iGCSE Biology Paper 1

Unlock all answers in this set

Unlock answers
question
Organelles, Cells, Tissues, Organs, Systems
answer
LEVELS OF ORGANISATION
question
Nucleus,Cytoplasm,Cell membrane, Cell wall, Chloroplast, Vacuole, Mitochondria
answer
CELL STRUCTURES
question
LARGE ,molecules made up from smaller basic units
answer
STRUCTURE OF CARBOHYDRATES, PROTEINS & LIPIDS
question
From simple sugar
answer
STARCH & GLYCOGEN
question
From amino acids
answer
PROTEIN
question
From fatty acids and glycerol
answer
LIPIDS
question
Enzymes lower the activation energy of a reaction- making it faster (BIOLOGICAL CATALYST)
answer
ROLE OF ENZYMES IN METABOLIC REACTIONS
question
By changes in TEMPERATURE and changes in PH
answer
HOW FUNCTIONING ENZYMES ARE AFFECTED
question
The net overall MOVEMENT of particles of a GAS or SOLUTE from an area of HIGH CONCENTRATION to an area of lower concentration DOWN the concentration gradient
answer
DIFFUSION
question
When WATER moves across a PARTIALLY PERMEABLE MEMBRANE, from an area of HIGH CONCENTRATION to an area of lower concentration DOWN the concentration gradient
answer
OSMOSIS
question
The movement of substances AGAINST a concentration gradient/across a cell membrane, using ENERGY
answer
ACTIVE TRANSPORT
question
Can be by diffusion, osmosis and active transport
answer
MOVEMENT OF SUBSTANCES INTO AND OUT OF CELLS
question
Carbon dioxide + water > glucose + oxygen 6CO2 + 6H2O = C6H12O6 + 6O2
answer
PHOTOSYNTHESIS EQUATION
question
MAGNESIUM ions are needed for CHLRORPHYLL; NITRATE ions are needed for AMINO ACIDS
answer
MINERAL IONS FOR GROWTH
question
Respiration is a reaction that occurs in living things to create energy. It breaks down glucose to release energy
answer
RESPIRATION PURPOSE
question
The process by which FOOD molecules are BROKEN DOWN using OXYGEN to release ENERGY for the cells
answer
AEROBIC RESPIRATION
question
Cellular respiration in the ABSENCE of OXYGEN
answer
ANAEROBIC RESPIRATION
question
Glucose + Oxygen > Carbon dioxide + Water + Energy C6H12O6 + 6O2 → 6CO2 + 6H2O (+ energy)
answer
AEROBIC RESPIRATION EQUATION
question
PLANTS: Glucose > Lactic acid + Energy ANIMALS: Glucose > ethanol + carbon dioxide + energy
answer
ANAEROBIC RESPIRATION EQUATION
question
In the circulatory system oxygen enters the blood and carbon dioxide leaves the blood via gaseous exchange. Gasses move across the walls of alveoli to an area of lower density than they are in: Oxygen moves into the blood as there is a low density of oxygen in the blood; Carbon dioxide moves into the lungs as it is an area of lower density.
answer
ROLE OF DIFFUSION IN GAS EXCHANHANGE
question
In photosynthesis: 6CO2 + 12H2O > C6H12O6 + 6O2 + 6H2O So the plant takes up carbon dioxide and gives out oxygen In respiration: C6H12O6 + 6H2O > 6CO2 + 6H2O So the plant gives out carbon dioxide
answer
GAS EXCHANGE IN RELATION TO RESPIRATION AND PHOTOSYNTHESIS
question
Guard cells regulate the opening and closing of the stomata; allowing carbon dioxide and oxygen to be exchanged between the leaf and the atmosphere. The stomata is open during the day. At night, the stomata is closed
answer
ROLE OF STOMATA IN GAS EXCHANGE
question
Leaves are thin which allows gasses to diffuse quickly through them. In addition the stomata at the bottom of the leaf allow the diffusion of gasses in to the leaf- when a guard cell is shrunk gasses can enter the leaf
answer
ADAPTATION OF LEAF STRUCTURE
question
The intercostal muscles and diaphragm control ventilation in the lungs. When they contract the create more space in the lungs: drawing air in. When the relax the constrict the rings: pushing air out of the lungs
answer
ROLE OF INTERCOSTAL MUSCLES AND DIAPHRAGM IN VENTILATION
question
The alveoli have are thin, this allows gasses to diffuse through them easily. They are small and there are many of them meaning there is a large surface area through which much gas can diffuse at once. It also means there is a lot of surface in contact with the blood stream for gasses to diffuse into. Alveoli have a moist lining for gasses to dissolve into
answer
ADAPTATION OF ALVEOLI FOR GAS EXCHANGE
question
Tar can cause cancerous mutations in the lungs. Smoke removes the cilia- tiny hairs- which keep the lungs clean. Smoking also hardens the arteries, constricting the blood flow and putting strain on the heart, resulting in coronary heart disease.
answer
BIOLOGICAL CONSEQUENCES OF SMOKING
question
Unicellular organisms- including fungi and bacteria- have a large surface area to volume ratio and they are small and so the diffusion distance is short, meaning diffusion happens very quickly
answer
UNICELLULAR- NO NEED FOR TRANSPORT SYSTEM
question
Multicellular organisms have a small surface area to volume ratio and the distance for diffusion would be very large and so very slow. This wouldn't support the organism; so they have developed transport systems, like the ventilation system and the circulatory system which speed up diffusion enough to support themselves
answer
MULTICELLULAR SYSTEM- NEED FOR TRANSPORT SYSTEM
question
Transport nitrates, phosphates, water and other mineral salts from the roots to other parts of the plants, like the leafs, flowers and buds. Xylem consists of columns of hollow, dead cells. Substances are carried up the tube dissolved in water
answer
ROLE OF XYLEM
question
Roots branch to increase the surface area and to increase the chances of finding a water source. Root hairs are epidermal cells on the surface of the root: they also increase the surface area for absorption. They absorb minerals by active transport and water by osmosis. These substances then move to the xylem
answer
HOW WATER IS ABSORBED BY ROOT HAIR CELLS
question
The EVAPORATION if water from the surface of a plant
answer
TRANSPIRATION
question
Red blood cells / White blood cells / Platelets / Plasma
answer
COMPOSITION OF BLOOD
question
Contains WATER, UREA and SALTS
answer
URINE
question
Water is reabsorbed into the blood from the COLLECTING DUCT
answer
RE-ABSORPTION OF WATER
question
Occurs at the PROXIMAL convoulted tubule
answer
SELECTIVE RE-ABSORPTION OF GLUCOSE
question
Blood arrives in Bowman's casual under the high pressure of an artery, it travels it to the glomerulus where the pressure is further increased (as the tubes are smaller). Components of the blood are forced out of the blood vessel into the glomerulus due to the high pressure, creating glomerulas filtrate (water, slats ect.)
answer
ULTRAFILTRATION IN THE BOWMANS CAPSULE
question
Bowman's capsule, Glomerelus, Tubules, Loop od henley, Collecting duct
answer
STRUCTURE OF NEPHRON
question
Kidneys, ureters, bladder, urethra
answer
STRUCTURE OF URINARY SYSTEM
question
Sensitivity is one of the life processes (mrs gren); it is responding to the environment around. Living things must have receptors to be able to detect the change and effectors to be able to carry out a response
answer
ORGANISM RESPONSE
question
The maintenance of a constant internal environment and that body water content and body temperature are both examples of homeostasis
answer
HOMEOSTASIS
question
Requires a STIMULUS, a RECEPTOR and an EFFECTOR
answer
COORDINATED RESPONSE
question
Respond to STIMULI
answer
PLANTS
question
Geo-tropism is when a plant grows in response to gravity. Roots always carry out posotive geo-tropism, towards gravity/ down.Shoots always carry out negative geo-tropism, away from gravity/ up.
answer
DESCRIPTION OF GEOTROPIC RESPONSE
question
Stems experience positive photo-tropism, this means they always grow towards light. In a place where light shines there will be fewer auxins (growth hormones) this encourages the stem to bend towards the source of light.
answer
DESCRIPTION OF POSITIVE PHOTOTROPISM
question
consists of the BRAIN and SPINAL CHORD and is LINKED to SENSE ORGANS by NERVES
answer
CENTRAL NERVOUS SYSTEM
question
The SIMULATION of RECEPTORS in SENSE ORGANS sends ELECTRICAL IMPULSES along NERVES into and out of the CNS, resulting in RAPID RESPONSES
answer
HUMAN RESPONSE
question
source: PITUITARY GLAND roles: Controls WATER CONTENT of BLOOD effects: The KIDNEYS
answer
ADH
question
source: ADRENAL GLANDS roles: PREPARES body for STRESSFUL or PHYSICALLY ACTIVE situations effects: 'FIGHT OR FLIGHT'
answer
ADRENALINE
question
source: PANCREAS roles: lower and raise BLOOD GLUCOSE LEVELS
answer
INSULIN
question
source: TESTES roles: controls development of male secondary SEXUAL CHARACTERISTICS effects: SPERM PRODUCTION
answer
TESTOSTERONE
question
source: OVARIES roles: REGULATES MENSTRUAL CYCLE
answer
PROGESTERONE
question
source: OVARIES roles: controls development of female secondary SEXUAL CHARACTERISTICS
answer
OESTROGEN
question
Reproduction which involves the JOINING of TWO special HAPLOID SEX CELLS/ GAMETES to produce DIPLOID OFFSPRING which are genetically different from their parents
answer
SEXUAL REPRODUCTION
question
Reproduction which involves only ONE PARENT and produces IDENTICAL OFFSPRING to the parents
answer
ASEXUAL REPRODUCTION
question
Involves the FUSION of a male and female GAMETE to produce a ZYGOTE that undergoes CELL DIVISION and develops into an EMBRYO
answer
FERTILISATION
question
is lead to by the growth of the POLLEN TUBE followed by FERTILISATION
answer
SEED AND FRUIT FORMATION
question
Can be by NATURAL METHODS and by ARTIFICIAL METHODS
answer
ASEXUAL REPRODUCTION IN PLANTS
question
Develops BREASTS, BODY HAIR and the MENSTRUAL CYCLE begins
answer
ROLE OF OESTROGEN IN SECONDARY SEXUAL CHARACTERISTIC DEVELOPMENT
question
The GROWTH of the PENIS, TESTES, FACIAL & BODY HAIR, MUSCLE DEVELOPMENT AND VOICE BREAKING
answer
ROLE OF TESTOSTERONE IN SECONDARY SEXUAL CHARACTERISTIC DEVELOPMENT
question
Contains CHROMOSOMES on which GENES are located
answer
NUCLEUS
question
Is a section of a molecule of DNA and a gene CODES FOR A SPECIFIC PROTEIN
answer
GENE
question
ADENINE & THYMINE, CYTOSINE & GUANINE
answer
DNA BASES
question
Are GENES existing in ALTERNATIVE FORMS, which gives rise to DIFFERENCES IN INHERITED CHARACTERISTICS
answer
ALLELES
question
The sex of a person is controlled by ONE PAIR of CHROMOSOMES
answer
SEX DETERMINATION
question
XX
answer
FEMALE CHROMOSOMES
question
XY
answer
MALE CHROMOSOMES
question
Produces TWO CELLS which contain IDENTICAL sets of CHROMOSOMES
answer
DIPLOID CELL DIVISION BY MITOSIS
question
Occurs during GROWTH, REPAIR, CLONING and ASEXUAL REPRODUCTION
answer
MITOSIS
question
Produces FOUR CELLS, EACH WITH HALF the number of CHROMOSOMES. This results in the formation of GENETICALLY DIFFERENT HAPLOID GAMETES
answer
CELL DIVISION BY MEIOSIS
question
Produces GENETIC VARIATION of offspring
answer
RANDOM FERTILISATION
question
HAPLOID= 23 DIPLOID=46
answer
HUMAN CELLS (CHROMOSOME NUMBER)
question
Can be GENETIC, ENVIRONMENTAL, or a COMBINATION of both
answer
VARIATION IN A SPECIES
question
Is a RARE, RANDOM change in GENETIC MATERIAL that can be INHERITED
answer
MUTATION
question
Organisms produce more offspring than the environment can support. Only those BEST ADAPTED to their environment will SURVIVE to breed and PASS ON THEIR CHARACTERISTICS
answer
PROCESS OF EVOLUTION BY MEANS OF NATURAL SELECTION
question
MANY are HARMFUL, but SOME are NEUTRAL and FEW are BENEFICIAL
answer
MUTATION EFFECTS
question
Can INCREASE in BACTERIAL POPULATIONS and an increase can lead to INFECTIONS being DIFFICULT TO CONTROL
answer
RESISTANCE TO ANTIBIOTICS
question
A group of individuals of the SAME SPECIES living in the SAME HABITAT and BREEDING TOGETHER
answer
POPULATION
question
ALL OF THE POPULATIONS of LIVING ORGANISMS living in an ecosystem at a PARTICULAR TIME
answer
COMMUNITY
question
The place where an animal or plant lives, including both the LIVING AND NON-LIVING aspects of the area
answer
HABITAT
question
ALL of the ANIMALS and PLANTS in an area, along with things that affect them, such as the SOIL and WEATHER. Includes all INTERACTIONS between all DIFFERENT LIVING ORGANISMS and the NON-LIVING COMPONENTS of their home
answer
ECOSYSTEM
question
A sample square is taken at random. The number of a population in that square is taken. This is repeated in different areas and compared to show where populations are dense and not.
answer
QUADRATS TO ESTIMATE POPULATION SIZE
question
A square of around a meter takes a sample from a area and the populations are counted. This can be repeated many times before being multiplied out as if it were the complete area of the land. Two different samples can be put in two separate areas and the sampling done for both will estimate population for both areas.
answer
QUADRATS TO ESTIMATE POPULATION SIZE IN 2 DIFFERENT AREAS
question
PRODUCER, PRIMARY CONSUMER, SECONDARY CONSUMER, TERTIARY CONSUMER, DECOMPOSER
answer
TROPHIC LEVELS
question
Respiration is carried out by animals and plants to release energy from glucose, the equation is: C6H12O6 + 6O2 → 6CO2 + 6H2O . This means carbon is produced. Photosynthesis is what plants do to create glucose the equation is: 6 CO2 + 12 H2O → C6H12O6 + 6 O2 + 6 H2O. This means carbon is used. Decomposition is happens when an animal dies, it is then eaten by a decomposer which releases the carbon in it back into the atmosphere. Combustion is burning, if something with carbon is burnt it will release it into the atmosphere, e.g. a tree, fossil fuel.
answer
STAGES IN CARBON CYCLE
question
WATER VAPOUR, CARBON DIOXIDE, NITROUS OXIDE, METHANE, CFCs
answer
GREENHOUSE GASES
question
Result in an ENHANCED GREENHOUSE EFFECT and this may lead to GLOBAL WARMING and it's consequences
answer
INCREASE IN GREENHOUSE GASES
question
Can result from leached MINERALS FROM FERTILISER
answer
EUTROPHICATION
question
Can be used to develop ANIMALS and plants with DESIRED CHARACTERISTICS
answer
SELECTIVE BREEDING
question
Can be manufactured from genetically modified bacteria that are grown in a fermenter
answer
HUMAN INSULIN
question
When a virus or plasmid is inside a host cell it may pick up DNA, it may then carry this into another host cell. The foreign DNA is known as recombinant DNA
answer
PLASMIDS AND VIRUSES ACTING AS VECTORS
question
Plant clippings are taken and placed in a sterile growth medium. Roots will develop from the clipping (and shoots) making a whole new plant. The plant will then be transferred into compost and grown as a normal plant. The plant is a clone of the one is was taken from because it has the same DNA. This means that there will be no variation, so you can have the same plant every time.
answer
MICROPROPAGATION
question
In micropropagation, plant clippings are taken and put in a growth medium. They will develop into a new plant with the same DNA. This means that every plant made from the clippings of one plant will be clones with exactly the same characteristics. If many clippings are taken then you will have many clones
answer
HOW MICROPROPAGATION IS USED TO PRODUCE COMMERCIAL QUANTITIES OF CLONE PLANTS
question
A egg cell with the nucleus removed has the DNA of another cell put in (this will be have a complete set of chromosomes (diploid number of)). The embryo that forms will then have DNA from only one parent: the one the DNA was taken from. This means it will be a clone! for example dolly the sheep.
answer
STAGES IN PRODUCING CLONED MAMMALS
question
Contains all GENETIC INFORMATION and CONTROLS actions of the cell
answer
NUCLEUS STRUCTURE
question
Where the reaction in cells takes place
answer
CYTOPLASM
question
CONTROLS movement of CHEMICALS in and out of the cell
answer
CELL MEMBRANE
question
STRENGTHENS the cell (Made from CELLULOSE)
answer
CELL WALL
question
Used in PHOTOSYNTHESIS (Contain CHLOROPHYLL)
answer
CHLOROPLAST
question
Keeps the cell TURGID
answer
VACUOLE
question
A nucleus is in the centre of the cell; it is surrounded by cytoplasm; around the outside edge is the cell membrane
answer
ANIMAL CELL STRUCTURE
question
A vacuole in the centre is surrounded by cytoplasm; with in this is the nucleus and chloroplasts; surrounding this is the cell membrane; and around that is the cell wall
answer
PLANT CELL STRUCTURE
question
CARBON, HYDROGEN, OXYGEN
answer
CARBOHYDRATE AND LIPID COMPOSITION
question
CARBON, HYDROGEN, OXYGEN, SULFUR, PHOSPHORUS, NITROGEN
answer
PROTEIN COMPOSITION
question
Heat object with Benedict's Reagent. if it turns from blue to orange then glucose is present.
answer
TEST FOR GLUCOSE
question
Apply iodine to the object you are testing, if it turns from red to blue/black then there is starch.
answer
TEST FOR STARCH
question
Put starch into a test tube; either heat or cool it. Add amylase With this mixture on white tiles, add iodine Time how long it takes for the iodine to stop being blue black Repeat at different temperatures and compare When the iodine stops being blue/black there is no starch present, so it must have been digested by the enzymes
answer
ENZYME ACTIVITY EFFECTED BY TEMPERATURE (TEST)
question
with a larger surface area- molecules have more surfaces through which to diffuse, this increases the rate of moment
answer
HOW SURFACE AREA AFFECTS THE RATE OF MOVEMENT OF SUBSTANCES INTO AND OUT OF CELLS
question
Increased temperature means increased kinetic energy- this will mean molecules collide with the cell wall more often making movement through it more likely
answer
HOW TEMPERATURE AFFECTS THE RATE OF MOVEMENT OF SUBSTANCES INTO AND OUT OF CELLS
question
This is the difference between the concentration inside and outside of the cell. The bigger the difference is the more opportunity molecules have of diffusing.
answer
HOW CONCENTRATION GRADIENT AFFECTS THE RATE OF MOVEMENT OF SUBSTANCES INTO AND OUT OF CELLS
question
Put a coloured substance (like food colouring) into a clear one (like water) Time how long it takes for all the liquid to be the same colour. Change the temperature of the liquid and make observations. The higher the heat, the more kinetic energy meaning the colour moves through the liquid faster
answer
EXPERIMENT TO INVESTIGATE DIFFUSION
question
Cut two roughly equal pieces of potato and weigh them. Put one in distilled water and one in salt water. After a given amount of time weigh them. The one in salt water will have lost mass as the water in the potato moves to the less highly concentrated salt water. Where as in the pure water the potato will have gained mass as it was less dens with water.
answer
EXPERIMENT TO INVESTIGATE OSMOSIS
question
Photosynthesis is the process in which energy- from the sunlight- is used to create glucose. Light energy is absorbed by chlorophyll in plants leaves. It is then used to convert carbon dioxide (from the air) and water (from the ground) into glucose; which is used for respiration. Oxygen is a by-product of this process. This is using light energy, from the sun, to create chemical energy (glucose); which conserves the energy from the sun. This energy is then passed through the food chain, which is why plants are called the producer (producing the chemical energy in the chain from the sun light.)
answer
PHOTOSYNTHESIS & IMPORTANCE OF ENERGY CONSERVATION
question
If there is insufficient carbon dioxide a plant will not be able to photosynthesis to its full potential. Because there is less carbon dioxide- less reactant- there has to be less product being made.
answer
HOW CARBON DIOXIDE CONCENTRATION AFFECTS RATE OF PHOTOSYNTHESIS
question
If the light is at a low intensity the rate of photosynthesis is lowered because the energy that the light provides is less, so the reaction is slowed down. A higher light intensity will enable photosynthesis to happen faster.
answer
HOW LIGHT INTENSITY AFFECTS RATE OF PHOTOSYNTHESIS
question
In colder temperatures the rate of photosynthesis will decrease. If the temperature is too high however, the plant will not be able to photosynthesise
answer
HOW TEMPERATURE AFFECTS RATE OF PHOTOSYNTHESIS
question
In terms of the basic features leaves have a large surface area; this allows them to absorb more sunlight. They are also thin, meaning that carbon dioxide has a shorter way to travel. In addition the stomata allow the entrance of carbon dioxide.
answer
LEAF ADAPTATIONS FOR PHOTOSYNTHESIS
question
he most common experiment for this is using pond weed, which is placed under water then factors are varied: A lamp is moved further from the plant; Baking powder is added to the water (increasing CO2); A white leaved plant is tested against a green leaved plant (green has more chlorophyll). The gas it gives off- being the products of photosynthesis- is counted as bubbles or measured by downwards displacement. This shows the speed of photosynthesis under different conditions. Iodine can be used to test the production of starch.
answer
EXPERIMENT TO INVESTIGATE PHOTSYNTHESIS
question
IMMEDIATE ENERGY bananas, brown rice, wholemeal foods and potatoes.
answer
CARBOHYDRATE FUNCTION
question
GROWTH & REPAIR sea food, eggs, pork and soy
answer
PROTEIN FUNCTION
question
LONG TERM ENERGY STORE, INSULATION & PROTECTION fish, eggs, milk and beef.
answer
LIPID FUNCTION
question
MAINTAINING NORMAL REPRODUCTION, GOOD VISION, FORMATION AND MAINTENANCE OF HEALTHY SKIN, TEETH AND SOFT TISSUES & IMMUNE FUNCTION Milk, cheese, eggs, fatty fish, yellow-orange vegetables and fruits such as carrots, pumpkin, mango, apricots, and other vegetables such as spinach, broccoli.
answer
VITAMIN A FUNCTION
question
AIDING ABSORPTION OF IRON AND COPPER, HEALTHY BONES & HELPS TO FIGHT INFECTION Blackcurrants, orange, grapefruit, guava, kiwi fruit, raspberries, sweet peppers (Capsicum), broccoli, sprouts
answer
VITAMIN C FUNCTION
question
IMMUNE FUNCTION, HEALTHY SKIN & MUSCLE STRENGTH Sunlight on skin allows the body to produce Vitamin D. Few foods contain significant amounts however main dietary sources are fortified margarine, salmon, herring, mackerel, and eggs.
answer
VITAMIN D FUNCTION
question
DEVELOPMENT AND MAINTENANCE OF BONES AND TEETH, GOOD FUNCTIONING MUSCLES AND NERVES & HEART FUNCTION Milk, cheese, yoghurt, bony fish, legumes, fortified soy beverages and fortified breakfast cereals.
answer
CALCIUM FUNCTION
question
HAEMOGLOBIN IN RED BLOOD CELLS, COMPONENT OF MYGLOBIN Red meats - beef, lamb, veal, pork, fish, chicken and wholegrain cereals
answer
IRON FUNCTION
question
CHEMICAL REACTIONS IN CELLS NEED WATER & FOR RESPIRATION
answer
WATER FUNCTION
question
KEEPS BOWELS FUNCTIONING WELL Cereals, bread, rice, beans and nuts.
answer
DIETARY FIBRE FUNCTION
question
Mechanical digestion happens here- your jaw action. A bolus is created; this is a ball of food covered in saliva. This is help full as the food is lubricated to enable swallowing and enzymes in the saliva can begin to break down the food. (amylase)
answer
THE MOUTH (HUMAN ALIMENTARY CANAL)
question
this tube connects you mouth and stomach. It is next to the trachea which is covered by the epiglottis when you swallow so the food only enters the oesophagus. Peristalsis- or muscular contractions- moves the food downward.
answer
THE OESOPHAGUS (HUMAN ALIMENTARY CANAL)
question
Churning mechanically digests whilst enzymes do so chemically. Chyme is the name for liquid food existing in the stomach.
answer
THE STOMACH (HUMAN ALIMENTARY CANAL)
question
This absorbs digested molecules into the blood stream. Villi cover the inside giving it a large surface area which many molecules can diffuse through into the blood.
answer
THE SMALL INTESTINE (HUMAN ALIMENTARY CANAL)
question
This absorbs water from undigested food, producing faeces.
answer
THE LARGE INTESTINE (HUMAN ALIMENTARY CANAL)
question
This produces the enzymes lipase, amylase and protease.
answer
THE PANCREAS (HUMAN ALIMENTARY CANAL)
question
MOUTH> OESOPHAGUS>STOMACH>SMALL INTESTINE>LARGE INTESTINE>PANCREAS
answer
HUMAN ALIMENTARY CANAL STRUCTURE
question
The process in which large insoluble molecules of food are broken down into smaller ones.
answer
DIGESTION
question
the process by which soluble molecules produced by digestion are taken from the gut (occurs mostly in the small intestine.) The soluble products of digestion are then transported to the various tissues by the circulatory system.
answer
ABSORPTION
question
the cells of the tissues absorb the molecules for use.
answer
ASSIMILATION
question
removal of waste- undigested- products as faeces.
answer
EGESTION
question
removal of waste products that have been in the body.
answer
EXCRETION
question
Food is moved through the gut by peristalsis. Muscles move food because mechanical action is needed to get food through the system.
answer
HOW AND WHY FOOD IS MOVED THROUGH THE GUT
question
Enzymes break down food into useful things that our boddies need. Different enzymes break down different components of our food.
answer
ROLE OF ENZYMES
question
AMYLASE & MALTASE
answer
CONVERSION OF STARCH TO GLUCOSE
question
PROTEASE
answer
CONVERSION OF PROTEINS TO AMINO ACIDS
question
LIPASE
answer
CONVERSION OF LIPIDS TO FATTY ACIDS AND GLYCEROL
question
PRODUCED IN THE LIVER & STORED IN THE GALL BLADDER
answer
BILE
question
Enzymes in the small intestine work best in alkaline conditions but the food is acidic after being in the stomach. Bile is alkaline and so when it is released into the small intestine it enables the enzymes to work.
answer
NEUTRALISING STOMACH ACIDS
question
Bile also emulsifies fat; this gives it a larger surface area, which means that it is easier for lipase to work.
answer
EMULSIFYING LIPIDS
question
in the small intestine. The are like lumps on this inside of the small intestine. They are the surface through which food diffuses into the blood stream. They have very thin walls, only one cell thick, this enables molecules to pass through easily. They also increase the surface area of the small intestine wall On the outside of villi there are capillaries which pick up the diffused food into the blood stream.
answer
VILLI
question
When the heart and lungs cannot work fast enough to provide to oxygen needed for aerobic respiration: for example when exercising The energy released is less in anaerobic respiration because the glucose cannot be fully broken down.
answer
WHEN ANAEROBIC RESPIRATION IS USED
question
During exercise cells respire more quickly (to provide more energy for movement) this means oxygen has to be delivered more quickly and carbon dioxide taken away more quickly. As a result of this the lung muscles contract and relax more rapidly and the heart beats faster. Measure a persons breaths per 10 seconds when stationary. Then after one minute after running at 5mph then at two minutes and so on. You will find a linear relationship as described above between the two.
answer
EXPERIMENT TO INVESTIGATE THE EFFECT OF EXERCISE ON BREATHING IN HUMANS
question
In the circulatory system oxygen enters the blood and carbon dioxide leaves the blood via gaseous exchange. Gasses move across the walls of alveoli to an area of lower density than they are in: Oxygen moves into the blood as there is a low density of oxygen in the blood; Carbon dioxide moves into the lungs as it is an area of lower density
answer
ROLE OF DIFFUSION IN GAS EXCHANGE
question
In photosynthesis: 6CO2 + 12H2O > C6H12O6 + 6O2 + 6H2O So the plant takes up carbon dioxide and gives out oxygen In respiration: C6H12O6 + 6H2O > 6CO2 + 6H2O So the plant gives out carbon dioxide
answer
GAS EXCHANGE IN RELATION TO RESPIRATION & PHOTOSYNTHESIS
question
The intercostal muscles contract The ribs move up and out The diaphragm contracts and moves down The trachea carries air towards the lungs; it splits into two bronchi- one leading to the left lung, and one o the right- which then split into even smaller tubes, called bronchiles; these end in alveoli where gas exchange takes place. The pleural membranes prevent friction
answer
BREATHING IN
question
The intercostal muscles relax The ribs drop down The diaphragm also relaxes and moves upward These things reduce the space inside the lungs, pushing the air out.
answer
BREATHING OUT
question
Increased humidity decreases transpiration. This is because high water content outside the leaf will mean there is little difference in concentration, so the water will not be able to move- as it naturally does- from an area of low concentration to an area of high concentration.
answer
EFFECT OF HUMIDITY ON RATE OF TRANSPIRATION
question
Increased wind speed will increase transpiration. Because if the wind blows away the water vapour being produced their will be a greater difference in water concentration, meaning water will be able to continue leaving the leaf.
answer
EFFECT OF WIND SPEED ON RATE OF TRANSPIRATION
question
Increased temperature increases transpiration, as increased heat makes evaporating easier.
answer
EFFECT OF TEMPERATURE ON RATE OF TRANSPIRATION
question
Increased light intensity increases transpiration, as more heat is absorbed by the leaf meaning more water will be evaporated, also there is more photosynthesis meaning more water is being transported through the leaf (so more will need to leave the leaf.)
answer
EFFECT OF LIGHT INTENSITY ON RATE OF TRANSPIRATION
question
Support a plant in a tray filled with a given amount of water. Place in different conditions and record the time taken for all the water in the way to be taken up by the plant.
answer
EXPERIMENT TO INVESTIGATE THE ROLE OF ENVIRONMENTAL FACTORS IN DETERMINING THE RATE OF TRANSPIRATION
question
Is a solvent and a liquid; so plasma carries these different things around the body disolved in water: Carbon- Hydrogen carbonate Digested food- soluble sugars and amino acids Urea Hormones. Water also carries heat, which is important in the regulation of body temperature.
answer
ROLE OF PLASMA IN TRANSPORT OF WATER
question
They have haemoglobin- which is made from iron- that can bond to oxygen. They have no nucleus to make more room for haemoglobin.There are no mitochondria as the cells respire anaerobically. The biconcave shape enables them to pass through narrow capillaries and increase the surface area and decrease the distance for diffusion meaning that diffusion of oxygen happens quickly.
answer
ADAPTATIONS OF RED BLOOD CELLS
question
They can detect the presence of pathogens because of chemicals they give off. The cell then engulfs the pathogen. If then destroys the cell with digestive enzymes.
answer
PHAGOCYTES (SPECIALISED WHITE BLOOD CELL)
question
They release anti-bodies that are specific to the pathogen. When a lymphocyte meets its specific pathogen it divides: one cells it creates being a memory cell; the other being the cell which will create anti-bodies. One type of anti-body will attach to the pathogen to attract phagocytes. The other type will disable the cell. A third type will group the pathogens together so that phagocytes can engulf them all. If the memory cells every meet the pathogen again they will create the anti-bodies very quickly.
answer
LYMPHOCYTES (SPECIALISED WHITE BLOOD CELL)
question
During exercise muscles require more energy which is created by respiration, that requires more oxygen to be brought to cells and more carbon dioxide to be taken away, this means the heart needs to increase its speed so that more blood is sent to muscles.
answer
HOW HEART RANGE CHANGES DURING EXERCISE
question
Adrenaline is produced in the adrenal glands in top of the kidneys- stimulates adrenegic receptors in the heart which increase the rate that your heart cells work at.
answer
HEART RANGE CHANGES UNDER THE INFLUENCE OF ADRENALINE
question
he right atrium fills with blood (from the vena cava) and the valve is closed; This area is squeezed forcing the blood through an atrio-ventricular valve into the right ventricle; This area contracts forcing the blood through the pulmonary artery where it is oxygenated at the lungs; the pulmonary vein fills the left atrium with blood; This contracts forcing the blood into the left ventricle; when the left ventricle contracts the blood is forced out through the aorta.
answer
FUNCTION OF THE HEART
question
Take blood away from the heart Blood in them is under high pressure They are delivering blood to an organ Thick, muscle wall; small lumen (to give high blood pressure)
answer
ARTERIES
question
Take blood to the heart Blood is under low pressure Their blood is returning from an organ Relatively thin wall; large lumen (to give ow blood pressure) Valves stop blood flowing back in the wrong direction
answer
VEINS
question
Exchange is taken place Very thin cell walls (one cell thick) so that substances can diffuse easily
answer
CAPPILARIES
question
TO the heart
answer
VEIN
question
AWAY from the heart
answer
ARTERY
question
PULMONARY
answer
LUNG
question
HEPATIC
answer
LIVER
question
RENAL
answer
KIDNEY
question
GASTRIC
answer
STOMACH
question
BETWEEN GUT AND LIVER
answer
HEPATIC PORTAL VEIN
question
RESPIRATION-carbon dioxide is a waste product and is excreted from the leaf through the stomata. PHOTOSYNTHESIS-the glucose is used for energy and oxygen is a waste product, it leaves the leaf through the stomata.
answer
ORIGIN OF CARBON DIOXIDE & OXYGEN AS A WASTE PRODUCT OF OXYGEN AND LOSS THROUGH THE STOMATA OF A LEAF
question
LUNGS, KIDNEYS and SKIN
answer
ORGANS OF EXCRETION
question
amino acids contain nitrogen- which is toxic to the body- the liver converts it into urea. The kidneys filter urea from the blood stream and combine it with water to create urine which then moves into the bladder.
answer
HOW KIDNEYS CARY OUT EXCRETION
question
The kidneys react to ADH hormone released by the pituitary gland. If there is too little water ADH will be released and the kidneys won't absorb any water, but if there is too much water then less ADH is released and the kidneys absorb water from the blood stream.
answer
HOW KIDNEYS CARRY OUT OSMOREGULATION
question
Excess or lack of water is detected by the hypothalamus in the brain, it causes the pituitary gland to produce Anti-diuretic hormone, or ADH. This hormone then travels through the blood stream to the kidneys, when it reaches them the kidneys lower the amount of water that is excreted by the body, and increase the amount of water that is reabsorbed into the blood stream. The urine is then more concentrated with a lower volume. If there is too much water the levels of ADH are lowered and the opposite effects happen, resulting with a more dilute urine and less water in the blood.
answer
ROLE OF ADH IN REGULATING WATER CONTENT OF BLOOD
question
The nervous system and hormones both coordinate responses with in the body. The nervous does this by electrical impulses so it is very fast.
answer
RESPONSES CONTROLLED BY NERVOUS COMMUNICATION
question
Hormones do this with chemicals which travel, a little slower, at the speed of the blood stream they are travelling in.
answer
RESPONSES CONTROLLED BY HORMONAL COMMUNICATION
question
A reflex is an automatic reaction, for example removing your hand from extreme heat. A reflex arch is the path of the reaction. It starts at a sense organ e.g a finger; receptors pick up stimuli e.g heat; Sensory neurones carry an electrical impulse to the CNS; A relay neuron carries the impulse through the CNS where a response is decided; The new impulse is sent through a motor neurone; This makes an effector carry out a response e.g muscle contracts to bring finger away from heat
answer
REFLEX ARC (WITHDRAWAL OF FINGER)
question
The eye is a receptor of light, it has light receptor cells in its retina. These cells turn stimuli into electrical impulses.
answer
STRUCTURE & FUNCTION OF AN EYE AS A RECEPTOR
question
stamens: INSIDE petals stigma: STICKY, INSIDE petals petals: LARGE & BRIGHT nectaries: PRESENT pollen grains: LARGE & STICKY
answer
INSECT POLLINATED FLOWER
question
stamens: OUTSIDE petals stigma:FEATHERY & STICKY, OUTSIDE petals petals: SMALL & USUALLY GREEN nectaries: ABSENT pollen grains: SMALL, SMOOTH & LIGHT
answer
WIND POLLINATED FLOWER
question
Testis- produce sperm cells, they are stored in the epididymus Vas deference- carries sperm to the penis The prostate- adds fluid to the sperm, creating semen (as does the seminal vesicles) The urethra- carries sperm to the end of, and out of the penis.
answer
MALE REPRODUCTIVE SYSTEM
question
Ovaries- produce eggs Oviducts- carry the eggs to the uterus, is the site of fertilisation Uterus- develops the fertilised egg on the placenta Cervix- entrance to uterus
answer
FEMALE REPRODUCTIVE SYSTEM
question
produced in the ovaries; thickens the womb lining; prompts the release of LH.
answer
OESTROGEN IN THE MENSTRUAL CYCLE
question
produced in the corpus lutiem; maintains the lining of the womb
answer
PROGESTERONE IN THE MENSTRUAL CYCLE
question
Monohybrid inheritance is the inheritance of one gene.
answer
MONOHYBRID INHERITANCE
question
A pedigree diagram shows a specific gene in a family. It will have a key but most often: a circle represents a female and a square represents a male; often coloured in represents one allele and blank another (but sometimes they are different colours.)
answer
INTERPRETATION OF FAMILY PEDIGREES
question
To work out the probability of a child inheriting a genotype, you see how many times it comes up and divide it by 4 then times by 100 for a percent
answer
PREDICTING GENOTYPE PROBABILITIES
question
Genetic diagrams work the same as mono-hybrid inheritance diagrams: showing the mothers and fathers and then the different out comes. The only difference is, they will always be the same because one parent is always male and one parent is always female (XY, XX)
answer
HOW TO DETERMINE SEX
question
shows the transfer of energy up the food chain beginning with the producers then the primary consumers and so forth.
answer
FOOD CHAIN
question
links several animals within a habitat showing what consumes what and is consumed by what.
answer
FOOD WEB
question
progresses through the trophic levels of a food chain representing the number of each species by the area of the pyramid block
answer
PYRAMID OF NUMBERS
question
represents the mass of each consumer (and producer) by the area of a pyramid block.
answer
PYRAMID OF BIOMASS
question
shows the transfer of energy through the food chain.
answer
PYRAMID OF ENERGY
question
As one thing consumes another the energy and other things inside it- for example fat and vitamins- get transferred to the consumer. If you eat a fatty piece of beef you get the fat from the cow.
answer
TRANSFER OF SUBSTANCES AND ENERGY ALONG THE FOOD CHAIN
question
The reason why not all of the energy will make it to the next tropic level is that some of it will be used up on the level it is at. The energy is used for the life processes of the animal that it is in.
answer
WHY ONLY 10% OF ENERGY IS PASSED FROM ONE TROPHIC LEVEL TO THE NEXT
question
Sulfur dioxide and carbon monoxide are created by many processes we use in factories and homes. When in the atmosphere they can dissolve in rain water to create rain the is acidic. Acid rain corrodes metals and rocks like limestone which can damage buildings and statues. Acid rain can also change the PH in soil or rivers, this can mean that some species can not survive in that area.
answer
BIOLOGICAL CONSEQUENCES OF SULFUR DIOXIDE & CARBON MONOXIDE POLLUTED AIR
question
Many of the processes that we carry out in homes and factories produce or release gasses with the greenhouse effect. Many things release greenhouse gasses when they are burned; reactions can create greenhouse gasses; some plants and animals that we keep a lot of naturally release greenhouse gasses. Processes that produce greenhouse gasses include burning fossil fuels and keeping large amounts of live stock.
answer
HOW HUMAN ACTIVITIES CONTRIBUTE TO GREENHOUSE GASES
question
loss of nutrient from soil. Normally nutrient is rained into the soil; absorbed by plants; shed in their leaves/when they die; digested by decomposers so its back in the soil. If you take away the vegetation you remove nutrients from the cycle. In addition to this the soil is not protected by plants and so when it rains there will be a higher rate of surface run off, this will take the nutrients from the soil with it. Soil erosion is also caused by the fact that without plants to protect the soil there is more surface run off, because soil is taken with it.
answer
EFFECTS OF DEFORESTATION (LEECHING)
question
Plants absorb water from the soil and lose water from their leaves (through transpiration) in to the atmosphere which goes on to make clouds. If there are less plants then less water is evaporated into the atmosphere, this means there are less clouds; less clouds means less rain, which can mean drought.
answer
EFFECTS OF DEFORESTATION (DISTURBANCE OF WATER CYCLE)
question
Plants also convert carbon dioxide into oxygen when they photosynthesise. Forests carbon sinks, they use more carbon than they release: this means they help to make sure there aren't too high levels of CO2 in the atmosphere. When forests are cut down this process is lost and additionally the trees are usually burnt which releases CO2 into the atmosphere.
answer
EFFECTS OF DEFORESTATION (BALANCE OF CARBON DIOXIDE AND OXYGEN)
question
In glasshouses and polythene tunnels conditions can be controlled. This control means that all the limiting factors for plant growth can be set to the optimum conditions; this will result in more growth, so higher yield.
answer
HOW GLASS HOUSES AND POLYTHENE TUNNELS INCREASE YIELD OF CERTAIN CROPS
question
Glass houses and polythene tunnels increase the heat in the environment that crops are growing in. Reactions happen faster when there is more heat, for example photosynthesis. Given photosynthesis produces energy that the plant needs to grow, if there is more heat there is more growth and so higher yield.
answer
EFFECTS ON CROP YIELD OF INCREASED TEMPERATURE
question
Carbon dioxide is a reactant in photosynthesis. If there is a more than enough carbon dioxide, then every plant will be able to photosynthesise as best as it can. The more photosynthesis the more glucose, the more glucose the more energy, the more energy the more growth. Hence crop yield is increased.
answer
EFFECTS ON CROP YIELD OF INCREASED CARBON DIOXIDE
question
contain minerals that plants require to grow; most of them are called NPK fertilisers, this means they contain nitrates, phosphates and potassium.
answer
FERTILISER
question
are needed to make proteins- proteins are what plant cells are made of. If there is a lot of nitrate in the soil then plants have the ability to grow as much as they can.
answer
NITRATES (FERTILISER)
question
are involved in respiration and growth- both things are needed to sustain a plant.
answer
PHOSPHATES (FERTILISER)
question
must be present for enzymes to work- with out it the plant wouldn't be able to carry out reactions and so would die or have very limited growth.
answer
POTASSIUM (FERTILISER)
question
Pests can eat crops or damage them so they can't be sold.
answer
REASONS FOR PEST CONTROL
question
Pesticides are used to kill pests that reduce crop yield. The assure that crops won't be damaged. Fast and accurate to apply. Instant results. They can harm other wildlife
answer
ADVANTAGES IF PESTICIDES
question
Killing the pest may affect biodiversity. Pesticides can leech into the soil and possibly pollute rivers or surrounding habitats. Pests can become immune.
answer
DISADVANTAGES OF PESTICIDES
question
is introducing a predator into the environment with the crops to kill the pests. Cheep. Self regulating. The predator may enter the wild and effect the biodiversity.
answer
BIOLOGICAL CONTROL
question
Yeast converts sugar to ethanol and CO2 when it respires anaerobically.ethanol is alcohol...
answer
ROLE OF YEAST IN PRODUCTION OF BEER
question
Have a test tube of yeast in glucose solution. Put a layer of oil on top if you want the yeast to respire anaerobically (as it will prevent oxygen entering the solution.) Put the test tube in a water bath, heat the water to vary the temperature. Collect gas coming off in a tube then: count the bubbles; use downwards displacement.
answer
EXPERIMENT TO INVESTIGATE CARBON DIOXIDE PRODUCTION BY YEAST
question
Fish are a source of protein in many diets, humans consume a lot of fish for this reason. Fish farms are used to supply fish because: the fish's food safety standard is monitored; fresh water fish are declining; the demand for fish is increasing.
answer
FISH DEMAND
question
Fresh water fish may have come into contact with unclean water; containing sewage, waste, chemicals. In fish farming the water is filtered to make sure the fish don't come into contact with anything it would be unsafe to digest. Also if the water is cleaned regularly the spread of disease is minimised and the oxygen levels are high enough to maintain the respiration of the fish.
answer
WATER QUALITY (FISH FARMING)
question
is the fish being bred eating each other, this can be stopped by: separating fish of different ages; separating fish of different genders; feeding fish regularly; giving fish adequate room.
answer
INTERSPECIFIC PREDATION (FISH FARMING)
question
fencing the area the fish are in; putting nets around the area the fish are in; keeping the fish in inside tanks.
answer
PREVENTION OF INTERSPECIFIC PREDATION (FISH FARMING)
question
the water the fish are in should be changed regularly and their surroundings sterilised often. Also if small amounts of fish are kept together then disease can only contaminate a few fish.
answer
MINIMISING SPREAD OF DISEASE (FISH FARMING)
question
by changing the water in a tank, or changing the nets and location of fish kept outside.
answer
WASTE REMOVAL (FISH FARMING)
question
Fish need to be fed often in small amounts, this is so they don't starve but they wont be able to over eat. It is important to feed fish food with nutrients in for growth.
answer
FEEDING (FISH FARMING)
question
can ensure that farmers produce fish with desired characteristics by letting only the fish with the right characteristics breed and pass on the gene.
answer
SELECTIVE BREEDING (FISH FARMING)
question
can be used to join together different sections of DNA.
answer
LIGASE ENZYMES
question
effectively cut through DNA strands so that a section of DNA can be taken from a cell.
answer
RESTRICTION ENZYMES
question
Although GM plants appear to be only of benefit, there are people who claim side effects observed in lab animals such as: sterility; infant mortality; allergies; stunted growth. Another disadvantage would be that a broad spectrum herbicide that can be spread on GM crops will kill many plants in the wild not just the weeds threatening the crops.
answer
SIDE EFFECTS (GENETICALLY MODIFIED PLANTS)
question
Plants may also have DNA which makes them more resistant: for example genetically modified soya plants. This means that a broad spectrum herbicide that kills many different types of plant can be spread on the crops to kill weeds; where as before many different types of herbicides would have to be spread to avoid killing the crop (time consuming/ expensive.)
answer
RESISTANCE (GENETICALLY MODIFIED PLANTS)
question
They may have DNA which gives them more nutritional value: like golden rice which is rice with carotene in. This will benefit a population which eats a lot of rice by giving them a better diet.
answer
NUTRITIONAL VALUE (GENETICALLY MODIFIED PLANTS)
question
are ones with desired characteristics which are meant to enhance a crop.
answer
GENETICALLY MODIFIED PLANTS
Get an explanation on any task
Get unstuck with the help of our AI assistant in seconds
New