Organisation Flashcards
Cells
Basic building blocks that make up all living organisms
Tissue
Group of similar cells that work together to carry out a particular function
Organ
Group of different tissues that work together to perform a particular function
Organ system
Group of organs working together to perform a particular function
Why can’t temperature be raised to speed up bodily reactions
- would speed up both useful and unwanted reactions
- cells would be damaged if temperature raised too high
Enzyme
Biological catalyst which increases the speed of a useful chemical reactions in the body without being changed or used up
How do enzymes get unique shape
- they are large proteins so made up of chains of amino acids
- chains folded into unique shapes
Active site
Enzyme’s uniquely shaped area where only substance involved in reaction binds
Induced fit enzyme model
Active site slightly changes shape as the substrate binds to get a tighter fit
Effect of temperature on enzymes
- higher temperature increases rate of reaction
- too high temperature breaks some bonds holding enzyme together, causing active site shape to change and substrate not fit
What does optimum temperature mean
Temperature which enzymes work best at
How does PH affect enzymes
Too high or low PH interferes with bonds holding enzyme together, changing shape of active site so substrate no longer fits
Optimum enzyme PH
- PH which enzymes work best at
- usually 7
Denatured enzyme
Enzyme which no longer works
Enzymes practical
- iodine drops in spotting tile
- Bunsen burner on heatproof mat with tripod and gauze over
- beaker of water on top heated to 35°C using thermometer
- syringe adds 1cm³ of amylase solution and 1cm³ of buffer solution with PH 5 to boiling tube
- place in test tube holders next to water for 5 minutes
- different syringe adds 5cm³ of starch solution to boiling tube
- mix boiling tube and start stop clock
- continuously sample how long it takes for amylase to break down starch
- use a pipette to drop fresh sample from boiling tube into iodine every 30 seconds until iodine is browny-orange
- repeat with different PHs
- calculate rate of reaction with 1000/time
What is amylase
A carbohydrase
What does amylase break down
Starch
What is starch broken down into
Glucose
Where is amylase made
- small intestine
- pancreas
- salivary glands
What does protease break down
Proteins
What is protein broken down into
Amino acids
Where is protease made
- small intestine
- pancreas
- stomach
What does lipase break down
Lipids
What are lipids broken down into
- fatty acids
- glycerol
Where is lipase made
- small intestine
- pancreas
Function of bile
- neutralises hydrochloric acid from stomach
- emulsifies fat
How does bile neutralise stomach acid
It is alkaline
Why must bile neutralise stomach acid
Enzymes in small intestine work best in alkaline conditions
Fat emulsification
Breaks fat down into tiny droplets with bigger surface area for lipase to act on, speeding up digestion
Where is bile produced
Liver
Where is bile stored
Gallbladder
Where is bile released into
Small intestine
Where are enzymes in digestive system produced
Specialised cells in gut lining
Salivary glands
Produce amylase in saliva
Oesophogus
- where food passes through to enter stomach
- uses peristalsis to contract and relax muscles and squeeze food down
Stomach
- pummels food with muscular walls
- produces protease enzyme - pepsin
- produces hydrochloric acid to kill bacteria and give right PH (2) for protease
Pancreas
Produces enzymes and releases them into small intestine
Small intestine
Digested food is absorbed out of digestive system into blood
Large intestine
Excess water is absorbed from food
Rectum
Where faeces is stored before leaving through anus
What mainly makes up faeces
Indigestible food
How to prepare food sample
- break up food in pestle and mortar
- add to beaker with distilled water
- stir with glass rod to dissolve
- filter using funnel and filter paper to get rid of solid bits
Types of sugars
- reducing
- non-reducing
How to test for reducing sugars
- add food sample to test tube
- add around 10 drops of Benedict’s solution using pipette
- place test tube in 75°C water bath for 5 minutes
Positive result for reducing sugars
Blue to green/yellow/brick-red
Negative result for reducing sugars
No colour change
How to test for starch
- add food sample to test tube
- add few drops of iodine and gently shake
Positive result for starch
Browny-orange to black blue
Negative result for starch
No change
How to test for proteins
- add food to test tube
- as biuret solution and gently shake
Positive result for protein
Blue to purple
Negative result for protein
No change
How to test for lipids
- add food to test tube
- add 3 drops of Sudan III solution and gently shake
Positive result for lipids
Mixture will separate into 2 layers with top bright red
Negative result for lipids
No separate layer
Where are lungs
In the thorax
Thorax
Top part of the body
What separates thorax from lower body
Diaphragm
What surrounds lungs
Rib cage and pleural membranes
Where does inhaled air go
Through the trachea, bronchi, bronchioles and into alveoli for gas exchange
What surrounds alveoli
Network of blood capillaries
How do alveolus carry out gas exchange
- oxygen diffuses from alveolus to blood
- carbon dioxide diffuses from blood to alveolus to be breathed out
How does gas exchange happen between body cells and blood
- oxygen diffuses from red blood cells to body cells
- carbon dioxide diffuses from body cells to blood and is carried back to lungs
What type of circulatory system do humans have
Double circulatory system