Energy for life: Digestion Flashcards
What are the function of carbohydrates?
Fuel for respiration
What is the function of protein? [2 points]
- growth and repair of tissues
- fuel for respiration
What is the function of lipids/fats? [3 points]
- Store of energy
- Thermal and electric insulation
- fuel for respiration
What enzyme breaks down starch?
Amylase
What affects enzyme activity? [4 points]
- Temperature
- pH
- Substrate concentration/ enzyme concentration
What is the food test for Glucose? (And explain what cilour it turns and how to prepare it)
Benedict solution, which start blue and then turns red or orange is startch is present.
Must be heated.
How is the vili adapted for absorption of molecules? [3 points - list and explain for all points]
- Has microvili for a large surface area
- Thin walls for short diffusion distance
- Near blood vessels > good blood supply means there is a high concentration gradient, which means diffusio happens very quickly.
What is the role of bile? [2 points]
- Emulsifies fats
- Neutralises stomach acid
How does food move down the Oesophagus?
Peristalis
What is the function of bile?
- emulsifies fats
- neutralises stomach acid
What is an enzyme?
A biological catalyst
Why are enzymes described as ‘specific’?
Because they are complimentary to 1 substrate.
Describe how enzymes work: [6 points]
- The enzyme and substrate collide
- Substrate binds to the active site of the enzyme
- Active site is specific// complementary to one type of substrate –> Allows the reaction to occur.
- Binding the active site strains the chemical bonds in the substrate molecules, and so the reaction occurs by an alternative pathway with a lower activation energy (the energy needed for the reaction to occur).
- Once the reaction has occurred, the products do not fit the active site’s shape as well, so they are released.
- After the reaction the enzyme molecule is free to catalyse the next reaction
What is energy measured in?
Kilojoules
Describe how you would measure the energy content of a banana chip: [7 points + equation]
- measure 25 cm3 of water into a boiling tube
- measure mass of food
- measre starting temperature of food
- set light to food suing bunsen burner and hold under boiling tube of wate runtil it goes out
- relight and repeat until it won’t catch fire.
- meauser finishing temperature of water
- calculate temperature change >
Energy content = (volume of water* temperature change *4.2)/mass of food
Where is hydrchloric acid produced?
Stomach
What is the role of the mouth?
Digestion of food starts in the mouth. Teeth break down the food and mix it with the enzymes in saliva.
What is the role of the salivary gland?
Helps digest the starches in food (releases saliva into your mouth and releases amalase, which breaks the stach down into maltose.)
What is the role of the oesophagus?
Thin tube that connects the mouth to the stomach
What is the role of the small intestine? [2 points]
Here, carbohydrates, proteins and lipids digest. The nutrients produced are then absorbed into the blood.
Whtat is the role of the large intestine?
Food that cannot be taken down (mostly fibre) is passes through. Water absorbed into the blood from here.
What is the role of the pancreas?
Releases enzymes which break down carbohydrates, proteins and lipids.
What is the role of the liver?
Releases a chemical called bile into the intestines. Bile breaks down lipids in the food.
What is the role of the gall bladder?
Stores bile.
Where is Amylase secreted? (by which gland?)
Salivary glands
What it eh function of the duodenum?
FInal site of digestion
What is the function of iron?
Form the part of haemoglobin that binds to oxygen
What is the function of calcium?
Needed to form bones and teeth
state a food source of iron:
- red meat
- liver
- spinach
state a food source of calcium:
- milk/dairy products
- fish
- fresh vegetables
Deficiency disease of iron?
Anaemia
Deficiency disease of calcium?
rickets
use of vitamin A in the body [2 points]
- making chemicals in the retina
- protecting eye surface
Use of vitamin C in the body [1 point]
Neede for cells and tissues to stick together
Use of viatmin D in the body [1 points]
needed to absorb calcium and phosphate ions from food
State the effect of the deficiency caused by lack of vitamin A [2 points]
Night blindness, damaged cornea
State the effect of the deficiency caused by lack of vitamin C
scurvy
State the effect of the deficiency caused by lack of vitamin D [and explain]
Rickets, caused by weak bones
Which food source(s) can vitamin A be found? [state 2]
- fish
- liver oil
- liver
- butter
- carrots
Which food source(s) can vitamin C be found? [state 2]
fresh fruit and vegetables
Which food source(s) can vitamin D be found? [state 2]
- Dairy products
- oily fish
Define ingestion
Taking food in through the mouth and swallowing.
Define digestion [2 points - hint: physical and chemical]
Breaking down large insoluble molecules in food into smaller pieces (physical digestion) and smaller, soluble molecules (chemical digestion)
Define absorption [2 points]
Movement of small soluble molecules out of the gut and into the blood by diffusion and active transport
Deifne egestion
passing out of undigested food through the anus.
How does peristalis work? [2+1 points]
2 sets of muscles push food down
- Circular muscles contract behind the bolus, pushing it along
- longitudinal muscles contrast, making the oesophagus wider.
What is the ball that food is shaped into before swallowing called?
Bolus
What is the name of the enzyme that is produced in the gastric glands of the stomach, and what does it digest?
Pepsin, whcih digests proteins into peptides (shorter chains of amino acids)
What does contractino fo the sotmach do? [2 points]
causes mixing of the contents of the stomach, maximising contact between enzymes and food
What is pepsin’s optimum conditions? (Give point and exaplin why)
acidic pH. The conditions in the stomach are acidic due
to the release of hydrochloric acid by the gastric
glands.
How does the stomach protect against HCl?
Mucus lining
What is the duodenum?
The final site of chemical digestion
Give the names of the 3 enzymes secreted by the pancreas
trypsin, amylase and lipase.
What enzyme digests protein and what does it digest into?
trypsin digests protein into peptides
What enzyme digests lipids and what does it digest into?
lipase digests lipids into glycerol and 3 fatty acids
where is bile produced and stored [2 points]
produced in the liver, stored in the gall bladder
What enzyme digests starch and what does it digest into?
amylase digests starch into maltose
What enzyme digests maltse and what does it digest into?
Maltase digests maltose into glucose
What enzyme digests peptides and what does it digest into?
Peptidase digests peptides into amino acids
what are the two parts of the small intestine called?
the duodenum and the ileum
what are the adapatations of the villi? [3 points - exaplain all]
- large surface area (folding of ileum, and microvilli)
- short diffusion distance - villi are one cell thick
- high concentration gradient - provided by capillary network and lacteals removing absorbed molecules
What are the 2 sections of the large intestine?
Colon and rectum
What is the function of water in a balanced diet?
conponent in metabolic reaction
Function of colon in ds?
absorbs water into the blood
Function of rectum in ds?
stores feces before egestion
