June 2019 Component 1 Paper

Question 1

Suggest a unit on the x axis (1)

Answer 1

Hours/days

Question 2

State what is represented with line E (1)

Answer 2

Carrying capacity

Question 3

Identity phases A B D (3)

Answer 3

A - LAG PHASE - slow rate of reproduction
B - LOG /EXPONENTIAL PHASE - rapid rate of reproduction
C - STATIONARY PHASE - carrying capacity is reached

Question 4

Suggest one factor that has caused in the shape of the graph in phase C what would u expect in population at the end of phase D (2)

Answer 4

. Build of of ethanol/ toxic waste
. Death phase / population will go into decline

Question 5

Identify the phase during which you would expect sexual reproduction of the yeast cell to be occurring. Explain why u think sexual reproduction would be an advantage to yeast (3)

Answer 5

. C and D
. Sexual reproduction leads to genetic variation
. Some individuals may survive as spores

Question 6

Describe a method that you could use to determine the number of living bacteria in the orginal sample prior to heat treatment (4)

Answer 6

. 100* series of dilution
. Volume 1cm^3 plated on each plate
. Incubated at 25-37C for 24-48hours
. Number of colonies counted
. Repeat 3* and calculate the mean

Question 7

Describe the effect of heat in the process of pasteurisation on the protein in the bacteria (3)

Answer 7

. Increased kinetic energy + denatures protein
. Shape of active site changes
. Protein can no longer carry out function

Question 8

Identify pigment x

Answer 8

Chlorophyll a

Question 9

4 difference of chemosynthesis and photosynthesis (4)

Answer 9

.Chemosynthesis - no light required, no chloroplast, sulfur produced, use of oxygen and production of water

. Photosynthesis- light energy required, chloroplast, sulfur not produced, and use of water.

Question 10

State 3 biological molecule and the inorganic molecule ion required for synthesis (3)

Answer 10

. Amino acid - nitrates
. Phospholipid - phosphates
. Nucleotide - nitrates and phosphate
. Chlorophyll - magnesium

Question 11

Explain how blocking electron transport from photosystems with this herbicide could lead to death of a plant (4)

Answer 11

. Destruction of chlorophyll- unable to absorb light
. Less atp for light independent reaction
. Less synthesised for respiration
. Destruction of cell membranes- kill /dried out cell

Question 12

Explain the term allosteric inhibition (2)

Answer 12

. Inhibitor binds to a site other than active site
. Changing the shape of active site / substrate can no longer fit in

Question 13

Explain why the cells uses inhibition of PFK as the main method of slowing glycolysis rather than using the inhibition of Hk (2)

Answer 13

. Glucose 6P can be converted to glycogen
. Allow storage of glucose

Question 14

Explain the role of photo systems in the light dependent stage of photosynthesis (3)

Answer 14

. Absorb light energy
. Excites electron
. Which can be used to power proton pump and synthesis ATP

Question 15

Explain how 3-BrPa acts as a potential anti cancer drug (3)

Answer 15

. HK is no longer able to bind with glucose
. No ATP produced so cell dies
. Glycosis cannot take place

Question 16

Explain why mitochondria were initially suspended in ice cold, isotonic buffer(4)

Answer 16

. Ice cold - stops enzyme activity
. Isotonic - maintain same water potential inside and outside of cell / stop water movement
. Buffer - maintain optimum pH

Question 17

Explain why pyruvate was used as the respiratory substrate and not glucose (2)

Answer 17

. Glycolysis occurs in the cytoplasm
. Pyruvate is the substance used in link reaction/ by mitochondria

Question 18

State one conclusion off the reliability of the results show on the table (3)

Answer 18

. 40C is optimum temperature
. 10C is very unreliable
. Use of data with 60C

Question 19

What is the process salt marsh community is formed (1)

Answer 19

Primary succession

Question 20

What is the first organism to colonises the mud (1)

Answer 20

Pioneer

Question 21

Give 3 abiotic factors which can cause this environment to be extreme for plant survival (6)

Answer 21

. HIGH SALT CONTENT - rooted plants will have problems getting water

. WATERLOGGING SOIL- roots need oxygen for active uptake of minerals

. TIDAL FLOW- causes a sideway drag on plants and 2 tides a day can possibly uproot a plant

. HIGH NITRATE - eutrophication

. WATER CONTAINS SAND PARTICLE - covering leaf preventing photosynthesis

Question 22

State why denitrification is classified as a biotic factor (1)

Answer 22

. Involves denitrifying bacteria
. Pseudomonas which are living organism

Question 23

Identify 2 factors affecting denitrification (3)

Answer 23

. Temperate affect the rate of dentrifaction
. Water logging - more detrification
. Nitrate level in mud - higher dentrification in summer as more farming runoff

Question 24

Describe a practical method which you could carry out on the salt marsh to investigate the change in vegetation over time (5)

Answer 24

Mark out a permanent/ same area each time (1)
B. 10m × 10m / other sensible area/ transect (1)
C. Method of sampling - use of quadrats (1)
D. Reviewed periodically (1)
E. All species {identified/ counted/ percentage
cover/abundance/frequency}/ measure species diversity
(1)
F. Ref to H & S issues re tide/ minimising damage to area (1

Question 25

Calculate approxmiate number of breeding pairs (3)

Answer 25

1455

Question 26

In areas where red kites were absent and then reintroduced the numbers increased much more rapidly that in areas where they were already established. Explain the reason for this (3)

Answer 26

. Fewer Predators . Less intraspecfic competition . For food/ nest sites / habitat . Less likely to pass on diseases as fewer numbers

Question 27

Suggest 2 ways in which society could improve the survival rate of red kites (2)

Answer 27

. Prosecution / legislation . Ecotourism / increase awareness . Making holding of poisons illegal . Feeding sites . Breeding programmes

Question 28

State what is meant by SSSI and why red kites may breed more successfully in these sites (2)

Answer 28

. Site of Special Scientific Interest (1) . SSSIs protected from development or other damage (1)

Question 29

9 marker

Answer 29

People burning fossil fuels 2. Trees store carbon in wood, stems, and leaves—biomass. 3. Deforestation eliminates plants which take carbon out of the atmosphere as they grow/ref to less PS removing CO2 4. 5. 6. 8. Clearing land for other use Replaced by crops which store less carbon/less wood. Replaced by other animals/ cattle producing CO2/ methane 7. Increased decay of vegetation. Ref to oceans absorbing heat which slows/gives a lag of increasing CO2 and increasing temps – will not have reached Max Data usage – Section B 1. Significant increase in both CO2 levels and temp since {approx. 1 850 - 1 900/ industrial revolution} 2. 3. 4. Ref to Temperature + year Ref to CO2 levels ppm + year Currently at 408ppm / increase of approx. 25-31 ppm since 2000 5. Correlation between CO2 levels ppm in atmosphere and global temperatures very close/ indicating {direct relationship/ link} between the two. 6. 7. human activities increasing CO2 raising global temperatures. Rising to highest level since 1 000 years ago. Aquatic – Section C 1. Dissolving carbon dioxide in the ocean creates carbonic acid, which increases the acidity of the water. 2. Shells end up being thinner and more fragile. 3. Could be increased photosynthesis 4. Increased algal blooms with higher temperatures 5. Higher temperatures = lower O2 in water – effect on fish 6. Migration of fish to cooler/warmer waters 7. Effect on fisheries/ fish 8. Coral reef destruction/coral bleaching/ loss of biodiversity