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| Question | Answer |
| how does carbon dioxide enter a leaf, and how does oxygen exit it? | DIFFUSION (1) • from an area of high concentration to an area of low concentration/down a concentration gradient (1) • through the STOMATA (1) |
| Describe the basic process of photosynthesis, in words. | photosynthesis (1) takes place in the chloroplast, using chlorophyll (1) It requires carbon dioxide, water (1) and light (energy) )(1) • (to produce) glucose (1) |
| How does water enter the root hair cell? | by osmosis |
| How do mineral ions enter the root hair cell? | By active transport |
| What is plasma? What does it carry? | Plasma is a pale, straw-colored liquid which carries all the components of the blood: 1. Red blood cells (ERYTHROCYTES) w HAEMOGLOBIN which may be bonded to OXYGEN (and contains iron) 2. White blood cells (LYMPHOCYTES and PHAGOCYTES) 3. PLATELETS 4. GLUCOSE, mineral ions and other nutrients 4. Carbon dioxide! 5. Hormones 6. ANTIBODIES and anti-toxins 7. Proteins 8. Urea (between liver and kidneys) |
| Describe the role of microorganisms in the carbon cycle. (3 marks) | Microorganisms in the carbon cycle are DECOMPOSERS. (1) They break down waste products and dead organisms (1) and release CO2 through RESPIRATION as they do so. (1) |
| Describe the water cycle. | 1. EVAPORATION - ENERGY from the sun makes water EVAPORATE from the land and sea, turning it into WATER VAPOR. Water also evaporates from plants in a process known as TRANSPIRATION. 2. CONDENSATION - The warm water vapour is carried upwards, as warm air rises. When it gets higher up, it cools and CONDENSES to form clouds. 3. PRECIPITATION - Water falls from the clouds in the form of rain, snow, or hail. When it falls on the land, it provides fresh water for plants, animals, and fungi. 4. DRAINAGE - Liquid water flows towards the lowest point, draining towards the ocean, and the whole process starts all over again. 5. The water is recycled endlessly. Fresh water is necessary for all life on land. |
| How do plants transport nutrients to different parts of their bodies? | through the phloem |
| what is an herbicide? | An herbicide is a substance that is toxic to plants, used to destroy unwanted vegetation. example "the number of weed species resistant to this herbicide has increased" |
| Describe how the nitrogen found in dead leaves are eventually absorbed by other plants. (4 marks) | DECOMPOSERS turn PROTEINS in dead leaves into AMMONIA. (1) Then NITRIFYING BACTERIA turn ammonia into NITRITES (1) and then into NITRATES. (1) Plants can absorb nitrates through their root hair cells. (1) |
| Cellular respiration is not the same as breathing!!!! Breathing (inhaling and exhaling) is to enable gas exchange in the lungs. Describe cellular respiration. | Cellular respiration is an EXOTHERMIC reaction which occurs CONTINUOUSLY in living cells to RELEASE ENERGY for metabolic processes... includes aerobic and anaerobic respiration |
| What is crop rotation? | Crop rotation is a farming method used to ensure that nutrients in the soil are not depleted. Instead of growing the same crop each year, farmers grow different crops each year in a cycle. The cycle usually includes a NITROGEN-FIXING crop, such as peas, beans or other LEGUMES, which helps to put NITRATES back into the soil for another crop to use. |
| Why would a farmer spread animal manure or composted plants onto a field used for growing crops? | Farmers and gardeners spread animal waste and compost into order to return nitrogen and other nutrients to the soil through DECOMPOSITION. This can be more economical than using chemical fertilzers. |
| What is Type 2 diabetes? | In a person with type 2 diabetes, the amount of insulin released is not enough, and the person's cells have become resistant to insulin. Insulin is the hormone which signals the body to remove glucose from the blood by converting the glucose into glycogen. So a person with type 2 diabetes may have trouble regulating their blood sugar levels. |
| Plants cannot use nitrogen directly from the air, but need it to make proteins. How do plants get the nitrogen they need to make proteins? | Link at least 3 of the following: • plants can only take nitrogen in as NITRATES (1) • fertilisers/compost added to the soil can contain nitrates(1) • nitrogen fixing bacteria in the soil can produce nitrates (1) • plants absorb the nitrates through their roots (1) • absorption is by ACTIVE TRANSPORT through the root hair cells (1) |
| What are fish farms? How do fish farms reduce biodiversity? | Fish farms in areas of open water (e.g. lakes or the sea) can reduce biodiversity in the surrounding area. Here's how: 1) Food is aded to the nets to feed the fish, which produce huge amounts of waste. Both the food and the waste can leak into the open water, causing EUTROPHICATION & the death of wild species. 2) Fish farms in open water often act as a breeding ground for large numbers of PARASITES. These parasites can get out of the farm & infect wild animals, sometimes kiling them. 3) PREDATORS (e.g. sea lions) are attracted to the nets & can become trapped in them & die. 4) Sometimes NON-INDIGENOUS farmed fish can escape into the wild , which can cause problems for wild INDIGENOUS populations of indigenous species, by out-competing them for resources and carrying disease. |
| Which gland is oestrogen released by? | The ovaries |
| Explain the problems associated with an increase of nitrate and phosphate levels in a lake. | Excessive richness of nutrients in a lake, or EUTROPHICATION, causes INCCREASED GROWTH OF ALGAE/an algal bloom, which blocks sunlight to the lower levels of water. Plants at the bottom of the lake cannot get enough sunlight to photosynthesize, and die. Organisms decomposing the lake-bottom bodies consume OXYGEN, DEPLETING the lake of oxygen. More organisms die. Biodiveristy is reduced. |
| Describe the functions of white blood cells. (3 Marks) | 1. White blood cells are involved in defence against disease. They are part of the IMMUNE SYSTEM (1) 2. PHAGOCYTES perform PHAGOCYTOSIS (1) - they are able to engulf and ingest foreign cells • LYMPHOCYTES produce ANTIBODIES (1) and also Anti-toxins |
| Which gland is FSH released by? | The pituitary gland |
| What is the main pollutant that causes acid rain? | Sulfur dioxide |
| What is mutualism? Give an example. | Mutualism is when two or more organisms benefit from living in each other's presence. Example 1: algae and fungus live together to form lichen. The algae makes food for the fungus, and the fungus provides shelter and structure for the algae. Example 2: Oxpecker birds eat ticks off the skin of a zebra. The birds get food and the zebra gets pest control. Example 3: nitrogen fixing bacteria relationship with leguminous plants such as beans bacteria live inside root nodules bacteria fix nitrogen for the plant to use bacteria obtain nutrition from the plant and are protected from the environment Example 4: Tube worms and chemosynthetic bacteria - the bacteria live inside the tube worms, protected from predators while producing food for the tube worms. |
| Describe the carbon cycle. | 1. Carbon dioxide is in the atmosphere 2. Plants absorb this CO2 while doing PHOTOSYNTHESIS (also return it while doing RESPIRATION) 3. Animals eat plants including carbon 4.Animals return some CO2 to atmosphere while doing respiration 5. Animals and plants die and DECOMPOSE into the earth 6. Decomposers such as bacteria, fungi, and beetles return CO2 to atmosphere while doing respiration 7. Some carbon, which was left in the earth, over millions of years builds up under pressure to become fossil fuels such as coal, oil, and natural gas. 8. When these fuels are COMBUSTED (burned), a lot more CO2 is returned to the atmosphere. |
| What happens to a plant if it does not get enough nitrogen? | Plants need nitrogen to make AMINO ACIDS so they can make PROTEINS. If it does not get enough nitrogen it may NOT GROW as much as other plants. |
| What gland is LH released by? | Luteinizing hormone is released by the pituitary gland. |
| What is the difference between anaerobic respiration and aerobic respiration? | AEROBIC RESPIRATION uses OXYGEN (1) produces water (1) releases more ENERGY (1) does not produce / release alcohol (1) occurs in the MITOCHONDRIA ANAEROBIC RESPIRATION -occurs without oxygen -in humans produces LACTIC ACID -in yeast, and plants, produces ALCOHOL -occurs in the CYTOPLASM |
| Name something found in saliva that would help digest bread into simple sugar. | carbohydrase / amylase / enzymes / maltase |
| What are the limiting factors of photosynthesis? | 1. temperature 2. carbon dioxide concentration 3. light intensity |
| Progesterone is released by? | The corpus luteum. |
| Describe the nitrogen cycle | 1. Nitrogen gas in air 2. Nitrogen gas can be "fixed" into soil nitrates by root nodule bacteria in some plants, by lightning, or by some bacteria in soil 3. Plants absorb nitrates by active transport through root hair cells 4. Animals eat plants 5. When plants or animals die, the nitrogen in their bodies is broken down back to soil nitrates by DECOMPOSERS including soil bacteria 6. Some soil bacteria convert nitrates back to atmospheric nitrogen. |
| How are materials such as carbon, oxygen, nitrogen recycled through both the BIOTIC and ABIOTIC components of an ecosystem? | 1. Living things are made of elements, that they take from the environment (ie, plants take carbon, oxygen, from the air and nitrogen from the soil) 2. They turn these elements into complex compounds (MACROMOLECULES) such as CARBOHYDRATES, LIPIDS, and PROTEINS that make up living organisms. 3. Elements are passed along FOOD CHAINS when animals EAT plants or another animal. 4. The elements are RECYCLED when the organisms die or excrete waste products - DECOMPOSERS break them down and the elements are returned to the soil or air, ready to be taken in by other organisms and put back into the food chain. |
| When is clomifene therapy needed, and how does it work? | Some women are infertile because they don't ovulate or they don't ovulate regularly. These women can take a drug called clomifene. This works by causing more FSH and LH to be released by the body, which stimulate egg maturation and ovulation. By knowing when the couple will be ovulating, the couple can have intercourse during this time period to improve the chance of becoming pregnant. |
| Why would you use a belt transect? How? What kind of data could you collect? Give an example. | BELT TRANSECTS are used to measure the DISTRIBUTION of organisms along a HABITAT GRADIENT. To do so, place quadrats at regular intervals along a line and collect data - such as # of a certain organism, % cover by a certain organism, height of plants, light intensity etc. For example, investigate population density of a certain kind of snail from the low tide zone to the high tide zone by the ocean, or of a certain species of grass from a shaded woodland area to a sunny open area. Then, PLOT GRAPHS to find if the CHANGING ABIOTIC FACTOR is correlated with the change in distribution of the species you are investigating. |
| How does the human body prevent glucose from becoming too high or too low? | The human body LOWERS blood glucose concentrations: insulin is released from the pancreas into the bloodstream causing glucose to be converted to glycogen glycogen is stored in the liver / muscle tissue that is how blood glucose concentrations are lowered. The human body RAISES blood glucose concentrations by: glucagon is released from the pancreas into the bloodstream causing glycogen to be converted to back into glucose glucose is released into the bloodstream that is how blood glucose concentrations are raised. |
| Draw a diagram of the human circulatory system, including: -heart -lungs -aorta -vena cava -pulmonary artery -pulmonary vein -capillaries | |
| Explain how deoxygenated blood moves from the heart to the lungs. | The heart muscles contract to pump (1) Deoxygenated blood from the RIGHT ATRIUM (1) into the RIGHT VENTRICLE (1) and blood flows through the PULMONARY ARTERY to the LUNGS (1) |
| Explain how oxygenated blood moves from the lungs to the rest of the body. | Blood receives oxygen in the LUNGS. It then moves to the heart through the PULMONARY VEIN. The heart muscles contract and pump the oxygenated blood through the LEFT ATRIUM and LEFT VENTRICLE. The blood then leaves the heart and flows to the rest of the body, distributing oxygen to the cells through the CAPILLARIES. |
| Do arteries carry blood toward the heart or away from it? How about veins? | Arteries carry blood away from the heart. Veins carry blood toward the heart. |
| Explain how substances are exchanged between capillaries and body cells. | (NAME A SUBSTANCE) Glucose, oxygen, carbon dioxide, etc (1) DIFFUSES (1) through the capillary walls from a high concentration to a low concentration (down a concentration gradient) (1) |
| What happens if arteries are narrowed or their carrying capacity is reduced? | less blood flows to cells cells do not work as effectively lactic acid builds up, more likely to get cramps fatigue / tiring more easily less oxygen in the blood less glucose less aerobic respiration less energy released body cells start / increase anaerobic respiration less waste products removed |
| Explain how water enters a plant and is moved to the leaf. | 1- WATER ENTERS ROOT by osmosis through root hair cells root hairs increase surface area from a high water concentration to a low water concentration, towards higher concentration of solutes because there are more solutes in cytoplasm of root cells (than in soil) through a partially permeable membrane 2 - WATER MOVES ACROSS ROOT TO XYLEM cell to cell by osmosis as next cell in sequence has lower water concentration 3 - WATER MOVES UP THE STEM TO THE LEAVES up the xylem xylem is a tube transpiration stream by capillary action water moving from xylem into leaf cells draws more water up xylem transpiration / evaporation of water maintains gradient water moves from xylem to leaf cells by osmosis |
| What are the products of cellular respiration in plants? | Ethanol, and CO_2. |
| What is a parasite? | A parasite is an organism that lives on or in a host organism, and benefits at the host's expense. |
| Explain how water, glucose, and mineral salts are transported through the plant. | **WATER** • up through the XYLEM by CAPILLARY ACTION • by OSMOSIS into cells in the leaf • it EVAPORATES from leaves in what is called the TRANSPIRATION STREAM • it DIFFUSES into the atmosphere THROUGH the stomata **GLUCOSE** • converted to sucrose • dissolved in water •is transported through the phloem • bidirectional **MINERAL SALTS** • are dissolved in water and transported up through the XYLEM, from root to tip |
| What can any cell with chloroplasts and chlorophyll do, that other cells cannot do? | photosynthesis |
| What are hormones? What are the glands called that produce them? | Hormones are chemical messengers. (1) They are produced in a range of endocrine glands (1) and carried by the blood (1). |
| What is Human Growth Hormone? What does it do? Where is it produced? | GROWTH HORMONE stimulates cells in muscles and bones to divide. It is produced in the PITUITARY gland. |
| What is Thyroxine? What does it do? Where is it produced? | THYROXINE affects the metabolic rate, causing heart cells to contract more rapidly and strongly, and increasing the rate at which proteins and carbohydrates are broken down inside cells. Thyroxine is produced in the THYROID gland. |
| What is adrenaline? What does it do? Where is it produced? | ADRENALINE is released from the ADRENAL glands. Adrenaline is responsible for the "fight-or-flight" response when a body feels threatened, and affects several different organs: -It causes the heart to contract more rapidly and strongly -It dilates blood vessels leading to the muscles -It contracts blood vessels leading to other organs -It tells the liver to convert more glycogen to glucose, increasing blood sugar supply |
| What is the male sex hormone? Where is it produced and what does it do? | Male sex hormone is called TESTOSTERONE, and it is produced in the TESTES. More testosterone is released during puberty and causes an increase in HGH, which causes an increase in growth rate. |
| What are the female sex hormones? Where are they produced and what do they do? | The female sex hormones are ESTROGEN and PROGESTERONE. They are produced in the ovaries. They help control the menstrual cycle. |
| Where are eggs stored in the human female body? | THE OVARIES |
| What is an antibiotic? | An ANTIBIOTIC is a substance that either kills bacteria or inhibits their cell processes, so they cannot grow or reproduce. |
| What is Type 1 Diabetes and how is it treated? | |
| Discuss three different contraceptive methods, how they work, and their relative efficacy. | 1. MALE CONDOM - 98% success rate - placed over erect penis, physically prevents sperm from entering the vagina. 2. DIAPHRAM or VAGINAL CAP - 92-96% success rate - placed over the CERVIX or entrance to the uterus, physically prevents sperm from entering the uterus. 3. HORMONE PILL or IMPLANT - >99% success rate - releases hormones to prevent ovulation and thickens mucus at cervix, making it difficult for sperm cells to pass through. |
| What is contraception? | CONTRACEPTION is the prevention of FERTILISATION. |
| Name six benefits for humans of maintaining biodiversity (preventing species from going extinct). | 1. Protecting the human food supply - for example, fish 2. Ensuring minimal damage to food chains - if one species becomes extinct, it will affect all the organisms that feed on and are eaten by that species - conserving one species may help others to survive. 3. Cultural heritage - plants or animals may have important symbolic or artistic value to humans-- for example the bald eagle is the national symbol of the USA. 4. Future medicine - many of the medicines we use today come from plants. Undiscovered plant species in a biodiverse area may contain new medicinal chemicals. If these plants become extinct, we could miss out on valuable medicines. 5. Ecotourism - people enjoy and will pay to visit beautiful, scenic areas with good variety of animal and plant species. This makes the tourists feel good, and also brings money into the local economy. 6. Providing new jobs - ecotourism, conservation, and reforestation schemes provide employment opportunities for local people. |
| Explain how reforestation affects biodiversity. (3 marks) | Reforestation increases biodiversity in deforested areas (1) because it increases the number of tree species in an area (1). Trees provide food and shelter for animal species (1). |
| Name the three kinds of blood vessels, explain their functions, and rank them in order of lumen size. | 1. VEINS - carry blood back to heart - largest lumen (opening) size 2. ARTERIES - carry blood away from heart 3. CAPILLARIES - tiny vessels that exchange substances with cells throughout the body - walls only one cell thick, smallest lumen |
| What is the formula for stroke volume in a beating heart? | stroke volume = cardiac output/heart rate |
| Explain how veins are adapted to carry blood back to the heart. | 1. They have a bigger LUMEN than arteries to help the blood flow, despite lower pressure 2. They have VALVES to keep the blood flowing in the right direction 3. The walls don't need to be as thick as arteries, since blood is at lower pressure |
| Why are capillary walls only one cell thick? | Having such thin walls increases the RATE OF DIFFUSION of substances between the blood and the cells. |
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