, the more active enzymes become)
explain this graph (impacts of temp on enzyme activity)
At the start, the temperature is increasing, resulting in more kinetic energy, thus successful collisions, meaning this is an increase in the rate of reaction. Eventually, the temp exceeds the enzymes’ optimum, so the amino acids in its structure break(enzymes denature) and can’t form an enzyme-substrate complex anymore.
explain this graph (impacts of pH on enzyme activity)
at the ranges of 6-7 pH, it shows that it’s the enzyme’s optimum pH, as that’s when enzyme activity is the highest, compared to too acidic or alkalic pHs which result in denaturing of an enzyme, meaning it can’t for enzyme-substrate complexes anymore.
How does food pass down the oesophagus?
via peristalsis, which is a mechanism of waves of muscular contractions
What’s the alimentary canal
tube of organs including the esophagus, stomach, and intestines
P.S: stomach is a muscular bag which mixes food and drinks with acid (mechanically and chemically breaks it down)
Role of small and large intestines
small- digests macronutrients which then are absorbed into the bloodstream
large- where fiber(food that can’t be broken down) passes through and absorbs water from it into the blood
P.S: rectum stores foeces or undigested food whilst anus is the opening through which foeces exits
Roles of pancreas, liver and gall bladder
Liver- produces bile
Pancreas- secretes enzymes into small intestine
Gall Bladder- releases bile
Role and source of bile
Bile is a fluid that is made and released by the liver and stored in the gallbladder. Bile helps with digestion; it breaks down fats into fatty acids, which can be taken into the body by the digestive tract
Name two diseases: one’s caused by calcium deficiency, one’s caused by vitamin c deficiency
calcium deficiency- Rickets
vitamin c deficiency- Scurvy
How can the energy in food be experimentally tested?
by recording the energy burnt from a food sample (finds the energy content)
Define emulsification and what purpose it serves for the body?
it’s the break down of large droplets into smaller droplets.
Bile emulsifies fats, which increases their surface area so that lipase enzymes break them down easier and quicker
How is the small intestine adapted to absorbing nutrients quickly?
It has thin walls which means the diffusion pathway is short, has a large surface area:volume ratio and gets good blood supply which means a high concentration gradient, resulting in a higher rate of nutrient diffusion.
Which pasrts of the biody ttest uestion
