Usuario
it contains the genetic material of the cell
cells that contain a nucleus and organelles, and are enclosed by a plasma membrane.
simple cells that lack a nucleus and other membrane-bound organelles. They are much smaller then eukaryotic cells
10x the size of an object, every order of magnitude is 10x greater then the other e.g = 10x, 100x, 1000x
it is where all chemical reactions take place
Controls the substances that enter in and out the cell
Inside the mitochondria
Inside the ribosomes
It strengthens the cell and keeps a rigid structure. Made by cellulose
a hole in a plant cell that contains cell sap. Glucose can be stored there and it helps keep the shape of the cell
They only have 23 chromosomes
they have a flagellum to allow them to swim
streamlined shape
many mitochondria for energy through respiration
contain digestive enzymes
They have an axon which carry eletrical impulses from one part of the body to another
Myelin inslutaes the axon and speeds up the transmission of nerve impulses
Dendrites increase the surface area so that other nerve cells can connect to it more easily
They can contract using protein fibres which can decrease or icrease the length of the cell
They have many mitochondria to provide the energy for muscle contraction
The hairs increase the surface area of the root so that it can absorb water and minerals more effectively
They do not contain chloroplast because they are underground
The xylem carry water and dissolved minerals up the plant
They have a very thick wall containin lignin, it provides support to the plant
Xylems cell end walls have completely broken down
They contain no chlororplast nucleus cytoplasm or vacuole
To carry dissolved sugars up and down the plant
They are made up of two types of cells:
The phloem vessel cell
A companion cell
They have no nucleus and limited cytoplasm
The end walls of the cells have pores called sieve plates They allow sugar to move through the cell
They are connected to the phloem vessel cells by pores
They provide energy to the vessel cell through respiration. They have many mitochondria
- They are cheaper then electron microscopes
- limited power of magnification
- limited resolution on the image
- Higher resolution then light microscopes
- Higher magnification then light microscpoes
Cell division (no gametes)
- In the first stage the dna is replicated to form copies of each chromosome, The cell then grows and copies its internal structures such as mitochondria
- In the second stage one set of chromosomes are pulled to each side of the cell, the nucleus then divides
- In the final stage of the mitosis the cell membrane and the cytoplasm then divide to from 2 identical daughter cells
It is a undifferentiated type of cell that can differentiate into any type of cell
Adult stem cells can only differentiate into blood cells
Bone marrow cells must be compatible with the donor
Viruses from the donor could be passed on to the patient
Plant cells are found in the meristem tissue and they can differentiate into any type of plant cell throughout its lifetime
Diffusion is the net movement of particles from an area of high concentration to an area of low concentration
Concentration gradient - the gretaer the concentration the faster the rate of diffusion
Temperature - the higher the temperature the faster the rate of diffusion due to the particles having more kinetic energy
Surface area - The larger the surface are the faster the rate of diffusion
Cells on the surface can get their oxygen through diffusion however cells in the centre of the organism are too far away to be able to do this
They have exchange systems with very high surface area such as gas exchange and the lungs
oxygen rich water passes in the mouth then flows over the gills where the oxygen is then transported into the bloodstream
deoxygenate blood passes through the filament, oxygen then diffuses from the water and into the blood. Oxygentaed blood is then returned to the body.
- They have a massive surface area
- They have a thin membrane to provide a short diffusion pathway
- They have efficient blood supply to take the oxygenated blood away ensuring that the concenttration gradient is always high
Osmosis is the movement of water particles from an area of high concentration to an area of low concentration through a semi permeable membrane
The cell shrinks and becomes flaccid.
The cell will expand and swell up becoming turgid
The movement of substances across a cell membrane from an area of low concentration to an area of high concentration against a concentration gradient requiring energy
A group of similar cells working together to perform a function
An organ is a group of tissues working together to perform a specific fuction
They are broken down by digestive enzymes into smaller food molecules which are then absorbed into the bloodstream
- It starts in the mouth chewing breaks down the food to be able to be swallowed and Amylase in the saliva breaks down the starch into smaller sugar molecules (glucose)
-The food then passes down the oessophagus and into the stomach where the digestion of protein begins.
-The stomach contains hydrochloric acid which assists the protease in digesting the proteins breaking them down into amino acids
- The churning action of the stomach muscles turns the food into a fluid therefore increasing the surface area for enzymes to digest
-Chemicals are the released from the liver and the pancreas into the small intestines
- The pancreas releases enzymes which continue the digestion of protein and starch and also starts the digestion of lipids turning them into fatty acids and glycerol
- The liver releases bile which emulsifies the fat and also neutralises the Ph from the stomach acid
- The food makes it way into the small intestine where digestion is still continued. At this point the food molecules produced by digestion are absorbed into the bloodstream by active transport or diffusion.
They are large protein molecules containing an active sight. This is what the substrate attaches to
- As the temperature increases the enzyme activity increases as they are now moving faster meaning there will be more collisions between the substrate and the active sight per second
- At a certain temperature the enzyme is working at the fastest rate possible, this is their optimum temperature
-Past the optimum temperature the enzymes activity rapidy decreases to zero. This is because at higher temps the enzyme molecule vibrates and the shape of the active sight is changed. This causes the substrate to no longer fit and the active sight has denatured
Each enzyme has a specific optimum PH. If the solution containing the enzyme is too acidic or too alklai it will cause the enzyme to denature
- it is around 5 metres providing a very large surface area for absorbing the smaller food molecules
- The interior of small intestine are covered in millions of villi which massively increases the surface area for absorbtion
- On the surface of the villi there are micro villi that increase the surface area even further
- Villi have very good blood supply so the bloodstream rapidly removes the products of digestion which increases the concentration gradient
- The villi have a thin membrane to maintain a short diffusion pathway
- The vena cava carries deoxygenated blood to the hearts right atrium the valves then open to allow it to flow into the left ventricle.
- The blood then passes from the heart to the lungs through the pulmonary artery where the blood collects oxygen
- The oxygenated blood then passes from the lungs to the heart through the pulmonary vein
- the oxygenated blood is then pumped to the rest of the body by the aorta
They stop the backflow of blood into the atria when the ventricle contracts
This is because the left side of the heart pumps blood throughout the entire body
- They have very thick muscular walls which allows them to withstand the high pressure of the blood
- Arteries contain elastic fibres that stretch and then recoil inbetween the surges of blood which keeps the blood moving
- Capillaries have very thin walls so that there is a short diffusion pathway for exygen to go in and carbon dioxide to go out
- They have a thin wall since the blood pressure is low
- They contain valves to stop backflow of blood. When blood is flowing in the right direction the valves open. When backflow occurs the valves shut
it transports soluble digestion products such as glucose around the body from the small intestine
It transports co2 from the organs to the lungs to be breathed out
They transport the waste product urea from the liver to the kidneys to be excreted as urine
They transport oxygen from the lungs to the body cells
- They contain haemoglobin which combines with the oxygen in the lungs forming oxyhaemoglobin. The red blood cell then travels to the organ where the oxygen is released
- They have no nuclues so there is more space for more haemoglobin therefore it can intake more oxygen
- They have a bi-concave disk shape for a higher surface area so that oxygen can diffues rapidly out and in
They are tiny fragments of cells that help the blood to clot
Diseases concerning the heart and blood vessels
They provide oxygen to the muscle cells of the heart
Fatty material build up in the coronary arteries which causes them to narrow
This causes the blood flow through those arteries to reduce resulting in a lack of oxygen supplied to the heart
They are drugs used to reduce the level of cholesterol in the blood
This slows down the rate that fatty materials build up in the arteries
They have been proven to reduce the risk of CHD
They can have negative side effects such as headaches memory loss and liver problems
It is a metal mesh tube inserted inside the coronary artery to keep it open
- The blood can flow normally through the artery
- The stent will not prevent other regions in the artery from narrowing
- It does not treat the underlying cause of the disease
They can be replaced with a mechanical valve or a biological valve form another animal
- They last a lifetime
- Increases the risk of bloodclotting so patients have to take anti clotting drugs
Biological valves dont last forever and need to be replaced
Patients do not ned to take drugs
They pass through a tube called the trachea. They contain rings of cartilage to prevent collapse when inhaling
They then split into two smaller cubes called bronchi branching into each lung
Further into the lungs the bronchi further divide into smaller tubes called bronchioles.
The bronchioles end in tiny air sacs called alveoli
They are where gases diffuse in and out of the bloodstream. They are the sites of gas exchange
- The millions of alveoli meants that the lungs have a huge surface area
- The alveoli have very thin walls so there is a short diffusion pathway for oxygen to diffuse into the blood and co 2 to diffuse out
- They have a very good blood supply rapidly removing the ocygenated blood from the area to maintain a high concentration gradient
They are the abnormal growth of cells found in one area
They are usually contained in a membrane
They do not invade other parts in the body. They stay in one place
- Malignant cells invade other tissues and move into the bloodstream
- Once in the bloodstream they spread to different parts of the body and they form new tumours
Some are genetic meaning passed on to the offspring
examples include : breast cancer prostate cancer and large intestine cancer
- Lung cancer risks is smoking
- Too much exposure to ultra violet light can cause skin cancer
- Alcohol can cause mouth and throat cancer
They are cause by pathogens and are can be spread from person to person
They are not cause by pathogens and cannot be passed from person to person
It is the studying patterns of disease to determine risk factors
Diet - Eating foods that are high in fat will increase the amount of cholesterol in the blood which will increase the rate that fatty material builds up in the arteries. A diet high in salt can increase blood pressure
- Smoking massively increases the risk
- Exercise decreases the risk
- Smoking contains carcinogens which can cause cancer
- Increases the risk of miscarraige or premature birth
- Baby being bored with low body mass
- excessive alcohol can lead to fetal aclohol sydnrome. Children born with this have learning difficulties
- Adults can develop liver cirrosis or liver cancer
Obesity - They have a much higher risk of developing this
They are made of epidermal tissue and they protect the surface of the leave
The upper eperdermis is transparent to allow light to flow through to the photosynthetic cells
An oily substance on the surface of the leave that reduces water loss through evaporation
They allow oxygen to leave the leaf and CO2 to enter
They also help control the amout of water vapour that is able to leave the leaf.
They are filled with palisade cells that are full of chloroplast. They contain chlorophyll which absorbs the light energy needed for photosynthesis
This layer is full of air spaces to allow carbon dixoide to diffuse from the stomata through the spongy mesophyll and into the palisade cells
Oxygen also diffuses from the palisade cells through the spongy mesophyll and out the stomata
They can contain magnesium which are used to make chlorophyll
If temperature is higher then the rate of transpiration is faster because evaporation is quicker at higher temps
It is alos faster in dry conditions this is wvaporation will be faster
Windy conditions increase the rate of transpiration as it removes any water vapour
They are microorganisms that cause diseases
Virus
Bacteria
Protists
Fungi
They rapidly divide and then release toxins. They damage toxins and make us feel ill
A virus invades a host cell and begins to reproduce. Then the virus then reproduces inside the host cell damaging it. The virus then leaves the cell by bursting it open causing it to die
Through water droplets
Through physical contact/sexual contact
Through water
Basic hygeine
Reduced direct contact
Isolation(Only for highly infectious)
Vaccination
Its is a viral disease spread by water droplets in the air
Rash and fever
Breathing problems
Can be fatal
There is a vaccination against it
It is a viral disease spread by sexual contact
First few weeks there are flu like symptoms but they disappear
The virus begins to attack the immune system and severley damage it. Eventually the immune system cannot fight off infections that other people can easily deal with
They are also unable to to fight of cancer cells
Can be treated with drugs stopping the virus from multiplying but they must be taken from the rest of their lives
This bacteria is spread from ingesting infected foods. The kind that are prepared in unhyeigenic conditions
They release harmful chemicals which cause the symptoms:
fever
abdominal cramps
vomitting
diarrhoea
They can be found in chickenm but they are vaccinated against it
It is a bacteria that is sexually transmitted
Symptoms include a thick yellow or green discharge from the penis or vagina and pain with urination
Gonorrhoea used to be treated with penicillin but it became resistant so different anti biotics are used.
The spread of this can be prevented with barriers such as condoms
It is a protist disease carried by the vector mosquitoes
They experienced repeated fevers and can be fatal
Life cycle:
An infected person is bitten by a mosquito and the malaria pathogen passes into the mosquito. The mosquito then bites another person and passes malaria onto them
Can be prevented by using insecticides to kill mosquitoes
Can be prevented by sleeping in a mosquito net
They prevent pathogens form entering the human body
They act as a protective barrier covering the body.
The outer layer of the skill contains dead cells making it hard for pathogens to penetrate
They produce sebum which can kill bacteria
Scabbing prevents cells from entering when the skin is damaged
They have hair and mucus which can trap pathogens before reaching the breathing system
They are covered in tiny hairs called cilia
They are covered in mucus to trap pathogens. The pathogens are then wafte up towards the throat that are then swallowed by throat and killed by the stomach
Phagocytosis:
White blood cells can ingest and destroy pathogens. It detects chemicals released by the pathogen and move towards it after they ingest it. The white blood cell now uses enzymes to destroy the pathogen
Anitbodies:
They are protein molecules produced by white blood cells. They stick to the pathogens trigerring it to be destroyed.
Antibodies are extremely specific to one pathogen
Antibodies can remain in the blood for a long time
Antitoxins:
They stick to toxin molecules and prevent them from damaging cells.
Infects many types of plants including tomato plants
It causes the leaves to discolour i a mosaic pattern reducing the rate of photosynthesis and the rate of the plant
A fungal disease infecting plants
It causes a black or purple spot to form on the leaf. Then the leaves often turn yellow and fall off. reduces photosynthesis and growth of the plant
Can be spread by waiter or wind
Can be prevented with fungicides
Removing and destroying infected leaves
- It invloves injecting a small quantity of dead or inactive forms of pathogens into the body
- The white blood cells are then stimulated to produce antibodies against the dead or inactive pathogen
- The white blood cells now multiply through mitosis. These white blood cells can stay for decades so if the same virus is detected it can produce the correct antibodies quickly
If enough people are vaccinated it also protects unvaccinated people as they unvaccinated cant catch the disease from anyone else
Penicillin
This is when a bacteria evolves to no longer be killed by the antiobiotic gainin a resistance to it. This is because of overuse
It came from the plant foxglove
Willow trees
Toxicity
Dosage
If it actually treats the disease
Side affects
It is carried out on cells tissues and live animals
Very low dosgae of the drug is given to human volunteers to check if its safe for humans
If it is safe the the testing is continued to find the optimum dosage for the drug with the fewest side affects
A tablet or injection with no active drug inside of it
This is where a group of patients are given the active drug
The control group recieve the placebo of the active drug which looks identical
In this trial neither the patients or the doctors know who has recieved the actual drug and who recieved the placebo to reduce bias
The process in which plant makes glucose. It is a endothermic reaction
In the leaves they contain chlorophyll chich absorbs light energy
Firstly the plant takes carbon dioxide and water into the leaves. It then absorbs the light energy through the chlororphyll. The light energy is then used to covert the CO2 and water into glucose and oxygen
Light intensity - if intensity is increased up to a certain point then the rate of photosynthesis is also increased
CO2 Levels in the air - The lower concentration fo C02 in the air the slower the rate of photosynthesis
Temperature - The enzyme involved in photosynthesis
Used for respiration
To form the insolube storage molecule starch
To produce cellulose for things like the cell wall
To keep warm
Respiration with oxygen. It is an exothermic reaction
It converts glucose and oxygen into CO2 water and energy
Because the glucose molecule has been fully oxidised
Respiration that takes place when theres a shortage of oxygen
It produces lactic acid and energy in human cellsfrom glucose
From glucose yeast and CO2 is produced in plant cells
Not alot of energy is release because the glucose molecule isnt fully oxidised
It can cause them to become fatigued and at this point it must be removed from the body
The amount of extra oxygen the body needs after exercise to deal with the accumalated lactic acid
It is the sum of all chemical reactions in the body