UNDECIMO NACIONAL Name Student:

Biology Paper I & II

1 1/2 hour

Friday 09 December 2011

INSTRUCTIONS TO CANDIDATESDo not open this examination paper until instructed to do so.Answer all the questions.For each question, choose the answer you consider to be the best and indicate your choiceAnswer all in the spaces provided.Use pen onlyUse clear handwriting

Paper I

Paper II

Paper I

1. Having two different alleles for a trait; hybrid

EJE 1Evaluación Semestral II Periodo Núcleo Genética Teórica

Puntos

Nota

20-20 719-17 616-14 513-12 411-8 37-4 23-1 1

Puntos

Nota

20-20 719-17 616-14 513-12 411-8 37-4 23-1 1

a. Heterozygousb. Homozygousc. Phenotyped. Genotype

2. Mendel's name for a specific trait that appeared in the F1 generationa. Hybridb. Homozygousc. Genotyped. Dominant

3. Mendelian law that states a random distribution of alleles occurs during the formation of gametesa. Geneticsb. Dominantc. Law of segregationd. Law of independent assortment

4. The condition in which an organism has extra sets of chromosomesa. Polyploidyb. Hybridc. Recessived. Allele

5. New combinations of genes produced by meiosis & fertilizationa. Fertilizationb. Law of segregationc. Genotyped. Genetic recombination

6. Random distribution of alleles that occurs during gamete formationa. Crossing overb. Dominantc. Law of segregationd. Law of independent assortment

7. A double set of chromosomesa. Traitb. Hybridc. Diploidd. Haploid

8. Genetic information passing from one generation to the next through reproductiona. Traitb. Recessive

EJE 2Evaluación Semestral II Periodo Núcleo Genética Teórica

c. Heredityd. Gene

9. A single set of chromosomesa. Hybridb. Diploidc. Haploidd. Allele

10. An organism's genetic makeup, or allele combinationsa. Genotypeb. Genec. Phenotyped. Allele

11. When the two alleles of a pair are different, one can be dominant and the other recessive, dominant will mask recessivea. Law of segregationb. Homozygousc. Law of dominanced. Dominant

12. First law of heredity stating that pairs of alleles for a trait separate when gametes (sperm or egg) are formeda. Law of segregationb. Law of dominancec. Genotyped. Allele

13.

EJE 3Evaluación Semestral II Periodo Núcleo Genética Teórica

a. Show punnett square and genotype ratios for cross Aa x Aab. In pea plants, the allele for yellow (Y) is dominant and green (y) is recessive, and the allele

for round is (R) and wrinkled is (r). Cross a heterozygous yellow, heterozygous round pea plant with a heterozygous yellow, heterozygous round plant. What are the phenotypes of the offspring?

c. In pea plants, the allele for yellow (Y) is dominant and green (y) is recessive. Cross a Heterozygous yellow pea plant with a homozygous green plant. What are the genotypes and phenotypes of the offspring?

d. Law of dominance

14.Name of the two new cells produced during Mitosis.a. Interphaseb. Daughter Cellsc. Sex cellsd. Body cells

15.First phase when the chromosomes make identical copies of themselves.a. Anaphaseb. Interphasec. Telophased. Metaphase

16.Second phase when Mitosis begins and the poles and spindle fibers appear.a. Telophaseb. Prophasec. Anaphased. Metaphase

17.The process that produces four different sex cells.a. Meiosisb. Metaphasec. Mitosisd. Telophase

18. - Variable proportions of cells in the body are of normal karyotype/downs karyotype-occurs as a result of non-disjunction in the zygote-phenotypically the child has a milder form of the condition- Affects approx 1% of downs syndrome children

EJE 4Evaluación Semestral II Periodo Núcleo Genética Teórica

a. Describe the clinical features of downs syndromeb. What is the genetic abnormality in Down's syndrome?c. What is mosaicism and what proportion of downs syndrome children have this?d. What Ultrasound finding may be suggestive of Downs syndrome in utero?

19. Non-dysjunction- error of meiosis- one pair of chromosome 21 fails to separate--> one gamete has two 21s and one has none-80% of times this is in the female --> incr assoc of downs with maternal age

a. What other mechanisms can give rise to trisomy 21?b. What is the commonest mechanism for trisomy 21?c. What is the genetic abnormality in Down's syndrome?d. Describe the clinical features of downs syndrome

20.Mild to moderate intellectual disabilities, low muscle tone, upward slant to the eyes, flat facial profile, enlarged tongue

a. What detects down syndrome in fetuses 70% accurarately?b. When does down syndrome occur?c. What characteristics would someone with down syndrome present with?d. Why are more down syndrome born to women under the age of 35?

Paper II

1.Mendel is known as the father of genetics for his extensive experimental work with peas and different types of crosses.

EJE 5Evaluación Semestral II Periodo Núcleo Genética Teórica

a. Complete the punnet grid below to show the outcome of the monohybrid cross [5]

a. Complete the punnet grid below to show the possible outcomes of a cross between two members of the F1 generation. Describe all genotypes produced.

[5]

2. Hemophilia is a blood-clotting disorder that is also recessive and sex-linked.

EJE 6Evaluación Semestral II Periodo Núcleo Genética Teórica

a. State the normal function of the gene associated with hemophilia. [2]

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b. Describe the effects and symptoms of hemophilia. [1]

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c. Use the pedigree chart to deduce the possible genotype(s) of the named individuals. [7]

Leopold

Helen

Alice

Mary

Rubert

Bob

Britney

¡Enjoy the science!

EJE 7Evaluación Semestral II Periodo Núcleo Genética Teórica