Topic 2- Organisation Flashcards
What type of cells form tissues?
Specialised cells
When does differentiation occur
During the development of a multi cellular organism
What is the purpose of glands in the digestive system?
It is found in the pancreas and salivary glands, produces digestive juices
Definition of organ
A group of tissues that work together to perform a certain function
Definition of enzymes
Biological catalysts
Definition of catalyst
A substance which increases the speed of a reaction without being changed or used up
What are enzymes made of?
Proteins, and all proteins are made of chains of amino acids
What does every enzyme have?
An active site with a unique shape that fits onto the substance involved in a reaction
Name of the diagram that shows enzyme action
“Lock and key” model
How is the lock and key different to the reality and what is it called
In reality, the active site changes shape a little as the substrate binds to get a tighter fit and it is called induced fit
2 things that affect enzymes
Temperature and pH
What happens to an enzyme when the temperature is too high?
Some of the bonds holding the enzyme together break, and this changes the shape of the active site, so the substance won’t fit. It is said to be DENATURED.
What is the use of pepsin enzyme in the stomach
It is used to break down proteins in the stomach
Optimum pH of pepsin?
pH 2
What does the enzyme amylase catalyse?
It catalyses the breakdown of starch to maltose.
What will the colour of iodine solution be, when starch is present?
Blue black
Describe the practical for how pH affects amylase activity
A drop of iodine solution in each spotting tile. Heat water in beaker until 35°c. In a test tube, add 1 cm^3 of buffer solution with pH 5 and 1 cm^3 of amylase solution and wait 5 mins. Then add 5 cm^3 of starch solution,mix and start clock. Every 30 secs, add a drop, when the iodine solution remains browny orange, starch is no longer present. Repeat with different pH buffer solutions to see how pH affects time.
What is the meaning of rate?
Rate is a measure of how much something changes over time.
Formula to work out the rate
Rate = 1000
——–
time
Why do starch, proteins and fats have to be broken down?
Because they are big molecules. They are too big to pass through walls of the digestive system, smaller molecules are easier to absorb into bloodstream.
Protease breaks down _ _ _ _ _ _ _ _ into _ _ _ _ _ _ _ _ _ _ _
Proteins into amino acids
All three enzymes are found in?
Small intestines and pancreas
What is another name for protease in the stomach?
Pepsin
What is starch broken down i)by ii)into?
i) amylase ii) maltose
An example of carbohydrase?
Amylase
Where are lipases found?
In the pancreas and small intestines.
Where is amylase found where the other enzymes aren’t?
Salivary glands.
Example of other sugars apart from maltose
Dextrins
What are lipids?
Fats and oils
Where is bile produced?
In the liver
Where is bile released into
Small intestines.
What does bile do in the small intestines
HCl in the stomach is too acidic. Bile is alkaline. Enzymes in small intestines work best in akaline conditions.
What does bile do?
It emulsifiers fat, meaning it breaks down the fat into tiny droplets, increasing the surface area of fat for enzymes to work on, making digestion faster.
What is the purpose of HCl in the stomach?
To kill bacteria and to give right pH for protease enzyme to work
4 things you must do to prepare a food sample.
Break up food using pestle and mortar
Transfer food to beaker and add water
Stir mixture with glass rod to dissolve food
Filter solution using filter paper to get rid of solid bits of food.
What is the name of the test for sugar
Benedict’s test
Describe the test for sugar
Prepare food sample and transfer 5 cm^3 to test tube and set water bath to 75°c. Add Benedict’s solution (10 drops) to test tube and leave in bath for 5 mins. If reducing sugar is present, the colour will change from blue to green, yellow or brick red.
Test for starch
Make food sample and transfer 5 cm^3 to test tube. Add iodine solution and shake to mix. Solution will change from brown orange to black or blue black
Test for proteins
Prepare sample and transfer 2cm^3 to test tube. Add 2 cm^3 of Buiret solution to sample and shake to mix. If protein present, colour will change from blue to pink or purple.
Test for lipids
Prepare sample and transfer 5 cm^3 to test tube. Add 3 drops of Sudan III stain solution and shake to mix. If lipids present, it will separate to top layer bright red.
What is the thorax?
The top part of your body
How is the top part of your body separated from the lower part?
The diaphragm
What are the lungs surrounded by?
Pleural membranes
Where does gas exchange take place?
Small bags at the end of bronchioles called alveoli
Diffusion in alveoli
Oxygen diffuses out of the alveoli into blood and CO^2 diffuses out of blood into alveoli.
Red blood cells action after gas exchange
Red blood cells release oxygen and diffuses into body cells and body cells release CO^2 which diffuses into blood and carried back to lungs.
Formula to calculate breathing rate.
Breaths per minute= number of breathes
———————
Number of minutes
Describe the double circulatory system
The right side of the heart pumps deoxygenated blood to the lungs and returns with oxygen to the heart.
The left side of the heart pumps oxygenated blood to the rest of the body and returns with deoxygenated blood.
What is the walls of the heart mostly made of?
Muscular tissue