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Biology > Structure and Functions in living organisms > Flashcards

Structure and Functions in living organisms Flashcards

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1
Q

nucleus

A

controls the cells activity (by making proteins)
contains the chromosomes (strands of DNA which carry genes which code for a protein)

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2
Q

cell membrane

A

boundary between the cytoplasm and the cell’s surrounding.
controls what substances enter and exit the cell.

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3
Q

cytoplasm

A

jelly-like liquid where reactions occur

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4
Q

mitochondria

A

carries out some aerobic respiration, which produces ATP

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5
Q

ribosomes

A

synthesize (assemble) proteins and amino acids

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6
Q

chloroplasts

A

contain chlorophyll, absorb light energy and use it to carry out chemical reactions of photosynthesis making biological molecules for plants.

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7
Q

cell wall

A

helps keep plants in a fixed shape

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8
Q

vacuole

A

filled with a water liquid called cell sap, stores dissolved sugars, mineral ions and other substances.

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9
Q

similarities of plants and animal cells

A

nucleus
cytoplasm
mitochondria
cell membrane
ribosomes

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10
Q

differences of plants and animal cells

A

plants only:
cell wall (cellulose)
vacuole
chloroplasts

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11
Q

what is the acronym of chemical molecules in carbs, lipids and protein

A

CHO CHO CHON

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12
Q

carbohydrate structure

A

large molecules made up of smaller basic units.
starch and glycogen from simple sugars (smallest unit of carbs).
complex carbs are made up of 1000s of simple sugars joined together.

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13
Q

lipid structure

A

large molecules made up of smaller basic units.
fatty acids and glycerol.
made of 3 fatty acids joined to a glycerol.

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14
Q

protein structure

A

large molecules made up of smaller basic units. made of many amino acids joined together.
20 different amino acids can be joined together in any order to create millions of different proteins.
the shape of a protein helps it carry out its job

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15
Q

why are starch and glycogen good storage molecules

A

less soluble as simple sugars so have less effect on osmosis

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16
Q

what uses starch and glycogen

A

plants store glucose as starch
animals and fungi store glucose as glycogen

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17
Q

practical - investigate food samples for the presence of glucose

A

glucose - benedicts test
1. add benedicts solution to a sample of food
2. place in water bath at 80’c for 5 mins
3. colour changes from blue -> brick red

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18
Q

functions of lipids

A
  • thermal insulation
  • electrical insulation (around nerve cells)
  • buoyancy
  • part of cell membranes
  • energy storage (can be used in respn)
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19
Q

functions of proteins

A
  • structural molecules
  • controlling chemical reactions (enzymes are proteins)
  • messenger molecules (hormones are proteins)
  • combatting disease (antibodies are proteins)
  • transport (haemoglobin and cell membrane proteins)
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20
Q

practical - investigate food samples for the presence of starch

A

starch - iodine test
1. add a few drops of orange iodine solution to the sample on a spotting tile
2. color changes from orange to blue/black

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21
Q

practical - investigate food samples for the presence of proteins

A

protein - buriets test
1. add 2cm water to a food sample and shake
2. add equal volume of dilute potassium hydroxide and shake
3. add 2 drops of 1% copper sulphate solution
4. original colour -> pale purple

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22
Q

practical - investigate food samples for the presence of lipids

A

lipid - emulsion (ethanol)
1. food sample is placed in test tube
2. add a small volume of absolute ethanol and shake to dissolve any lipid in the alcohol
3. add equal volume of water
4. original colour -> cloudy white

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23
Q

what is an enzyme

A

a biological catalyst

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24
Q

how does temperature affect enzyme function

A

as temperature increases the enzyme and substates have more kinetic energy which means they move faster so have more successful collisions

once temperature has got to a certain point the temperature breaks the bonds that hold together the amino acids (which make the proteins) which changes the shape of the enzyme.

this is denaturing

once the enzyme has denatured the substrate can no longer fit in the active site (as it has lost its shape) meaning that the reaction will stop

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25
Q

practical - investigate how enzyme activity can be effected by changes in temperature

A

amylase digests starch

  1. mix 10cm of 10% starch solution with 5cm of 5% amylase in a boiling tube.
  2. heat in a water bath
  3. every minute add 1 drop of this solution to 1 drop of iodine in a spotting tile
  4. repeat using different temps of water baths

when the starch has been fully digested (so none is present) iodine will stay orange

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26
Q

diffusion

A

the random movement of particles from a high to a lower concentration

so particles of O2 will move out of the lungs into the RBCs as the lower conc of O2 is in the RBCs

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27
Q

active transport

A

the movement of molecules from a low to high concentration using ATP

plants use active transport in their root hair cells to absorb mineral ions.

organisms have special carrier proteins in the cell membrane. These use ATP to provide the energy to move the substances across the membrane against the concentration gradient.

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28
Q

osmosis

A

the movement of water molecules from a high potential to a lower potential across a partially permeable membrane

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29
Q

how does surface area to volume ratio affect movement of substances in and out of cells

A

A larger surface area speeds up the rate of diffusion as there are more opportunities for the molecules to move, which is why surfaces such as alveoli in lungs are so large. Surface area to volume ratio is more significant, as the two counteract (oppose) each other: an efficient exchange surface has a surface area which is very large compared to the distance the molecules must travel. SA:V is increased when structures are small.

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30
Q

how does distance affect movement of substances in and out of cells

A

Diffusion takes longer if the molecules have to travel further. Therefore cells are small (smaller volume reduces distance).

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31
Q

how does temperature affect movement of substances in and out of cells

A

At higher temperatures, molecules have more kinetic energy and so move faster.

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32
Q

how does concentration gradient affect movement of substances in and out of cells

A

If there is a very large difference in concentration between to areas, molecules will diffuse from the higher to the lower concentration quickly. If the concentration gradient (difference) is small, diffusion will happen more slowly.

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33
Q

practical - investigate diffusion and osmosis using living systems

A
  1. Make a 5 different concentration of sucrose solutions
  2. Measure 5cm3 of each dilution into separate test tubes.
  3. Use a cork borer to cut out six potato chips and cut down the sections into identically sized chips. Dry each chip using a paper towel to remove excess
    water but do not squeeze.
  4. Weigh each before the start of the experiment.
  5. Place a potato chip in each test tube (one per sucrose concentration) and leave
    for 20 minutes.
  6. Remove each potato chip, dry gently using paper towel, and weigh them in turn.
  7. Calculate the percentage change in mass for each sucrose solution.
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34
Q

practical - investigate diffusion and osmosis using non-living systems

A
  1. Add sucrose solution to a section of Visking tubing – a selectively permeable substance used to model a cell membrane.
  2. Weigh the Visking tubing and its contents.
  3. Add the Visking tubing to a beaker of water.
  4. Leave for 1 hour.
  5. Pat the Visking tubing dry to remove excess water.
  6. Reweigh the Visking tubing and its contents.
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35
Q

what does photosynthesis do

A

plants produce glucose from simple inorganic molecules – carbon dioxide and water – using light energy

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36
Q

word equation for photosynthesis

A

water + carbon dioxide -> (light energy) oxygen + glucose

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37
Q

chemical equation for photosynthesis

A

6CO2 + 6H2O → C6H12O6 + 6O2

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38
Q

how do CO2 levels affect photosynthesis rate

A

adding more CO2 increases rate of reaction because there are more molecules for the enzymes to collide with. there is a point where it doesn’t matter how much CO2 there is as other factors are now limiting

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39
Q

How does light intensity effect the photosynthesis rate

A

adding more light (increasing brightness) increases rate of reaction because there is more energy for the reaction to occur. there is a point where it doesn’t matter how much light there is as other factors are now limiting

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40
Q

How does temperature affect the rate of photosynthesis

A

increasing temperature increases the rate of reaction because the enzymes and substrates have more kinetic energy up until a point where the temperature increases too much when the enzymes will denature

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41
Q

how is the SA of the leaf specialized for photosynthesis

A

large SA and thin, to maximize SA of the leaf absorption of sunlight by the photosynthesis cells. it also increases the amount of stomata, so CO2 can diffuse quicker

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42
Q

how is the upper epidermis of the leaf specialized for photosynthesis

A

upper epidermis is transparent which allows light to pass through to the mesophyll

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43
Q

how is the palisade of the leaf specialized for photosynthesis

A

palisade mesophylls are long and thin and tightly packed. they contain large numbers of chloroplasts which maximize sunlight absorption. the palisade mesophylls is the main site of photosynthesis

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44
Q

how is the stomata of the leaf specialized for photosynthesis

A

stomata allow gas to diffuse into the air spaces of the leaf. this allows a short diffusion distance for CO2. also can close to reduce water loss (at night)

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45
Q

how is the xylem of the leaf specialized for photosynthesis

A

xylem transports the water into the leaves. this provides a short distance for the water to diffuse into the photosynthesis cells

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46
Q

why do plants need mineral ions

A

to grow

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47
Q

why do plants need magnesium ions

A

for chlorophyll

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48
Q

why do plants need nitrate ions

A

for amino acids

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49
Q

practical 2.23 - evolution of oxygen from a water plant

A
  1. Take a bundle of shoots of a pondweed
  2. Submerge them in a beaker of water
  3. Use a light a set distance from the plant (measure with a ruler)
    As oxygen is produced, the bubbles of gas will appear
  4. count the number of bubbles over a set time, eg 60 secs

Repeat steps for different distances of the light
and calculate mean

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50
Q

what are the components of a balanced diet

A

carbohydrates, proteins, lipid, vitamins, minerals, water, dietary fiber

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51
Q

what foods give carbs

A

bread, potatoes, pasta, rice, cereals, fruit

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52
Q

what food give protein

A

meat, eggs, fish, quinoa, quorn

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53
Q

what foods give lipids

A

butter, cooking oils, cream, avocados

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54
Q

functions of carbs

A

fuel for respiration

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55
Q

functions of proteins

A

growth and repair of cells and tissues
fuel for respiration

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56
Q

functions of lipids

A

store of energy
fuel for respiration
insulation for (thermal and electrical)

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57
Q

sources of iron

A

red meat, liver, spinach

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58
Q

sources of vit A

A

fish liver oil, liver, butter, carrots

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58
Q

sources of calcium

A

milk and dairy products

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59
Q

sources of vit C

A

fresh fruit and vegetables

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60
Q

functions of iron

A

forms part of hemoglobin which binds to oxygen

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61
Q

sources of Vit D

A

dairy products, oily fish

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62
Q

functions of calcium

A

needed to form bones and teeth

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63
Q

functions of vit A

A

making a chemical retina and also protects the surface of the eye

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64
Q

functions of vit C

A

needed for cells and tissues to stick together

65
Q

functions of vid D

A

needed to absorb calcium and phosphate ions from food

66
Q

iron deficiency

A

amenia

67
Q

calcium deficiency

A

rickets

68
Q

vit A deficiency

A

night blindness and damaged corena

69
Q

vit C deficiency

A

scurvy

70
Q

vit D deficiency

A

rickets caused from weak bones

71
Q

functions of water

A

water is an essential solvent and is used to transport the components of blood and is crucial for temperature regulation by sweating

72
Q

functions of dietary fibre

A

fiber helps the movement of food through the intestine, preventing constipation and bowel cancer.

73
Q

how does age affect energy requirements

A

Young people need more energy requirements as it is used for growth and muscle development

74
Q

how does activity levels affect energy requirement

A

When a person is more active there is more energy requires as there are more muscle contractions which requires more respiration as it needs more energy

74
Q

how does pregnancy affect energy requirement

A

Energy requirements increase as energy is needed to support fetus, and the larger mass the mother needs to carry

74
Q

ingestion

A

taking food in through the mouth and swallowing

75
Q

digestion

A

breaking down large insoluble molecules into smaller pieces (physical digestion) and smaller soluble molecules

76
Q

absorption

A

movement of small soluble molecules out of the gut and into the blood by diffusion and active transport

77
Q

egestion

A

passing out undigested food out through the anus

78
Q

assimilation

A

building larger biomolecules from the small soluble molecules in all cells

79
Q

what are the first 2 parts of the digestive system

A

mouth + oesophogus

80
Q

what happens in the mouth

A

mechanical + chemical digestion + swallowing

mechanical - food is broken down into smaller molecules by chewing. this increases SA for enzymes and prevents discomfort when swallowing

chemical - saliva is released by the salivary glands. saliva makes food easier to swallow and it contains amylase

swallowing - before swallowing food is shaped into a ball and pushed to the back of the mouth by the tongue. this ball is called a bolus. there is a flap called epiglottis which blocks food from entering the trachea

81
Q

what is chemical digestion

A

food broken down into smaller soluble molecules by enzymes, bile and acids

82
Q

what is mechanical digestion

A

food broken down via physical methods such as churning, grinding and chewing

83
Q

what happens in the oesophagus

A

long tube that connects the mouth and the stomach. the bolus is pushed down/through by peristalsis

84
Q

what is peristalsis

A

the gut muscles contracting and relaxing to form a wave to push the bolus down/through the oesophagus.

circular muscles contract + longitudinal muscles relax
circular muscles relax + longitudinal muscles contract

85
Q

what happens in the stomach

A

the gastric glands in the stomach walls secrete pepsin which starts to digest protein

contractions of the stomach wall causes the contents to mix maximizing the contact between the enzymes and food

the stomach is acidic because HCl is released from the gastric glands as the optimum pH for pepsin is acidic. the low pH would burn through the stomach walls so they are covered in mucus to prevent this. the HCl also kills most bacteria and fungi present in the food.

86
Q

what happens in the small intestine

A

both digestion and absorption happen in the small intestine

87
Q

what happens in the duodenum

A

the final place of chemical digestion.
the pancreas makes several enzymes and secretes them into the duodenum.
trypsin, amylase, lipase

the duodenum also contains glands which secrete the enzymes they produce into the duodenum
maltase, peptidase

the duodenum also contains bile

88
Q

what is bile

A

bile is produced by the liver and stored in the gall bladder

  1. neutralizes the stomach acid because the duodenum enzymes work best at 7-8 pH
  2. emulsifies lipids - breaks down the large droplets into smaller droplets, increasing SA for lipase to digest the fat
89
Q

what happens in the ilium

A

absorption begins. the small soluble molecules are absorbed. some by diffusion but some such as glucose by active transport.

90
Q

how is the ilium optimized for diffusion

A

large SA - folding of the ileum, villi & microvilli (folds on the surface of cells lining the villi) increase SA

short diffusion distance - the villi cells are one cell thick

high concentration gradient - provided by capillary network and lacteals removing absorbed molecules

91
Q

what happens in the colon

A

site of all reabsorption of water

92
Q

what happens the rectum

A

the faeces are stored in the rectum and egested from the anus

93
Q

whats execretion

A

the removal of waste products by chemical reactions
eg urea removed by the kidneys and sweating

94
Q

what does the pancreas do

A

produces and secretes amylase, trypsin, lipase into the duodenum
secretes an alkaline fluid into the duodenum to neutralize the acidity of the stomach

95
Q

practical 2.23 - show chlorophyll is required for photosynthesis

A
  1. Drop a variegated leaf in boiling water (heated by a bunsen burner)
    This denatures the enzymes in the leaf and breaks down the cell walls (meaning photosynthesis stops)
  2. Turn off the bunsen burner
  3. Transfer the leaf into hot ethanol in a boiling tube for 5-10 minutes
    This removes the chlorophyll so color changes from iodine can be seen more clearly
  4. Rinse the leaf in cold water
    This is done to soften the leaf tissue after being in ethanol
  5. Spread the leaf out on a white tile and cover it with iodine solution

In a variegated leaf, the green parts of the leaf will turn blue-black as photosynthesis is occurring in these areas of the leaf as they contain chlorophyll.
The area of the leaf that was white will remain orange-brown as it does not contain any chlorophyll and so could not photosynthesize, while the green area will turn blue-black

these results show chlorophyll is essential to photosynthesis

96
Q

practical 2.23 - show that a plant requires light to photosynthesis

A

Destarch a plant by placing it in a dark cupboard for 24 hours
This ensures that any starch already present in the leaves will be used up and will not affect the results of the experiment
Following de-starching, cover a leaf of the plant with aluminium foil and place the plant in sunlight for a day
Remove a covered leaf and a uncovered leaf and test for starch using iodine using the method below

  1. Drop a the leaves in boiling water (heated by a bunsen burner)
    This denatures the enzymes in the leaf and breaks down the cell walls (meaning photosynthesis stops)
  2. Turn off the bunsen burner
  3. Transfer the leaves into hot ethanol in a boiling tube for 5-10 minutes
    This removes the chlorophyll so color changes from iodine can be seen more clearly
  4. Rinse the leaf in cold water
    This is done to soften the leaf tissue after being in ethanol
  5. Spread the leaves out on a white tile and cover it with iodine solution

the uncovered leaf will turn blue/black because it had access to light in order to photosynthesis.
the covered leaf will stay orange/brown because it did not have access to light which stops photosynthesis occurring

97
Q

practical 2.23 - show a plant requires CO2 to photosynthesis

A

place one leaf into a conical flask containing soda lime (which absorbs CO2)
place another leaf into a conical flask without anything in

  1. Drop a the leaves in boiling water (heated by a bunsen burner)
    This denatures the enzymes in the leaf and breaks down the cell walls (meaning photosynthesis stops)
  2. Turn off the bunsen burner
  3. Transfer the leaves into hot ethanol in a boiling tube for 5-10 minutes
    This removes the chlorophyll so color changes from iodine can be seen more clearly
  4. Rinse the leaf in cold water
    This is done to soften the leaf tissue after being in ethanol
  5. Spread the leaves out on a white tile and cover it with iodine solution

the leaf in the soda lime will remain orange/brown as there was no CO2 which is required to photosynthesis
the leaf without soda lime will turn black/blue as there is CO2 so it can photosynthesis

98
Q

how is the small intestine adapted for absorption

A

villi and micro villi
very long which increase SA and time for diffusion and active transport
peristalsis mixes food together and keeps things moving

99
Q

why do leaves normally contain starch

A

leaves are the site of photosynthesis which produces glucose.
any excess glucose is stored as starch which is why the starch test proves photosynthesis is occurring

100
Q

starch ->

A

starch –(amylase)–> maltose

101
Q

maltose ->

A

maltose –(maltase)–> glucose

102
Q

protein ->

A

protein –(pepsin)–> peptides

103
Q

peptides ->

A

peptide –(peptidase)–> amino acids

104
Q

lipid ->

A

lipid –(lipase)–> glycerol and 3 fatty acids

105
Q

practical 2.33B - investigate the energy content in a food sample

A

BANANA CHIP

  1. attach a boiling tube to a clamp stand
  2. Use the measuring cylinder to measure out 25cm3 of water and pour it into the boiling tube
  3. Record the starting temperature of the water using the thermometer
  4. Weigh the initial mass of the food sample
  5. Set fire to the sample of food using the bunsen burner and hold the sample 2cm from the bottom of the
    boiling tube until it has completely burned
  6. Record the final temperature of the water
  7. (Once cooled) weigh the mass of any remaining food and record
  8. Repeat the process with different food samples

A larger increase in water temperature indicates a larger amount of energy contained by the sample
We can calculate the energy in each food sample using the following equation:

Energy transferred (J) =
(mass of water (g) x 4.2 x temperature increase (°C)) ÷ (mass of food (g))

106
Q

how do living organisms produce ATP

A

respiration!!

107
Q

how do cells get energy to carry out their life processes

A

ATP from respiration

108
Q

what is cell respiration

A

cells constantly break down food molecules to produce ATP
this happens continuously because without it the cell would have no energy and die

109
Q

does cell respiration happen in plants

A

yes it is part of the process as they photosynthesis to create glucose and then respire the glucose to create energy

110
Q

protein ->

A

protein –(trypsin)–> peptides

111
Q

what is the difference between anaerobic and aerobic respiration

A

aerobic respiration requires O2 whereas anaerobic respiration does not

aerobic respiration completely breaks down glucose whereas anaerobic respiration does not

aerobic respiration releases a lot of energy whereas anaerobic respiration only produces a little

112
Q

what are carbohydrases

A

they are enzymes that break down carbohydrates into simple sugars
amylase and maltase

113
Q

what are proteases

A

they are enzymes that break down protein into amino acids
pepsin, trypsin, peptides

114
Q

what are lipases

A

they are enzymes that break down lipids into glycerol and fatty acids
lipase

115
Q

word equation for aerobic respiration

A

oxgyen + glucose —> water + carbon dioxide

116
Q

chemical equation for aerobic respiration

A

C6 H12 O6 + 6O2 → 6CO2 + 6H20

117
Q

why does aerobic respiration produce more ATP than anaerobic respiration

A

aerobic respiration fully oxidizes glucose whereas anaerobic respiration doesn’t

118
Q

word equation for anaerobic respiration in animals

A

glucose —-> lactic acid

119
Q

word equation for anaerobic respiration in plants + fungi + bacteria

A

glucose —-> ethanol + carbon dioxide

120
Q

2.39 practical - investigate the evolution of CO2 and heat for respiring seeds

A
  1. place some alive seeds soaked in Milton solution (bleach which kills any bacteria present which would also
    respire affects results) in a thermos flask
  2. place some dead seeds (boiled to denature enzymes) soaked in Milton solution in another thermos flask
  3. Make sure the cotton wool is plugging the top of each flask
  4. place a thermometer and the flasks
  5. place a delivery tube into the flasks and collect the gas produced
  6. Record the initial temperature
  7. After 4 days, record the final temperature

The thermometer in the flask with the germinating seeds should show an increase in temperature
the dead seeds should remain at room temperature
This is because the alive seeds are respiring and producing heat energy in the process
This shows that respiration is an exothermic reaction
The dead seeds are not respiring because they are dead, so the temperature remains the same

bubble the collected gas though limewater which will turn cloudy is CO2 is present
the gas produced from respiration is CO2 so the gas from the alive seeds will turn limewater cloudy
the gas from the dead seeds won’t as they haven’t produced CO2 as they can’t respire

121
Q

what is coronary heart disease

A

coronary arteries supply heart muscle tissue with blood. this blood provides muscle cells with O2 and glucose for aerobic respiration and the blood also removes CO2 produced from aerobic respiration.

fatty deposits will build up in your artery walls which narrow the lumen (space for blood) in the arteries. this reduces the amount of blood that can pass through to the arteries and therefore the amount of blood that reaches the heart muscle cells.

less blood reaching the working muscle cells means that less O2 (and glucose) meaning the cells respire aerobically less have to respire anaerobically more. anaerobic respiration produces lactic acid which is poisonous.

this poisoning of the heart muscle cells will lead to a heart attack

122
Q

what factors make coronary heart disease more likely to happen

A

diet - eating lots of saturated fats increases blood cholesterol and increases the risk of fatty deposits

smoking - increases blood pressure and increases the risk of fatty deposits forming

high blood pressure - damages artery lining and increases the rick of fatty deposits occurring

obesity - being obese will increase blood pressure

123
Q

chemicals in cigarettes

A

nicotine
tar
carbon monoxide
+ more than 4000 others

124
Q

effects of nicotine

A

narrows blood vessels leading to an increased blood pressure
increases heart rate
both of these effects can cause blood clots to form in arteries leading to a heart attack or a stroke

125
Q

effects of carbon monoxide

A

CO binds permanently to haemoglobin (forming carboxyhaemoglobin) which reduces the capacity to carry oxygen
this puts more stress on the breathing system as breathing frequency and depth need to increase to get the same amount of oxygen into the blood
also puts more strain on the circulatory system to pump blood faster around the body and increases the risk of coronary heart disease and strokes

126
Q

effects of tar

A

tar is a carcinogen
carcinogens are chemicals that can alter the DNA and increase the risk of cancer (rapid, uncontrolled cell growth)

127
Q

how does smoking affect the cilia cells and etc

A

in a healthy person the trachea and bronchi are specialized to prevent dirt and bacteria entering the lungs.
goblet cells produce mucus which traps dirt and pathogens
the cilia of the lining cells waft the mucus up the airways

the chemicals from smoking destroy the cilia.
at the same time the mucus production will increase because of the smoke (with all of the bad stuff in it)
the destroyed cilia cells cannot then waft the mucus up so the mucus builds up resulting in a cough (smokers cough) and increases the risk of infection.

bronchitis is a disease resulting in the build up of infected mucus in the bronchi and bronchioles

128
Q

how does smoke damage the alveoli

A

the smoke breaks down the alveoli’s walls and so fuse together forming larger irregular air spaces. this decreases SA and so less oxygen diffuses into the blood

129
Q

2.50 practical - investigate breathing in humans, including the release of CO2 and effect of exercise

A
  1. get 2 or more students
  2. Work out student A’s breathing rate at rest
  3. Count their number breaths for 15 seconds and multiply by 4
  4. Repeat several times to calculate an average
  5. Student A should then exercise for a set time (at least 4 minutes)
  6. Immediately after exercising, count the breaths taken in 15 seconds and multiply by 4 to obtain the
    breathing rate per minute
  7. Compare the result to the breathing rate at rest in order to work out the change in breathing rate as a
    result of exercise
  8. Repeat this last step every minute after exercise for 5 minutes
    Repeat the process for student B

Frequency of breathing increases when exercising
This is because muscles are working harder and aerobically respiring more and they need more oxygen to be delivered to them (and carbon dioxide removed) to keep up with the energy demand
If they cannot meet the energy demand they will also respire anaerobically, producing lactic acid
After exercise has finished, the breathing rate remained elevated for a period of time
This is because the lactic acid that has built up in muscles needs to be removed as it lowers the pH of cells and can denature enzymes catalyzing cell reactions
It can only be removed by combining it with oxygen - this is known as ‘repaying the oxygen debt’

This can be tested by seeing how long it takes after exercise for the breathing rate to return to normal
The longer it takes, the more lactic acid produced during exercise and the greater the oxygen debt that needs to be repaid and therefore the more unfit the student is

130
Q

how is water absorbed by the root hair cells

A

plants take in water from the soil through the root hair cells. the root hair cells (RHC) are specialized to increase their surface area which then increases rate of active transport.

the plant actively transports the mineral ions from the soil into the root hair cells. the mineral ions lower the water potential of the root hair cells. the water will then osmosis from the soil to the RHCs as the RHCs have the lower water potential. (osmosis - water moves from high to low conc)

this gradient is maintained as the water is continually being taken up by the xylem.

131
Q

transpiration

A

water lost from the leaves, mainly from the stomata

(water evaporates into the air spaces in the spongy mesophyll then diffuses out of the stomata)

132
Q

how is transpiration rate affected by humidity

A

Very humid air contains a great deal of water vapour – there is a smaller concentration gradient, so transpiration slows down.
In dry air the diffusion of water vapour from the leaf to the atmosphere will be rapid.
Transpiration therefore increases if humidity decreases.

133
Q

how is transpiration rate affected by wind speed

A

In still air, the region around a transpiring leaf will become saturated (full) with water vapour so that no more can escape from the leaf –causing transpiration to slow down.
In moving air, the water vapour will be blown away from the leaf as fast as it diffuses out. This will speed up transpiration.
Transpiration therefore increases as wind speed increases.

134
Q

how is transpiration rate affected by temperature

A

On a hot day, water will evaporate quickly from the leaves of a plant as the water molecules have more kinetic energy.
Transpiration therefore will increase as temperature increases

135
Q

how is transpiration rate affected by light intensity

A

Light itself does not affect evaporation, but in daylight the stomata of leaves are open to supply carbon dioxide for photosynthesis.
This allows more water to diffuse out of the leaves and into the atmosphere

136
Q

2.58B practical - investigate the role of wind in determining the rate of transpiration for a leafy shoot

A

potometer!!

  1. The potometer must be set up under water - this prevents any air bubbles from entering the
    system and blocking the xylem..
  2. Cut the stem of a shoot whilst submerging the shoot
  3. Put the shoot stem into the bung, grease the joint with plenty of petroleum jelly - this prevents
    water loss and air entry
  4. Put the bung into the potometer.
  5. Make sure the tap is closed and it is full of water (no bubbles). Then lift the potometer out of the
    water.
  6. Leave the end of the capillary tube out of the water until an air bubble forms then put the end
    into a beaker of water.
  7. place a hairdryer so its blowing on the plant to recreate wind
  8. You can measure the transpiration rate as distance the bubble travels in five minutes (or the
    time taken for the bubble to travel a set distance). You should take a number of readings and
    calculate a mean rate.
137
Q

2.58B practical - investigate the role of increased temperature in determining the rate of transpiration for a leafy shoot

A

potometer!!

  1. The potometer must be set up under water - this prevents any air bubbles from entering the
    system and blocking the xylem..
  2. Cut the stem of a shoot whilst submerging the shoot
  3. Put the shoot stem into the bung, grease the joint with plenty of petroleum jelly - this prevents
    water loss and air entry
  4. Put the bung into the potometer.
  5. Make sure the tap is closed and it is full of water (no bubbles). Then lift the potometer out of the
    water.
  6. Leave the end of the capillary tube out of the water until an air bubble forms then put the end
    into a beaker of water.
  7. make the room hot
  8. You can measure the transpiration rate as distance the bubble travels in five minutes (or the
    time taken for the bubble to travel a set distance). You should take a number of readings and
    calculate a mean rate.
138
Q

2.58B practical - investigate the role of humidity in determining the rate of transpiration for a leafy shoot

A

potometer!!

  1. The potometer must be set up under water - this prevents any air bubbles from entering the
    system and blocking the xylem..
  2. Cut the stem of a shoot whilst submerging the shoot
  3. Put the shoot stem into the bung, grease the joint with plenty of petroleum jelly - this prevents
    water loss and air entry
  4. Put the bung into the potometer.
  5. Make sure the tap is closed and it is full of water (no bubbles). Then lift the potometer out of the
    water.
  6. Leave the end of the capillary tube out of the water until an air bubble forms then put the end
    into a beaker of water.
  7. surround the plant in a clear plastic bag
  8. You can measure the transpiration rate as distance the bubble travels in five minutes (or the
    time taken for the bubble to travel a set distance). You should take a number of readings and
    calculate a mean rate.
139
Q

2.58B practical - investigate the role of light in determining the rate of transpiration for a leafy shoot

A

potometer!!

  1. The potometer must be set up under water - this prevents any air bubbles from entering the
    system and blocking the xylem..
  2. Cut the stem of a shoot whilst submerging the shoot
  3. Put the shoot stem into the bung, grease the joint with plenty of petroleum jelly - this prevents
    water loss and air entry
  4. Put the bung into the potometer.
  5. Make sure the tap is closed and it is full of water (no bubbles). Then lift the potometer out of the
    water.
  6. Leave the end of the capillary tube out of the water until an air bubble forms then put the end
    into a beaker of water.
  7. make the room dark
  8. You can measure the transpiration rate as distance the bubble travels in five minutes (or the
    time taken for the bubble to travel a set distance). You should take a number of readings and
    calculate a mean rate.
139
Q

what is excretion

A

the removal of toxic waste products that have been made by cells

140
Q

what do the lungs excrete

A

CO2

141
Q

what do the kidneys excrete

A

Urea

142
Q

what does the skin excrete

A

Urea

143
Q

what are the organs of excretion

A

skin, lungs, kidneys

144
Q

what does the kidney do

A

excrete toxic waste products and substances in excess
osmoregulation

145
Q

whats osmoregulation

A

the process of maintaining water and salt concentrations across membranes in the body

example of homeostasis

146
Q

what are the 3 parts of the kidney

A

cortex - the outmost region
Medulla - the inner section of the kidney
Renal pelvis - the tube linking the kidney to the ureter

147
Q

where are the nephrons

A

in the kidney
Nephrons start in the cortex of the kidney, loop down into the medulla and back up to the cortex

148
Q

where do the contents of the nephron go

A

drain into the renal pelvis and the urine collects there before it flows into the ureter to be carried to the bladder for storage

149
Q

structure of the nephron

A

The nephron is made up of a kidney tubule which has several sections:
glomerulus inside the bowman’s capsule
Proximal convoluted tubule
Loop of Henlé
Distal convoluted tubule
Collecting duct

150
Q

what is the proximal convoluted tubule

A

section of nephron after the bowmans capsule and before the loop of henle

151
Q

what is the distal convoluted tubule

A

section of nephron after the loop of henle and before the collecting duct

152
Q

how does the kidney excrete

A

Ultrafiltration
Selective reabsorption of glucose
Reabsorption of water and salts

153
Q

what is ultrafilterisation

A

Arterioles branch off the renal artery and lead to each nephron, where they form a knot of capillaries (the glomerulus) sitting inside the cup-shaped Bowman’s capsule
The capillaries get narrower as they get further into the glomerulus which increases the pressure on the blood moving through them (which is already at high pressure because it is coming directly from the renal artery which is connected to the aorta)
This eventually causes the smaller molecules being carried in the blood to be forced out of the capillaries and into the Bowman’s capsule, where they form what is known as the filtrate
This process is known as ultrafiltration
The substances forced out of the capillaries are glucose, water, urea, salts
Some of these are useful and will be reabsorbed back into the blood further down the nephron

154
Q

what is in the glomerular filtration

A

glucose, water, urea, salts

155
Q

selective reabsorption of glucose

A

After the glomerular filtrate enters the Bowman’s Capsule, glucose is the first substance to be reabsorbed at the proximal convoluted tubule
This takes place by active transport (by specialized cells)
The nephron is adapted for this by having many mitochondria to provide energy for the active transport of glucose molecules
Reabsorption of glucose cannot take place anywhere else in the nephron as the gates that facilitate the active transport of glucose are only found in the proximal convoluted tubule

156
Q

whats in urine

A

water, urea, ions

157
Q

what happens in the loop of Henle

A

Salts are reabsorbed by diffusion and active transport as well as water by osmosis

also makes the medulla salty which makes osmosis more efficient

158
Q

what is absorbed in the distal convoluted tubule

A

The distal convoluted tubule (DCT) assists in the regulation of potassium, sodium, calcium, and pH levels in the body.

Biology (5 decks)

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