Unit 2 Biology Flashcards
What are cells eg rd blood cell
The thing that makes up all living things
Order the levels of organisation
Cell, tissue, organ, organ system
What are tissues.
A group of specialised cells that carry out a specific function. Eg muscle tissue
What are organs
A collection of tissues that work to do a specific function. Eg heart
What is an organ system
A collection of similar organs to carry out a function. Eg circulatory system
Describe the functions of three organs in the digestive system
Glands- produce digestive juices with enzymes to help break food down.
Stomach- acidity kills bacteria and is the right pH for enzyme reactions. Small intestine- where small molecules diffuse into the blood.
Liver- produces bile to help break down lipids
Large intestine- absorbs water from undigested food
What is an enzyme
A protein based biological catalyst
Describe the lock and key method
1.) enzyme and substrate are complimentary to each other
2.) they bind together to create an enzyme substrate complex
3.) a chemical reaction takes place in the active site and the substrate is split into smaller molecules for diffusion
What 2 conditions determine an enzymes effectiveness
pH and temperature
What happens to the enzyme if temperature is too high
It loses its shape and denatures so the active site isn’t complimentary
What does amylase do and where is it produced
Converts carbohydrates into simple sugars. Produced in salivary glands, pancreas and small intestine
What does protease do and where is it produced
Converts proteins into amino acids. Produced in the stomach pancreas and small intestine
What does lipase do and where is it produced
Breaks down lipids into glycerol and fatty acids. Produced in the pancreas, salivary glands and the stomach
How does bile help digestion
Alkaline so it neutralises the stomach for quicker enzyme reactions. Emulsifies large droplets of fat into smaller ones
Food test for sugar
Put 2cm^3 of Benedict’s reagent into a sugar solution placed in a hot water bath. Change from blue to brick red
Food test for proteins
Add 2cm^3 of biurets reagent to a protein solution and observe a colour change from blue to purple
Food Test for starch
Put a drop of iodine on a simple tray and observe the colour change to bluey black
Food test for lipids
Mix solution with ethanol to observe a cloudy emulsion
How is the circulatory system adapted to better pump blood around
Double circulatory system- deoxygenated blood in the right atrium and around the lungs to pick up oxygen. Oxygenated blood into the left atrium and back out to the rest of the body
Eg what is the normal rate of heartbeat and what controls it
70bpm, pacemaker
What can we do about an irregular heartbeat ?
Use an artificial pacemaker