Download Chapter 6 – Exam style questions Q1. Bk Ch6 Exam MQ1 What is

Chapter 6 – Exam style questions
Q1.
Bk Ch6 Exam MQ1
What is the impact of the discoveries of fossils of ‘transitional’ forms of living things which appear to
have features of two major groups of organisms?
A They cause scientists to revise their classification systems.
B They are usually considered to be hoaxes.
C They are only useful when the age of the specimens has been determined.
D They support the idea that one type of living thing may have developed from another.
A1.
Bk Ch6 Exam MA1
D. Transitional forms of fossils suggest that one kind of living organism may have evolved from an
earlier and similar organism.
Q2.
Bk Ch6 Exam MQ2
Natural selection over many generations can result in similar adaptations in unrelated species that live
in similar environments. Which of the following is the correct term to describe this?
A divergent evolution
B convergent evolution
C parallel evolution
D adaptive evolution.
A2.
Bk Ch6 Exam MA2
B. Convergent evolution is characterised by two unrelated species having similar adaptations in
response to similar selective pressures.
Q3.
Bk Ch6 Exam MQ3
Which of the following is the expected proportion of offspring from a cross between a homozygous
short pea plant (tt) and a heterozygous tall pea plant (Tt)?
A all short
B all tall
C half tall, half short
D three-quarters tall, one-quarter short.
A3.
Bk Ch6 Exam MA3
C.
t
t
T
Tt
Tt
t
tt
tt
Q4.
Bk Ch6 Exam MQ4
Which statement best describes dominant characteristics?
A They are more common than recessive characteristics.
B They mask recessive characteristics.
C They are masked by recessive characteristics.
D They occur in equal proportions to recessive characteristics.
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A4.
Bk Ch6 Exam MA4
B. Dominant characteristics always appear in the phenotype even when only one allele is present in the
phenotype; they mask recessive alleles.
Q5.
Bk Ch6 Exam MQ5
What is the chemical composition of repeating units of DNA?
A sugar–base–phosphate
B lipoprotein
C complex carbohydrates
D deoxyribonucleic acid.
A5.
Bk Ch6 Exam MA5
A. ‘Sugar–base–phosphate’ is the structural unit of nucleic acids.
Q6.
Bk Ch6 Exam MQ6
Which of the following processes describes how variability of offspring produced through sexual
reproduction?
A crossing over during gamete formation
B random fusion of unique gametes during fertilisation
C both A and B
D neither A nor B.
A6.
Bk Ch6 Exam MA6
C. Crossing over and random union of gametes are two factors that contribute to variability in offspring
produced in sexual reproduction.
Q7.
Bk Ch6 Exam MQ7
Which of the following processes is made possible by the complementary nature of the bases in DNA?
A the inheritance of coded information by offspring from their parents
B the exact copying of the two strands of the molecule during replication
C pairing of adenine only to guanine, and thymine only to cytosine
D coding of one nucleotide to the next along the length of the molecule
A7.
Bk Ch6 Exam MA7
B. Because adenine pairs with thymine and cytosine pairs with guanine in the DNA double helix, an
exact copy can be made when the helix unravels and a new strand is manufactured, according to the
base-pairing rules.
Q8.
Bk Ch6 Exam MQ8
How does the manufacture of proteins in cells occur?
A It occurs directly by the DNA in the nucleus.
B It occurs by the process of transcription.
C It occurs by the process of translation.
D It occurs as a result of the processes of transcription and translation.
A8.
Bk Ch6 Exam MA8
D. Proteins are produced as a result of both the processes of transcription of the DNA code in the
nucleus and then translation at the ribosomes.
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Q9.
Bk Ch6 Exam MQ9
Which of the following statements best describes mutations?
A They are the result of cancers.
B They always affect the next generation.
C They are changes in the genetic material of an organism.
D They are changes in the chromosome number of a species.
A9.
Bk Ch6 Exam MA9
C. This is the definition of a mutation.
Q10.
Bk Ch6 Exam MQ10
Which of the following definitions of transgenic organisms is correct?
A they are created when the DNA from an organism of one species is inserted into the DNA of an
organism of another species
B they are hybrids produced when a male and female from different species interbreed
C they are produced as a result of mutation
D all of the above
A10.
Bk Ch6 Exam MA10
A. Transgenic organisms are genetically engineered using foreign DNA.
Q11.
Bk Ch4 Exam MQ11
Study the following diagram of a duplicated chromosome.
Which of the following does this chromosome represent?
A a cell undergoing mitosis
B replication of homologous chromosomes
C crossing-over during meiosis
D a chiasma event during a mitotic division.
A11.
Bk Ch4 Exam MA11
C. Segments of the ‘pale’ and ‘dark’ chromatids have joined and when the chromosomes separate they
will remain with the chromatid of the different colour. This only occurs during meiosis and is called
crossing over.
Chapter 6 – Short answer questions
Q1.
Bk Ch6 Exam SQ1
Study the diagram illustrating the stages of embryological development for different kinds of
organisms.
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a
b
Explain how comparative embryology supports the theory of evolution.
Describe how the theory of evolution of life on Earth is supported by two of the following areas
of study.
i palaeontology
ii biogeography
iii comparative anatomy
iv biochemistry
Use specific examples to illustrate your answers.
A1.
Bk Ch6 Exam SA1
a
b
Comparative embryology of the vertebrates shown clearly indicates similarities between the
different organisms in the early stages of development. Such similarities suggest an evolutionary
relationship between the organisms such that at some point in the history of their development
they shared a common ancestor.
Students should choose two only.
i Palaeontology: The study of similar fossils from different geological eras suggests that
organisms have changed over time, one form giving rise to another form. Example:
Archaeopteryx was a flying dinosaur with which modern birds share many features.
Scientists believe that birds evolved from the reptiles.
ii Biogeography: The distribution of different but related organisms on landmasses that are
isolated from one another suggests that the organisms had a common ancestor at a time
when the landmasses were joined. Example: The waratah belongs to a family of plants
whose distribution includes Australia, New Guinea and South America.
iii Comparative anatomy: The similarities shared by many different groups of organisms is
evidence that they are related and share a common ancestor. Example: Present-day
vertebrates share the presence of pentadactyl limbs, a fact that provides evidence for a
common ancestor.
iv Biochemistry: Analysis of molecular structure such as DNA and proteins between species
provides further evidence of evolutionary relationships. The greater the similarity between
two species, the more closely related they are said to be. Example: DNA hybridisation
indicates a close evolutionary relationship between humans and chimpanzees with the gorilla
being more distantly related.
Q2.
Bk Ch6 Exam SQ2
The litter resulting from the mating of two black guinea pigs consists of four black and one white
offspring.
a
Explain the inheritance pattern observed.
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b
c
Suggest genotypes for the parents and the offspring in this cross.
Use a Punnett square to show the expected ratio of genotypes and phenotypes.
A2.
Bk Ch6 Exam SA2
a
b
c
Black coat colour in guinea pigs is dominant to white. In order for the two black parents to
produce a white offspring they must both be carrying the allele for white coat colour. However,
the white colour is masked in the parents and shows up in the offspring.
Genotype of both parents: Bb where B is black (dominant), b is white (recessive).
Genotype of white offspring: bb.
Genotype of black offspring: Bb or BB.
Expected genotypes:
B
b
B
BB
Bb
b
Bb
bb
Expected phenotypes: three-quarters black, one-quarter white.
Q3.
Bk Ch6 Exam SQ3
The following diagram illustrates the stages of meiosis. However, the stages are shown in incorrect
order.
a
b
Rewrite the letters corresponding to each stage so that the order correctly reflects the behaviour of
chromosomes during the process of meiosis.
How do the daughter cells resulting from meiosis differ from those produced in mitosis?
A3.
Bk Ch6 Exam SA3
a
b
B, D, F, A, E, C
Meiosis results in four genetically different haploid daughter cells whereas mitosis produces two
genetically identical diploid daughter cells.
Q4.
Bk Ch6 Exam SQ4
Examine the DNA strand shown.
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a
b
Name the molecule represented by structure
i X
ii Y
iii A, C, G and T.
Draw the complementary strand for the DNA sequence shown.
A4.
Bk Ch6 Exam SA4
a
b
i phosphate group
ii sugar
iii bases adenine, cytosine, guanine and thymine respectively
The complementary strand:
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Q5.
Bk Ch6 Exam SQ5
The following tree diagram illustrates a possible evolutionary pathway for the some of the finch species
that Darwin observed on the Galapagos Islands.
insect eaters
ancestral group
seed eaters
cactus eaters
Explain how the theory of natural selection can account for the evolution of the different finch species.
In your answer, discuss the effects of genetic variation, adaptation, isolation and time.
A5.
Bk Ch6 Exam SA5
An ancestral species of finch inhabited the area but populations inhabited different islands and became
isolated from one another. Some variation already existed within the population. Finches with features
that were most suited to obtaining the available food resources had a better chance of survival
compared to finches that did not have those features. Because the finches with the favourable
characteristics or most suitable adaptations had the best chance of survival they also had the better
chance of reproducing and passing on their favourable characteristics to their offspring. Over time and
many generations the different finch populations became increasing adapted to the particular
environment in which they lived and increasingly different from the finch populations on neighbouring
islands. Eventually they became so different from one another that they could be regarded as separate
species.
Q6.
a
b
Seals (mammals) and turtles (reptiles) both inhabit the sea and have flippers for locomotion.
Explain why they are not placed in the same phylum despite these similar characteristics.
Isolated islands often have distinctive flora and fauna. Australia has a large number of kangaroo
species. Explain how the theory of evolution accounts for this.
A6.
Bk Ch6 Exam SA6
a
b
These are only two characteristics out of many shown by each animal and are not enough to
place the organisms together. The flippers that each possess are an example of convergent
evolution, they both have limbs modified for swimming.
The diversity of kangaroos found in Australia is accounted for by divergent evolution.
Kangaroos spread out and colonised different environments and, over time, the differences
between them increased.
Q7.
Bk Ch6 Exam 7
a
b
c
Define ‘transgenic species’.
Use a specific example to explain how a transgenic species can be produced.
Outline two ethical issues arising from the technology that makes the production of transgenic
species possible.
A7.
Bk Ch6 Exam SA7
a
A transgenic organism is one that has had genetic material from another species inserted into its
DNA and is capable of passing this on to the next generation.
b
The human gene has been the subject of genetic engineering involving the production of
transgenic bacteria. The gene responsible for insulin production in humans is isolated from human
Ch 6 Exam style Q
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c
DNA and inserted into a bacterial plasmid. The plasmid is then inserted into the bacterium. The
transgenic bacterium is grown in a culture. The bacteria grows and reproduces, rapidly producing
large quantities of insulin that can be used to treat insulin-dependent diabetics.
Ethical issues include:
•
What, if any, long-term effects might there be for humans using substances produced by
transgenic species?
•
What, if any, long-term effects might there be for humans consuming transgenic food items?
•
What is the cost of the research and the technology?
•
Could the technology be abused, for example by inserting foreign DNA into humans?
•
How widespread is the application of this technology? How widespread is it likely to
become in the future?
•
Could the production of transgenic species compromise the already diminishing biodiversity
of our planet?
•
What controls are there on this kind of research?
•
Could transgenic bacteria have the potential to damage other organisms, including humans?
Q8.
Bk Ch6 Exam SQ8
Haemophilia is a recessive sex-linked condition. In an affected person the normal clotting of blood
during injury does not occur and the individual experiences excessive bleeding.
a
Explain what is meant by sex linkage.
b
Consider the case in which a woman who is a carrier of the disease marries a normal man. Use a
Punnett square and appropriate notation to illustrate the possible genotypes and phenotypes you
would expect in their offspring.
c
What is the probability of these two people having an:
i affected child
ii affected son
iii affected daughter
iv unaffected child?
A8.
Bk Ch6 Exam SA8
a
b
Sex linkage refers to the presence of certain genes on the X chromosome. As a result the
characteristics controlled by these genes appear more often in one sex than the other.
N: normal, no haemophilia (dominant); n: haemophilia (recessive).
Genotype of parents: mother XNXn  father XNY
X
XN
XNXN
Xn
XNXn
Y
XNY
XnY
N
c
Expected offspring: All daughters will be normal but 50% will be carriers for haemophilia. Half
the sons will be normal and half will have haemophilia.
i One-quarter
ii One-half
iii Zero
iv Three-quarters
Q9.
Bk Ch6 Exam SQ9
George Beadle and Edward Tatum conducted experiments to investigate the relationship between
genes and proteins.
a
What is a mutation?
b
Describe the experiment they undertook using the bread mould Neurospora crassa that led them
to the ‘one gene, one polypeptide’ hypothesis.
c
What is meant by the ‘one gene, one polypeptide’ hypothesis?
d
i List two different kinds of mutagenic agents.
ii How do mutagens affect DNA?
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A9.
Bk Ch6 Exam SA9
a
b
c
d
A mutation is a change in the genetic make-up of an individual.
Beadle and Tatum subjected the bread mould Neurospora crassa to X-rays to produce mutated
strains. Each of the mutated strains lacked the ability to manufacture an amino acid or vitamin
that was needed for normal growth. They were able to establish that this resulted from the lack of
a particular enzyme. They deduced which enzyme was missing in each case by exposing the
different strains to a variety of nutrient combinations. After establishing that the mutations
coincided with particular sites on the chromosomes of the bread mould and that these sites related
to each of the missing enzymes, they concluded that one gene is responsible for the production of
a particular protein. Today we call this the ‘one gene, one polypeptide’ hypothesis.
The ‘one gene, one polypeptide’ hypothesis refers to the idea that a single gene controls the
production of a particular kind of polypeptide.
i Any two of: radiation such as ultraviolet radiation from the Sun and X-rays; chemicals such
as dieldrin and dioxin.
ii Mutagens affect DNA in different ways; for example, DNA can be lost from a chromosome
(deletion) or a piece of DNA can be repeated several times (duplication and amplification); a
piece of DNA can break away from a chromosome and rejoin the wrong way around
(inversion) or join onto the end of another chromosome (translocation).
Q10.
Bk Ch6 Exam SQ10
The following pedigree shows the inheritance of a particular autosomal disease in humans.
a
b
c
d
e
Is the disease inherited as a dominant or recessive trait? Give reasons for your answer.
Use appropriate notation to assign genotypes to individuals I-1, I-2, II-2, II-7 and III-1.
Suggest possible genotypes for individual II-3.
Use a Punnett square to show what proportion of offspring produced by parents I-1 and I-2 are
expected to have the disease.
Suppose individual II-9 has no family history of the disease. What is the probability of this couple
having an affected child? Explain.
A10.
Bk Ch6 Exam SA11
a
b
c
d
Recessive. Neither individuals I-1 or I-2 show the condition, yet they have three children who do.
N: normal, no disease (dominant); n: has disease (recessive).
I-1: Nn; I-2: Nn; II-2: Nn; II-7: either NN or Nn; III-1: nn.
II-3: either NN or Nn.
N
n
e
N
NN
Nn
n
Nn
nn
Only the homozygous recessive individuals will have the disease; one-quarter of the offspring
would be expected to have the disease.
If individual II-9 has no family history of the disease we can presume they are homozygous
dominant, NN. Individual II-8 has genotype nn. All of their offspring would be carriers but none
would show the disease. That is, there is zero chance of an affected child.
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