Studied by 3 peopleHow do cells become specialised?
differentiation
What are organ systems made of?
organs
What are organs made of?
tissue
What are tissues made of?
specialised cells
Def: organ system
a group of organs working together to carry out a specific function
Eg: organ system
digestive system
Def: organ
group of tissues working together to carry out a specific function
Eg: organ
heart
Def: tissue
a group of similar cells working together to carry out a specific function
What are the 3 types of tissue?
muscular, glandular, epithelial
What is the function of muscular tissue?
allows movement through contracting
What is the function of glandular tissue?
makes and secretes hormones and enzymes
What is the function of epithelial tissue?
to cover parts of the body e.g inside of gut
Def: enzyme
biological catalyst
How do enzymes work?
lock and key theory
What is the optimum temperature for enzymes?
40°C
What is the (general) optimum pH for enzymes?
pH 7
What happens if an enzyme is exposed to too high temps or high/low pH
denatures
Def: denature
active site of an enzyme changes shape and substrate no longer fits
RQ: enzyme activity
amylase breakdown
Independent variable of RQ: enzyme activity
pH of buffer solution
Dependent variable of RQ: enzyme activity
rate of amylase breakdown
How is rate of amylase breakdown measured?
how quickly iodine solution turns blue-black
What are the control variable of RQ: enzyme activity
concentration of amylase solution, volume of amylase solution, temperature of solution
Formula: rate of reaction
1000/ time
What are the 3 digestive enzymes?
amylase, protease, lipase
What is the process of amylase?
starch → simple sugars
Where is amylase made?
salivary glands, pancreas, small intestine
What is the process of protease?
proteins → amino acids
Where is protease made?
stomach, pancreas, small intestine
What is protease in the stomach called?
pepsin
What is the process of lipase?
lipids → glycerol and fatty acids
Where is lipase made?
pancreas, small intestine
What are the functions of bile?
neutralises stomach’s hydrochloric acid so as not to denature small intestine enzymes and emulsifies fat
Where is bile made?
liver
Where is bile stored?
gall bladder
Why are large food molecules broken down?
so they can be absorbed into the bloodstream
What is the food test for sugar?
Benedict’s solution - after preparing it in a water bath add some to sample. The more red it is, the higher sugar content.
What is the food test for starch?
Iodine - add iodine to sample. If it turns blue/black starch is present
What is the food test for proteins?
Biuret test - add Biuret’s solution. If proteins are present the solution will turn from blue to pink/purple
What is the food test for lipids?
Sudan III solution - add to solution. If lipids are present the solution will separate into 2 layers with the the top layer a bright red.
How does air get to the alveoli?
trachea → bronchi → bronchioles → alveoli
How is has exchanged in the lungs?
high concentration of O₂ in the alveoli it diffuses into the bloodstream to be carried around the body
high concentration of CO₂ in the blood diffuses into alveoli to be exhaled
What are the features of alveoli that help with its function?
thin walls
large surface area
lots of capillaries
Why are thin walls an adaptation of alveoli?
easy diffusion
Why is a large surface area an adaptation of alveoli?
more substances exchanged
Why is lots of capillaries an adaptation of alveoli?
easy access to bloodstream
What does the right ventricle do?
pumps deoxygenated blood to the lungs
What does the left ventricle do?
pumps oxygenated blood from the heart around the body
Def: heart valves
one way valves that keep blood flowing in the right direction
How does the heart work?
blood flows into the atria then ventricles
ventricles contracts
blood moves out of the heart
blood flows around the body
repeat
Where does blood enter the right atrium?
vena cava
Where does blood exit the right ventricle?
pulmonary artery
Where does blood enter the left atrium?
pulmonary vein
Where does blood exit the left ventricle?
aorta
What gives the heart its blood supply?
coronary arteries
What controls the contractions of the heart?
pacemaker
How does the pacemaker control the heart?
sends out electrical impulse
Where is the pacemaker found in the heart?
right atrium wall
What are the 3 types of blood vessel?
arteries
capillaries
veins
Def: arteries
carries oxygenated blood
at high pressure
small lumen
thick walls
Def: capillaries
exchanges substances with cells
very small
thin cell walls
permeable walls
Def: veins
carries deoxygenated blood
at low pressure
large lumen
valves
Rate of blood flow =
volume of blood / number of minutes
What are the components of blood?
red blood cells
white blood cells
platelets
plasma
Def: red blood cells
carry oxygen around the body
What the adaptations of a red blood cell?
biconcave shape
don’t have a nucleus
contain haemoglobin
Why do red blood cells have a biconcave shape?
large surface area for absorbing oxygen
Why do red blood cells not have a nucleus?
to have more space for oxygen
Def: haemoglobin
a red pigment that binds to oxygen
Def:
cells that defend against infection
How do white blood prevent infection?
phagocytosis
produce antibodies
produce antitoxins
Def: phagosytosis
phagocytes surround a bacterium and engulf it, destroy it with enzymes
Def: antibodies
proteins produced by a B lymphocyte that attack foreign bodies unique to each pathogen
Def: antigen
flags foreign bodies to the immune system
How do antibodies work?
destroy cells that are marked by antigens, antibodies are also carried round the blood stream to destroy any similar cells
How do anti-toxins work?
neutralise toxins
Def: platelets
small fragments of cells that clot wounds
What are the consequences of a lack of platelets?
excessive bleeding and bruising
Def: plasma
liquid that carries other components of the blood
Def: cardiovascular disease
disease of the heart or blood vessels
Def: Coronary heart disease
when coronary arteries are blocked by layers of fatty build up
What can CHD lead to?
heart attack
How is CHD treated?
stents
statins
Def: stents
tubes placed inside arteries allowing blood to pass through
What are the pros of stents?
lower risk of heart attack
long lasting
quick recovery time
What are the cons of stents?
risk of surgical complications
risk of thrombosis (clotting) post surgery
Def: HDL cholesterol
‘good’ cholesterol
Def: LDL cholesterol
‘bad’ cholesterol
Def: statins
a drug that lowers LDL cholesterol levels → less build up in coronary arteries
What are the pros of statins?
lowers risk of heart attack
increases levels of HDL cholesterol
lowers levels of LDL cholesterol
some studies suggest statins prevent other diseases
What are the cons of statins?
long term drug
side effects (e.g kidney failure)
take time to take effect
What are the pros of an artificial heart?
can enable a wait for a donor
less likely to be rejected
What are the cons of an artificial heart?
major surgery
artificial hearts don’t work as well as real hearts
What are the pros of valve replacement surgery?
less drastic procedure
can be artificial
What are the cons of valve replacement surgery?
biological valves can be rejected
major surgery
can cause clots
Def: artificial blood
a substitute for blood to give time for patient to produce blood of their own or get a transfusion
Def: communicable diseases
can spread from person to person
Def: non-communicable diseases
cannot spread between people
Def: cancer
uncontrolled cell growth and division
Note
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