key definitions Flashcards
whats a pathogen?
-organism that causes disease
cell differentiation?
-process by which a cell becomes specialised for its job
how can stem cells be used? (2)
-to cure disease
-replace faulty cells
diffusion?
-net movement of particles from an area of higher concentration to an area of lower concentration
osmosis?
-net movement of water molecules across a partially permeable membrane from region of high water concentration to region of low water concentration
active transport?
-movement of particles against a concentration gradient using energy released during respiration
whats carbs made up of?
-carbon
-hydrogen
-oxygen
whats proteins made up of?
-carbon
-hydrogen
-nitrogen
-oxygen
whats lipids made up of?
-carbon
-hydrogen
-oxygen
what is a balanced diet?
-gives all the essential nutrient you need in the right proportions
calc energy of food in joules
mass of water x temp chance of water x 4.2
what does amylase convert?
-starch to maltose
what does maltase convert?
-maltose to glucose
what does proteases convert?
-proteins to amino acids
what does lipases convert?
lipids to glycerol and fatty acids
what does bile do?
-neutralises acids
-emulsifies fats
villi adaptations? (4)
-large SA for absorption
-each villi have microvilli (inc SA)
-single permeable layer of surface cells
-good blood supply (quick absorption)
word eq for photosynthesis?
carbon dioxide + water = glucose + oxygen
waxy cuticle?
-protective layer on leaf
-prevents water from evapourating
upper epidermis?
-thin and transparent to allow light to enter
palisade mesophyll?
-packed with chloroplasts for absorbing light
spongy mesophyll?
-air spaces increase the SA: volume ratio for diffusion
lower epidermis?
-contains guard cells and stomata
guard cells?
-absorb and lose H20 to open and close stomata
stomata?
-gas exchange occurs
and evaporation of water
why do plants need nitrates?
-making amino acids and proteins
-will turn yellow without
why do plants need phosphates?
-making DNA
-needed for respiration and growth
-leaves turn purple
why do plants need potassium?
-needed for photosynthesis
-discoloured leaves without
why do plants need magnesium?
-required for making chlorophyll
what do xylem tubes do?
-transport water and minerals
what do phloem tubes do?
-transport sugars (sucrose and amino acids)
-known as translocation
root hair cells?
-long hairs (big SA)
-mitocondria to release energy
whats transpiration?
-loss of water from plant
what happens during evaporation?
-creates shortage of water
-water drawn up through xylem vessels
how does light intensity affect transpiration?
-more light=more transpiration
-when its dark, stomata close so water cant escape
how does temperature affect transpiration?
-warmer=more transpiration
-water particles have more energy to evaporate and diffuse out of stomata
how does wind speed affect transpiration?
-higher windspeed=more transpiration
how does humidity affect transpiration?
-drier the air=more transpiration
whats respiration?
-the process of transferring energy from glucose, happening constantly in every living cell
what do plants exchange gases by?
-diffusion
why are leaves broad?
-inc SA for diffusion
why are leaves thin?
-so gases can travel short distance to reach cells
why are there air spaces?
-C02 and 02 can diffuse in and out
what happens when you breathe in?
-intercostal muscles and diaphragm contract
-thorax volume inc
-decreases pressure, drawing air in
what happens when you breathe out?
-intercostal muscles and diaphragm relax
-thorax volume decreases
-air forced out
how are alveoli specialised?
-large SA bcoz there are many alveoli
-moist lining for gases to dissolve in
-thin walls for quick diffusion distance
-good blood supply to maintain a high conc gradient
-permeable walls to gases can diffuse easily
what does smoking do to alveoli?
-damages wall
-reduces SA for gas exchange
-tar damages cilia
-chest infections happen
4 main components in blood?
-RBC
-WBC
-platelets
-plasma
what is plasma?
-transports everything around body
what are platelets?
-they clot to prevent blood loss
-held together by fibrin
what do RBC do?
-transport 02
-contain haemoglobin which binds to 02
what do phagocytes do?
-ingest pathogens
what do lymphocytes do?
-produce antibodies
what does vaccination involve?
-injecting dead pathogens into body
-carry antigens
-trigger an immune response
-lymphocytes produce antibodies
what do arteries do?
-carry blood away from heart
what do capillaries do?
-involved in exchange of materials at tissues
what do veins do?
-carry blood to heart
2 things the arteries have…
-elastic fibres for expansion
-thick walls to make them strong
2 things the capillaries have?
-permeable walls to substances can diffuse in and out
-one cell thick walls to decrease diffusion distance
