organisation 🍁 Flashcards
what are organelles, cells, tissues, organs and organ systems?
1) organelle- specialised unit with a specific function in a cell
2) cell- building block of life in organisms
3) tissue- group of cells working together with the specific functions
4) organ- group of tissues working together with the specific functions
5) organ system- group of organs working together with specific functions
what is the digestive system?
an organ system in which organs work together to break down and absorb food
what is the function of carbohydrates?
provide energy through glucose
what is the function of proteins?
growth and repair of cells/muscles
what is the function of lipids?
1) energy
2) make up cell membrane, therefore needed for growth
what are carbohydrates, proteins and lipids made from?
1) carbohydrates- glucose/sucrose
2) proteins- amino acids
3) lipids- fatty acids and glycerol
what is the function of the stomach in the digestive system?
begins to digest proteins and absorbs small molecules by churning with stomach acid
what is the function of the small intestine in the digestive system?
absorb digested sugars, amino acids, fatty acids and glycerol through villi
what is the function of the large intestine in the digestive system?
absorption of water from food
what are the functions of the liver and gall bladder in the digestive system?
1) liver- produces bile
2) gall bladder- stores bile
how are the villi adapted for exchange?
1) large surface area as it is folded and has microvilli
2) short distance to diffuse (walls are one cell thick)
3) good blood supply maintains high concentration gradient
what is an enzyme and what are they made out of?
a biological catalyst that speeds up reactions without being used up
they are made from amino acids
what enzyme breaks down each molecule? (carbohydrate, protein, lipid)
1) carbohydrate- amylase
2) protein- protease
3) lipids- lipase
where can amylase/carbohydrase be found?
1) mouth/ salivary glands
2) pancreas
3) small intestine
where can be protease be found?
1) stomach
2) pancreas
3) small intestine
where can lipase be found?
1) small intestine
2) pancreas
what is the function of digestive enzymes?
break down food into small, soluble molecules for absorption
what is the lock and key theory?
every enzyme has a region called an active site
each molecule is a specifically shaped substrate that ONLY fits into its corresponding enzyme’s active site
(e.g. protein and protease)
the substrate fits into the active site and the enzyme breaks it down
what factors affect enzyme action?
1) temperature
2) pH
how does low temperature affect enzyme action?
collisions between enzymes and substrates are less frequent as they have less energy so enzymes work less efficiently
how does high temperature affect enzyme action?
it changes the shape of the enzyme’s active site, causing it to work less or stop working entirely
this means the enzyme is denatured
how does pH affect enzyme action?
extreme pH’s denature enzymes, sometimes permanently
what is the optimum temperature and pH for enzymes (including stomach protease/pepsin) ?
temp:
> 37*C in the human body
pH:
> most enzymes- pH7
> stomach protease (pepsin)- pH2 from stomach acid
what does bile do?
1) emulsifies lipids (breaks them into smaller pieces with a larger surface area to be broken down by lipase)
2) neutralises stomach acid for optimum pH for enzymes excluding stomach protease (pepsin)
what is the equation for rate of reaction?
rate of reaction =
1/ time taken
what is the food test for sugars, including solution name and colour change?
> add drops of Benedict’s solution
place the test tube into a water bath for 5 minutes
sugars present = orange/brick red
what is the food test for starch, including solution name and colour change?
> add drops of iodine
iodine present = blue/black
what is the food test for protein, including solution name and colour change?
> add drops of Biuret solution
protein present = violet/purple
what is the food test for lipids, including solution name and colour change?
> add drops of ethanol
shake and add distilled water
lipids present = cloudy white
describe the method of required practical 4 (pH and enzymes).
1) place 1 drop of iodine into each well of a spotting tile
2) set up 3 test tubes, one with starch, one with amylase one with pH buffer (controls pH)
3) leave the tubes in a 30*C water bath
4) mix the buffer and amylase, starting a stop watch when you add the starch
5) place back into water bath
6) add a drop of the starch/amylase/buffer mixture into a different well of the spotting tile every 30 seconds
7) stop when the colour changes to blue to orange (all the starch has been digested)
8) repeat with different pH and record to see the effects of different pH on enzymes
what are some problems with required practical 4 (pH and enzymes) ?
1) colour change is only recorded every 30 seconds, so it is not exact
2) colour change is gradual, so you cannot always determine when the reaction is finished
how are the lungs/alveoli adapted for gas exchange?
1) large surface area due to capillaries
2) one cell thick, moist walls of alveoli and thin walls of capillaries
3) well ventilated (maintains diffusion gradient)
4) good blood supply due to large capillary network (for high concentration gradient)
what are the intercostal muscles in the lungs?
muscles between the ribs which control its movement when exhaling and inhaling
what is the trachea in the lungs?
windpipe that connects mouth and nose to lungs, lined with ciliated cells that move mucus to the mouth
what are the bronchi and bronchioles in the lungs?
bronchi- large tubes branching off trachea to each lung, lined with ciliated cells
bronchioles- bronchi split into smaller smaller tubes, connected to alveoli
what are the alveoli in the lungs?
tiny moist air sacs where gas exchange takes place
what gases are exchanged in the alveoli?
carbon dioxide diffuses out the blood to be breathed out
oxygen diffuses into the blood after breathing in
what happens when we inhale?
1) diaphragm contracts, pulling down
2) intercostal muscles contract
3) ribs move outward and up
what happens when we exhale?
1) diaphragm relaxes, moving up
2) intercostal muscles relax
3) ribs move outwards and down
on a diagram, where are the atriums and ventricles?
atriums are at the top, ventricles are at the bottom
what is the difference between the right and left sides of the heart?
right- deoxygenated blood FROM the body TO lungs for gas exchange (pulmonary circulation)
left- oxygenated blood FROM lungs TO the body (systematic circulation)
describe the vena cava, pulmonary artery, pulmonary vein and aorta, and where the blood comes from/goes to.
vena cava- deoxygenated blood from body into the right atrium and then ventricle
pulmonary artery- deoxygenated blood goes from heart to lungs to be oxygenated
pulmonary vein- oxygenated blood from lungs into the heart through left atrium and then ventricle
aorta- oxygenated blood goes from heart to the rest of the body
what are the valves and where are they?
between the atrium and the ventricle in the heart, and in veins and arteries
valves closing prevents blood flowing backwards (in the wrong direction)