cape biology

One of the roles of water in living organisms is that it acts as a transport medium in blood.

The diagram below shows the structure of a triglycride.

Which of the following properties of water accounts for this role? (A) (B) (C) (D)

o

H

I H-

C-

H-

C-

-

X

-

C

/'o../"v"'V

-

II C

/'o../"v"'V

I

High specific heat capacity Strong cohesive forces between molecules High heat of vapor isat ion Solvent for polar molecules and ions

I C-X

II C

X

/'o../"v"'V

o

II

o

I H

The diagram below shows a ring structure of glucose.

Which of the following represents the bond labelled X?

-N-

I H

-C-

I OH

Which of the following indicates the form of glucose and in which molecule it is present?

(A) (B)

(C)

(D)

3.

-C-

II o

Where resent Cellulose Starch Cellulose starch

a a

f3 f3

This figure below is part of a growing polysaccharide chain.

~ Polar amino

X

acid

The name of the bond labelled X is (A) (B)

(C) (D)

glycosidic peptide hydrogen diester

Which of the following correctly names the type of bond represented by the broken line (---) in the diagram above? (A) (B) (C) (D)

Ionic bond Hydrogen bond Hydrophobic bond Oisulphide bond GO ONTO THE NEXT PAGE

-36.

Food tests were carried out on four different solutions. Which of the following combinations shows the solutions that contained only starch and sucrose? Biuret Test

Solution

(A) (B) (C) (D)

Acid Hydrolysis then Benedict's Test

~ x ~ x

Key

~ ~ x x

Iodine in Potassium Iodine

Benedict's

x

x x ~ ~

~ x ~

x = negative result

~ = positive result

Which of the structures labelled I, II, III and IV is concerned with protein synthesis? • (A) (B) (C) (D)

I II III IV

Which of the following is NOT a function of the Golgi apparatus? (A) (B) (C)

(D)

Which of the following, labelled I to IV, gives the correct site where xylem tissue is found in a diotyledonous stem?

Lipid synthesis Manufacture oflysosomes Packaging of glycoproteins Membrane formation

(A) (B) (C) (D)

10.

I II III IV

Which of the following combinations correctly identifies the phloem and xylem tissues?

(A) (B) (C)

(D)

Phloem M N 0 P

Xylem N 0 P M

Which of the following cells is represented by the diagram below?

Four identical samples of plant tissue are placed in four different solutions. Each sample of plant tissue has a water potential of 800 kPa. In which solution would full plasmolysis occur within the tissue?

(A) (B) (C) (D)

(A) (B) (C) (D)

Neurone Plant cell Bacterium Sperm

I.

III. IV.

(A) (B) (C) (D)

(A) (B) (C) (D)

Channel protein Cholesterol Glycoprotein Extrinsic protein

300 kPa 500 kPa 800 kPa 1100 kPa

Which of the following pairs of statements explains the mode of action of enzymes?

II. Which of the foHowing identifies the structure represented by X in the diagram below?

-

They are globular proteins and as a result are soluble. They bond to the substrate molecules at their active sites. They break down substrate molecules into products. They lower the activation energy for the reaction. I and II only II and III only II and IV only III and IV only

Item 15 refers to the diagram below which represents the activation energy for an enzyme-catalysed and an uncatalysed reaction.

15.

The activation energy for an enzyme-catalysed reaction is represented by the region labelled \l\}

\.

(B) (C\

II

(D)

16.

III

N

The graph below shows the time course of the activity of the enzyme sucrase at various temperatures.

Quantity

of product formed

At which of the following temperatures does the enzyme work at the FASTEST rate? (A)

10 DC

(B)

25 DC

(C) (D)

37 DC 60 DC

Item 17 refers to the diagram below which shows a typical portion ofthe DNA molecule of the chromosome.

The amino-acid sequence leucine-lysine-valine occurs in a portion of a polypeptide molecule. The table below shows the DNA codes for these amino-acids.

Leucine GAA

Valine CAA

Transfer RNA molecules with anticodons needed for the synthesis of this polypeptide are (A) (B) (C) (D)

GAA GAA CUU CUU

TTT UUU AAA UUU

CAA CAA GUU GUU

One structure that may be observed in animal cells during mitosis but is NOT seen in plant cells is (A) (B) (C) (D)

Which of the following is NOT represented by the region labelled X? (A) (B) (C) (D)

Hydrogen bonds between base pairs Two anti-parallel strands Pyrimidine to pyrimidine base pairing One complete turn of the double helix

Which of the following events occurs in transcription as well as in replication of DNA ? (A) (B) (C) (D)

Free nucleotides bond to the DNA strand. Two new DNA molecules are produced. Uracil nucleotides bond to adenine on the DNA strand. Only part of the DNA molecule containing a gene unwinds.

spindle fibres centro meres centrioles chromatids

Which of the following statements correctly describes homologous chromosomes?

IY.

They are the same length. They are held together centromere. They have the same gene loci. They have identical alleles.

(A) (B) (C) (D)

I, II and III only I and III only I, III and IV onl}' III and IV only

III.

by

Item 24 refers to the diagram below which shows the longitudinal section of part of a flower.

Which of the following combinations correctly represents the chronological order of the events occuring in meiosis? Chromatid pairs line up at rightangles to the equatorial plane. Homologous chromosomes are pulled apart by spindle fibres. Chiasmata form between chromosomes ofthe bivalents. Individual chromatids migrate to poles. Chromosomes shorten and thicken and appear as pairs of chromatids. (A) (B) (C) (D)

I, III, IV, II, V III, V, II, IV, I V, I, II, III, IV V, III, I, II, IV

Item 23 refers to the diagram below which shows a pollen grain,just prior to germination.

24.

The micropyle and funicle are represented by (A) (B)

(A) (B)

(C) (D)

a diploid tube nucleus and a haploid generative nucleus a diploid tube nucleus and a diploid generative nucleus which divides into two gametes a haploid tube nucleus and a haploid generative nucleus a haploid tube nucleus and a diploid generative nucleus which divides into two gametes

(C) (D)

I and V II and V III and IV IV and V

- 9The following diagram shows the formation of gametes in a carpel of a flowering plant.

One feature that is common to both sperm, (male gamete) and egg (female gamete), is (A) (B)

Flower [2n]

l l

(C) (D)

Carpels

Embryo sac mother cells

y

The following list represents some stages in the process of fertilization: I. II. III. IV.

Q]

/

~

(A) (B) (C) (D)

~

Which of the following correctly identifies the number of sets of chromosomes present at each numbered stage?

(A) (B) (C) (D)

I 2n 2n n 2n

II 2n 2n 2n n

III n 2n 2n n

Acrosome releases enzymes. Sperm enters cell. Sperm contacts jelly coat of egg. Impenetrable layer forms at egg surface.

Which of the following indicates the correct order of these stages?

~ Fused polar nuclei

Female gamete

a diameter of approximately IOO~m the abundance of mitochondria in the cytoplasm a haploid nucleus a food store

I, II, IV, III III, I, II, IV IV; II, I, III IV, III, II, I

Item 29 refers to the simplified diagram below which shows an embryo and surrounding membranes.

IV 2n 2n n 2n

Which of the following identifies the structure which provides nourishment for the spermproducing cells in the testes? (A) (B) (C) (D)

Seminiferous tubule Sertoli cell Interstitial cell Connective tissue 29.

The region which ftmctions in protecting the embryo from mechanical shock and injury is labelled (A) (B) (C) (D)

I II III IV

Flower colour in a certain species of plant can be white, light pink or dark pink. There are two hypotheses to explain this: Hypothesis 1: Hypothesis 2:

There are two co-dominant alleles. There are three alleles, one for each flower colour.

analysing the flower pigments in several different flowers using chromatography to find out whether some plants contain more than one pigment controlling cross-pollination of the different varieties, in all possible combinations, and recording the colours shown by the offspring controlling self-pollination of many individuals of each colour variety and recording the colours shown by the offspring of each individual plant sampled surveying large wild populations randomly and fmding the ratios of the different colours in these populations

Two parents, both of blood group A, have a son of blood group A. The probability that their next child will have blood group 0 is (A) (B) (C) (D)

0.25 0.375 0.50 0.75

Item 32 below shows the inheritance of a recessive allele 'a' that causes a genetic disorder which appears in the double recessive form, 'aa'.

6 Which females the disorder? (A) (B) (C) (D)

7

are heterozygous

for

3 only 5 only 3 and 5 only 3,5 and 7

Which of the following does NOT cause variation to occur in a population? (A) (B) (C) (D)

Reshuffling of genes Mutations of chromosomes Random fertilization Petrification of genetic material

Which ofthe following increases the number of different alleles in a population of organisms? (A) (B) (C) (D)

Crossing over Gene mutation Random fusion of gametes Reassortment of chromosomes meiosis

in

In the Caribbean, sweet potato plants are propagated asexually by tubers. Twenty tubers collected from one plant were grown to produce 20 second-generation plants. All the tubers from these second-generation plants were collected, weighed and their mean weight calculated. Twenty tubers closest to the mean weight were grown under the same circumstances as before. All the third generation tubers were collected, weighed and their mean weight calculated.

In the hereditary disease, sickle-cell anaemia, the amino acid, glutamic acid, found in normal haemoglobin, is substituted at a particular location by the amino acid valine. The codon for glutamic acid is GAA. The codons for valine can be either GUU, GUC or GUA. One single base alone is changed during the mutation. Which of the following would be the corresponding DNA nucleotide responsible for the change? (A) (B)

(C) (D)

Compared to the second-generation the third generation tubers have

CAA CAT CAU CAG

(A) (B) (C) (D)

tubers,

a greater mean weight and increased genetic variation a greater mean weight and unchanged genetic variation an unchanged mean weight and reduced genetic variation an unchanged mean weight and an unchanged genetic variation

Animalia I

I

Chordata I

I Mammalia I

I Primates I

I Cercopithidae I

I Cercopithecus I I I Cercopithecus mitis Cercopithecus aethiops blue monkey green monkey

37.

I Colobus

I Colobus badius red colobus

Which of the above represents the genus to which the green monkey belongs? (A) (8) (C) (D)

Mammalia Primates Cercopithidae Cercopithecus

I

.

I

Colobus poly koma black and white colobus

- 12 -

Three of the hypotheses natural selection are: I.

II. III.

in the theory of

39.

Speciation is the process by which new species arise. Which TWO of the following ways, listed I to IV, BEST promote this?

Individuals may differ from one another as a result of chance variation. More offspring are born than can survive and reproduce. There is a struggle for existence between the individuals and their environment.

Organisms produce large numbers of progeny. A local population becomes isolated from the main bulk of the population. The isolated genome experiences a favourable mutation. The individuals in a populations are identical and do not show variations in their characteristics.

From these statements, which of the following is the MOST likely deduction? (A) (B) (C)

The number of individuals in the environment increases with each generation. The individuals best suited to the environment are those with the least variation. The individuals with variation are hybrids, sterile and are unsuccessful in the struggle. The individuals which cope with the struggle have variations suited to the environment.

(D)

I and II I and IV II and III II and IV

KINGDOMS Fungi

(A) (B) (C) (D)

Prokaryotes

Plants

Protoctists

(A)

Alga

Moss

Breadmould

Bacterium

(B)

Breadmould

Bacterium

Moss

Alga

(C)

Moss

Breadmould

Alga

Bacterium

(D)

Breadmould

Bacterium

Alga

Moss

order phylum class phylum

class class order order

phylum order phylum class

Item 42 refers to the the diagrams below which illustrate a variety of leaf shapes found in nature.

42.

Which of the leaves above would be grouped together classification scheme? (A) (B) (C) (D)

I and II I and IV II and III III and IV

Which of the following is an example of in situ conservation of an endangered species?

P ~f

J',J

(A) (B) (C) (D)

Botanic garden Sperm bank Forest reserve Seed bank

in a

Y.., I

1) -

P ~::"l; •

Which ofthe following is NOT a conservation aim when zoos are established?

45.

Which of the following is NOT a major cause of deforestation in tropical areas?

c;CP2,9 'I)

t.

A)

Destruction of trees by atmospheric pollution i\'~ (B) w" Replacement of native trees with ,., fast-growing species Cutting trees for timber used in the construction industry Dynamiting and other activites involved in quarrying for minerals v

Species can he bred in captivity and then re-introduced into their natural habitat Species can be kept in conditions favourable for breeding Species are protected from their natural predators Species held in captivity may inbreed

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