LC Biology Sample Paper 2 HL Solutions - Edco

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LEAVING CERTIFICATE BIOLOGY HIGHER LEVEL EXAM PAPER SOLUTIONS Sample Paper 2 Section A Q1

(a)

(b) (c) (d) (e)

Q2

A = Radicle B = Hypocotyl (Hook) C = Testa D = Cotyledon E = (True) Leaf Cotyledon and endosperm Starch (or fat or oil) Digestion To allow enzyme action

s n

(a)

Present

Pro-Eukaryotic

Prokaryotic

Reproduction

(d)


(e)

u l o

s

Yeast

Present Eukaryotic

Fission Budding

May be either

Size

(c)

eb

Binary

Auto/Heterotrophic

(b)

it o

Bacteria Cell wall

Heterotrophic

w

Smaller

o c d

Round, Rod, Spiral

10 (2 marks)

Bigger

10 (1 mark) 3 (1 mark)

E

Bacteria

Virus

Have nuclear membrane

No nuclear membrane

Have cell wall

No cell wall

Have cell organelles

No organelles

Food, water, pH, temperature, oxygen (present/absent), external solute concentration Spores (or endospores)

any 2 (1 mark)

any 3 (1 mark) (2 marks)

9


Q3

(a)

(i) (ii) (iii) (iv)

(v)

Food chain Spider or Thrush Snails and greenflies or greenfly and apple moth State what they compete for (e.g. lettuce or apples) Producer = lettuce or apples Primary consumer = snail, greenfly or apple moth Secondary consumer = Robin, Spider or Thrush Any correct example e.g.

(3 marks) (3 marks) (3 marks) (1 mark) (1 mark) (1 mark) (1 mark) (3 marks)

Mites



Aphids Oak tree

(b)

The statement is true It is true because of the huge loss of energy between each trophic level

s n

Q4

(a) (b) (c) (d) (e) (f)

Q5

(a) (b) (c) (d) (e)


(f)

Restriction enzymes cut DNA at particular sites (or where a certain sequence of bases occur) 3 10910 Ligation or splicing It combines DNA from different species Named animal e.g. sheep Product e.g. makes human clotting protein

eb

o c d

it o

so

lu

(3 marks) (3 marks) (3 marks) (3 marks) (3 marks) (2 marks) (3 marks)

w

E

Herbs speed recovery from colds As above (i) Too small or too few (ii) Selection was not random/all 5 had colds/all 5 were female Another group should not get herbs/but give them a non-active substance instead (placebo) The experimenter does not know who gets herb or placebo The people being investigated do not know who gets herb or placebo Law

10

(1 mark) (3 marks)

(2 marks) (2 marks) (2 marks) any 2 (2 marks) 2(2 marks) (2 marks) (2 marks) (2 marks)


Q6

(a)

(b)

Metabolism = all chemical reactions in an organism. Anabolic = where simpler substances form more complex ones. Catabolic = where complex substances are broken down to simpler forms.

3 (2 marks)

Anabolic enzyme = DNA ligase etc Catabolic enzyme = Any digestive enzyme e.g. amylase

2 (2 marks)

(c)



Substrate changed

s n

Enzyme – Substrate complex Diagrams Labels (d) (i) (ii) (iii) (iv)

(a)

(b)

it o

Rate of molecular movement increases/ Enzymes and substrate meet more often Enzyme changes shape Denatured pH

eb

o c d

Section B Q7

Enzyme unchanged

2 (2 marks) any 2 (1 mark)

u l o

s

any (1 mark) (1 mark) (1 mark) (1 mark)

w

Correct diagram Labels (pondweed, lamp, sodium hydrogen carbonate, water bath, any one other label.) Factor named = no marks How varied = same lamp/different distances or different amounts or concentrations/of sodium hydrogen carbonate Constant = temperature/CO2 conc. or temperature/light How kept constant =

(3 marks)

E

3 (1 mark)

2 (3 marks) (3 marks)

Temperature

Water bath / Same temperature

CO2 conc.

Same volume / Sodium hydrogen carbonate solution

Light

Same lamp / At same distance


Any 1 = 2 (3 marks) Estimate photosynthesis = Count number of bubbles/min Invalid result = any one reason, e.g. bubbles not counted properly or bubbles may be different sizes or plant produces less bubbles after some time

11

2 (3 marks)

(3 marks)


Q8

Q9

(a)

Glucose Diagram Labels (Glucose solution, yeast)

(3 marks) (3 marks) 2 (2 marks)

(b)

Chemical = potassium dichromate (or alternative) Change = colour goes from orange to green Other product = CO2 Substance = limewater Change = colour goes from clear to milky or cloudy Control = no yeast or no glucose

(3 marks) 2 (2 marks) (3 marks) (3 marks) 2 (2 marks) (3 marks)

(a)

A = Eyepiece lens B = Coarse adjustment (or focus) C = Fine adjustment (or focus) D = Objective lens E = Platform (or stage) F = Condensor (or diaphragm)

s n

it o

x 400

(c)

How a thin section was obtained/add stain/name of stain/indicate what stain shows or highlights/blot off surplus stain/add water/add cover slip/at an angle

eb

o c d

w

s

Diagram Labels – Plasma membrane Any two others (cell wall/nucleus/cytoplasm) Low power = to see a number of cells before examining a specific cell at HP.

E


u l o

6 (1 mark)

(b)

(d)



12

(3 marks)

4 (3 marks) (3 marks) (1 mark) 2 (1 mark) (3 marks)


Section C Q10

(a)

(i) (ii)

External factors = temperature/light/CO2 concentration/water/minerals Two named tropisms Benefit = maximum growing conditions in each example

(b)

(i)

Named promoter = auxin (or IAA) Example = cell elongation or fruit or root formation Named inhibitor = Ethylene or abscisic acid Example = Ethylene = leaf fall or ageing. Abscisic acid = prevents germination Named promoter = IAA Named tropism = phototropism How works = made in tip/passes down shady side/elongates cells/bending to light Commercial growth regulator use e.g. stimulates rooting or forms tissues or acts as weedkiller Benefit = as appropriate, e.g. cuttings grow faster or used in micro-propagation to form plants or kills weeds (dicots) but not crop (monocot)

(ii)

(iii)

3(1 mark) 2(1 mark) 2 (2 marks) (3 marks) (3 marks) (3 marks) any 1 (3 marks) (3 marks) (2 marks) 4 (1 mark)

s n

(3 marks)

it o

(c)

(i)

(ii)

eb

o c d


Q11

(a)

u l o

Chemicals/made in one place/transported in organism Act somewhere else/example of plant regulator/details of any hormone by way of example Plant protection (e.g. epidermis/cuticle/thorns/stings/heat shock proteins/stress protein) Name methods Explain how protect

(3 marks)

s

w



4 (3 marks)

any 2 (3 marks) 2 (3 marks)

E

Homeostasis = maintain constant internal environment Excretion = getting rid of waste products of metabolism Immunity = resisting infection

3 (3 marks)

(b)

Diagram = Labels = (i) Infection protection = barrier (ii) Maintain temperature in cold = hair upright or blood vessels contract (iii) Maintain temperature in cold = sweating or blood vessels dilate

(6 marks) 6 (2 marks) (3 marks) (3 marks) (3 marks)

(c)

(i) (ii) (iii) (iv) (v)

(3 marks) (3 marks) 2 (3 marks) (3 marks)

(vi)

All (or most) of the glucose and water passed into glomerular filtrate Glucose is re-absorbed Amino acids are small enough to pass through/red blood cells are too big ADH (or vasopressin) Production = pituitary gland Action = distal tubules or collecting ducts Plasma is too concentrated or equivalent statement

13



Q12

(a)

Any 1 benefit Any 1 harmful effect One other benefit or harmful effect

(b)

(i) (ii) (iii) (iv)

(c)

(i)

Diagram Labels Heterotrophic or saprophytic Spores and stolons Diagram Account = 2 hyphae grow close/swellings form/nuclei (or gametes) move into swellings/cross walls form/swellings touch/end walls breakdown/fertilisation/diploid zygote/forms zygospore/zygospore dormant/zygospore grows by meiosis 5 kingdoms 5 correct features

(ii)

Q13

Organism

Kingdom

Insect Fern Amoeba Bacterium Yeast Brown alga Daffodil

Animal Plant Protoctista (or protist) Monera Fungus Protoctista (or protist) Plant

eb

Viruses are not living (or they are borderline)

(a)

Red petals and large leaves

(b)

(i)

o c d

(iii)

(c)

E

Cross A R = Red petals r = White petals

s n

RrLi

Rl

Rrll

rL

rrL

rl

rrll

10 (1 mark)

s

7 (1 mark) (7 marks)

(5 + 4 marks) Cross B L = large leaves l = small leaves

4 (2 marks) 2 (2 marks) 2 (1 mark) (2 marks)

11 (1 mark)

(i)

(ii)

9 (1 mark)

u l o

Parents = RR and rr Gametes = R and r Offspring = Rr RrLl x rrll RL

(3 marks) 5 (1 mark) (3 marks) 2 (2 marks) (3 marks)

it o

w

(iii)

(ii)


(3 marks) (3 marks) (3 marks)



2 (6 marks)

Red petals and large leaves/white petals and small leaves Ratio = equal numbers or 1:1 or 50%:50%

14



Q14

(a)

(b)

(i)

Name of plant Gradient named or indicated Belt transect/ % cover/in each quadrat/shown as a table or list or chart or graph or histogram/frequency calculated

any 4 (3 marks)

(ii)

Plant named/% cover stated/in at least 5 quadrats Explanation = relate results to gradient

any 2 (3 marks) (2 marks)

(iii)

Frequency calculation explained % cover estimation explained

(i)

Competition = organisms struggle/for scarce resource

(ii)

Any relevant example State resource competed for State ecosystem investigated

(iii)

(c)

(i)

(ii)

(2 marks) (2 marks)

(3 marks) (3 marks) 2(3 marks)

s n

it o

Contest competition = physical struggle / between 2 (or more) organisms / one wins and rest lose Example Scramble competition = all organisms get some of the resource Example

eb

u l o

s

Any 2 methods of disease control, e.g. vaccination, antibiotics, improved sanitation, improved surgical methods. Or more food available/less deaths due to war

co

w



Contraception/smaller family size (due to social/education reasons) (In parts (i) and (ii) the reasons must be explained)


any 2 (3 marks) (3 marks) (3 marks) (3 marks)

(8 + 7 marks) (8 + 7 marks)


d E

15


Q15

(a)

(b)

(i)

Enzyme = A biological (or protein) catalyst Name of enzyme Name of substrate (these must match) Activity of enzyme = Time taken for colour change (or height of foam/in a given time)

(3 marks)

(ii)

pH = A measure of the acidity or basicity of a substance Scale = 0 to 14 Range in this experiment = 2 to 10


(iii)

Optimum pH = 7 Activity reduces = Shape of enzyme (or active site) alters Other factor = temperature


(i)

Immobilized enzyme = enzymes attached to each other (or to an inert material) Two methods described = Attached to a support or enclosed in a gel or membrane or attached to each other Two diagrams


s n

it o

(ii)

(iii)

(c)

(i)


(ii)

u l o

Bioreactor = a vessel in which a biological reaction is carried out Two advantages = efficiency of enzyme not affected/enzymes may be reused/product formed is free of enzymes/enzyme activity may be improved

s

eb

w

Name one immobilised enzyme = glucose isomerase or penicillin acylase or lactase Describe its use = as appropriate

o c d

E

Mechanical digestion = Physical breakdown of food Chemical digestion = Breakdown of food using enzymes Substance

Role

(3 marks) 2 (3 marks) 2 (3 marks) (3 marks)

any 2 (3 marks)

(3 marks) (3 marks) 2 (3 marks) (4 marks) Mechanical or chemical

An amylase

Starch to Maltose

Bile salts

Emulsify (breakdown) fats

Mechanical

Stomach contractions

Churn food

Mechanical

A lipase

Fat to fatty acids and glycerol

Chemical

A protease

Protein to peptide or amino acids

Chemical

10 (1 mark)

5 (2 marks)

16



Chemical
