Answers Paper 2

4551/2 BIOLOGY Marking scheme

SULIT

1

JABATAN PELAJARAN NEGERI MELAKA

MARKING SCHEME

BIOLOGY PAPER 2 TRIAL EXAMINATION SPM 2007

SECTION A QUESTION 1 Question 1 (a)(i)

(a)(ii)

Marking Criteria

Marks

Remark

Able to name the structure P,Q and R Answer P : Phospholipid bilayer Q : Pore protein R : Carrier protein Able to state the process at R

1 1 1

3

1

Answer: Process at R: Active transport Able to explain the process at R Sample answer: P1:

P2:

1 (b)

The movement of particles/molecules/ions againts the concentration gradient across the plasma membrane/ from the lower concentration of particles to the higher concentration of particles The process requires energy provided by ATP

1 1

3

1

1

Able to explain the differences between the process at P and Q Sample answer P allows small water soluble molecules, lipid soluble molecule and gaseous to move across the plasma membrane while Q has specific shape and charge that only allow specific ions/molecule to pass through.

1(c)

Able to explain the process red blood burst.

© 2007 Trial exam

4551/2 BIOLOGY Marking scheme

Sample answer F :The concentration of solution outside a cell is lower than the concentration inside the cell. E1 :Water molecules enters/diffuse into the cell (causing it to swell up) E2 :The plasma membrane is too thin/delicate to with stand the osmotic pressure that develops within the cell. 1 (d)(i)

SULIT

2

1 1 1

max 2

Able to explain what happen to the plant after two days watered with fertilizer.

F = must

Sample answer: F : The soil solution become more concentrated/hypertonic than the cell sap of the roots E1 : water diffuses from the cell sap into the soil by osmosis E2 : the cell are plasmolysed (d)(ii)

Able to draw the plasmolysed plant cell.

1 1 1

Max 2 1

Sample answer

Total Marks

QUESTION 2

© 2007 Trial exam

12

4551/2 BIOLOGY Marking scheme

Question 2(a)

SULIT

3

Marking Criteria Able to name structures R and Y Answer : R - palisade mesophyll Y - chlorophyll Able to explain the reactions which take place in P (granum) and Q ( stroma).

Marks 1 1

2

Sample answer: 2(b)(i)

2(b)(ii)

2(c)(i)

Structure P: - In P (granum), light energy is absorbed/captured by chlorophyll to produce chemical energy / ATP - Water molecules are split into ions H+ and OH-/ Photolysis occurs Structure Q: - In Q (stroma), dark reaction occurs - Hydrogen atoms combine with carbon dioxide to form glucose Able to write down the full equation of photosyntesis

1 1 1 1

4

1

1

2

2

Answer: light Water + carbon dioxide

glucose + oxygen chlorophyll

light // 6H2O + 6 CO2

C6H12O6 + 6O2 chlorophyll

2(c)(ii)

Able to draw the arrows. Sample answer.

3 arrows √ ___ 2 marks 2 arrows √ ___ 1 mark 2 (d)(i)

Able to state the importance of photosynthesis

© 2007 Trial exam

Remark

4551/2 BIOLOGY Marking scheme

SULIT

4

Sample answer:

2(d)(ii)

E1 Provide food to human beings/animals// E2 Provides/replaces oxygen in the atmosphere// E3 Help maintaining percentage of CO2/O2 in the atmosphere Able to explain the affect of air pollution in the rate of photosyntesis.

1 1 1

Any 1

1 1 1 1 1

m ax2

Sample answer: F1 E1 E2 E3 E4

Particles accummulate on the leaf surface Covers the stomata//reduces O2 and CO2 gas exchange Cuts/reduces light intensity (that reached the leaves) Rate of photosynthesis decreases Less CO2 is absorbed from atmosphere and less O2 is released

12 Total Marks

QUESTION 3 Question 3(a)

3(b)(i)

Marking Criteria Able to name the vitamin S and Ion T Answer Vitamin S:Vitamin K Ion T: Ion Ca 2+ Able to name structure W Answer: Structure W: Fibrin

Marks

1 1

2

1

1

3(b)(ii) Able to explain how structure W is formed Sample answer: P1:

When the blood vessel damage the plateles release a protein called thromboplastin.

P2:

Tromboplastin, with the help of calcium and vitamin K, convert prothrombin to trombin.

1

Trombin acts as an enzyme to convert fibrinogen into structure W / fibrin

1

P3:

3(b)(iii)

Able to state the necessity for the formation structure W/

© 2007 Trial exam

1

3

Remark

4551/2 BIOLOGY Marking scheme

SULIT

5

blood clotting. Sample answer 1. to prevent serious blood loss 2. to prevent the entry of microorganisms and foreign particles into the blood 3. to maintain normal blood pressure 4. to maintain circulation of blood in a closed circulatory system. 3(b)(iv)

3(c)

3(d)

1 1 1 1

max 2

Able to explain why the structure W does not normally formed in intact blood vessels. Sample answer F: Heparin in plasma/action of anticoogulants P: prevent clot formation by suppressing activation of the platelets. Able to name the health problem due to the blood clot within the unbroken blood vessel. Answer Trombosis Able to suggest one method. Answer

1 1 1

2 1

1

1

Injection with blood factor TOTAL

© 2007 Trial exam

12

4551/2 BIOLOGY Marking scheme

SULIT

6

QUESTION 4 Question 4(a)

Marking Criteria Able to state the function of kidney in osmoregulation.

Marks

Sample answer: E1:Kidney regulates salts/solutes and water levels in the blood

4(b)(i)

4(b)(ii)

E2:to maintain a constant water potential in the body / regulates the osmotic pressure of the blood Able to state the blood osmotic pressure after drinking access of water Answer : osmotic pressure in plasma decreases // water potential increases. Able to explain hypothalamus and gland M response to the condition after drinking access of water.

1 1

2

1

1

Sample answer: Hypothalamus:

4(c)(i)

4(c)(ii)

4(d)

E1: Osmoreceptor (in hypothalamus) detect the changes / less stimulated

1

Gland M : E2:Pituitary gland / gland M is less/ not stimulated/trigger E3:Hence less hormone P / ADH secreted E4:Less water reabsorbed

1 1 1

4

1

1

Able to state the hormone Q Answer : Hormon Q = aldosterone hormone Able to explain the mechanism of hormone Q to restore the osmotic pressure back to normal levels. Sample answer: E1:(Adrenal gland less stimulated) , less aldosterone produced, E2: less salt is reabsorbed / most of it will be secreted through urine Able to explain the operation of haemodialysis machine Sample answer : E1:the separation of solute molecules based on the principle’s of dialysis / their different diffusion rates E2:across a semi- permeable membrane

© 2007 Trial exam

1

2

1 1 TOTAL

QUESTION 5

1

2 12

Remark

4551/2 BIOLOGY Marking scheme

Question 5(a) 5(b)(i) 5(b)(ii)

5(b)(iii)

SULIT

7

Marking Criteria Able to name the types of wings in fruit flies. Answer (i) vestigal/short wing (ii) normal wing Able to state one factor cause variation in fruit flies. Answer : genetic factor Able to explain how the factor that cause the variation Sample answer : E1:crossing over and independent on random assortment E2:produce a different gene in it’s content Able to draw a graph shows the different types of variation in fruit flies Answer:

marks

Remark

2

2

1

1

1 1

2

1 1 1

3

Number of fruit flies

10

5

0

Norrmal

Vestigal types of wing wing wing Labelled axis bar chart normal bar chart vestigal

5(c)(i) 5(c)(ii)

Able to state one factor that cause mutation. Sample answer : 1 UV ray /Gamma ray / X-ray Able to describe the differences between two mutation in diagram 5.2(i) and diagram 5.2(ii) Sample answer : E1: 5.2(i) deletion and 5.2(ii) inversion. 1 E2: deletion is a segment of chromosomes break off and lost and join up to give a shorter chromosome but the segment 1 of chromosome in inversion break off and reattached in and inverted position. 1 E3: Deletion and inversion can caused mutation TOTAL

© 2007 Trial exam

1

3 12

4551/2 BIOLOGY Marking scheme

SULIT

8

QUESTION 6 Question 6a(i)

Marking Criteria

Marks

Remark

Able to state the type of skeleton in organism P and Q Able to explain each type of skeleton correctly Sample answer Organism P - Hydrostatic skeleton - The support is derived from body fluid contained within the bodys cavity Organisma Q - endoskeleton - The support is derived from hard skeleton of bones inside the body.

6a(ii)

1 1 1 1

4

1 1

2

Able to state one similarity Explanation Sample answer -

The skeleton supports important body organ It protects the organ from damage.

Able to state two differences Sample answer

1. Exoskeleton found in the bodies of invertebrate such as arthropods but endoskeleton found in the bodies of all vertebrate including fishs,amphibians, birds, reptiles and mammals. 2. Exoskeletons are non-living meanwhile endoskeletons are living structure. 3. exoskeleton is made up of chitin whereas in crab, it contains lime, but endoskeleton made up of calcium and phosphate. TOTAL

© 2007 Trial exam

1+1

Any two

1+1 1+1

4

10

4551/2 BIOLOGY Marking scheme

SULIT

9

Marks Question 6(b)

Remark

Marking Criteria Able to state the cause of each problem Able to suggest ways to overcome each health problem Sample answer 1. Muscle cramp F1: caused by involuntary and painful contractions which develop when there is a lack of stretching during an exercise. E1: Heat, massage, rubbing and rest can reduce cramps. 2. Muscular dystrophy F2: Caused by mutations in a gene on the X chromosome. E2.1: The mutated gene makes the body unable to produce the protein needed to build and maintain healthy muscle. E2.2:Medicine and therapy are provided to slow the course of the disease 3. Osteoporosis F3: cause by the reabsorption of calcium and phosphates into the bloodstream is more than the withdrawing of calcium during the formation of bones. E3.1: Prevention beginning from childhood, with good nutrition and exercise E3.2:A balance diet including and adequate calcium intake E3.3:Fall prevention in elderly people. 4. Arthritis F4:cause by the exhaustion of cartilage, depletion of sinovial fluid and degeneration of sinovial membrane at the joint. E4: Certain drug such as colchicine and non-steroidal anti flammatory drugs are used to reduce the pain. TOTAL

© 2007 Trial exam

1 1 1 1

1

1

1 1 1 1

1 10 10

4551/2 BIOLOGY Marking scheme

SULIT

10

QUESTION 7 Question

Marking Criteria

Marks

7(a) Able to explain the importance of meiosis in maintaining the number of chromosomes in human. Sample answer The importance of meotic cell division P1-

P2P3P4P5P6-

7(b)

Meiosis is the process of cell division that reduces the number of chromosomes in new cells// meiosis halved the number of chromosomes in the parent cell. Meiosis produce haploid reproductive cells or gametes. Each gamete receives one chromosomes from every pair of homologous chromosomes. The gametes contain only 23 chromosomes / haploid numbers of chromosomes Sexual reproduction involves the fusion of two haploid gametes during fertilization. This results in the formation of a diploid zygote with 46 chromosomes( similar number of chromosomes with parent).

1

1 1 1 1 1

max 4

Able to explain how the plant being cloned Sample answer; Technique – Tissue culture

1

P1-

Small pieces of tissue(explants) taken from sterilized parent plant. P2- The explants are then placed inside a test tube containing nutrient and growth hormones. P3- Plant cells divide by mitosis to form a callus (undifferentiated mass of tissue) P4- Cells in the callus develop into embryo and later into plantlets P5- The rooted plantlets are then transferred to soil and kept in controlled environment until they grow into adult plants P6- From one original plant, hundreds of genetically plants could be produced Skill of application Q1- Must have P2&P4&P5 TOTAL

© 2007 Trial exam

1 1 1 1 1 1

max 5

1

1 10

Remark

4551/2 BIOLOGY Marking scheme Question 7(c)

SULIT

11

Marking Criteria Able to explain the adaptive characteristics of organ P,R,S and T that enable the mangrove trees to survive at the swampy seashore.

Marks

Remark

Sample answer Organ P F1- The leanes have thick cuticle//sunken stomata E1- reduce transpiration F2- The leaves are thick and succulent E2- to store water Organ R F3- Highly branched root system(that spread over a big area) Prop roots E3- to support the plants in soft ground F4- Cell sap of mangrove root in hypertonic to seawater// cell sap has a salt content that is higher than that of seawater E4- able to withstand the high salt content of seawater to prevent water loss by osmosis from the root. Organ S F5- Breathing root call pneumatophores E5- Grow upward and protrude out of the ground to absorb atmospheric oxygen Organ T F6- Viviparous seed(the seed start geminating while they are still attached to the parent plant) E6- seedling do not drown/ drift to the sea

1 1 1 1 1 1 1

1

1 1

1 max 9 1

Able to analyse Q1- Any F and E that compliment

1 1 TOTAL

10

QUESTION 8 Question

© 2007 Trial exam

Marking Criteria

Marks

8(a)(i)

Able to define the meaning of menstrual cycle

4551/2 BIOLOGY SampleMarking answer scheme :

8(a)(ii)

SULIT

12

1) the production of ovum by the ovary of the female 2) follow a cycle in 28 days Able to describe the role of hormones FSH, LH, oestrogen and progesterone which have a different level in the menstrual cycle to produce an ovum

1 1

2

Sample answer:

F1: What FSH/hormone P does ♦It stimulates the development of the follicles in the ovaries. Usually one follicle ripens to become the Graafian follicle in one of the ovaries during each cycle. ♦It also stimulates the follicles in the ovary to secrete oestrogen. F2: Effects of oestrogen/ hormone X ♦After menstruation, it causes the repair and growth of the uterine lining (endometrium). ♦The uterine lining becomes thick and spongy with blood vessels. ♦A high concentration of oestrogen in the blood Inhibits FSH production, preventing the ripening and growth of more follicles. ♦It stimulates the pituitary gland to secrete luteinising hormone (LH).

F3: Functions of LH/ hormone R ♦It causes ovulation. ♦It also causes the formation of the corpus luteum. F4: Corpus luteum ♦ The corpus luteum secretes progesterone and also some oestrogen. F5: Functions of progesterone/ hormone Y ♦It keeps the uterine lining thick and well supplied with blood, it for the implantation of the © 2007 Trial♦preparing exam embryo. ♦It inhibits both FSH and LH production.

1 1

1 1

1 1

1 1

1 1

1 1 1

max 8

Remark

4551/2 BIOLOGY Marking scheme

SULIT

13

QESTION 9: Marks Question 9 (a)(i)

Remark

Marking Criteria Able to name the environmental problem Answer Drought/ global warming Able to explain how it happens based on the following criteria. C1 – Increase in the carbon dioxide in atmosphere. C2 – Factor which contribute to increase of carbon dioxide content in the athmosphere C3 – Increase in global temperature C4 – Factors which contribute to the increase in global temparature Sample Answer E1: Extensive cutting down of trees increases the Earth’s temperature E2: More carbon dioxide brings about greenhouse effect E3: Increase carbon dioxside content in the atmosphere E4: Carbon dioxside trap heat E5: Buildings with glasses reflect heat E6: Increase in surrounding temperature E7:Increase the frequency of drought

(a)(ii)

1 1 1 1 1 1 1

Any 4

Able to state the steps to overcome the environmental problem C5: Reduce burning C6: Control deforestation Sample Answer E1: Replacing energy of fossil fuel eg energy generate from wind / water E2: Limit open burning E3: Limit deforestation E4: Replanting after deforestration E5: Promotes green world Skill to synthesize Q1- Ability to relate carbon dioxide content with the increase in atmospheric temperature and means to decrease the

© 2007 Trial exam

1 1 1 1 1

5

1

1

4551/2 BIOLOGY Marking scheme

SULIT

14

carbon dioxide content and temperature in the atmosphere. Explain C1, C3, C5, C6. (b)

Able to explain the affect of sewage to the pond and aquatic animal. Sample answer: Sewage released gradually: E1:Sewege has nitrate and phosphate salts which encourages algae growth E2:Algae is the main produce of food for aquatic organisms E3:Aquatic animal will get enough food encouraging their growth and reproduction E4: the size and numbers of aquatic organism will thus increase

1 1 1 1

sewage content increase: E5:Sewage increase will cause algae to grow and reproduce rapidly E6:Algae will cover the pond surface this prevent sunlight from reaching aquatic plants at the bottom of the pond E7:The submerged aquatic plants will die as they cannot photosynthesis.

1

E8:The decomposition by bacteria will take place using oxygen

1

E9:The dissolve oxygen level will drop

1

E10:Aquatic animals will die due to lack of oxigen in water.

1

1 1

10

TOTAL 20

© 2007 Trial exam