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21 Cards in this Set
- Front
- Back
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List 3 differences between animal and plant cells.
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1)Plant cells have a cell wall as well as a cell membrane, while animal cells have only a cell membrane.
2)Chloroplasts are present in plant cells, while none are in animal cells. 3)Carbohydrates are stored as starch in plant cells, and glycogen in animal cells. 4)A large permanent vacoule is present in most plants. It has a definite fixed shape. |
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What is diffusion?
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Diffusion is the movement of molecules from an area of high concentration to one of low concentration across a concentration gradient until they are evenly distributed.
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What is osmosis?
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Osmosis is the movement of water molecules from an area of high concentration to an area of low concentration across a semi-permeable membrane until they are evenly distributed.
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What is photosynthesis?
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Photosynthesis is the process by which green plants make organic food from simple inorganic substances like carbon dioxide and water. Oxygen is a waste product and glucose is the first carbohydrate formed.
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What are the two stages of photosynthesis, and what happens in each?
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The two stages are the light dependent stage and the light independent stage. In the light dependent stage, solar energy trapped by chlorophyll in the chloroplasts is used to split water molecules into hydrogen and oxygen. The oxygen diffuses out through the stomata of the leaf.
In the light independent stage carbon dioxide is combined with the hydrogen to form glucose. |
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How are leaves adapted for photosynthesis?
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1)Broad and flat to absorb a lot of light and CO2.
2)Lie at 90 degrees to sunlight and are spaced around stem to catch as much light as possible. 3)Chloroplasts in the palisade mesophyll layer are mobile so they can catch as much sunlight as possible. 4)Xylem vessels transport water to the leaf cell. 5)Phloem tubes carry organic food to rest of the plant. 6)There is a waxy cuticle at the top of the leaf which helps to prevent water loss from the surface, and is transparent to let light through. |
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Discuss guard cells.
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Guard cells are B-shaped cells that are surrounds the stoma. They regulate its open and closing.When turgid, opens the stoma, when flaccid, closes it.
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Why do most stomata open in the day and close in the night?
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To reduce water loss.
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What are the limiting factors which affect photosynthesis?
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1)Light Intensity
2)Temperature 3)Carbon dioxide concentration 4)Water Availability |
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What is etiolation?
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Etiolation is when a plant that is not in the presence of sunlight undergoes a period of rapid growth towards an area with sunlight using its stored food reserves so it can photosynthesize normally.
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What is a diet?
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A diet is the quality and quantity of food eaten each day.
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What is a balanced diet?
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A balanced diet contains the correct proportion of nutrients to ensure good health.
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Name the 5 stages of holozoic nutrition and describe what happens in each
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Ingestion - This is the taking in of food.
Digestion - This is the process of breaking down organic food into smaller simple soluble molecules. Absorption - The diffusion of soluble food molecules into the bloodstream. Assimilation - This is the use of food molecules in the blood for growth and repair and respiration in body cells. Egestion - The removal of undigested from the food substances from the body as faeces. |
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What are enzymes?
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Enzymes are organic food substances that speed up the rate of chemical reactions in the body.
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What is gaseous exchange?
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The process involved in the exchange of oxygen from the air with carbon dioxide from the body.
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What are the properties of enzymes?
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1)They are all proteins.
2)They are specific as each enzyme only catalyzes a certain chemical reaction. 3)They are required in small amounts. 4)They are inhibited by poisons. 5)They are denatured or destroyed by high temperatures. 6)They work best at a particular temperature and pH. |
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What causes peptic ulcers?
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Heliobacter pylori, a specices of bacterium that lives in the gut.
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What does saliva contain?
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It contains water, mucus, salivary amylase and sodium hydrogencarbonate.
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What does gastric juice contain?
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1)Mucus
2)HCl 3)Pepsin |
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What does bile do?
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It emulsifies fats, increasing surface area for lipase to act on.
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What is commensalism?
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Commensalism is a type of feeding relationship in which one organism benefits and the other is not harmed in any way.
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