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GCSE Biology Food
Terms in this set (68)
What is a trophic level?
Any of the sequential stages in a food chain, occupied by producers at the bottom and in turn by primary, secondary, and tertiary consumers. Decomposers (detritivores) are sometimes considered to occupy their own trophic level.
Identify factors affecting food security?
Disease affecting farming
high cost of farming eg fertilisers
describe how different factors affect food sequrity
In poorer countries demand for things like coffee means farmers are farming food to sell rather than to eat which is affecting overall food security in that country.
examples of reason loss of biomass and energy at each trophic level in a food chain?
amount of fiber they eat so don't waste energy in excretion
how can intensive farming methods increase the efficiency of biomass transfer?
BY keeping animals in door it will decrease there amount of movement, heat loss as they are all together and will be warmer and therefore having more energy to create biomass Reduces energy transferred to environment so more energy available for growth
Evalauate modern intensive farming techniques?
Even tho intensive farming does increase the amount of energy used for growth there are also some disadvantages.
Increased risk of disease. Lower quality product. Ethical concerns.
Describe and evaluate some uses of bio technology
The exploitation of biological processes for industrial and other purposes, especially the genetic manipulation of microorganisms for the production of antibiotics, hormones, etc. Biotechnology has helped to increase crop productivity by introducing such qualities as disease resistance and increased drought tolerance to the crops.
What is the word equation for photosynthesis?
carbon dioxide + water - glucose + oxygen
what do chloroplasts do?
Chloroplasts absorb sunlight and light energy they then covert it to chemical energy and then with water and carbon dioxide gas to produce food for the plant.
describe the use of light and chloroplast in Photosynthesis?
Green plants absorb light energy using chlorophyll in their leaves. They use it to react carbon dioxide with water to make a sugar called glucose. The glucose is used in respiration, or converted into starch and stored. Oxygen is produced as a by-product.
Explain why chloroplast absorb energy?
Chloroplast absorb energy to drive chemical reactions. Chloroplasts are the tiny structures in plant cells where photosynthesis happens. Chloroplasts contain chlorophyll, a green pigment that absorbs light energy for photosynthesis. ... These cells absorb the water needed by the plant for photosynthesis.
Why is photosynthesis an endothermic reaction?
Photosynthesis is an example of an endothermic chemical reaction. In this process, plants use the energy from the sun to convert carbon dioxide and water into glucose and oxygen. This reaction requires 15MJ of energy (sunlight) for every kilogram of glucose that is produced.
Factors that affect Photosynthesis?
Light intensity. Without enough light, a plant cannot photosynthesise very quickly, even if there is plenty of water and carbon dioxide. ...
Carbon dioxide concentration. ...
How can the rate of photosynthesis be increased?
By increasing the light intensity, carbon concentration and temperature.
what are the effects of limiting factors in photosynthesis?
Three factors can limit the speed of photosynthesis - light intensity, carbon dioxide concentration and temperature. Without enough light, a plant cannot photosynthesise very quickly, even if there is plenty of water and carbon dioxide. Increasing the light intensity will boost the speed of photosynthesis.
identify parts of a leaf and there structure?
How are leaves adapted for efficient photosynthesis?
Leaves are adapted to perform their function eg they have a large surface area to absorb sunlight.
How is glucose used by a plant?
The glucose made in photosynthesis is transported around the plant as soluble sugars. Glucose is used in respiration to release energy for use by the plant's cells. However, glucose is converted into insoluble substances for storage.
How does water travel in plant?
Water is passively transported into the roots and then into the xylem. The forces of cohesion and adhesion cause the water molecules to form a column in the xylem. Water moves from the xylem into the mesophyll cells, evaporates from their surfaces and leaves the plant by diffusion through the stomata.
Adaptations of xylem and phloems?
Xylem transports water and solutes from the roots to the leaves, phloem transports food from the leaves to the rest of the plant. Transpiration is the process by which water evaporates from the leaves, which results in more water being drawn up from the roots. Plants have adaptations to reduce excessive water loss.
Describe experiments on the rate of Photosynthesis?
lamp, Pondweed in tests tube amount of bubbles
how do different factors affect transpiration?
The environmental factors affecting transpiration in plants include light, relative humidity, temperature, availability of water, and wind. Specifically, these are climatic elements which also affect photosynthesis and other plant growth and development processes.
the movement of sugars in a leaf.
Name organs in human digestive system
Describe the structure of the human digestive system?
What are enzymes function?
Enzymes are biological molecules (typically proteins) that significantly speed up the rate of virtually all of the chemical reactions that take place within cells.
What do substrate molecules do?
Sunstrate molecules fit into active sites of enzymes. Lock and key!
How do pH and temperature affect enzymes?
if they are to high or to strong it can denature them
what is the effect of surface area to volume ratio on diffusion
he surface-to-volume ratio of a sphere is 3/r; as the cell gets bigger, its surface-to-volume ratio decreases, making diffusion less efficient . The larger the size of the sphere, or animal, the less surface area for diffusion it possesses.
Describe the lock and key theory?
The specific action of an enzyme with a single substrate can be explained using a Lock and Key analogy first postulated in 1894 by Emil Fischer. In this analogy, the lock is the enzyme and the key is the substrate.
Use collision theory to describe enzyme action?
Different reactions can happen at different rates. Reactions that occur slowly have a low rate of reaction. Reactions that happen quickly have a high rate of reaction. For example, rusting is a slow reaction: it has a low rate of reaction. Burning and explosions are very fast reactions: they have a high rate of reaction.
Explain how the small intestine is adapted for efficient food absorption?
The inside wall of the small intestine is thin, with a large surface area. This allows absorption to happen quickly and efficiently. To get a big surface area, the inside wall of the small intestine is lined with tiny villi. ... They also contain blood capillaries to carry away the absorbed food molecules.
what are the names of the four chambers of the heart?
Right Chambers, - right atrium, right ventricle
Left Chambers, - left atrium, left ventricle
what are the names of the four main blood vessels that lead to and from the heart?
Aorta, Vena cava , Pulmonary artery and Pulmonary vein
what is deoxygenated blood?
blood with little oxygen
what is oxygenated blood?
Blood with plenty of oxygen
where does blood become oxygenated?
in the lungs
Which cells in the blood carry oxygen?
RED BLOOD CELLS
Why do tissues of the body need oxygen?
Tissues need oxygen to respire
What is the name of the group of cells that ensures the heart beats in a coordinated and regular manner?
The sinotrial node (SAN) the hearts own pace maker
What happens if the blood vessels supplying the heart muscle become blocked?
If the blood vessels become blocked it causes a heart attack
What is the name of the blood vessel that supply the heart muscle itself?
blood vessels leading from the heart?
Blood vessels leading to the heart?
name the three types of blood vessels
Veins, Capillaries, Arteries
Name the organ where bile is produced and the organ where it is stored
Produced; liver stored ; gallbladder
Describe two functions of bile
Bile is alkaline as it neutralists the hydrolic acid in the stomach to make the conditions more suitable for enzymes to work in small intestine
The bile also breaks the fat down into tiny droplets (emulsifies fats) this gives the fat much bigger surface area so the enzymes can speed up digestion.
Which group of digestive enzymes does amylase belong to?
What is the product of the reaction catalysed by amylase?
Describe the role of digestive enzymes in the process of digestion?
The different enzymes break down proteins, alluouse , starches and other food groups so that the intestines absorb the nutrients.
Give two ways in which the products of digestion can be used for the body?
Glucose is used in respiration to provide energy and amino acids are used to build new proteins.
Name the digestive enzyme produced in the salivary glands?
Where are pro tease, enzymes involved in digestion produced?
Stomach, pancrease and small intestine
Name the type of enzyme that catalyses the breakdown of lipids ?
what is the job of the circulatory system?
To transport blood around the body to the muscles and tissues.
Where does aerobic respiration in a cell occur?
In a cell aerobic respiration occurs in the part of a cell called the mitochondria
How is oxygen debt repaid?
Blood flowing through the muscles transports the lactic acid to the liver where it is converted back to glucose.
What is oxygen debt?
Oxygen debt is the amount of extra oxygen the body needs after exercise to react with the accumulated lactic acid and remove from the body/blood.
factors which affect diffusion
surface area to volume ratio
Transport is the movement of oxygen ,nutrients, hormones, waste and heat around the body
what is osmosis?
Osmosis is the net movement of water molecules from an area of high water concentration to an area of low water concentration through a partially permeable membrane.
What is the cell membrane like? (osmosis)
the cell membrane has very small holes in it. Small molecules can pass through, larger ones can not.
How does oxygen move in and out of cells?
How does water move in and out of cells?
What is active transport?
Active transport is the process that transports particles from a low concentration to a high concentration.
Active transport- key stuff
-This does require energy
-particle move against a concentration gradient
-the more energy there is the faster the rate of active transport.
Anaerobic respiration equation?
glucose - lactic acid + energy
Aerobic respiration equation?
glucose + oxygen - carbon dioxide + water + energy
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