Download 3 U Biology – Genetics Unit Test

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3 U Biology – Genetics Unit Test
Name : __________________________
Part A - Answer on Scantron cards. Please use a pencil.
1. The alleles Tt (T=tall, t=short) are an example of
(A) homozygous dominant genotype (B) heterozygous genotype
(D) recessive phenotype
(E) none of them
(C) homozygous recessive genotype
2. All the offspring from a certain cross are heterozygous. The most likely explanation for this common genotype is:
(A) both parents are homozygous dominant.
(B) both parents are heterozygous.
(C) both parents are homozygous recessive.
(D) one parent is heterozygous, the other is homozygous.
(E) one parent is homozygous dominant, the other homozygous recessive.
3. Which of the following is not part of Mendel’s Law of Segregation?
(A) Hereditary characteristics are determined by distinct factors.
(B) Identical factors make up a pure line.
(C) For each characteristic, an individual carries one factor from each parent.
(D) The two factors of each pair separate into the gamete.
(E) Both A and C.
4. According to the Law of Independent Assortment, gametes produced by an individual with genotype AaBb may
carry the following combinations alleles:
(A) A,a,b,B
(B) AB and ab only
(C) AB, Ab, aB and ab (D) A and B only
(E) AaBb only
5. In humans, normal females have the following genotypes:
(A) XX
(B) XY
(C) X
(D) XXX
(E) XXY
6. The carrier of a sex-linked or X-linked condition, such as hemophilia, has ____ recessive gene(s), and is
always__________. The missing terms in order are:
(A) 1 and female (B) 2 and female
(C) 3 and male
(D) 4 and male
(E) 1 and male
7. Down syndrome is caused by:
(A) alcoholism (B) an extra chromosome
(C) X rays
(D) dominant genes
(E) recessive genes
8. Homer Simpson has blood type O and Mrs. Simpson has blood type AB. They have three children of their own,
and they’ve adopted another one. Which of the children is/are adopted if Bart has blood type O, Belinda blood type B,
Zebedee, and Tyler both have blood type A .
(A) Bart
(B) Belinda
(C) Zebedee
(D) Tyler
(E) both Zebedee and Tyler
9. When red carnations are crossed with white ones, the offspring are all pink. This is an example of:
(A) straight dominance
(B) recessive genes
(C) incomplete dominance
(D) co-dominance
(E) dominant genes
10. Rare genetic diseases, such as Tay Sachs disease are caused by:
(A) a poor diet
(B) two dominant alleles
(D) birth problems
(E) faulty blood types
( C ) two recessive alleles
11. Select the CORRECT statement:
(A) Lethal genes cause curable diseases.
(B) Most genetically caused diseases affect women.
(C) An individual with XXY chromosomes is a normal female.
(D) Human skin colour is determined by several genes , i.e. it is an example of multifactorial inheritance.
(E) An individual with XO has Down syndrome .
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12. The normal number of chromosomes in a human
(A) 12
(B) haploid
( C ) 23
reproductive cell is:
(D) 46
(E) both B and C
For questions 13 to 20, match the statement in the left column, with the terms in the right column. Continue to use
your Scantron card. Some answers need TWO letters.
13. Structure that holds sister chromatids together
A. Zygote
14. They contain similar but not always identical genetic
information.
B. Cross-over
15. During prophase, a chromosome consists of
these structures
C. Diploid
16 It consists of two homologous
chromosomes during prophase I of meiosis
D. Tetrad
17. The exchange of chromosome parts
during prophase I of meiosis
E. Non-disjunction
18. The chromosome number in the daughter cells at the
end of meiosis.
AB. Homologous chromosomes
19, Chromosome number in the daughter cells
of mitosis.
AC. Centromeres
20. The faulty separation of chromosomes that
results in major abnormalities
AD. Chromatids
AE. Centrioles
BC. haploid
21. Which of the following would not be an example of asexual reproduction:
(A) cloning
(B) budding
(C) pollination
(D) binary fission
(E) growing from cuttings
22. A change on the genetic structure of an organism is called:
(A) a mutation
(B) a genotype
(C) a heterozygote
(E) a hybrid
(D) a phenotype
23. The term locus refers to the _____________ of _______________ in a chromosome. The missing terms, in order,
are:
(A) number, traits
(B) presence, alleles (C) types, genes
(D) position, a particular gene
(E) kind, abnormality
24. Select the INCORRECTLY matched pair of terms:
(A) aneuploidy – extra chromosome
(B) Sex-linked traits – Y-chromosome
(C) autosomes – non-sex chromosomes
(D) karyotype – types of chromosomes
(E) determines child’s gender- sperm cells
25. In which part of the cell cycle dies the division of the cytoplasm take place:
(A) mitosis
(B) interphase
(C) G phase
(D) S phase
(E) cytokinesis
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25 marks
Part B. Answer on this page.
Please note that you should clearly state the phenotypes as well as the genotypes in each problem.
1. Human ABO blood type is determined by three alleles, IA, IB, and i. The first two are dominant and the last is
recessive. Show clearly by means of a Punnett square.
(a) that two parents with blood types A and B respectively may have children with all the four blood types,
(b) that two parents , both with blood type O, can have children only with blood type O.
6 marks
2. Eye colour in fruit flies is a sex-linked trait carried on the X chromosome only, with the red allele ( XR) dominant
and the white allele (Xr) recessive. Males in fruit flies have XY chromosomes and females , XX chromosomes. Show
by means of a Punnett square the possible offspring of a red-eyed heterozygous female and a white-eyed male.
4 marks
3. Given T= tall, t=short and Y=yellow and y=green in a particular plant, show by means of an appropriate Punnett
square all the possible offspring of the following dihybrid cross and state the phenotype ratios.
TtYy X Ttyy
6 marks
4. Define the meanings of the following terms:
(a) phenotype
(b) trisomy
(c) incomplete dominance
(d) cross-over
4 marks
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