Biology Paper 1 Topics Flashcards
What is the function of mitochondria?
Mitochondria is where aerobic respiration takes place
What is the function of the cell membrane?
The cell membrane is responsible for the movement of substances in and out of the cell
What is the function of the ribosomes?
The ribosomes is where proteins are made (protein synthesis)
What is the function of the cytoplasm?
The cytoplasm is where all the chemical reactions take place
What is the function of the nucleus?
The nucleus contains the genetic material
What is the function of chloroplasts? (plants)
Chloroplasts are where photosynthesis occurrs
What is the function of the permanent vacuole? (plants)
The permanent vacuole contains the cell sap
What is the function of the cell wall? (plants)
The cell wall is made up of cellulose and strengthens and supports the cell
What are the differences between electron and light microscopes?
Electron microscopes were invented later than light microscopes, and have higher magnification and resolution than light microscopes. This means they let us see smaller things in more detail, meaning we can understand subcellular structures better now
What subcellular structures are only found in bacterial cells?
Bacterial cells contain DNA loops (floating in the cytoplasm) and plasmids (small rings of DNA)
What are the differences between prokaryotes and eukaryotes?
Prokaryotes don’t have a nucleus whereas eukaryotes do have a nucleus
Prokaryotes are smaller than eukaryotes
Prokaryotes are unicellular whereas eukaryotes are multicellular
How do you calculate magnification?
You can calculate magnification by dividing the image size by the real size
What is differentiation?
Differentiation is the process by which cell changes to become specialised for its job
How are sperm cells differentiated?
Sperm cells are differentiated by having a long tail + a streamlined head for swimming to the egg. They are also packed with mitochondria for energy for movement
How are nerve cells differentiated?
Never cells are differentiated by being long to cover a large distance, as well as having branches to form a network of connections
How are xylem cells differentiated?
Xylem cells transport substances along a plant, so their cells are hollow, so that water flows easily
How are phloem cells differentiated?
Phloem cells are differentiated by having fewer subcellular structures so that’s substances can flow through easier
How are muscle cells differentiated?
Muscle cells are used for contraction, so they are long so they have space to contract, as well as having lots of mitochondria for energy. Muscle cells store glycogen which can be broken down into glucose for energy/respiration
How are root hair cells differentiated?
Root hair cells are differentiated by having a large surface for absorbing water and mineral ions from the soil
What are stem cells?
Stem cells are undifferentiated cells, which can divide to produce more stem cells and differentiate into other types of cells
What can stem cells in the adult bone marrow do?
Stem cells in adult bone marrow can become any kind of cell
What can stem cells in a human embryo do?
Stem cells in human embryo can become any kind of animal cell
What can stem cells in plant meristem do?
Stem cells in plant meristem can become any kind of plant cell
How can stem cells be used in medicine?
Stem cells can be used in medicine in therapeutic cloning, where an embryo can be made with the same genes as the patient so the stem cells won’t be rejected
How can stem cells be used in plants?
Stem cells can be used in plants to produce clones of plants quickly and cheaply eg for rare species and desirable characteristics
Describe the practical for using light microscopes
1) . Start with the lowest powered lens then move the stage up with the coarse adjustment lens
2) . Lockdown the eyepiece and adjust the focus with the adjustment knobs (use the coarse one first)
3) . To see the slide with greater magnification, swap to the high powered lens and refocus
How do you prepare a slide for microscopy?
Prepare the slide for microscopy by placing a specimen stained with iodine on a coverslip, adding a drop of water.
What is 1mm in micrometres?
1mm = 1000μm (x1000)
What is diffusion?
Diffusion is the movement of particles from an area of high concentration to an area of low concentration
What factors affect the rate of diffusion?
Factors that affect the rate of diffusion include a high concentration gradient, a high temperature and a large surface area
What is osmosis?
Osmosis is the movement of water molecules from an area of high concentration to an area of low concentration across a semi-permeable membrane
What is active transport?
Active transport is when particles move against the concentration gradient - from an area of low concentration to an area of high concentration
What is the difference between active transport and diffusion + osmosis?
Active transport requires energy from respiration
What does active transport allow for in plants?
Active transport allows for mineral ions (for plant growth) to be absorbed from the soil into the root hair cells
What does active transport allow for in people?
Active transport allows for glucose (for cell respiration) to be absorbed into the bloodstream from the gut
Describe the method for finding the effect of different concentrations of sugar or salt solutions on plant tissue - using potatoes
1) . Cut potato into cylinders
2) . Measure the mass of each cylinder
3) . Prepare beakers containing different concentrations of sugar or salt concentration and one of pure water
4) . Put 1 cylinder into each beaker
5) . Leave for 24hrs and dry cylinders and measure masses
What are the independent and dependant variables for finding the effect of different concentrations of sugar or salt solution on plant tissue using potatoes?
Independant variable = concentration of sugar / salt solution
Dependant variable = potato cylinder mass
How does osmosis affect the mass of plant tissue?
When water is drawn in by osmosis, mass increases. When water is drawn out by osmosis, mass decreases.
How do you calculate the percentage change in mass?
Percentage change in mass = ( ( new mass - original mass) divided by original mass ) x 100
What is a cell?
A cell is a basic building block that all living organisms have
What is a tissue?
Tissue is a group of similar cells that work together
What is an organ?
An organ is a group of different tissues that work together
What is an organ system?
An organ system is a group of organs working together
What do enzymes do?
Enzymes catalyse chemical reactions
How happens when substrate binds to an active site of an enzyme?
When a substrate binds to an active site, an enzyme-substrate complex is formed which eventually breaks into products. The enzymes remain unchanged.
What factors change the shape of active sites?
High temperatures and High/Low pHs change the shape of the active site of enzymes, meaning the enzymes no longer works
How do high temperatures affect active sites of enzymes?
High temperatures cause enzymes to denature after reaching their optimum temperature
What do digestive enzymes do?
Digestive enzymes break down large molecules into smaller soluble ones so they can be absorbed into the blood
What does amylase break down?
Amylase breaks down starch into maltose + other sugars
Where is amylase produced?
Amylase is produced in the salivary glands, small intestines and pancreas
What does protease break down?
Protease breaks down protein into amino acids
Where is protease produced?
Protease is produced in the stomach, small intestine and pancreas
What does lipase break down?
Lipase breaks down lipids (fats) into glycerol and fatty acids
Where is lipase produced?
Lipase is produced in the small intestine and pancreas
What is the role of bile?
Bile makes conditions alkaline so enzymes in the small intestine work better + they emulsify fat so there’s a larger surface area for lipase to work on
Where is bile made and where is it stored?
Bile is made in the liver and stored in the gallbladder
What do pacemaker cells control?
Pacemaker cells in the right atrium wall control resting heart rate
What do valves do?
Valves stop blood from flowing backwards
What is the job of the coronary arteries?
The coronary arteries supply the heart muscle cells with oxygenated blood, allowing them to respire and contract
What is the function of red blood cells?
Red blood cells carry oxygen around the body
How are red blood cells adapted to their function?
Red blood cells contain haemoglobin which binds to oxygen. They also have a biconcave shape which gives them a bigger surface area so they can absorb more oxygen
What is the function of white blood cells?
White blood cells defend against infection
How are white blood cells adapted to their function?
White blood cells are adapted by containing antitoxins and antibodies, as well as having the ability to undergo phagocytosis
What is the function of platelets?
Platelets help the blood to clot at a wound
How are platelets adapted to their function?
Platelets can change shape
What is the function of plasma?
Plasma carries everything in the blood
How is plasma adapted to its function?
Plasma is made primarily of water meaning it can carry more soluble substances
What are the risk factors of non-communicable disease?
The risk factors of non-communicable disease include human cost and financial costs
Whats the name for the test for sugars? And how does it work?
The test for sugars is Benedicts test. Add benedict solution to food sample and leave for five minutes at 75 degree celsius. Positive result = blue solution will turn green