2022 eduqas unit 2 paper

Question 1

Holozoic?

Answer 1

internal digestion of food

Question 2

Saprotrophic?

Answer 2

external digestion of food by secretion of enzymes onto the food
( extracellular digestion)

Question 3

Photoautotrophic?

Answer 3

formation of organic molecules from inorganic molecules using light energy

Question 4

What secretes lipase?

Answer 4

pancreas

Question 5

What secretes bile?

Answer 5

liver

Question 6

What is the site of mechanical digestion?

Answer 6

mouth/stomach

Question 7

Absorption of water?

Answer 7

colon

Question 8

Why was it necessary to stain the tissue before it was viewed under the microscope?

Answer 8

seem more detailed structures
differences between tissue layers

Question 9

Calculating actual size of the villus?

Answer 9

actual size = image/magnification

36 x 1000 / 29.47 = 1221.4 micrometres

Question 10

the function of the villi and how villi are adapted to their function?

Answer 10

absorption of nutrients
they are highly folded, therefore increases the surface area

Question 11

Calcium ions?

Answer 11

strengthens bones and teeth

Question 12

Phosphate ions?

Answer 12

constituent of phospholipids, ATP/nucleic acids

Question 13

why is the muscle layer of the wall of the oesophagus thicker than that of the duodenum?

Answer 13

food is solid in the oesophagus so increased force is needed using peristalsis of circular and longitudinal muscles to contract

Question 14

Phylogenetic tree?

Answer 14

The more recent the branching the more related the cone snails

Question 15

Explain what is meant by the binomial system and the reasons for scientists using it?

Answer 15

Binomial system is naming system made of 2 parts - the Genus and Species
Common name could vary regionally
Could cause confusion when identifying species

Question 16

Explain how DNA analysis could be used to determine the position of the organisms?

Answer 16

Carry out (DNA) base profiling
More similarity closer related

Question 17

State how the genetic diversity within 1 species of cone snail could be assessed?

Answer 17

by analysing the proportion of the population with a specific allele

Question 18

Explain why the offspring were not fertile?

Answer 18

They were the same species

Question 19

Explain the mechanism of stomatal opening which allows gas exchange to take place?

Answer 19

K+ pumped into guard cells using active transport in light
stomach is converted to malate
lowering water potential in guard cells
water moves in by osmosis
guard cells become turgid
uneven bending of guard cells

Question 20

Describe and explain 3 adaptations which reduce in loss of water vapour in plants that are in low water conditions?

Answer 20

xerophytes
Sunken stomata so less air movement
hair ( trichomes) to trap water vapour and reduce water potential gradient
thick cuticle to reduce evaporation

Question 21

Suggest why the method used to obtain the impression in image 3.1 would not be a suitable technique to measure stomatal density in the leaf?

Answer 21

Sunken stomata

Question 22

Suggest how the method used to obtain the impression of the stomata in image 3.1 may need to be modified if using a hydrophyte leaf

Answer 22

apply nail varnish to the upper surface

Question 23

Complete the risk assessment for the main hazard in the fish head dissection?

Answer 23

Hazard
scalpel is sharp
cuts to skin
cut away from body

Question 24

Explain 4 ways in which gills are adapted for gas exchange?

Answer 24

Gill filaments - increase surface area
rich blood supply to maintain concentration gradient for oxygen
counter current flow of blood to maintain concentration gradient
one cell thick for short diffusion distance

Question 25

Why is salmon is more efficient than the shark in absorbing oxygen from the water passing over the gills?

Answer 25

blood and water flow in opposite directions across the gill plate
diffusion occurs along whole gill plate
higher oxygen in the blood

Question 26

Suggest a difference in the variation rate?

Answer 26

more ventilation moves more water across the gills per minute
to get some volume of the oxygen
in order to meet metabolic needs

Question 27

The independent variable for the potometer?

Answer 27

the distance of the lamp from the plant

Question 28

The dependent variable for the potometer?

Answer 28

the height of the water

Question 29

Why was oil added to the surface of the water in the reservoir before the investigation started?

Answer 29

to prevent water escaping the reservoir
only route for water loss is through transpiration

Question 30

Identify 2 other factors which could affect the water loss from the plant used in the experiment
justify why factors need to be controlled?

Answer 30

Temperature -
Higher temperature would result in
increased transpiration by evaporation

Humidity - Higher humidity would result in decreased
gradient

Air movement - Higher air movement would result in
increased evaporation

Surface area of leaves - Change stomatal density

Question 31

Calculate the volume of the water taken up by the roots per minute when the lamp was 30cm from the plant using
pir2 x h
diameter was 8 mm?

Answer 31

v = pi x 4^2 x 4
v = 150.72 / 60
2.51

Question 32

How is the method modified to investigate the effect of windspeed on water uptake by the roots?

Answer 32

control light intensity
range of wind speeds

Question 33

Why is the rate of water uptake by the roots not equal to the rate of water loss?

Answer 33

water is used to maintain turgidity

Question 34

One precaution that should be taken when preparing the cut shoot in order to not affect the movement of water in the xylem?

Answer 34

cut shoot under water
prevent air bubbles entering the xylem
prevent breaking transpiration stream

Answer 35

ECG
p wave - atria contract
( systole)
QRS depolarisation - ventricle contracts before ventricular systole
T repolarisation of the ventricles ( diastole)
SAN send impulses of excitation across the atria
impulse passes to the AVN
impulse down bundle of His to apex of the heart
impulse travels up to the purkinge fibres and causes ventricles to contract from the base upwards

Normal
1 Normal P wave
QRS is the same
T wave is the same
QRS - regular intervals
fewer beats per minute

Patient
many p waves
irregular intervals
( more beats per minute )

Problems
SAN firing too quickly
Atria not contracting
arrhythmia
Atria are not able to fill
not enough blood to ventricles