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GCSE Biology 2020-2022 OCR Gateway


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What are Eukaryote Organisms?
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-This is simply Organisms that are made from Eukaryotic Cells - Complex Cells

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GCSE Biology 2020-2022 OCR Gateway - Details

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What are Eukaryote Organisms?
-This is simply Organisms that are made from Eukaryotic Cells - Complex Cells
What are the two types of cells? And what are there differences?
They are eukaryotic which are plant, animal etc cells and there are prokaryote which are bacteria. There differences are that eukaryotic have nucleus to store there DNA while prokaryote cells have their DNA freely. Eukaryotic cells also have many membrane-bound organelles while Prokaryote has 1, Ribisomes
What are Prokaryotes?
-These are Organisms that are made from Prokaryotic Cells - Simple Cells
In Animal cells, what are the main mini organelles?
The main mini organelles are the nucleus which stores the cells DNA, Cytoplasm where most of . the reaction takes place, Mitochondria which has aerobic respiration taking place [aka where energy is created.] Ribosomes which is where proteins are made and the Cell membrane which can determine what goes in and out.
What is in an Animal Cell, and States its Function
-Nucleus: Has the DNA in Chromosomes that Controls what the Cell Does -Cytoplasm: Gel-ish Substance that has Most of the Chemical Reactions -Mitochondria: Places where Respiration happens. Simple -Cell Membrane: Has all of the Cell Together, and Controls what goes In and Out. Also has Receptor Molecules that are used for Communication.
What extra mini organells do Plant cells have?
They have a cell wall and a vacuole which together can help the cells structure and support and you also have Chloroplast which is where Photosynthesis [food in a way] takes place
What is in a Plant Cell, and State its Function
-Has Everything that's in a Animal Cell +.. -Cell Wall: Supports the Cell. Simple -Chloroplasts: The Hub for Photosynthesis, and has a Green Substance called Chlorophyll.
What would happen if a plant cell didn't have any Chloroplast?
This already happens in some plant cells as because they are deep underground so it would be very useless. But they still need nutrients or they are screwed. So they use a transport system with another cell that can make photosynthesis or food and they it gets sent to them for their own usage
What's in a Prokaryotic Cell? State its Function
-Chromosomal DNA: Simply a Long Circular Chromosome that controls the Activity of the Cell. It can just float around in the Cytoplasm -Plasmids: This is Loops of DNA that aren't connected with the Chromosome. They mainly contain Genes that are Resistance for Drugs [eg] which can be Passed between Bacteria
How can Cells be Studied?
-Microscopes allow us to See Cells, as it has Lens which Magnify Images. Resolution also Increases meaning we can Actually see Better in more Focus.
What does Resolution mean?
-This simply means how well a Microscope can Separate 2 Points that are Close Together - Detail in a Nutshell
What is a: 1. Light Microscope 2. Electron Microscope 3. Transmission Electron Microscopes
1. Light Microscopes use the Light to see Nuclei and Chloroplasts. They can give Colour, but compared to the Other Microscopes, they aren't that Specific 2. Electron Microscopes use Electrons to Depict Images, like Plasmids or Viruses. They can give a Better Resolution and Magnification then Light Microscopes - but more Expensive and No Colour 3. TEM's can give a very High Magnification, but can't be Moved and are Stupidly Expensive. They also can't be used to see Living Tissues.
What is triplet code?
This is where three nucleotide code for one amino acid
What does DNA stand for?
DNA stands for Deoxyribose nucleic acid
Where about is it?
It is located inside the cells chromosomes which is inside the nucleus [or nucleoid]
What are nucleotides?
They are 1 phosphate, 1 Pentose sugar [contains 5 carbon atoms] and 1 Base come together
What are the 4 componentes bases in DNA
They are Thymine, Adenine, Cytosine, Guanine.
What is a section of DNA called?
It is called a Gene. this contains a specific code for a protein of some sort.
What are actually on the DNA?
The important bit of DNA is that it has the coding for all the proteins the cell can make.
What does mRNA stand for?
This stands for Ribonucleic acid
What is mRNA?
MRNA copies information from DNA and transports it to the ribosomes where the amino acids there can use the given instructions given from the mRNA to construct the protein.
What is a triplet code?
It is 3 nucleotides coding for a specific amino acid in the ribisomes
Why are they triplets?
The reason they are triplets is because if you made them double, you would restrict them to 16 different combination, which isnt enough. Triplets allow them to have 64 different combination which is much more than enough, another reason is that the amino acids reads in 3's so doing it in triplets can help them out alot.
What does transcription and translation mean?
Transcription simply means to copy. This would happen when the mRNA is copying inside the nucleus. Translation means to change language [be able to read.] This would occur when the amino acids are reading it.
What differences does mRNA make when it copies from DNA
It replaces Thymine with Uracil and it also switches Cytosine and Guanine around. eg CGC-GCG
What is a Enzyme?
An enzyme is a catalyst that speeds up specific reactions.
What is a catalyst?
A catalyst is something that speeds up reactions without it being changed
What is a substrate and how are they involved?
A substrate is simply a compound element. They get involved by getting broken down in to products. eg H2O2 gets broken down into Water and Oxygen.
Where does substrate lock on to?
The substrate locks on to the active site which is part of the enzyme. When its fully locked on, it gets broken.
What does denatured do to the enzyme?
If the enzyme denatures, that means that its active site has changed shape. If that happens then the substrates it used to lock on may not lock on anymore. This can happen if the temperature is above its optimum temperature.
What does optimum mean?
Optimum means what pH or temperature the enzyme works best and this differs with every enzyme.
How can this help us?
One of the reasons it can help us is because harmful compound elements can be broken into elements that can help us. H2O2 is a harmful product but can be broken into things that wont do anything to us. [Oxygen and Water]
What do Microscopes use
They use lenses in order to magnify images [make them bigger] They also increase the resolution of an image to increase the detail you can see.
How would you find out the total magnification?
You would do the eyepiece lens magnification x objective lens magnification.
How would you find out Magnification [if you dont know which lens was present]
You would do the image size divided by the real size. It has to be in the same measurement.
What are electron microscopes and why are they useful?
They do the same purpose as a light microscope except use electron to scope and make the image. This means there is no colour but can allow us to see the very small things in big images and amazing detail. This can help us understand deadly tiny things like viruses and plasmids.
What happens if you have a thick specimen?
You would cut a thin slice to allow the light throw it.
What exactly is respiration?
This is the process of transferring energy via the breakdown of glucose.
Why do cells need to respire?
Respiration is used to create a substance called ATP which stores the energy created. This can be used for cell processes and to keep them alive
What is aerobic respiration?
This is when glucose is broken down WITH oxygen. It is the best way to make ATP's [32] and is the most common used. This takes place in the Mitochondria.
What is the equation for aerobic respiration
6 Oxygen [O2] + Glucose [C6H12O6] = 6 Carbon Dioxide [CO2] + 6 Water [H2O]
What happens when you exercise?
When you exercise, muscles cells need more energy to move more. This simply means the rate of respiration rate goes up because you need more oxygen to supply your cells. Thats also why you start breathing more and your heart rate increase to get rich oxygen blood to your cells.
What is anaerobic respiration?
This is when your cells respire WITHOUT oxygen. This is much more efficient as it creates only 2 ATP oppose to 32. This is used when your exercising and there is not enough oxygen to breakdown the glucose.
What is the equation for anaerobic respiration?
Glucose [C6H12O6] = Lactic acid [C3H6O3]
What is lactic acid?
Lactic acid is made from anaerobic respiration and can is the sole reason for stitches and cramps. it makes your muscles fatigue.
What is a oxygen debt?
When you finish exercising, you breath hard because you need a lot of oxygen to break down the lactic acid that built up.
What do plants and fungi do thats different?
They use anaerobic respiration except they make ethanol [alcohol] and carbon dioxide. Thats why they can use it for a long time
What does Exothermic mean?
This means heat or energy is released. Respiration is a key example because it burns glucose and releases heat energy which is kept via an ATP. Thats also why its quite warm when you breathe out.
What are polymers and monomers
Polymers are a long chain of molecules while a monomer is a molecule
What is a Carbohydrate
Carbohydrate molecules are made up from Carbon, Hydrogen and Oxygen. The monomers are simple sugars like Glucose while the polymers are complex large carbohydrate like Starch.
What is a Protein
Proteins are polymers are made up via large chains of amino acids. Amino acids are made up from Carbon, Nitrogen, Hydrogen and Oxygen.
What is a Lipid
Lipids are made from glycerol and three fatty acids. They are not a polymer as they dont form a long chain of repeating units. Lipids contain Carbon, Hydrogen and Oxygen.
What is Photosynthesis?
This is when plants use the sunlight the energy to make their own food [glucose]. They are the only living being to do that
How does this help us?
This helps us as some of the glucose the plant makes is used for large, complex molecules that the plant grows. This makes the organism's biomass which gets eaten by animals, the food chain. So Photosynthesis supports almost every life on Earth
Where does Photosynthesis take place?
This takes place in the Chloroplast. They contain Chlorophyll which absorbs light via energy transferring it via the environment.
What is the equation for Photosynthenesis
6 Carbon Dioxide [CO2] + 6 Water [H2O] --{Light}--> Glucose [C6H12O6] + 6 Oxygen [O2]
What does endothermic mean
This means energy is absorbed from the surrounding like Photosynthesis. They absorb sunlight energy from the Environment
What is the rate of Photosynthesis affected by?
It is affected by Light intensity, CO2 concentration and Temperature.
How are they affected?
If Light Intensity is increased, the rate increases too until it reaches a point when CO2 levels or the Temperature can't keep up. If CO2 levels is increased, it would follow the same fate as Light Intensity as because its now not a limiting factor. If the temperature is changed, It can depend. The reaction can keep going up until it reaches past its optimum temperature. It will soon plumit down as the enzymes would denature and become useless.
What is Diffusion?
Diffusion is just the movement of particles from a high concentration to a low concentration
What states can it happen and why?
Liquid and Gases. This is because the particles are free to move around randomly.
What in the cell is used to allow diffusion and is there a limit?
The Cell Membrane. They allow stuff in and out as well as keeping the cell together. The size has to be small however. eg Glucose
So how does diffusion work?
Lets take oxygen molecues for example. The cell has a low concentration of oxygen while the outside has a high concentration. The particles spread out and go towards the low concentration [the cell] The cell spends no energy and gets the resources it needs.
What is the Diffusion gradient?
This is just showing the particles concentration and destination in picture.
What is Active Transport?
This is the opposite of Diffusion. This is moving particles from a low concentration to a high concentration. Energy is required for this process as the particles want to spread out and not go in.
Examples of Active Transport?
Plants use this to get the minerals via the soil.
What is Osmosis?
This is like diffusion, but with water molecules moving from a higher concentration to a lower concentration.
Is their any differences with Osmosis
Yes. The membrane has to be semi-permeable membrane/ partially permeable membrane
What is water potential?
This is saying if its a high or low concentration. High water potentital=high concentration of water molecules. Pure water has the highest water potential
What are Turgid cells?
They are located in Plants. This links in with water potenital in the soil. If its high, then the cell becomes turgid and the cell insides push against the cell wall. This helps support the plant tissues. If the soil has a low water potential, then the cell becomes flaccid, where the cell walls retract. They don't loose their shape, as their inelastic cell wall keeps it in position.
Does Osmosis increase mass?
It can. If you put a potato [for example] in a pure water solution, where the outside has a higher concentration then the insides, water molecules will be drawn into the potato therefore adding the mass onto the cell. It can be seen visually too. The opposite can happen. If the solution has got a lower water concentration then water molecules will go out and therefore will lower the mass.
How would you find out the percentage change in mass?
You would do: Final mass-Intial mass ---------[Divide]-------- x 100. Inital mass
Can the rates of Diffusion, Osmosis and Active transport be affected?
Yes Surface area: Volume ratio. The smaller a object can be, the higher the ratio is. This can help it diffuse more effectivley and quicker Temperature: When it gets hotter, particles gets more energy, kinetic energy. They move around quicker which means they can go in/out quicker Concentration Gradient: If the line is steeper, the particles quantity will be increased in terms of moving across.
Why do we need to exchange surfaces?
To allow the organism to live by transporting oxygen glucose and getting rid of waste products
Why is it easier to diffuse in single cell structures then multi cell structures
Substances have to travel not very far and they have a larger surface area: volume. This means it can diffuse enough substances to reach the demand of the volume. Multi cell structures have cells too deep inside meaning the joruney is too long and the surface area cant reach its demand of getting enough substances for its volume
What do Multi cell strucutres do differently?
They have specialised exchange organs with a specialised exchange surface to help the demand
What else do Multi cell strucutures have?
They have transport system to ensure the substances get to the cells needing it. It is also to get rid off waste products.
Examples of Transport Sytems?
In the Plant, you have the Xylem and Phloem. Animals have the circulatory system.
How are specilaised exchange organs adapted?
They are thin. The substances have a short distance to travel They have a large surface area : volume ration The Cirulatory System has millions of blood vessels to get stuff in and out of cells. same with Gas Exchange.
How does Gas Exchange happen?
This happens in the Lungs where oxygen is transported to the bloodstream. How this happens comes down to the alveoli where it happens. The Alveoli are adapted to this by having: Massive surface area : Volume ratio, Tiny walls, A moist lining for dissolving gases and a good blood supply. The Capillary next to the Alveoli gives it Carbon Dioxide and in return gets Oxygen. The Blood in the stream is Deoxygented [no oxygen but lots of CO2] so diffusion can happen quickly. The oxygen is diffused in and is now carried to its destination
What is special about the Villi
They are adapted too. Found in the insides of the Small intenstine they help with the dissolved food molecules going into the blood. They are a single layer of surface cells and have a massive amount of blood supply.
How are Leaves adapted?
Leaves need Carbon Dioxide for Photosynthesis and Oxygen for Respiration. Obviously when they are doing one of the two, the concentration will be higher outside which means diffsusion. Leaves makes it more quicker and easier. They are broad [larger surface area : volume] and are thin which makes the distance not far for the gases. They have air spaces inside it to let the gases to move at ease and also increases the ratio. Stomato at the bottom of the leave also lets the gases diffuse in/out They also allow water to escape [Transpiration]
How are Root Hair cells adapted?
They have long hairs which stick into the soil outwards. These hairs will cover the branches of the root which increases their surface area : volume ratio. Water can be in without fuss, the water potential outside is greater but the minerals have to be forced in [active transport] This is because the concentration is higher inside.
What is the Circulatory System
This is the system which has blood carry the substances to their destination.
What is it made up off? [Circulatory System
It is made up of the Heart, blood vessles and blood.
What is the Pulmonary system job?
This is the system that has blood carry deoxygenated blood to the lungs to gain oxygen which then returns back to the heart.
What is the other system job?
This is the system that carries the oxygenated blood to its destination. It then returns back to the heart.
Why is it good that we have a double system?
Blood pressure is increased which means the blood flow increases. This means blood can give its 'customer' its desiered products faster [Oxygen] Mamals need this to maintain their body temperature.
What does our Heart do exactly?
Our heart is the muscle of this operation. It keeps the blood flowing in the right direction due to its valves. [Thats also why you can hear your heart sometimes]
What happens in the heart?
So the heart is split in 4 main chambers. The Right Atrium, The Right Ventricle, The Left Atrium and The Left Ventricle. [Keep in mind, in a diagram the left of it is the right atrium, ventricle etc...] The Blood flows into the atriums via the Pulmonary vein or the Vena Cava [also a vein] The atriums contract, pushing the blood into the ventricles. The ventricles contract, forcing the blood to the Pulmonary artery or the Aorta. This keeps repeating itself again and again...
What is the heart made up of?
It is made up fo cardiac muscle which contains alot of mitochondria for ATP [Energy] They also need oxygen which means a blood supply so that the heart can keep beating. The vessles that supply them are called the coronary arteries.
Why is the left ventricle thicker then the right?
Destination wise. The right side only needs to go to the lungs and back. The right needs to go to everywhere else. To the brain and the toes.
What are the valves called?
The Tricuspid Valve [The valve in the Right Atrium], The Bicuspid Valve [The valve the in Left Atrium] and the Semi Lunar Valve [The valve in the Artery]
What are the 3 types of blood vessels and whats their function
Arteries, They carry the blood away from the heart Veins, They carry the blood towards the heart Capillaries, They exchange substances in the tissues.
How are arteries made and adapted?
They pump blood away at high pressures. The walls are therefore elastic and strong which covers the lumen [the hole] Their muscle has many thick layers for strength and elastic fibres to stretch and spring back. They can also branch into arterioles.
How are Capillaries made and adapted?
They come from the Arterioles branches which make them really small. In tissues, the network of those capillaries are called capillary beds. They carry the blood really close to each cell to exchange materials [eg Oxygen for Carbon Dioxide] Capillaries have permeable walls, which allows diffusion They are one cell thick, which increases massively the ratio for surface area to volume. They can be branched to Venules.
How are Veins made and adapted?
Veins are formed from the joint up Venules. Blood pressure here is lower so the walls are not as thick. They do however have a larger lumen to help the blood flow. They also have valves, to ensure the direction of the blood to the heart.
How does cross section area of vessels affect the blood flow?
When the cross section increases, the velocity of the blood decreases. So capillaries slow it down not for a bad reason, but a good one. In the capillary beds, the blood flow is slow which allows the exchange of materials. If it had the same velocity as arteries, nothing would be diffuesed. Artieries have the highest velocity as its closer to the heart.