GCSE Biology- B2 Organisation

What are cells?

smallest unit of living organisms and the building block of life

What is tissue?

A group of the same type of specialised cells working together to perform a specific function.

What is an organ?

A group of different tissues that work together to perform a certain function.

What is an organ system?

a group of organs working together to perform a certain function

Examples of organ systems

cardiovascular, skeletal, nervous, digestive, respiratory, muscular, circulatory, reproductive

What are the two types of digestion?

Mechanical (physical) and chemical

What is mechanical digestion?

physical breakdown of foods into smaller pieces to be absorbed or broken down by chemical digestion

What is chemical digestion?

chemicals or substances to break down foods

Where is physical digestion in the mouth?

teeth

Where is chemical digestion in the mouth?

saliva

What does saliva contain that breaks down foods?

saliva contains amylase enzymes that break down carbohydrates

What does the liver produce?

bile

Where is the bile stored after being produced in the liver?

the gallbladder

What happens in the stomach?

both chemical and physical digestion, bacteria destroyed by stomach acids

What does the large intestine do?

absorbs water from undigested food

What is the small intestine made of?

villi

What does the small intestine do?

absorbs broken down materials in the bloodstream

What does the anus do?

release food waste the body doesn't want

How does food travel in the digestive system?

Mouth, oesophagus, liver, stomach, gallbladder, pancreas, small intestine, large intestine, anus

What is a gland?

organs which produce and release substances that perform specific functions in the body

What is an enzyme?

a biological catalyst made from protein

What is the digestive system?

A long tube that starts at the mouth and breaks down food that is specific to one reaction

What are all chemical reactions controlled by?

enzymes

Facts about enzymes

they are not alive, they don't need energy, they have an active site

What do enzymes do?

build and break molecules

What is the 'lock and key theory'?

there is only one specific enzyme for each substrate, the active site of the enzyme is complimentary to the shape of the substrate

Where does chemical reactions happen in a enzyme?

in the active site

What is the substrate?

substance that the enzymes works on, chemical reactions take place with the active site; new products are made from the substrate

What is digestion?

the breakdown of large insoluble molecules into smaller soluble molecules for absorption into bloodstream

What are carbohydrates?

they provide fuel for respiration, starch from it breaks down to glucose

What are examples of carbohydrates?

rice, pasta, potatoes, bread

What is the formula for respiration?

6O2 + C6H12O6 -> 6CO2 + 6H2O

What are proteins?

they are used to make cells/tissues, structures and enzymes, they can be broken down to amino acids

What are examples of proteins?

meat, fish, eggs, nuts

What are lipids?

efficient fuel source and insulation, used to make hormones and cell membranes, insoluble in water, broken down into glycerol and fatty acids

What are examples of lipids?

butter, cheese, cream, fats

What does amylase do?

break down carbohydrates (starch) into glucose

Where is amylase produced?

salivary glands, small intestine, pancreas

What does protease do?

break down proteins into amino acids

Where is protease produced?

stomach, small intestine, pancreas

What does lipase do?

break down lipids/fats into glycerol and fatty acids

Where is lipase produced?

small intestine, pancreas

Where is bile produced?

in the liver

Where is Bile stored?

in the gallbladder

Where is bile released?

in the small intestine

What does bile do?

emulsifies fats and lipids to provide a larger surface area for enzymes to act on, neutralises stomach acid before small intestines, provides optimum pH for enzymes in small intestine

What is a catalyst?

a substance that speeds up a reaction

What is the active site?

the region of the enzyme where the reaction takes place

What is a substrate?

the substance being broken down

What is synthesis?

the process which describes making something new

What is denaturing?

the process where the active site changes shape and no longer fits the substrate

What is the 'optimum condition'?

the highest rate of reaction

What are factors affecting enzyme activity?

pH, temperature

What is the optimum pH for amylase?

pH7

Which type of enzyme has the highest optimal range (works best in most conditions)?

Lipase

effect of temperature on enzyme activity graph (RP)

What does increasing the temperature do to enzyme activity (RP)?

increase the rate of reactions, enzymes and substrate move faster, more collisions; more reactions

What does the optimum temperature mean for enzyme activity (RP)?

maximum rate of reaction, active site is unchanged and particles are moving fast enough, Enzyme begins to denature

What happens when the rate of reaction for enzyme activity reaches zero (RP)?

no reaction, all enzymes have denatured

How does a low temperature affect enzyme activity (RP)?

rate of reaction is slow as enzymes and substrates move slowly, they don't collide as often, therefore fewer reactions (not no reaction, just low rate of reaction)

Effect of pH on enzyme activity graph (RP)

What happens to enzyme activity when the pH is away from the optimum (RP)?

there is a decreasing rate of reaction, enzymes begin to denature and the active site changes shape and no longer fits with substrate

What is the independent variable in the enzymes RP?

pH or temperature

What is the dependent variable in the enzymes RP?

enzyme activity (time taken for starch to be broken down)

What are the control variables for the enzyme RP?

volume of amylase, pH buffer, volume of substrate

What do carbohydrates help do?

quick release energy

What do proteins help do?

help the body grow and repair itself

What do fibres help do?

prevent constipation

What do water help do?

helps digest food

What do fats and oils (lipids) help do?

source of energy, insulation and form cell membranes

What do vitamins help do?

helps body work properly

What is the test for starch?

Iodine, if remains orange/yellow= no starch, if it changes to blue/black= starch present

What is the test for glucose?

Benedict's solution (blue liquid), if colour is blue (no change)= no glucose, if it is green or brick red= glucose present

What is the test for protein?

Biuret solution (blue liquid), if remains blue (no change)= no proteins, if changes to purple= proteins present

What is the test for lipids?

Sudan III (red liquid), if no layers of oil= no lipids, if layer of oil forms and floats= lipids present

What is the other test for lipids?

emulsification test

How does the emulsification test for lipids work?

ethanol added to sample, shake mixture add mixture to water, positive result= cloudy white liquid formed, negative result= no cloudy liquid

What are arteries?

it carries blood away from the heart, mostly oxygenated blood

What are veins?

it carries blood to the heart, mostly deoxygenated blood

What are capillaries?

exchanges gas, carries both oxygenated and deoxygenated blood, small blood vessels

What is the heart known as?

cardiac muscle, double pump

why is the human heart called a double pump?

the heart has two sides, one which pumps blood to the lungs, one which pumps blood to the rest of the body

What are the benefits to having a double pump?

more efficient, allows blood to be sent at very high pressures, gives blood cells only oxygen instead of both oxygenated and deoxygenated

What are coronary arteries?

arteries that supply the heart with blood that it needs, seen clearly on outside of heart

Where is the pacemaker?

in the right atrium

What is the vena cava?

the vein carrying deoxygenated blood into the right atrium

What is the pulmonary artery?

artery carrying deoxygenated blood to the lungs

What is the aorta?

artery carrying oxygenated blood to the body

What is the pulmonary vein?

carries oxygenated blood from the lungs to the left atrium

What do the valves do?

prevent the back-flow of blood

Diagram of the heart

What is the hearts natural resting rate?

athletes= 30-50 BPM

normal = 60-80 BPM

unhealthy = 80+ bpm

What is BPM?

the beats per minute the heart pulses, found in right atrium of heart

What is arrhythmia?

abnormal heart rhythm

What happens when the heart rate is too fast?

cannot pump blood properly

What is the treatment for fast heart rate?

ablation- removal of faulty pathways, defibrillation- electrical shock to reset

What happens when the heart rate is too slow?

not enough oxygen pumped into body

What is the treatment for slow heart rate?

pacemaker