Organisation Flashcards
What is a cell?
The basic building block of a living organism
They make up all living things
What is a tissue?
A group of cells with a similar structure and function which all work together to do a function
E.g muscular tissue contracts to produce movement
Glandular tissue produces substances such as enzymes and hormones
Epithelial tissue covers organs
What is an organ?
A group of different tissues working together to preform a specific function
E.g muscle tissue that contracts to churn the contents
Glandular tissues to produce digestive juices
Epithelial tissue to cover the outside and inside of the stomach
What is an organ system?
A group of organs working together to preform specific functions
Lots of organ systems work together to make an organism
E.g the digestive system contains several organs which work together to digest and absorb food
What is the main function of the digestive system?
To digest food and absorb the nutrients obtained from digestion
What is the function of salivary glands?
Produces salvia which contains enzyme carbohydrase
What is the function of the oesophagus?
Tube that connects mouth to stomach
What is the function of the liver?
Produces bile which emulsifies fats to increase surface area which allows lipase enzyme to work more efficiently
Bile also neutralises acid making sure no enzymes are denatured
What is the functions of the gall bladder?
Stores bile
What is the function of the small intestine?
Where soluble food molecules are absorbed into the bloodstream
What is the function of the mouth?
Chews up food
What is the function of the stomach?
Contains protease enzyme and produces hydrochloric acid which kills bacteria and provides the optimum acidic pH for protease enzyme to function
What is the function of the pancreas ?
Produces amylase, carbohydrase,lipase and protease enzymes and releases them into the small intestine
What is the function of the large intestine?
Absorbs water from undigested food, producing faeces
What is the function of the rectum?
Stores faeces
What is the function of the anus?
Where faeces leaves the body
What are enzymes?
Biological catalysts that are made of protein that speed up reactions
What is the role of enzymes in the digestive system?
Enzymes act as biological catalysts which speed up the rate of biological reactions(the breakdown of food) without being used up
How does the shape of an enzyme affect its function?
Enzymes have a specific active site which is complementary to their substrate
What is metabolism?
The sum of all the reactions in a cell or an organism
What types of metabolic reactions do enzymes catalyse?
Building larger molecules from small molecules e.g glucose to starch
Changing one molecule to another e.g glucose to fructose
Breaking down larger molecules into smaller molecules e.g carbohydrates to glucose
What is digestion?
Is the break down of large food molecules into smaller water soluble molecules
What is the muscular system?
Needed for movement
What is circulatory system?
Circulates blood around body
What is reproductive system?
Produces and transports sex cells
What is skeletal system?
Supports the body
What is the alimentary canal?
A muscular tube that runs through the body from mouth to anus
What is the lock and key hypothesis of enzyme function/ how do enzymes work?
Substrate binds to the complementary active site
Forms enzyme substrate complex
Bonds within the substrate are broken
Products are released
What factors affect enzyme action?
PH and temperature
How does temperature affect enzyme action?
Increases temperature increases enzyme action as particles have more kinetic energy so are more likely to collide.
Optimum temp is where enzymes work best-36.5 degrees in humans
When temperature it too hot the enzyme denatures meaning the active site changes shape so it can no longer catalyse the reaction
How does pH affect enzyme function?
Every enzyme has a slightly different optimum pH normally 7
If pH is too extreme the forces that hold the amino acid chains that make up the protein will be affected those will change the shape of the active site and the enzyme may no longer work as it’s been denatured
Describe enzyme amylase
Produced in the salivary gland, pancreas and small intestine
Substrate- starch
Products- glucose
Uses- glucose used in respiration
Describe protease enzyme
Produced in stomach, pancreas and small intestine
Substrate- protein
Products- amino acids
Uses- amino acids used for growth and repair
Describe lipase enzyme
Produced in pancreas and small intestine
Substrate-fats/lipids
Products- fatty acids and glycerol
Uses- fatty acids and glycerol are used to make new fats
How are the products of digestion used?
They are used to build bigger molecules such as carbohydrates and proteins
Glucose is used as a substrate in respiration
What is the role of bile in the digestive system?
Bile is an alkaline substance which neutralises the hydrochloric acid secreted by the stomach
Bile emulsifies lipids to form droplets- this increases the surface area for the lipase enzyme to work
Describe how food is digested in the digestive system
In the mouth physical digestion occurs by chewing
Salivary glands release saliva which contains amylase- this is the start of chemical digestion
Oesophagus transfers food to stomach
In the stomach hydrochloric acid makes food very acidic
In the small intestine food is still acidic which will denature lipase and amylase so need to increase pH using bile
Bile is produced in the liver and stored in the gall bladder
Describe the effect of ph on amylase practical
-Place one drop of iodine solution into each well of a spotting tile
-add 2cmcubed of starch solution into a test tube
-add 2cmcubed of amylase solution into a test tube
- add 2cm cubed of a pH 5 buffer solution into the third test tube - used to control pH
-place all 3 test tubes in a water bath at 30 degrees. Leave for 10 mins to allow the solutions to reach the correct temperature
-combine the 3 solutions into one test tube and mix with a stirring rod. Immediately return test tube to water bath and start a stop watch
- after 30 seconds use a pipette to transfer one drop of solution to a well in the spotting tile which contains iodine
- the iodine should turn blue/ black to show starch is present
- take a sample every 30 seconds and continue until the iodine remains orange
- when iodine remains orange it tells us that starch is no longer present(the reaction has complete)
-repeat the experiment using different pH buffers e.g pH 6,7,8
What are the problems with the practical?
-are only taking samples every 30 seconds so only have an approximate time for the reaction to compete
Could fix this by taking samples every 10 seconds
- noticing when the iodine turns blue/ black isn’t always obvious as the colour change tends to be gradual so can be difficult to see when the reaction has finished.
Can ask different people to look at spotting tile and decide when reaction has completed
What are the variables for effect of pH on analyse practical?
Independent- pH of buffer solution
Dependent- time taken for the starch to be broken down by amylase
Control- volume of solution,temperature
What is the heart?
An organ that pumps blood around the body in a double circulatory system
What is the purpose of the circulatory system?
Carries oxygen and other useful substances to bodily tissues and removes waste substances
How does the double circulatory system work?
Blood passes the heart twice in one cycle through 2 different circuits/pathways
One circuit carries blood from heart to lungs- where the gaseous exchange of oxygen and carbon dioxide takes place
One circuit carries blood from heart to the tissues in rest of the body
Both sides of the heart operate separately
Describe the movement of blood through the heart/ what happens when our heart beats? Cardiac cycle
-deoxygenated blood enters the right atrium through vena cava
-blood moves through a valve and the atrium contracts, forcing blood into right ventricle and valves to shut
- blood then travels to lungs through pulmonary artery
-at the same time
-blood is oxygenated at lungs
-oxygenated blood enters left atrium through pulmonary vein
-blood moves into left ventricle through a valve
-blood then travels to the body through aorta
Why is the double circulatory system important?
It makes the circulatory system more efficient
For example- oxygenated blood can be pumped seeping body at a higher pressure by the left ventricle
Why is the wall of the left ventricle thicker?
Has to pump blood at a higher pressure around the whole body
What are the 4 main blood vessels associated with the heart?
Aorta(left) - carries oxygenated blood from heart to body
Pulmonary vein(left) - carries deoxygenated blood from lungs to heart
Vena cava(right) -carries deoxygenated blood from the body to heat through right atrium
Pulmonary artery (right) - carries deoxygenated blood from heart to lungs
What is the function of valves?
Prevents backflow of blood
What is the purpose of coronary arteries?
Supply the heart muscle with the oxygen it requires ( oxygenated blood)
What is the approximate value of the natural resting heart rate?
70 beats per minute
How is the heart rate controlled?
By a group of cells located in the right atrium which act as a pacemaker
They release waves of electrical activity which cause the heart muscle to contract
Called the SAN node
How can an abnormal heart rhythm be treated?
Using an artificial pace maker which are electrical devices used to correct irregularities in the heart rate
They send out electrical signals to correct the hearts rhythm
What are the 3 types of blood vessels in the body?
Arteries
Veins
Capillaries
How are arteries adapted for their function?
Function- carry oxygenated blood away from heart to body
Thick muscular layer- adds strength to withstand the high pressure of oxygenated blood
Thick elastic layer- allows arteries to stretch and recoil in order to withstand high pressure
Lumen is lined with smooth endothelial cells- reduces friction
Muscular artery allows it to contract to redirect blood flow
How are veins adapted for their function?
Function- carry deoxygenated blood from capillaries to heart and lungs
Valves- to prevent backflow of blood since they carry deoxygenated blood under low pressure
Skeletal muscles(calf) - help to push blood up the body and back to heart
Wide lumen- enables low pressure to flow through
How are capillaries adapted for their function?
Function- carries oxygenated blood from arteries to cells and deoxygenated blood from cells to heart/ enables transfer of substances between the blood and tissues
Walls are one cell thick- short diffusion pathway
Tiny blood vessels with narrow lumens- slows blood flow as the eh have to pass through in single file allowing more time for diffusion
Permeable walls- so substances can diffuse across
How would u calculate the rate of blood flow?
Volume of blood/ number of minutes
Where are the lungs found in the body?
Located in the thorax(within chest).
Are protected by rib cage and separated from rest of abdomen by the diaphragm
What tissues make up the gas exchange system?
Trachea
Intercostal muscles
Bronchi
Bronchioles
Alveoli
Diaphragm
Describe what happens during ventilation
Air must constantly move in and out of lungs to allow gases to diffuse into blood
Ventilation is the process of inspiration and expiration
What happens during inspiration/ how are the lungs ventilated?
-intercostal muscles contract
- ribcage moves upwards and outward
- diaphragm contracts and volume of chest increases
- increases volume in chest results in decreased pressure in lungs
- pressure in lungs now less than atmospheric pressure
-air is drawn into lungs down pressure gradient
-lungs inflate
What happens during expiration?
-intercostal muscles relax
-ribs move down and inwards
- diaphragm relaxes and volume of chest decreases
- decreases volume in chest increases pressure
- pressure in lungs now greater than atmospheric pressure
- air is forced out of lungs
-lungs deflate
Describe how gas exchange occurs at the alveoli
Oxygen diffuses from alveoli into capillary bloodstream down it’s concentration gradient
Co2 diffuses from capillary into alveoli down it’s concentration gradient
How would u calculate breathing rate?
Number of breaths/ number of mins
What substance carries different components of blood around the body?
Plasma
What substances are transported by plasma?
Red blood cells
White blood cells
Platelets
Co2
Urea
Amino acids
Glucose
Ions
What is plasma?
A yellow liquid within blood which carries dissolved substances around body
What is the purpose of red blood cells?
Transports oxygen around body
How are red blood cells adapted for their function?
-Biconcave shape- increased surface area to volume ratio
-No nucleus - more room for haemoglobin to bind to oxygen
-Very small- can fit through tiny capillaries
-contain haemoglobin- binds to oxygen
What is the purpose of white blood cells?
Form part of the immune system, which protects the body from invading pathogens/ infection
How are white blood cells adapted for their function
-Can produce antibodies and antitoxins
-Can engulf and break down the pathogen ( phagocytosis)
- can change shape so they can squeeze out of blood vessels
- have a nucleus, contains DNA which codes for proteins
What is the purpose of platelets?
Are small cell fragments which are responsible for the clotting of blood at the site of a wound
Why is the function of platelets important
They aid in the process of blood clotting (conversion of fibrinogen to fibrin) so red blood cells are trapped in the fibrin network, forming a clot which prevents excessive bleeding
- scab formation prevents bacteria from entering wound
What is coronary heart disease?
When coronary arteries are blocked by a buildup of fatty material which narrows the arteries, restricting the supply of oxygen to heart leading to a heart attack or death
CHD causes restricted blood flow so less oxygen and glucose to heart meaning less energy due to less respiration so heart can’t contract leading to a heart attack
What is a stent and how does it work?
A metal mesh tube that is inserted into a blocked artery so it remains open
Stent is inflated using a balloon, which is later removed to allow blood to flow freely
What are the advantages and disadvantages of stents?
Advantages
- quick recovery time
- non invasive
-lower risk of heart attack
- doesn’t need general anaesthetic
Disadvantages
Risk of infection
Risk of blood clots
What are statins?
Drugs which redirect the level of cholesterol in blood which contributes to the development of CHD
What are the advantages and disadvantages of statins?
Advantages
-less fat build up increases blood flow
- reduce risk of strokes, CHD and heart attacks
Disadvantages
- have to be taken continuously
- may have side effects
-Effect may not be immediate
What is a heart bypass surgery?
A surgery where blocked coronary arteries are replaced which sections of veins taken from other parts of the body
What are the consequences of leaky/faulty heart valves?
Pressure can’t build up in chambers so heart must work harder and Blood may flow in wrong direction or clot, causing the heart to become less efficient
Patients may become breathless and die as a result
What types of valves can replace leaky valves?
Mechanical- made of metal of polymers
Biological- taken from animals (pigs, sometimes humans)
What are the advantages and disadvantages of mechanical/biological valves?
Advantages
-strong and lasts for a long time
-efficient
-lots of donors (cows/pigs) so short waiting time
Disadvantages
-needs to be replaced so not long term
-religious objections (killing cows) so not accessible to everyone
What is the purpose of an artificial heart?
Support a patient’s heart while they wait for a suitable donor heart
What are the advantages and disadvantages of artificial hearts?
Advantages
-less likely to be rejected by immune system
- allows damaged heart to rest to help recovery, keeping patient alive
-keeps patient alive whilst waiting for a heart
Disadvantages
-risk of infection due to surgery
-risk of blood clots
- have to take blood thinning drugs
What is health?
Health is the state of physical and mental wellbeing
What is a communicable disease?
A disease caused by a pathogen which can be transmitted from one person to another eg the flu
What is a non-communicable disease?
A disease which can’t be transmitted from person to person eg cancer
How can diet affect health?
Too little food/lack of nutrition- anaemia, vitamin deficiencies
Too much unhealthy/ food- obesity, type 2 diabetes
How can stress affect health?
Prolonged stress is linked to a wide range of health problems- heart diseases, cancers and mental health issues
How can life situations affect health?
Life factors- location, gender, financial status, ethnic group and healthcare provision can impact a person’s mental and physical health
Give examples of how health problems can interact
-infection with certain viruses can lead to cancer eg hepatitis infections can lead to liver cancer
-compromised immune system can lead to a higher risk of infection with communicable diseases
- immune reactions caused by a pathogen can trigger allergic reactions
- problems with physical health can lead to mental health issues
What is a risk factor?
Is an aspect of a person’s lifestyle or a substance found in the body or the environment which can increase the risk of a disease
What is a casual mechanism?
Mechanism which demonstrates how one factor biologically influences another
Give examples of risk factors
Diet
Exercise
Smoking
Alcohol
Stress
Life situations
Substances inside body or environment
How do diet, smoking and exercise affect the development of cardiovascular disease?
Diet- high levels of cholesterol caused arteries to become blocked, increasing blood pressure and risk of heart attack
Smoking- nicotine increases heart rate, other chemicals damage the artery lining and increase blood pressure
Exercise- lowers blood pressure, reducing strain on heart
How does obesity affect the development of type 2 diabetes?
Fat makes the body less responsive to insulin, too much glucose is toxic
Obesity strongly linked with the onset of type 2 diabetes- a disease where the body stops responding to insulin
How does alcohol affect liver and brain function?
- excessive long-term alcohol use may lead to liver cirrhosis (scarring of the liver)
-increases risk of liver cancer - damages brain tissue and nerve cells as alcohol is toxic
How does smoking affect the development of lung disease and lung cancer?
- tar in tobacco can damage the alveoli of the lungs, leading to COPD (chronic obstructive pulmonary disease)
-tar also damages the cells which line the lungs, leading to lung cancer
How do smoking and alcohol affect unborn babies?
-carbon monoxide from tobacco smoke reduces the amount of oxygen the foetus receives, can lead to premature or still birth
- alcohol passes across the placenta and damages the developing foetus. Baby may have deformities and health problems
How do carcinogens affect the development of cancer?
Ionising radiation is a type of carcinogen which can cause mutations in DNA that could lead to cancer
What is cancer?
The development of a tumour as a result of uncontrolled cell division
Is also a group of diseases involving abnormal cell growth
What is a benign tumour?
A tumour that is contained in one location, usually within a membrane
- they aren’t cancerous and don’t invade other parts of body
- can grow very quickly- may cause damage to another organ
What is a malignant tumour?
A tumour that can spread around the body via the blood and lymphatic system
-can invade other tissues
-cells divide more rapidly and have a longer lifespan
-disrupts healthy tissues and may lead to death
Give examples of factors which can lead to cancer
Genetics- certain genes increase risk of breast and ovarian cancer
-smoking
-obesity
-ionising radiation- UV light and x-rays
-viral infections- HPV and cervical cancer
What is a tumour
Rapid cell growth
What is a cancerous cell cycle?
When abnormalities aren’t destroyed or repaired and continues to grow out of control
How is epidermal tissue adapted for its function?
Covers the entire plant. It has a waxy cuticle which helps reduce water loss from the leaf surface
How is palisade metoprolol tissue adapted for its function?
Contains lots of chloroplasts which allows photosynthesis to happen faster
How is spongy mesophyll tissue adapted for its function?
Has lots of air spaces which allows gases to diffuse in and out of the
How is xylem adapted for its function?
-Made up of dead cells which form a continuous hollow tube- allows movement of water and mineral ions from roots to leaves
- strengthened by lignin- makes the vessel strong and water proof
-has bordered pits-allow minerals to be transported to specific places
How is the phloem adapted for its function?
-made up of elongated living cells
-cells have sieve plates that connect them together- cell sap can move through plates into other cells
-sieve tube cells have few organelles to allow the efficient transport of substances
How is meristem tissue adapted for its function?
Made up of stem cells which can differentiate into many different cell types, allowing plant to grow
What tissues does the lead organ contain?
Epidermis
Palisade mesophyll
Spongy mesophyll
Xylem
Phloem
Guard cells
What is the function of guard cells?
Control the opening and closing of the stomata depending on the water content of the plant
How are stomata adapted for their function?
They allow the control of gaseous exchange and water loss from leaf
- more stomata on base of leaf, minimises water loss as this side is cooler and shaded
-have guard cells which control their opening and closing
How are root hair cells adapted for their function?
Allow the absorption of water and mineral ions from soil
- large surface area- maximises rate of absorption
-contain lots of mitochondria- releases energy for active transport of mineral ions
What is translocation?
The movement of dissolved sugars from the leaves to other parts of the plant
What is transpiration?
The evaporation of water vapour from the surface of a plant/ loss of water vapour from leaves and stems
How does transpiration work?
-water evaporates from the leaf surface via stomata
- water molecules are attracted to each other, so when molecules leave the plant the rest are pulled up through the xylem in an unbroken column
- means more water is taken up from soil- crating a continuous transpiration stream
How does temperature affect the rate of transpiration?
Increasing temp, increases rate of transpiration
- molecules move faster so evaporation happens at a faster rate causing rate of transpiration to increase
-rate of photosynthesis increases so stomata are open for gas exchange so more water evaporates and rate of transpiration increases
How does humidity affect the rate of transpiration?
Increasing relative humidity decreases rate of transpiration
-high relative humidity reduces the water vapour concentration resulting in lower rate of diffusion so rate of evaporation will decrease meaning rate of transpiration will too
How does wind speed affect the rate of transpiration?
Increasing wind speed/air movement increases rate of transpiration
-increased air movement lowers water vapour concentration outside of leaf, this increases the water vapour concentration so increases the rate of evaporation and transpiration
How does light intensity affect the rate of transpiration?
Increasing light intensity, increases rate of transpiration
-rate of photosynthesis increases so more stomata are open, allowing the rate of evaporation to increase, increasing rate of transpiration
