GCSE Biology Paper 1 Quiz (AQA)

Here are some quick questions to help you test your knowledge for AQA GCSE biology paper 1. If you haven't seen the full video going through everything you need to know for the paper yet, it's worth watching that first; link is in the description. Here we go.

Question one: Why are electron microscopes better than normal light microscopes? They have higher resolving power or resolution, meaning they allow finer details to be visualized, like cell organelles, sub-cellular structures.

Question two: In standard form, what is 5 micrometers when converted to meters? It's 5 * 10^-6 M. That's because micro means * 10^-6 or a millionth.

Question three: What three subcellular structures or organelles are only found in plant cells? They have chloroplasts, that's where photosynthesis takes place; they have a permanent vacuole where water and sap and other things are stored; and a cell wall, which is rigid due to it being made from cellulose.

Question four: What's the difference between eukaryotic and prokaryotic cells? Eukaryotic cells, like your normal plant and animal cells, their DNA is found in the nucleus. For prokaryotic cells, like bacteria, even though they have DNA, it's not found in a nucleus; they don't have a nucleus at all.

Question five: What are the stages of mitosis? The nucleus dissolves and the genetic material is duplicated; the two sets of chromosomes then move to opposite sides of the cell; the organelles are also duplicated; the cell then divides, producing two genetically identical diploid cells.

Question six: How many chromosomes do diploid and haploid human cells have? Diploid means two sets of chromosomes, so humans, we have 23 pairs or 46. In our haploid cells, just have one set, so that's just 23 chromosomes; these are your gametes, sperm and egg cells.

Question seven: What are the differences between diffusion, osmosis, and active transport? Diffusion is the movement of particles from an area of high concentration to an area of low concentration; we can say down the concentration gradient. This is passive; it doesn't require energy. Osmosis is the diffusion of water through a semi-permeable membrane to balance the concentration of solutions on either side, for example, sugar concentration in a cell. The water moves because the sugar is too large to fit through the holes in the membrane. The water always moves into the higher concentration solution in order to dilute it, to balance it out. This is how water enters root hair cells in a plant. Active transport is the movement of molecules from a low concentration to a high concentration, against the concentration gradient. This happens across a membrane via carrier proteins. This requires energy, hence the active part. This is how minerals get into root hair cells, which already have a higher concentration compared to the soil that they're in.

Question eight: How can you increase the rate of diffusion or osmosis? You can increase the temperature; that's because particles have more energy, so they move faster. You can increase the difference in concentrations. You can also increase the surface area the diffusion is occurring across.

Question nine: In the osmosis practical, how do you find the concentration of sugar inside the potato or whatever it is from the graph? We interpolate using a line of best fit where it crosses the x-axis; that's the concentration at which no osmosis would occur, showing that this concentration is therefore the same as that inside the potato cells.

Question 10: What is the role of bile in the digestive system? Bile is made by the liver and stored in the gallbladder. It then goes to the small intestine where it emulsifies lipids or fats to form small droplets. This increases their surface area, increasing the rate at which they're broken down by enzymes, specifically lipases.

Question 11: Where is amylase made and what does it do? Amylase is an enzyme that's secreted by your salivary glands and pancreas. It breaks down starch into glucose.

Question 12: What are villi? Villi are the cells in the small intestine that absorb nutrients into the bloodstream. They are hair-like in order to have a large surface area to increase the rate of absorption.

Question 13: What are enzymes? Enzymes are biological catalysts; they facilitate crucial processes in your body, such as the breaking down of polymers into monomers, for example, starch into glucose.

Question 14: What does it mean when we say that enzymes are specific? This means they only break down certain molecules due to their lock and key nature; only specific substrates, that's the molecule being broken down, will bind to the enzyme's active site in order to be broken down.

Question 15: What increases the rate of activity of an enzyme, and what does it mean when it denatures? Increasing temperature increases the activity of the enzyme until the temperature gets so high that it denatures; the active site changes shape and it no longer works. They also have an optimum pH; too high or low pH and the enzyme will denature.

Question 16: What do carbohydrases, proteases, and lipases break down and into what? Carbohydrases break down complex carbohydrates into simple sugars; amylase is one of these. Proteases break down proteins into amino acids. Lipases break down lipids, thus fats, into glycerol and fatty acids.

Question 17: In the enzyme practical, how do you know that the amylase has broken down all of the starch? The solution will no longer turn black or change color when added to iodine in the spotting tile.

Question 18: What are the tests for starch, sugars, protein, and lipids? Iodine turns from orange to black in the presence of starch; sugar turns Benedict's solution from blue to orange and maybe green in between; protein turns Biuret's reagent from blue to purple; and lipids turn cold ethanol cloudy.

Question 19: Describe the structure and function of alveoli. Alveoli are the air sacs in your lungs where gas exchange takes place. They have a large surface area to maximize the rate of diffusion of oxygen into and carbon dioxide out of the bloodstream.

Question 20: Describe the structure and function of red blood cells. Red blood cells transport oxygen around the body via the bloodstream as oxygen binds to the hemoglobin inside of them. Their biconcave shape maximizes the surface area the oxygen combines to.

Question 21: Name the parts of the heart blood passes through in order, starting from where it enters. It enters through the main vein, the vena cava; then it goes to the right atrium, right ventricle, pulmonary artery to the lungs; then back through the pulmonary vein to the left atrium, then to the left ventricle, and out through the aorta, the main artery to the rest of the body.

Question 22: How is the left side of the heart different from the right, and why? The left side has thicker walls to deal with the higher pressure as it pumps blood to the whole body, whereas the right side only pumps blood to the lungs.

Question 23: What are the differences between arteries, veins, and capillaries? Arteries carry blood away from the heart; they carry oxygenated blood apart from the pulmonary artery. They have thick walls and a small lumen to deal with the higher pressure. Veins carry blood towards the heart, and so they carry deoxygenated blood, that is apart from the pulmonary vein. They have thin walls and a large lumen, and they contain valves to prevent the backflow of this deoxygenated blood. Capillaries are very small blood vessels with one cell thick walls to facilitate gas and nutrient exchange between the blood and cells.

Question 24: Give one risk factor for each of these non-communicable diseases: diabetes, coronary heart disease (or just heart disease), liver disease, and lung disease. Poor diet and obesity increase the risk of diabetes; poor diet and lack of exercise for heart disease; alcohol increases the risk of liver disease; and smoking for lung disease.

Question 25: What is cancer, and what is the difference between benign and malignant cancers? Cancer is an autoimmune disease where cells mutate and start dividing uncontrollably, resulting in tumors. Anything that increases the risk of cancer developing is called a carcinogen. Benign cancer does not spread through the body, but a malignant cancer will.

Question 26: What are the functions of the xylem and phloem in a plant? Xylem are long unbroken tubes that carry water up the plant by transpiration caused by water evaporating from the leaves. This is unidirectional, just in one direction flow. Phloem are tubes of cells through which sugars and other molecules are transported up and down the plant, so it's bidirectional; they pass from one cell to the next by active transport.

Question 27: What three factors will increase the rate of transpiration? Increasing the temperature, increasing the air flow (that's decreasing the concentration of water around the leaves), and increasing the surface area of the leaves; all of these will increase the rate of evaporation of water from the leaves, therefore increasing the rate of transpiration.

Question 28: What is special about the meristem of a plant? The meristem is where new cells are made; these are stem cells which then specialize or differentiate to carry out a specific function.

Question 29: Explain the structure and function of the waxy cuticle, palisade mesophyll (or layer), the spongy mesophyll, and guard cells in a leaf. The waxy cuticle stops water evaporating from the top of a leaf. The palisade mesophyll is made of cells with lots of chloroplasts; this is where most photosynthesis takes place. The spongy mesophyll contains gaps allowing fast rates of gas exchange. And the guard cells in the lower epidermis; they control the size of the stomata, the holes through which gases enter and exit the leaf.

Question 30: What are the word and balanced symbol or chemical equations for respiration and photosynthesis? Respiration is this: glucose and oxygen makes carbon dioxide and water, which releases energy. The balanced chemical equation is C6H12O6 + 6O2 → 6CO2 + 6H2O. Photosynthesis is the reverse reaction; energy is required in the form of light.

Question 31: What are the word equations for anaerobic respiration in animal and plant cells? Anaerobic means without air or oxygen. In animals, including us humans, this is glucose being converted into lactic acid, which then has to be broken back down into glucose by the liver using oxygen afterwards. In plants, anaerobic respiration is the process of glucose being turned into ethanol and carbon dioxide; this is also called fermentation.

Question 32: What is the glucose made from photosynthesis used for? Plants use the glucose they make for respiration; they use it for making starch and fat to store energy; making cellulose; and making amino acids for proteins.

Question 33: What three factors increase the rate of photosynthesis? Increase temperature, increased light intensity, and increased carbon dioxide concentration.

Question 34: What happens to the light intensity if you move a plant twice as far away from the light source? The light intensity decreases to a quarter; it quarters. That's because light intensity and distance follow an inverse square relationship.

Question 35: What is likely to be the limiting factor for photosynthesis here? It's the CO2 concentration; we know this as we can see that increasing this results in an increased rate of photosynthesis.

Question 36: What is likely to be the limiting factor here? It's going to be the light intensity, as we can see that increasing the carbon dioxide and temperature don't increase the rate here, so it must be the light intensity.

Question 37: What are the two types of white blood cells and how do they combat viruses? Lymphocytes produce antibodies of varying shapes; once the right one is found, many copies are produced. These antibodies bind to the antigen on a virus's protein coat, stopping it from injecting its genetic material into cells, so more copies won't be synthesized. The antibodies also cause the virus to clump together, making it easier for phagocytes to ingest and destroy them.

Question 38: How does a traditional vaccine work? A normal vaccine is an inert copy of a virus; when injected, it cannot cause more copies of itself to be made, but it means your lymphocytes will have already found the right antibody to produce by the time you encounter the real virus; you now have immunity.

Question 39: What is the difference between blind and double-blind trials? When developing drugs, a blind trial involves a test group who were given the drug and a control group who were given a placebo; the test subjects don't know which group they're in, but the scientist or doctors carrying out the test do. For a double-blind trial, not even the doctors know which is which; this eliminates any bias. That's why pharmaceutical companies are doing them less and less as time goes on, sadly.

Finally, Question 40: Just for triple: How are monoclonal antibodies made? Lymphocytes from mice are combined with tumor cells to make hybridoma cells, which multiply quickly, producing many copies of the antibody. Leave a like and a comment if this has helped you. All the best for your exam, and I'll see you next time.