IGCSE Edexcel Biology Self Quizzing Tool - Year 10 Flashcards
1) Define the term ‘growth’
A permanent increase in size; an increase in the number of cells in an organism
2) Define the term ‘homeostasis’, giving two examples
Maintenance of a constant internal environment, e.g. temperature, water levels, blood glucose levels
3) Define the term ‘excretion’, giving three examples of waste excretory products.
Removal of metabolic waste products from the body, e.g. water (sweat), CO2 (waste product of aerobic respiration) and urea (produced in liver from excess amino acids)
4) Define the term ‘respiration’. How is nutrition important for respiration?
Respiration is the release of energy (production of ATP) from food (glucose). Without proper nutrition, we will not obtain suitable nutrients to respire (e.g. glucose, amino acids, glycerol and fatty acids)
5) State the difference between prokaryotic and eukaryotic cells
Prokaryotic cells (bacteria) have no membrane-bound organelles, e.g. mitochondria, chloroplasts, nucleus
6) State four examples of eukaryotic organisms (kingdom and specific ex.)
Animals > rhino, mosquito, shark, human
Plants > daffodil, wheat, daisy
Fungi > yeast, Mucor
Protoctists > amoeba, Chlorella, Plasmodium
7) Which kingdoms of organisms are ALWAYS unicellular?
Protoctists and bacteria
9) State the difference in cell wall composition between bacteria, fungi, plants and viruses
Bacteria -> MUREIN
Fungi -> CHITIN
Plants -> CELLULOSE
Viruses -> NO CELL WALL
10) Describe three differences in the structure of bacteria and viruses
Bacteria -> cell wall, cell membrane, cytoplasm, plasmids, flagella
Viruses -> no cell wall (protein coat), no cell membrane, no cytoplasm, smaller, no plasmids
11) State the difference in carbohydrate storage between plants, animals, bacteria and fungi
Plants -> STARCH or SUCROSE
Animals -> GLYCOGEN
Bacteria -> GLYCOGEN
Fungi -> GLYCOGEN
12) State the names of 2 diseases caused by viruses (disease-causing organisms are called pathogens)
AIDS (caused by HIV)
Flu (caused by influenza virus)
Ebola (caused by Ebola virus)
13) State the name of a non-pathogenic bacterium and a use for this bacterium
Lactobacillus (used in making yoghurt)
14) State the name of a multicellular fungus and describe how it feeds
Mucor- feeds by saprotrophic nutrition, extracellular secretion of digestive enzymes which break food down into smaller pieces which can then be re-absorbed
15) Describe how the tobacco mosaic virus (TMV) affects plants
It causes discoloration of the leaves by preventing the formation of chlorophyll
16) Describe the difference between how bacteria and viruses reproduce
Bacteria divide by binary fission (asexual reproduction)
Viruses rely on a host cell to self-replicate (they inject their DNA/RNA into the host cell which becomes integrated into host genome)
17) Which is the only kingdom to have nervous coordination?
Animals
18) Which bacterium causes pneumonia?
A spherical bacterium, Pneumococcus
19) Put the following structures the correct order of hierarchy, starting with the lowest: Liver cell, kidney, endocrine system, plant, mitochondria, cardiac tissue
Mitochondria, liver cell, cardiac tissue, kidney, endocrine system, plant
21) Describe the functions of the cell membrane, ribosomes, mitochondria, cytoplasm and nucleus
Cell membrane – controls the movement of substances into and out of cells
Ribosomes – where protein synthesis takes place
Mitochondria – site of aerobic respiration, releasing energy (producing ATP) for the cell
Cytoplasm – site of chemical reactions in the cell
Nucleus – controls the activities of the cell and contains the instructions (DNA) needed to make new proteins
22) Describe the differences between animal cells and plant cells
Plant cells contain chloroplasts, a cellulose cell wall and a permanent vacuole
24) Describe the functions of a cellulose cell wall, a permanent vacuole and chloroplasts
Cellulose cell wall – strengthens a cell and gives it support
Permanent vacuole – filled with cell sap; keeps cell rigid and provides support
Chloroplasts – contain chlorophyll which absorbs light for a plant to photosynthesise
25) Identify the chemical elements present in carbohydrates, proteins and lipids
Carbohydrates: C, H, O
Proteins: C, H, O, N
Lipids: C, H, O
26) Describe the basic structure of carbohydrates (e.g. starch and glycogen), proteins and lipids
Carbohydrates: simple sugars (e.g. glucose)
Proteins: amino acids
Lipids: glycerol and fatty acids
27) Describe how to test chemically for the presence of carbohydrates (e.g. glucose and starch) in a sample
Glucose: add Benedict’s solution and HEAT in a water bath. Colour changes from blue -> brick red if glucose is present
Starch: add iodine solution. If starch is present, colour changes from brown -> blue-black
28) Describe how to test for lipids both physically and chemically
Physical test: rub sample on filter paper; if paper becomes translucent, lipid is present
Chemical test: dissolve sample in ethanol; add cold water; if lipid present, a cloudy white emulsion forms
29) Describe how to test chemically for proteins in a food sample
Add Biuret solution; if protein is present, colour changes from blue -> purple
30) Define the term diffusion, giving both a living and non-living practical example
The movement of molecules from a region of higher concentration to a region of lower concentration
Down a concentration gradient
Passive process (does not require energy/ATP)
Living system: diffusion of purple pigments out of beetroot cylinders
Non-living system: spreading out of potassium permanganate (purple) through water; diffusion of coloured dye from skittles into water
31) Define the term osmosis, giving both a living and non-living practical example
The movement of water molecules
From a region of higher water concentration to a region of lower water concentration
Across a partially permeable membrane
Living system: movement of water in and out of potato cylinders when exposed to differing concentrations of sucrose/salt solution
Non-living system: movement of water in and out of Visking tubing when exposed to differing concentrations of sucrose/salt solution
32) Define the term active transport, giving two examples where this process occurs in a living organism
The movement of molecules (e.g. glucose) or ions
From a region of lower concentration to a region of higher concentration (against a concentration gradient)
Requires energy/ATP from respiration
Examples include: movement of mineral ions into root hair cells from the soil; movement of glucose/amino acids from small intestine into bloodstream
33) Describe how the following factors all affect the rate of movement into and out of cells: surface area to volume ratio, distance, temperature and concentration gradient
Increased temperature, particles have increased kinetic energy so move faster and more
Smaller distance -> reduced movement time
Increased SA:Vol -> increased rate of movement
Steeper concentration gradient -> increased rate of movement
34) Describe what is meant by the term photosynthesis
The process by which a plant makes its own food (glucose; converted into starch or sucrose for storage)- photoautotrophic nutrition.
The conversion of light energy into (stored) chemical energy
35) Write a word and balanced chemical equation for photosynthesis
Carbon dioxide + water -> glucose + oxygen
6CO2 + 6H2O -> C6H12O6 + 6O2
39) Explain how the upper epidermis of a leaf is adapted for photosynthesis
Clear/transparent to allow light through to reach the palisade cells
40) Explain the purpose of the waxy cuticle on a leaf’s upper surface
Waterproofing (excess water can run off)
Reduces water loss by transpiration
Protects the leaf from excess light (reflects much of the sunlight)
41) Explain how the palisade mesophyll cells are adapted for photosynthesis
Regular oblong shape; tightly packed together; means maximum light absorbed for photosynthesis
Contains most chloroplasts in leaf to absorb maximum sunlight
42) Explain how the spongy mesophyll cells are adapted for photosynthesis
Contain chloroplasts for photosynthesis
Air spaces between cells act as reservoirs for CO2; maintains high concentration gradient for diffusion into cells
43) Explain how the vascular bundle is important for the leaf in photosynthesis
Xylem vessels transport water to the cells in the leaf from the roots
Phloem vessels transport sucrose away from the leaf to other parts of the plant
44) Describe the role of stomata in the lower epidermis in photosynthesis
Stomata are open during the day (when there is light from the sun) to allow CO2 to enter the air spaces in the leaf; they also allow O2 to leave (waste product of photosynthesis)
Stomata close during the night to conserve water when there is not much light
The size of the stomatal pore is controlled by guard cells
45) Describe the role of magnesium and nitrates for plant growth. How do they enter the plant?
Magnesium is used in chlorophyll synthesis
Nitrates are used to make amino acids (joined together to make proteins)
Mineral ions enter via active transport from the soil into root hair cells
47) Describe an experiment that tests how the production of starch affects the photosynthesis of a plant.
Destarch a plant in a dark cupboard for 24 hours (plant converts starch into glucose, which it then respires to release energy and keep itself alive)
Place a plant in bright sunlight for a few hours to allow it to photosynthesise
Test leaf for presence of starch (if starch is present, plant has been photosynthesising)
48) Describe and explain how to SAFELY test a leaf for the presence of starch
Place leaf in boiling water (to kill leaf by denaturing the enzymes)
Boil leaf in ethanol (make sure no naked flames present; i.e. use water bath) to remove chlorophyll. NB: ethanol has a lower boiling point than water so a water bath is sufficient
Dip leaf in hot water again to soften/remove excess ethanol
Flood with iodine solution; if starch present, leaf will turn blue-black
51) Define the term ‘balanced diet’
Appropriate proportions of all major food groups, including carbohydrates, proteins, lipids, vitamins, minerals, water and dietary fibre
52) Identify two sources of each of carbohydrates, proteins and lipids. Give the functions of each nutrient.
Carbohydrates: pasta, rice, sugar, potatoes (respired to release energy/produce ATP)
Proteins: meat, fish (used in growth and repair; respired to release energy/produce ATP)
Lipids: butter, oils (insulation, high energy store, padding)
53) Vitamins A, C and D are all important for maintaining crucial body functions. State a source of each and a function.
Vitamin A: carrots, sweet potato (healthy skin and hair; good night vision)
Vitamin C: citrus fruits (prevents scurvy)
Vitamin D: sunlight, eggs, oily fish (healthy bones, calcium absorption)
54) Calcium and iron are vital mineral ions for us to have in our diet. State a source of each and their functions.
Calcium: milk, cheese (bone/teeth development)
Iron: red meat, spinach (makes haemoglobin)
55) State a source of dietary fibre and suggest a consequence of insufficient fibre in our diet
Sources: fruit, vegetables, cereals, wholemeal bread
Lack of fibre can lead to constipation
56) What three main factors do energy requirements depend upon?
Age
Gender (e.g. pregnancy in females)
Activity levels (sedentary jobs vs active jobs)
58) Define the term ‘respiration’
A process that produces ATP (releases energy) in living organisms to be used for growth, protein synthesis, movement etc.
59) Write a word equation for aerobic and anaerobic respiration in mammals
Aerobic
Glucose+oxygen -> carbon dioxide+water+energy
Anaerobic
Glucose -> lactic acid (+ energy)
60) Write a balanced chemical equation for aerobic respiration
C6H12O6 + 6O2 -> 6CO2 + 6H2O
61) Write a word equation for anaerobic respiration in plants and fungi. Suggest two commercial foodstuffs that this process is used to make
Glucose -> Ethanol + carbon dioxide
Brewing beer; baking bread; making yoghurt
63) Describe how air is taken into the lungs in inhalation. (HINT: consider the diaphragm and intercostal muscles)
Intercostal muscles contract; ribcage moves up and out
Diaphragm contracts (flattens; moves down), increasing the volume of the thorax and therefore decreasing the pressure
Air moves into lungs down a pressure gradient
64) Describe the role of the diaphragm in exhalation
Relaxes; becomes dome-shaped (moves up); volume of thorax decreases and pressure increases
65) What structures within the lungs prevent friction between the lungs and ribcage?
Pleural membranes (contain pleural fluid to act as a lubricant)
67) Explain how alveoli are adapted for gas exchange by diffusion between air in lungs and blood in capillaries
Large surface area for gas exchange
Moist lining for gases to dissolve in
Thin walls; decreases diffusion distance
Great blood supply (capillaries) to maintain a high concentration gradient
Permeable walls for diffusion
68) Describe and explain the biological consequences of smoking
Damages alveolar walls, reducing their surface area (EMPHYSEMA)
Tar damages cilia; this means infections more likely due to build up of mucus containing pathogens (CHRONIC BRONCHITIS)
Tar irritates bronchi/bronchioles encouraging mucus to be produced (SMOKER’S COUGH)
Carbon monoxide binds irreversibly to haemoglobin in red blood cells (FATIGUE)
Tobacco smoke contains carcinogens (CANCER)
69) Describe experiments to investigate the effect of exercise on breathing rate and to demonstrate that CO2 is produced
Sit still for 4 minutes and then count breaths in a minute; do four minutes of exercise and count breaths for one minute; repeat steps above and calculate a mean (ensure exercise is same; breaths being counted in same way etc.)
Release of carbon dioxide in breathing can be demonstrated by breathing into limewater; turns cloudy
70) Why is simple diffusion sufficient for unicellular organisms but multicellular organisms require a transport system
Short diffusion distance in unicellular organisms across cell membrane
Direct diffusion would be too slow in multicellular organisms; substances would have to travel large distances to reach every cell
71) State the four main components of blood and briefly describe their functions
Red blood cells: carry/transport oxygen to respiring cells
White blood cells: phagocytes engulf and digest pathogens; lymphocytes produce antibodies
Platelets: involved in blood clotting
Plasma: transports CO2, heat energy, hormones, digested products, urea
72) Describe how red blood cells are adapted for the transport of oxygen
Biconcave shape: large SA:Vol ratio
No nucleus: more space for haemoglobin therefore more oxygen can be carried
Haemoglobin: binds reversibly to oxygen
Thin, elastic membrane: short diffusion distance; cells can squeeze through small gaps
73) Describe the role of phagocytes and lymphocytes in fighting infection
Phagocytes engulf and digest invading pathogens using enzymes
Lymphocytes produce antibodies specific to a particular antigen
74) *Describe the role of vaccination in defence against future infection
Enables manufacture of memory cells
Memory cells enable future antibody production (to a known pathogen) to occur sooner, faster and in greater quantity
75) Describe the role of platelets in blood clotting
Prevent blood loss and entry of microorganisms
77) Explain how exercise and adrenaline increase heart rate
Exercise- muscles need more energy so you respire more; more oxygen must be taken in and more CO2 removed; heart rate increases
Adrenaline- acts on receptors in the heart; cardiac muscle contracts more frequently and with more force; increased oxygen and glucose supply to respiring tissues ready for fight/flight
78) Describe the function of valves. Name the specific locations of valves in the heart
Valves prevent the backflow of blood
Tricuspid valve prevents backflow from right ventricle into right atrium
Bicuspid (mitral valve prevents backflow from left ventricle into left atrium
Semilunar valves prevent backflow from (i) pulmonary artery into right ventricle and (ii) aorta into left ventricle
79) Why does the left ventricle have a thicker muscular wall than the right ventricle?
Blood has to be pumped to all organs of the body except the lungs (right ventricle only pumps blood to lungs); greater force required
81) Describe how certain factors can increase the risk of developing coronary heart disease
Diet high in cholesterol/saturated fat; can form fatty deposits in arteries -> CHD
Smoking -> increases blood pressure which can cause damage to the insides of the coronary arteries -> atherosclerosis
Inactivity/obesity -> high blood pressure can damage lining or arteries; fatty deposits may form
82) Describe the nature and direction of the blood carried in arteries and veins
Arteries carry blood away from the heart; blood is oxygenated (except pulmonary artery) and at high pressure
Veins carry blood towards the heart; blood is deoxygenated (except pulmonary vein) and at low pressure
83) Describe how the structure of arteries, veins and capillaries relates to their function
Artery walls are strong and elastic (i.e. they can expand) which enables blood to be carried under high pressure; lumen is narrow to ensure high pressure
Veins carry blood at low pressure so walls don’t contain as much muscle/elastic; wide lumen; valves to prevent backflow of blood
Capillaries are really small; permeable walls for exchange of substances; thin walls to decrease diffusion distance; supply cells with glucose and oxygen
84) Name the largest artery + largest vein in the body
Aorta (artery) and vena cava (vein)
85) Define the term population
The number of organisms of a particular species in a habitat
86) Define the term community
Multiple populations of organisms within a habitat
87) Define the term habitat
The place where an organism lives
88) Define the term ecosystem
Multiple communities of interacting organisms and their environment (abiotic factors)
89) What is meant by the term trophic level?
A feeding level in a food chain
90) What name is given to the organism at the start of the food chain? How do they get their energy?
Producers: make glucose during photosynthesis (glucose can then be respired to release energy or stored as starch/sucrose)
91) What do the arrows in a food chain represent?
Transfer of energy (around 10% is transferred from one organism to another)
92) State three ways in which energy is lost between trophic levels
Respiration (movement, lost as heat energy, energy used for growth)
Excretion (CO2, urea, water), egestion
Not all organism eaten/not all digestible (bones, fur etc.)
93) State three processes in the carbon cycle that release CO2 back into the atmosphere
Respiration of animals and plants
Decomposition (respiration) by bacteria/fungi (decomposers)
Burning (combustion) of fossil fuels
94) State the name of a process that removes carbon dioxide from the atmosphere
Photosynthesis
95) *State the role of nitrogen-fixing bacteria in the nitrogen cycle
Convert nitrogen gas (air/soil) into ammonia; they are found in root nodules of leguminous plants (e.g. beans, peas, clover)
96) *State the role of nitrifying bacteria in the nitrogen cycle
Conversion of ammonia into nitrites; conversion of nitrites into nitrates (soluble, useable form of nitrogen for a plant)
97) *State the role of denitrifying bacteria in the nitrogen cycle
Conversion of nitrates into nitrogen gas
98) *State the role of decomposers in the nitrogen cycle
Break down dead/decaying animal/plant matter into ammonia
99) Name two pollutant gases and their effects
Carbon monoxide (binds to haemoglobin); sulfur dioxide (dissolves in rainwater to form acid rain)
100) State the names of 5 greenhouse gases
Nitrous oxides, methane, carbon dioxide, CFCs, water vapour
101) Describe how an enhanced greenhouse effect can lead to global warming
Increased CO2 means layer of greenhouse gases thicker
More long wave infrared radiation trapped inside Earth’s atmosphere
102) Describe some effects of global warming
Melting polar ice caps (sea levels rising/flooding)
Habitat destruction (polar bears)
Desertification
Extreme weather events more regular
103) Describe the biological consequences of pollution of water by sewage
Eutrophication (fertilisers, pesticides etc. leached into waterways)
Increased minerals for algae in lake (algal bloom forms on surface)
Sunlight blocked from photosynthesising plants; these die
Decomposers break these down and use all the oxygen in the water
Lake becomes starved of oxygen and all aquatic life dies
104) State four effects of deforestation
Leaching
Soil erosion
Disturbance of evapotranspiration/carbon cycle
Balance of atmospheric gases disturbed
