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)
how and where is the heart rate controlled?
specialised pacemaker cells generate electrical signals, causing the heart to contract
these cells are in the right atrium
what are artificial pacemakers and what are they used for?
when natural pacemaker cells are damaged, the heartbeat is irregular
an artificial pacemaker is a small battery operated device fitted in the chest that sends electrical impulses, so the heartbeat is made regular
where does the blood travel in veins and in arteries, and is the blood oxygenated or deoxygenated in each?
arteries- away from heart, oxygenated (apart from pulmonary)
veins- to the heart, deoxygenated (apart from pulmonary)
what are the differences between arteries and veins?
arteries:
1) high pressure blood
2) thick, muscular walls to withstand pressure
3) more connective tissue to withstand pressure
4) narrow lumen (inside space)
veins:
1) low pressure blood
2) thin, less muscular walls
3) less connective tissue
4) wide lumen (inside space)
what are capillaries and how are they adapted?
they connect the smallest branches of veins and arteries
they have thin walls (one cell thick) so molecules in blood can diffuse
how do you calculate blood rate?
blood rate (cm3) =
heart rate per min x stroke volume per beat
name the 4 components of blood.
red blood cells, white blood cells, plasma and platelets
what are the functions of red blood cells?
transport oxygen
how are red blood cells adapted?
1) no nucleus- carries more haemoglobin (protein that transports oxygen)
2) small and flexible- fit through small
capillaries
3) biconcave shape- maximise surface area
4) thin- short distance for oxygen to diffuse through
what are the functions of white blood cells?
ingest pathogens and produce antibodies
what is the function of plasma?
transport diffused substances (carbon dioxide, urea etc.) and blood cells
what are the functions of platelets ?
clot blood
what are the two ways a faulty heart valve can be treated?
1) mechanical valve
2) biological valve (human or animal donor)
what does a faulty heart valve lead to?
1) cannot open as wide, restricting blood flow and building pressure
2) cannot close properly, meaning blood leaks backwards into the atrium and into the heart
what are the limitations of biological valves and mechanical valves?
mechanical- blood can start to clot around the replacement valve
biological- can wear out
what do coronary arteries do?
supply blood and oxygen to the heart for respiration (so it has the energy to contract)
what is coronary heart disease (chd) ?
when the coronary arteries are blocked up with a build up of cholesterol, narrowing them and restricting blood and oxygen to the heart
what can happen if severe chd remains untreated?
the person receives chest pains due to a lack of oxygen. this can lead to a heart attack, where parts/all of the heart muscle dies as it doesn’t receive sufficient oxygen
what are statins?
drugs that lower cholesterol in blood by reducing cholesterol production in the liver
what are stents?
a metal device with a balloon. when placed in the artery, the balloon is inflated, widening the artery
evaluate the use of statins (strengths and weaknesses)
❌ lifetime usage is inconvenient
❌ side effects (headaches, memory loss, even links to diabetes and liver damage)
❌ not suitable for all (pregnant/breastfeeding women, liver disease)
✅ reduce ‘bad’ cholesterol, increase ‘good cholesterol’, even if genetic
✅ evidence of wider usage for other diseases
evaluate the use of stents (strengths and weaknesses)
❌ risk of bleeding, heart attack, stroke during operation
❌ risk of artery damage and blood clotting around it
✅ can be used when statins are not suitable/ineffective
✅ short recovery time
when is a heart transplant required?
heart failure- organs are starved of blood/oxygen. can occur as a result of CHD
evaluate heart transplants (weaknesses/limitations)
❌ large waiting times/not enough donors
❌ risk of rejection and infection
❌ long recovery time
❌ must take immunosuppressant drugs for a lifetime
why are artificial hearts used?
to prevent death when waiting for a transplant after heart failure and to give the heart rest to recover
what is the difference between communicable and non-communicable disease?
communicable disease- can be spread from person to person
non-communicable- can not be spread from person to person
define health and factors that affect it
the state of physical and mental well-being
1) diet/lifestyle (drugs/alcohol)
2) exercise
3) sleep
4) stress
how does defects in the immune system affect health and potential disease?
an individual is more likely to be susceptible to communicable disease
can viruses affect cancers?
yes (this is such a useless flashcard but it needs to be here)
how does the reaction of the immune system and pathogens affect you?
it can cause allergic reactions that lead to rashes and asthma
what is cancer?
the rapid and uncontrollable division of cells which leads to tumours
what are the two types of tumours and describe them
benign- cancers that stay in one area/membrane of the body and do not spread to other regions
malignant- cancers that spread through blood to other regions of the body, causing secondary tumours
what are carcinogens and how can they cause cancer?
chemicals and other agents that cause cancer
they can damage DNA and cause mutations, leading to an increased risk of cancer
what are risk factors that can cause cancer?
1) viruses linked to cancer (like HPV)
2) smoking (contains carcinogens)
3) alcohol
4) diet
5) UV/ionising radiation (skin cancer)
(some risk factors are genetic)
how are risk factors for diseases identified by researchers?
correlation between disease and factors are identified- positive correlation can signify a risk factor, but may not always be the cause
what is a risk factor?
lifestyle choices or environmental factors that lead to increased risks of non communicable disease
what diseases can smoking cause and why?
1) lung disease/cancer
2) cardiovascular disease
these diseases are caused as nicotine in cigarettes leads to damage of alveoli and blood vessels
what diseases can alcohol cause and why?
1) liver disease
2) impaired brain function
the breakdown of alcohol produces substances that can be toxic to the liver
neurones are also damaged by alcohol
what disease can obesity cause and why?
1) type 2 diabetes
2) cardiovascular disease
reduces the body’s sensitivity to insulin
how can smoking/drinking alcohol affect unborn babies?
carbon monoxide in cigarettes reduce oxygen flow around the mother’s body and therefore the foetus
alcohol can impair the brain development of a foetus
what must be taken into account when sampling in research?
1) bias of participant selection- must be random
2) sample must be representative of all ages, genders, races etc. to be applicable to all
name the 4 plant tissues/layer of the leaf.
1) waxy cuticle/upper epidermis
2) palisade mesophyll
3) spongy mesohpyll
4) lower epidermis
how is the upper epidermis adapted (2 ways) ?
wavy cuticle that prevents water loss from transpiration due to sunlight
thin and transparent allowing light to reach palisade layer
how is the palisade mesophyll adapted?
as it is on the upper surface, it receives the most sunlight
it is packed closely with chloroplasts for efficient light absorption for photosynthesis
how is the spongy mesophyll adapted
(2 ways) ?
contains air spaces for a larger surface area, making diffusion of carbon dioxide for photosynthesis easier
coated with a thin layer of water for gases to dissolve in when diffusing in/out the leaf
what are stomata?
small pores/holes at the bottom of the leaf where carbon dioxide diffuse in and water/oxygen diffuses out
they close at night and open during the day
how is the leaf in general adapted?
1) large surface area- maximum sunlight and carbon dioxide intake
2) thin and flat- less distance for carbon dioxide to diffuse through
what is the xylem’s function?
transports water/minerals from roots, up the stem and to the leaves for photosynthesis
what direction does water/minerals travel in the xylem?
ONLY upwards
does transport in the xylem require energy?
no- it is a physical process
how is the xylem adapted (2 ways) ?
1) no end walls- continuous tube for water/minerals to travel up
2) strengthened with lignin to keep the xylem/stem upright and supported
what are the cells that make up the xylem tissue called?
vessels
what is the function of the phloem?
to transport sugars around the plant to areas where they are needed
(e.g. growing, developing seeds)
what direction do sugars travel in the phloem?
both directions (up and down)
does transport in the phloem (translocation) require energy?
yes
how are the cells in the phloem adapted to their function?
1) sieve cells- have no nuclei and have perforated cytoplasm
2) companion cells- provide energy for translocation (attached to sieve cells)
what is transpiration?
the loss of water via evaporation when the stomata open for carbon dioxide
what is the transpiration stream?
water molecules in the xylem have strong attraction to one another
when transpiration occurs, the water lost is drawn from the xylem, moving the chain of water molecules up
what are the 4 factors affecting transpiration?
1) temperature
2) humidity
3) air flow/movement
4) light intensity
how does temperature affect transpiration?
the higher the temperature, the higher the rate of transpiration
the water molecules have more heat and therefore more energy so they evaporate quicker
how does humidity affect transpiration?
the more the humidity, the lower the rate of transpiration
when the air is humid, less water particles are in the air. this leads to less water transpiring out the leaf as the concentration gradient is less steep
how does air flow affect transpiration?
the more the air flow, the higher the rate of transpiration
air flow removes water from the leafs surface, increasing the concentration gradient for water to diffuse out the leaf
how does light intensity affect transpiration?
the higher the light intensity, the higher the rate of transpiration
when light intensity is high, more stomata are open for photosynthesis. this increases the amount of water that transpires out
what is the guard cell?
cells that control the stomata opening in bright light and closing in dim light
why are more stomata on the under side of the leaf?
less sunlight hits the under side of the leaf, meaning the stomata loses less water through transpiration due to light intensity and temperature
how is the root hair cell adapted (2 ways) ?
1) large surface area for more efficient absorption of water
2) many mitochondria provide energy for active transport
