key definitions

Question 1

whats a pathogen?

Answer 1

-organism that causes disease

Question 2

cell differentiation?

Answer 2

-process by which a cell becomes specialised for its job

Question 3

how can stem cells be used? (2)

Answer 3

-to cure disease
-replace faulty cells

Question 4

diffusion?

Answer 4

-net movement of particles from an area of higher concentration to an area of lower concentration

Question 5

osmosis?

Answer 5

-net movement of water molecules across a partially permeable membrane from region of high water concentration to region of low water concentration

Question 6

active transport?

Answer 6

-movement of particles against a concentration gradient using energy released during respiration

Question 7

whats carbs made up of?

Answer 7

-carbon
-hydrogen
-oxygen

Question 8

whats proteins made up of?

Answer 8

-carbon
-hydrogen
-nitrogen
-oxygen

Question 9

whats lipids made up of?

Answer 9

-carbon
-hydrogen
-oxygen

Question 10

what is a balanced diet?

Answer 10

-gives all the essential nutrient you need in the right proportions

Question 11

calc energy of food in joules

Answer 11

mass of water x temp chance of water x 4.2

Question 12

what does amylase convert?

Answer 12

-starch to maltose

Question 13

what does maltase convert?

Answer 13

-maltose to glucose

Question 14

what does proteases convert?

Answer 14

-proteins to amino acids

Question 15

what does lipases convert?

Answer 15

lipids to glycerol and fatty acids

Question 16

what does bile do?

Answer 16

-neutralises acids
-emulsifies fats

Question 17

villi adaptations? (4)

Answer 17

-large SA for absorption
-each villi have microvilli (inc SA)
-single permeable layer of surface cells
-good blood supply (quick absorption)

Question 18

word eq for photosynthesis?

Answer 18

carbon dioxide + water = glucose + oxygen

Question 19

waxy cuticle?

Answer 19

-protective layer on leaf
-prevents water from evapourating

Question 20

upper epidermis?

Answer 20

-thin and transparent to allow light to enter

Question 21

palisade mesophyll?

Answer 21

-packed with chloroplasts for absorbing light

Question 22

spongy mesophyll?

Answer 22

-air spaces increase the SA: volume ratio for diffusion

Question 23

lower epidermis?

Answer 23

-contains guard cells and stomata

Question 24

guard cells?

Answer 24

-absorb and lose H20 to open and close stomata

Question 25

stomata?

Answer 25

-gas exchange occurs and evaporation of water

Question 26

why do plants need nitrates?

Answer 26

-making amino acids and proteins -will turn yellow without

Question 27

why do plants need phosphates?

Answer 27

-making DNA -needed for respiration and growth -leaves turn purple

Question 28

why do plants need potassium?

Answer 28

-needed for photosynthesis -discoloured leaves without

Question 29

why do plants need magnesium?

Answer 29

-required for making chlorophyll

Question 30

what do xylem tubes do?

Answer 30

-transport water and minerals

Question 31

what do phloem tubes do?

Answer 31

-transport sugars (sucrose and amino acids) -known as translocation

Question 32

root hair cells?

Answer 32

-long hairs (big SA) -mitocondria to release energy

Question 33

whats transpiration?

Answer 33

-loss of water from plant

Question 34

what happens during evaporation?

Answer 34

-creates shortage of water -water drawn up through xylem vessels

Question 35

how does light intensity affect transpiration?

Answer 35

-more light=more transpiration -when its dark, stomata close so water cant escape

Question 36

how does temperature affect transpiration?

Answer 36

-warmer=more transpiration -water particles have more energy to evaporate and diffuse out of stomata

Question 37

how does wind speed affect transpiration?

Answer 37

-higher windspeed=more transpiration

Question 38

how does humidity affect transpiration?

Answer 38

-drier the air=more transpiration

Question 39

whats respiration?

Answer 39

-the process of transferring energy from glucose, happening constantly in every living cell

Question 40

what do plants exchange gases by?

Answer 40

-diffusion

Question 41

why are leaves broad?

Answer 41

-inc SA for diffusion

Question 42

why are leaves thin?

Answer 42

-so gases can travel short distance to reach cells

Question 43

why are there air spaces?

Answer 43

-C02 and 02 can diffuse in and out

Question 44

what happens when you breathe in?

Answer 44

-intercostal muscles and diaphragm contract -thorax volume inc -decreases pressure, drawing air in

Question 45

what happens when you breathe out?

Answer 45

-intercostal muscles and diaphragm relax -thorax volume decreases -air forced out

Question 46

how are alveoli specialised?

Answer 46

-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

Question 47

what does smoking do to alveoli?

Answer 47

-damages wall -reduces SA for gas exchange -tar damages cilia -chest infections happen

Question 48

4 main components in blood?

Answer 48

-RBC -WBC -platelets -plasma

Question 49

what is plasma?

Answer 49

-transports everything around body

Question 50

what are platelets?

Answer 50

-they clot to prevent blood loss -held together by fibrin

Question 51

what do RBC do?

Answer 51

-transport 02 -contain haemoglobin which binds to 02

Question 52

what do phagocytes do?

Answer 52

-ingest pathogens

Question 53

what do lymphocytes do?

Answer 53

-produce antibodies

Question 54

what does vaccination involve?

Answer 54

-injecting dead pathogens into body -carry antigens -trigger an immune response -lymphocytes produce antibodies

Question 55

what do arteries do?

Answer 55

-carry blood away from heart

Question 56

what do capillaries do?

Answer 56

-involved in exchange of materials at tissues

Question 57

what do veins do?

Answer 57

-carry blood to heart

Question 58

2 things the arteries have...

Answer 58

-elastic fibres for expansion -thick walls to make them strong

Question 59

2 things the capillaries have?

Answer 59

-permeable walls to substances can diffuse in and out -one cell thick walls to decrease diffusion distance