Animal tissues, organs and organ systems Flashcards
What does the digestive system do?
Breaks down large insoluble molecules, that your body cannot absorb, into smaller, soluble molecules that can be absorbed and used in your cells
Order of the digestive system?
mouth esophagus stomach liver/gall bladder pancreas small intestine large intestine rectum anus
What happens in the mouth?
chewing (physical digestion)
saliva contains amylase which breaks down starch
What happens in the stomach?
Churning (physical digestion)
Main place where enzymes break down the large insoluble food molecules into smaller particles
What is the pH in the stomach?
Low pH, very acidic
contains hydrochloric acid to kill the bateria
What happens in the liver/gall bladder?
Liver produces bile, which helps the digestion of lipids
The gall bladder stores the bile
What happens in the pancreas?
It is a gland that relases enzymes (protease, carbohydrase, lipase)
What happens in the small intestine?
Where the soluble food molecules are absorbed into the blood
What happens in the large intestine?
Absorbs water from undigested food
What happens in the rectum and anus?
Egestion
How is the digestive system adapted? (2)
- Temperature is kept at 37 to allow enzymes to work as fast as possible
- Body makes a variety of different chemicals that help keep conditions ideal for enzymes as different enzymes work in different pH levels
How is the stomach adapted? (3)
- Secrets pepsin
- Has hydrochloric acid to kill most of the bacteria in food
- Produces mucus that coats the stomach walls to protect it from the acid
How is the small intestine adapted? (3)
- One cell thick so that substances can pass through quickly
- Many tiny villi to create a large surface area
- Good blood supply to maintain concentration gradient
What are the two types of carbohydrates?
- Simple sugars that only contain 1/2 sugar units
2. Complex sugars that are long chains of simple sugars bonded together
What color are carbohydrates in Benedict solution?
blue
What color are carbohydrates in iodine solution?
blue/black
What are carbohydrates broken down into?
simple sugars
What are carbohydrate rich foods?
bread
potatoes
rice
pasta
What are lipids in relations to energy stores?
They are the most efficient energy store in your body and source of energy
Where in the body are lipids important? (3)
Cell membrane, as hormones and in your nervous system
What are lipids made up of?
3 molecules of fatty acids, joined to a molecule of glycerol
What are lipids broken down into?
Fatty acid + glycerol
What does bile do?
Breaks lipids into smaller molecules so it is easier for the lipids
What is protein used for in the body?
Used to build up cells and tissues of your body and the basis of all enzymes
What are protein rich foods?
meat
eggs
fish
What are lipid rich?
fats (solid)
oils (liquid)
What are proteins made of?
Long chains of amino acids
How do enzymes work?
The substance of the reaction, to be catalysed, fits into the active site of the enzyme. Once it is in place, the enzyme, and the substrate bind together. The reaction the takes place rapidly and the products are released from the surface of the enzyme
What do enzymes being specific mean?
- They have an active site
- It will only fit with a substrate that has a matching shape
What are enzymes made of?
Proteins. They are biological catalysts
- What are the products of carbohydrates?
- What are the enzymes of carbohydrates?
- Where is the enzyme made?
- Where does the enzyme function in?
- Simple sugars/maltose
- Amylase
- Salivary glands/pancrease
- Mouth/Small intestine
- What are the products of protein?
- What are the enzymes of protein?
- Where is the enzyme made?
- Where does the enzyme function in?
- Amino acids
- Pepsin, Trypsin
- Stomach, pancreas
- Stomach, small intestine
- What are the products of lipids?
- What are the enzymes of lipids?
- Where is the enzyme made?
- Where does the enzyme function in?
- Glycerol, fatty acids
- Lipase
- Pancreas
- Small intestine
- What are the products of maltose?
- What are the enzymes of maltose?
- Where is the enzyme made?
- Where does the enzyme function in?
- Glucose
- Maltase
- Small intestine
- Small intestine
- What are the products of sucrose?
- What are the enzymes of sucrose?
- Where is the enzyme made?
- Where does the enzyme function in?
- Glucose, frutose
- Sucrase
- Small intestine
- Small intestine
- What are the products of lactose?
- What are the enzymes of lactose?
- Where is the enzyme made?
- Where does the enzyme function in?
- Glucose, galactose
- Lactase
- Small intestine
- Small intestine
Factors affecting enzyme action? (4)
- temperature
- concentration
- surface area
- pH
How does temperature affect enzyme action?
If temperature is too high, structure of enzyme is affected. The long amino acid chains unravel, and the shape of the active site changes (enzyme is denatured) substrate won’t fit
Temp too low - frequency of collisions between enzyme and substrate is reduced because molecular movement decreases
How does concentration affect enzyme action?
Higher the enzyme concentration the faster the reaction
How does surface area affect enzyme action?
Rate of enzyme activity increased along with the surface area of a substrate
How does pH affect enzyme action?
Changing the pH of a enzymes surrounding will change the shape of the active site, it becomes denatured, no longer complementary to substrate
Test for starch?
- Place a few drops of the test solution / small piece of test food on a spotting tile
- Add 2/3 drops of iodine solution to the test material
Positive : black/blue coloration
Negative : doesn’t change colour
Test for sugar?
- Using a pipette put 2-3ml of test solution into a test tube
- Add equal amount out of benedict reagent
- Make sure the test tube is no more than 1/3 full
- Heat in water bath
Positive : changes colour
Negative : doesn’t change colour
Test for protein?
- Add 2/3ml of the test solution to a test tube
- Add 2/3ml of biuret solution
- Shake gently
- Use a controlled test
Positive : mauve
Negative : doesn’t change colour
Test for fat?
- Add ethanol to the fat in a test tube
- Shake the test tube
- Pour into another test tube of water
Positive : cloudly milky white emulsion is formed
Negative : clear
Explain how the small intestine are adapted for nutrient absorption.
There are millions of villi. The villi increase the surface area to volume ratio.
The wall of the villi are one cell thick, reducing the diffusion distance
A steep concentration gradient is maintained because the small intestines have a very rich blood supply
What is the role of bile in digestion?
It is alkaline to neutralise hydrochloric acid from the stomach.
It also emulsifies fat: breaks down large lipid droplets into small lipid droplets which increases the surface area:volume ratio. This is to help lipase work faster.
The alkaline conditions and large surface area increase the rate of fat breakdown by lipase.