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
Whats the name for the test for starch and how does it work?
The test for starch is the iodine test. Add a few drops of iodine to sample and mix. Positive result = brown solution will turn black
Whats the name for the test for protein and how does it work?
The test for proteins is the biuret test. Add biuret solution to sample and mix. Positive result = blue solution will turn purple
Whats the name for test for lipids and how does it work?
The test for lipids is the sudan III test. Add three drops of sudan III solution to sample and mix. Positive result = mixture separates into two layers - top layer is red
What is the job of the epidermal tissue?
The epidermal tissue is covered with a waxy cuticle in the leaf to reduce water loss. Cells in the upper layer are transparent to let light through
What is the job of the palisade mesophyll?
The palisade mesophyll is where most photosynthesis happens, so there are lots of chloroplasts
What is the job of the spongy mesophyll?
The spongy mesophyll has air spaces to allow the diffusion of gases
What is the job of the meristem tissue?
The meristem tissue is found at the growing tips of shoots and roots. The cells can differentiate into many types of cell so that the plants can grow.
How is the xylem cell adapted to its function?
The xlyem cell has hollow tubes made of dead cells to allow for the flow of water and mineral ions, and also has lignin for strength
What is the job of the phloem?
The phloem allows for food substances to move from leaves to the rest of the plant
What is translocation and where does it happen?
Translocation is the movement of food through phloem tubes, and it happens in the phloem
How is rose black spot spread?
Rose black spot is spread by water and wind
What are the symptoms of rose black spots?
The symptoms of rose blackspot include spots on leaves and reduced growth
How is rose black spot prevented/treated?
Rose black spot can be treated by removing infected leaves and by using fungicides
How is malaria spread?
Malaria is spread by mosquito vectors
What are the symptoms of malaria?
The sypmtoms of malaria include fevers
How can malaria be prevented/treated?
Using mosquito nests and stopping mosquitos from breeding reduce the spread of malaria
How is salmonella spread?
Salmonella is spread by eating contaminated food
What are the symptoms of salmonella?
The symptoms of salmonella include fever, stomach cramps, vomiting, diarrhoea
How can salmonella be prevented/treated?
Salmonella can be treated/prevented with vaccination of poultry and hygienic food preparation
How is gonorrhea spread?
Gonorrhea is spread by sexual contact
What are the symptoms of gonorrhea?
The symptoms of gonorrhoea include pain when urinating, yellow discharge
How can gonorrhea be prevented/treated?
Gonorrhoea can be prevented with condoms and treated with antibiotics
How is measles spread?
Measles is spread by airboune droplets
What are the symptoms of measles?
The symptoms of measles are fevers and rashes
How can measles be prevented/treated?
Malaria can be prevented by vaccinating children
How is HIV spread?
HIV is spread by sexual contact and exchanging bodily fluids
What are the symptoms of HIV?
The symptoms of HIV include flu-like symptoms and a damaged immune system at a later stage
How can HIV be prevented/treated?
HIV can be prevented by using condoms and not sharing needles and can be treated with antiretrovirals
How is the tobacco mosaic virus spread?
Tobacco mosaic virus is spread by contact between plants
What are the symptoms of the tobacco mosaic virus?
The symptoms of the tobacco mosaic virus include mosaic patterns on leaves, reduced growth
How can the tobacco mosaic virus be prevented/treated?
Tobacco mosaic virus can be prevented by cutting infected leaves off
How does the skin protect us from disease?
The skin acts as a barrier and secretes antimicrobial substances to kill pathogens
How does the nose protect us from the disease?
The nose protects us from disease by the hair mucus trapping particles containing pathogens
How do the trachea and bronchi protect us from disease?
The trachea and bronchi protect us from disease by its mucus trapping pathogens. The cilia waft mucus up the throat so that it can be swallowed
How does the stomach protect us from disease?
The stomach protects us from disease with its hydrochloric acid which kills pathogens
What is phagocytosis?
Phagocytosis is when white blood cells engulf and digest pathogens
What is the role of antibodies?
Antibodies are specific to pathogens produced and they attack all copies of the pathogen in the body
What do white blood cells produce to counteract bacteria?
White blood cells produce antitoxins to counteract the bacteria toxins
How do vaccinations work?
In vaccinations, dead or inactive pathogens are inserted into the body, so that if live pathogens were to attack, they would be recognised and destroyed by antibodies
What is active immunity?
Active immunity is when the body produces the antibodies whereas in passive immunity the body is given the antibodies
What is the difference between active and passive immunity?
In passive immunity, the antibody production is immediate whereas active immunity is not
What are monoclonal antibodies?
Monoclonal antibodies are produced from lots of clones of a single white blood cell (B-lymphocytes)
How are monoclonal antibodies created?
- inject a mouse with the antigen of antibody we want to bind to
- mouse produces b-lymphocytes, specific to that antigen
- combine those lymphocytes with malignant cells
- which makes a hybridoma, which is cloned to make many monoclonal antibodies
Why are B-lymphocyte clones fused with tumour cells to make monoclonal antibodies?
Fusing B-lymphocytes with tumour cells make the production of monoclonal antibodies faster
What are the three uses of monoclonal antibodies?
The three uses of monoclonal antibodies include cancer treatment, locating specific molecules in research, measuring levels of substances in blood or urine eg hormones eg pregnancy tests
How are monoclonal antibodies used for cancer treatment?
Adding a toxic drug/radioactive substace/chemical to the monoclonal antibody means that when the antibody binds to the antigens of cancer cells they can be destroyed
What are the positives of monoclonal antibodies?
Monoclonal antibodies target cancer cells, whereas other treatments may kill other cells
What are the negatives of monoclonal antibodies?
Monoclonal antibodies cause more side effects than expected so they aren’t widely used
How is blood carried around the body?
Deoxygenated blood goes from the heart to the lungs via the pulmonary artery, oxygenated blood is then carried from the lungs to the heart, the heart then transports oxygenated blood into the organs via the aorta where it then goes back to deoxygenated blood via the vena cava
How does blood move through the heart?
1) . Blood enters the left and right atrium
2) . Atriums contract and blood is forced into the ventricles
3) . Ventricles contract and force blood out of the heart
4) . Valves stop blood from flowing backwards
Why does the left side of the heart have thick muscular walls?
The left side of the heart has thick muscular walls because it transport blood all around the body and therefore needs a greater force
How can we increase the reliability of an experiment? eg the rate of photosynthesis experiment
We increase reliability by repeating an experiment, collecting values and finding averages
In the photosynthesis experiment where we measure how light intensity affects the rate of photosynthesis, why is counting the number of oxygen bubbles not a valid result?
Counting the number of oxygen bubbles to find the rate of photosynthesis is an inaccurate method because not all the bubbles produced are oxygen gas bubbles
What is the job of the stomata?
The stomata is found in the lower epidermis, and makes the diffusion of gases easier by opening and closing itself. Specialised guard cells are capable of closing stomata for specific reasons eg in high temperatures to reduce water loss
Where does the arteries carry blood to and from?
Arteries carry blood from heart to organs
Where does the veins carry blood to and from?
Veins carry blood from organs to the heart
Which circuit transports blood to the lungs?
The pulmonary circuit carries blood to the lungs
How does oxygen move into the lungs?
Oxygen diffuses from the air in the alveoli into the blood and is absorbed by haemoglobin in red blood cells
What is haemoglobin?
Haemoglobin are red proteins found in red blood cells
Which circuit transports blood around the body?
The systematic circuit carries blood around the body
What are the characteristics of the arteries?
Arteries:
- Carries blood away from the heart
- Has thick muscular walls
- Contain small passageways for blood (internal lumen)
- Contains blood under high pressure
What are the characteristics of veins?
Veins:
- Carries blood to the heart
- Has thin walls
- Has large passageways for blood (internal lumen)
- Contains blood under low pressure
- Has valves
What are the characteristics of cappilaries?
Capillaries:
- Are found in muscles and lungs
- Microscopic - one cell thick
- Very low blood pressure
- Where gas exchange takes place
How does the heart respond to intensive exercise?
In response to intensive exercise, the heart contract more often to increase the heart rate and contracts more powerfully so the stroke volume increases (pumps a greater volume of blood with each beat)
What is coronary heart disease?
Coronary heart disease is the build up of fatty plaques containing cholesterol, which causes heart attacks due to the cut off blood supply preventing heart from contracting
What are potential causes of CHD?
Potential causes of CHD are :
- Poor diet (high saturated fat)
- Smoking and stress (increases blood pressure)
What happens in the first stage of the cell cycle?
In the first stage of the cell cycle, the cells are growing by increasing the amount of subcellular structures they have. DNA duplicates to form x shaped chromosomes
What happens in the second stage of the cell cycle?
In the second stage of the cell cycle, mitosis occurs. This is where chromosomes line at the centre of the cell, before being pulled apart by spindle fibres. Cell membranes form around chromosomes and the nucleus divides. Cytoplasm and cell membranes divides also, which 2 identical daughter cells are then formed
Describe the process of binary fission
Binary fission:
1) dna and plasmid replicate
2) cell gets bigger and circular dna strands move to opposite poles of the cell
3) cytoplasm divides and two daughter cells produced. contains one copy of the dna each, but can have a variable number of copies of the plasmids
bacteria can divide quickly in the right environment eg warm and nutritional. if conditions are unfavourable, they stop dividing and die
Why do multicellular organisms have exchange surfaces?
Multicellular organisms have exchange surfaces as there is a small surface area to volume ratio, meaning an exchange surface is required for efficient diffusion
How are exchange surfaces adapted for diffusion?
Adaptations of exchange surfaces:
- thin membrane = short diffusion distance
- large sa = lots of substances can diffuse at once
- lots of blood vessels in animals, so things move quickly
- gas exchange surfaces eg alveoli in animals are often ventilated for movement of air in and out
What are the negatives of using stem cells?
Stem cell transplantation can transfer viral infections, and also carry the risk of being rejected by the patient’s immune system
What are some examples of living organism tissues?
Organism tissues: epidermal (protects against water loss), epithelial (protection/secretion/absorption), muscular (contracts)
Where is amylase produced?
Amylase is produced in the pancreas and the salivary glands
Where do waste products move out of cells and into the blood?
Waste products move out of cells and into the blood in the capillaries
What are the features of platelets?
Platelets have no nucleus, triggers blood clotting and are found in blood plasma
What are statins?
Statins are drugs that decrease cholesterol levels
What are stents?
Stents are medical devices that are inserted to keep coronary arteries open. Drugs are taken alongside stents to prevent blood clotting.
What are malignant tumours?
Malignant tumours are tumours that invade neighbouring tissues, which leads to the creation of secondary tumours
What is translocation?
Translocation is the movement of food from leaves to growing regions of the plants + storage organs
What is a potometer?
Potometers measure the rate of transpiration
Where are meristems found?
Meristems are found at the tips of shoots and roots
What are the factors that increase the rate of transpiration?
Factors that increase the rate of transpiration include: increased temperature, decreased humidity and increased light intensity
Why do we feel ill when we have a virus?
Virus invades cells and damage them, causing the cells to burst and make us feel ill
What is the vector for malaria?
The vector for malaria is the female anopheles mosqutio
What are fungi?
Fungi are unicellular or multicellular organisms that are made up of hyphae. The hyphae can grow and penetrate tissues such as skin. The hyphae produces spores
What are the non-specific defences of the human body?
Non-specific defences include tears and stomach acid
Describe the process of vaccination
The process of vaccination:
1) . Person injected with dead/inactive form of the pathogen
2) . White blood cells respond to the pathogen and produce antibodies
3) . Some white blood cells remain as memory cells, and attack the pathogen if it enters the body again in the future
What does a magnesium deficiency result in in plants?
Magnesium deficiency causes chlorosis, yellow leaves, lack of glucose
What factors affect the rate of photosynthesis?
Chlorophyll concentration, light intensity and temperature affect the rate of photosynthesis
What is glucose converted into in plant and yeast cells?
Glucose is converted into ethanol and carbon dioxide in yeast and plant cells
What type of protein is required for active transport?
Active transport requires carrier proteins
What does the waxy cuticles do in plants?
Waxy cuticles prevents water from entering the plant through the leaves
What happens to enzymes at low temperatures?
Enzymes at low temperatures have less kinetic energy and become inactive
How can we produce an uncontaminated culture of bacteria?
To produce an uncontaminated culture of bacteria:
- Use an incubating loop
- Open bottles near flame
- Open the lid as little as possible
- Work quickly
What is a result of damages to the mucus lining of the stomach?
Damaging the mucus lining causes hydrochloric acid from the stomach to damage cells and tissue
What are some potential errors in the osmosis practical?
Potential errors in the osmosis practical include inaccurate balance weighing, cylinders not dried properly and different temperatures
How does water move from roots to leaves?
Water moves from roots to leaves by transpiration in the xylem
How is the alveolus adapted for diffusion?
The alveolus is adapted for diffusion as it has a large surface area to volume ratio, has thin walls for short diffusion path (one cell thick), lots of blood vessels
What do liver cells do?
Liver cells carry urea, which is filtered in the kidneys
What are adaptations of the root hair cell?
Root hair cells contain lots of villi/hair to maintain a large sa:vol ratio, has a large sa for a larger concentration gradient, so more water in soil can diffuse
What happens in the osmosis practical if there is a greater concentration?
If there is a greater concentration, mass will decrease as water draws out by osmosis (high to low conc)
What is the first line of defence?
First line of defence : stomach, nose, trachea, bronchi stomach
What is the second line of defence?
The second line of defence is the immune system ie lymphocytes (specific) and phagocytes (non-specific)
What is the process of vaccination?
Syringe injects altered form of the pathogen, wbc releases complementary antibodies to the specific antigen, they attach and clump pathogens together, phagocytosis occurs
