topic 2: plant/animal nutrition

Question 1

carbohydrates

Answer 1

contain carbon, hydrogen and oxygen

starch and glycogen are large, complex carbohydrates that are made up of long chains of glucose/maltose molecules

Question 2

proteins

Answer 2

contain carbon, hydrogen, oxygen, nitrogen (sometimes sulfur and phosphorus)

made up of long chains of amino acids

Question 3

how to make a food sample

Answer 3

get a piece of food and crush it up using a pestle and mortar

transfer the pulp into a beaker and add some distilled water

give the mixture a good stir with a glass rod to dissolve the food as best as you can

filter the solution using a funnel + filter paper to get rid of the solid bits of food

Question 4

lipids

Answer 4

built from fatty acids and glycerol

contain hydrogen, carbon, oxygen

Question 5

test for glucose

Answer 5

prepare a food sample in a test tube

set a water bath to 75°C

add some benedicts solution to a test tube (about 10 drops) using a pipette

place the test tube in the water bath and leave it in there for five minutes

if the sample contains glucose, the solution will change colour depending on the concentration of glucose. (low to high - green -> brick red)

else it will stay blue

Question 6

test for starch

Answer 6

add a drop of iodine solution to the food sample, and shake to mix the contents

if the sample contains starch, solution will turn black/blueblack

else it will stay browny orange

Question 7

test for proteins

Answer 7

add 2cm^3 of biuret solution to the sample and gently shake the test tube to mix

if proteins are present, the solution will turn lilac

else, solution remains blue

Question 8

test for lipids

Answer 8

add 3 drops of sudan III solution to the test tube containing food sample and gently shake

if the sample contains lipids, the mixture will separate into two layers, where the top is bright red. else, no separate layer will form

alternatively:

add ethanol and distilled water to the the test tube containing food sample and gently shake

if the sample contains lipids, a milky white emulsion will form on the surface

Question 9

carbohydrates function

Answer 9

provides energy

Question 10

lipids function

Answer 10

provides energy, acts as an energy store, provides insulation

Question 11

proteins function

Answer 11

growth and repair

Question 12

vitamin a function

Answer 12

improves vision and keeps hair and skin healthy

Question 13

vitamin c function

Answer 13

prevents scurvy

Question 14

vitamin d function

Answer 14

needed for calcium absorption

Question 15

calcium function

Answer 15

makes bones and teeth and keeps them strong

Question 16

iron function

Answer 16

creates haemoglobin which is needed for healthy blood

Question 17

water function

Answer 17

literally everything - replaces the water lost through urinating, sweating, etc

Question 18

dietary fibres function

Answer 18

aids the movement of food through the gut

Question 19

factors that alter energy requirements

Answer 19

activity levels
age
pregnancy

Question 20

investigate the amount of energy a food contains through calorimetry (practical)

Answer 20

weigh a small amount of food before grabbing it with a pair of tongs

add a set volume of water to a boiling tube held with a clamp. this measures the amount of energy released when the food is burnt

measure the temperature of the water, then set fire to the food using a bunsen burner flame. make sure the bunsen isnt near the water or your results might be a little fucked up

immediately hold said food under the boiling tube until it goes out. then relight the food and hold it under the tube so on so forth

keep going until the food wont catch fire again

measure the temperature of the water. then, calculate the energy in food. using that answer calculate the energy per gram of food

Question 21

energy in food formula

Answer 21

energy in food (J) = mass of water (g) x temperature change in water (°C) x 4.2

Question 22

energy per gram of food formula

Answer 22

energy per gram of food (J/g) = energy in food (J) / mass of food (g)

Question 23

amylase

Answer 23

converts starch into maltose

Question 24

maltase

Answer 24

converts maltose into glucose

Question 25

protease

Answer 25

converts proteins into amino acids

Question 26

lipase

Answer 26

converts lipids into glycerol and fatty acids

Question 27

bile

Answer 27

alkaline so it neutralises stomach acid emulsifies fats by breaking fat into tiny droplets giving a bigger surface area of fat to make digestion easier

Question 28

peristalsis

Answer 28

waves of circular muscle contractions

Question 29

mouth

Answer 29

salivary glands in the mouth produce amylase enzyme in the saliva teeth break down food

Question 30

oesophagus

Answer 30

muscular tube that connects the mouth and stomach food moves down here by peristalsis

Question 31

liver

Answer 31

where bile is produced

Question 32

gallbladder

Answer 32

where bile is stored

Question 33

large intestine

Answer 33

colon excess water is absorbed from the food

Question 34

rectum

Answer 34

last part of the large intestine faeces is stored before you SHIT IT OUT

Question 35

stomach

Answer 35

pummels the food with its muscular walls produces the protease enzyme, pepsin produces hydrochloric acid for two reason - to kill bacteria - to give the optimum pH for the protease enzyme

Question 36

pancreas

Answer 36

produces protease, amylase and lipase enzymes. it releases these into the small intestines

Question 37

small intestine

Answer 37

produces protease, amylase and lipase enzymes to complete digestion this is alps where the nutrients are absorbed out of the alimentary canal into the body the first part is the duodenum, the second the ileum

Question 38

how is villi adapted for absorption

Answer 38

large surface area permeable layer of surface cells and a good blood supply to assist quick absorption microvilli very long so theres time to break it down and absorb all the food before it reaches the end

Question 39

photosynthesis equation

Answer 39

carbon dioxide + water -> glucose + oxygen 6CO2 + 6H2O -> C6H12O6 + 6O2

Question 40

waxy cuticle

Answer 40

reduces water loss by evaporation

Question 41

palisade mesophyll

Answer 41

contains chloroplasts and is located near the top of the leaf so they can get the most light

Question 42

upper epidermis

Answer 42

transparent for light to pass into the palisade layer

Question 43

vascular bundle

Answer 43

where the transport vessels (xylem and phloem) are supports the leaf structure takes away glucose produced by photosynthesis

Question 44

limiting factor + 3 examples

Answer 44

something that stops photosynthesis from happening any faster light intensity, co2, temperature

Question 45

test a leaf for starch (practical)

Answer 45

dunk the leaf in boiling water to stop chemical reactions from happening inside the leaf boil the leaf in ethanol - this gets rid of the chlorophyll and therefore the colour of the leaf. this is so we can see the colour change more effectively rinse the leaf in cold water and add a few drops of iodine solution - if starch is present the leaf will turn blue black

Question 46

show how chlorophyll is needed for photosynthesis (practical)

Answer 46

same as the starch test but use a variegated leaf

Question 47

show how CO2 is needed for photosynthesis (practical)

Answer 47

set up the apparatus (lamp shining on bell jar containing a plant and a pot of soda lime) soda lime will absorb the CO2 out of the air in the jar test for starch

Question 48

show how light is needed for photosynthesis (practical)

Answer 48

place the plant in a cupboard for 48 hours cut a leaf from the plant and test it for starch

Question 49

oxygen production showing the rate of photosynthesis (practical)

Answer 49

canadian pondweed can be used to measure the effect of light intensity on the rate of photosynthesis set up the apparatus (light source shining on a test tube filled with canadian pondweed and water and sodium hydrogencarbonate, clamped to a tube that leads to an empty gas syringe. there should be a ruler against the tube.) the pondweed is left to photosynthesise for a set amount of time. as it does so, the oxygen released will collect in the capillary tube at the end of the experiment, the syringe is used to draw the gas bubble in the tube up alongside a ruler, and the length of the bubbles are measured. this should be proportional to the volume of O2 produced repeat with the lightsource placed at different distances from the pondweed

Question 50

nitrates

Answer 50

contain nitrogen for making amino acids and proteins needed for cell growth deficiency shows leaves turning yellow

Question 51

phosphates

Answer 51

contains phosphorus for making DNA and cell membranes needed for respiration and growth deficiency shows poor root growth and purple leaves

Question 52

potassium

Answer 52

helps enzymes needed for photosynthesis and respiration deficiency shows poor flower and fruit growth and discoloured leaves

Question 53

magnesium

Answer 53

needed for making chlorophyll deficiency shows yellow leaves

Question 54

xylem

Answer 54

carries water and mineral salts from the roots up the shoot to the leaves in the transpiration stream

Question 55

phloem

Answer 55

transports sugars like sucrose and amino acids from where theyre made to other parts of the plant this movement of food is otherwise called translocation

Question 56

root hairs

Answer 56

each branch of a root contains microscopic hairs called root hairs this provides the large surface area for absorbing water from the soil

Question 57

transpiration

Answer 57

caused by the evaporation and diffusion of water from a plant's surface, mainly at the leaves said evaporation creates a shortage of water in the leaf, so the xylem has to draw up more water to replace it hence, more water is drawn up from the roots, so there's a constant transpiration stream of water through the plant

Question 58

factors that affect transpiration

Answer 58

light intensity humidity wind speed temperature

Question 59

light intensity

Answer 59

the brighter the light, the greater the transpiration rate this is because the stomata closes in the dark, meaning very little water can escape

Question 60

humidity

Answer 60

the drier the area around a leaf, the more transpiration that can happen if the air is humid, theres a lot of water in it already so theres not that much of a difference between the outside and the inside of a leaf. diffusion happens fastest when theres a large difference between the two concentrations

Question 61

wind speed

Answer 61

the higher the windspeed, the greater the transpiration rate when a windspeed is low surrounding a leaf, the water vapour is low and doesn't move away when windy, water vapour is swept away, creating a large difference between the two concentrations for diffusion

Question 62

temperature

Answer 62

the warmer it is, the faster transpiration happens water particles have more energy when warm to evaporate and diffuse out of the stomata

Question 63

measuring transpiration (practical)

Answer 63

potometer is a special piece of apparatus used to estimate transpiration rates by measuring the water uptake by a plant cut a shoot underwater to prevent air from entering the xylem. cut it at a slant to increase the surface area available for water uptake assemble the potometer in water and insert the shoot under water so no air can enter remove the apparatus from the water but keep the end of the capillary tube submerged in water make sure its watertight and airtight dry the leaves, allow time for the shoot to acclimatise and then shut the tap record the starting position of the air bubble start a stopwatch and record the distance moved by the bubble per unit time e.g per hour

Question 64

how can light intensity affect transpiration rate (practical)

Answer 64

use a lamp to increase the intensity place the potometer in the cupboard to decrease the intensity

Question 65

how can temperature affect transpiration rate (practical)

Answer 65

increase/decrease the temperature by putting the potometer in a room thats warm/cool

Question 66

how can humidity affect transpiration rate (practical)

Answer 66

increase the humidity by spraying water into a bag and sealing it around the plant

Question 67

how can wind speed affect transpiration rate (practical)

Answer 67

use a fan